Revert "Rewrite std::string("") to std::string(), Linux edition."

This reverts commit e59558b78e8c6a1b0bd916a724724b638c3c91b6.

Revert "Fix build after r193020."

This reverts commit 558a35897f6b3ffbcaefde927c1f150b815d140a.

Revert "Really fix build after r193020."

This reverts commit e3748a79b523a8d365d4a33ef986eebb4186fa78.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193030 0039d316-1c4b-4281-b951-d872f2087c98

664 files changed, 3730 insertions, 5049 deletions

diff --git a/base/debug/trace_event_unittest.cc b/base/debug/trace_event_unittest.cc
index 782f07b..8376660 100644
--- a/base/debug/trace_event_unittest.cc
+++ b/base/debug/trace_event_unittest.cc
@@ -1535,7 +1535,7 @@ TEST_F(TraceEventTestFixture, TraceCategoriesAfterNestedEnable) {
   trace_log->SetEnabled(std::string("foo2"), TraceLog::RECORD_UNTIL_FULL);
   EXPECT_TRUE(*trace_log->GetCategoryEnabled("foo2"));
   EXPECT_FALSE(*trace_log->GetCategoryEnabled("baz"));
-  trace_log->SetEnabled(std::string(), TraceLog::RECORD_UNTIL_FULL);
+  trace_log->SetEnabled(std::string(""), TraceLog::RECORD_UNTIL_FULL);
   EXPECT_TRUE(*trace_log->GetCategoryEnabled("foo"));
   EXPECT_TRUE(*trace_log->GetCategoryEnabled("baz"));
   trace_log->SetDisabled();
@@ -1558,8 +1558,7 @@ TEST_F(TraceEventTestFixture, TraceCategoriesAfterNestedEnable) {
 TEST_F(TraceEventTestFixture, TraceOptionsParsing) {
   ManualTestSetUp();
 
-  EXPECT_EQ(TraceLog::RECORD_UNTIL_FULL,
-            TraceLog::TraceOptionsFromString(std::string()));
+  EXPECT_EQ(TraceLog::RECORD_UNTIL_FULL, TraceLog::TraceOptionsFromString(""));
 
   EXPECT_EQ(TraceLog::RECORD_UNTIL_FULL,
             TraceLog::TraceOptionsFromString("record-until-full"));
diff --git a/base/file_util_posix.cc b/base/file_util_posix.cc
index 8bf164a..fa2c1ff 100644
--- a/base/file_util_posix.cc
+++ b/base/file_util_posix.cc
@@ -541,8 +541,7 @@ bool CreateDirectory(const FilePath& full_path) {
 base::FilePath MakeUniqueDirectory(const base::FilePath& path) {
   const int kMaxAttempts = 20;
   for (int attempts = 0; attempts < kMaxAttempts; attempts++) {
-    int uniquifier =
-        GetUniquePathNumber(path, base::FilePath::StringType());
+    int uniquifier = GetUniquePathNumber(path, FILE_PATH_LITERAL(""));
     if (uniquifier < 0)
       break;
     base::FilePath test_path = (uniquifier == 0) ? path :
diff --git a/base/file_util_unittest.cc b/base/file_util_unittest.cc
index 77dd7ac..1f10a335 100644
--- a/base/file_util_unittest.cc
+++ b/base/file_util_unittest.cc
@@ -1846,14 +1846,15 @@ TEST_F(FileUtilTest, FileEnumeratorTest) {
 
   // create the files
   FilePath dir2file = dir2.Append(FILE_PATH_LITERAL("dir2file.txt"));
-  CreateTextFile(dir2file, std::wstring());
+  CreateTextFile(dir2file, L"");
   FilePath dir2innerfile = dir2inner.Append(FILE_PATH_LITERAL("innerfile.txt"));
-  CreateTextFile(dir2innerfile, std::wstring());
+  CreateTextFile(dir2innerfile, L"");
   FilePath file1 = temp_dir_.path().Append(FILE_PATH_LITERAL("file1.txt"));
-  CreateTextFile(file1, std::wstring());
-  FilePath file2_rel = dir2.Append(FilePath::kParentDirectory)
-      .Append(FILE_PATH_LITERAL("file2.txt"));
-  CreateTextFile(file2_rel, std::wstring());
+  CreateTextFile(file1, L"");
+  FilePath file2_rel =
+      dir2.Append(FilePath::kParentDirectory)
+          .Append(FILE_PATH_LITERAL("file2.txt"));
+  CreateTextFile(file2_rel, L"");
   FilePath file2_abs = temp_dir_.path().Append(FILE_PATH_LITERAL("file2.txt"));
 
   // Only enumerate files.
diff --git a/base/files/file_path.cc b/base/files/file_path.cc
index 01d9eab..72604e8 100644
--- a/base/files/file_path.cc
+++ b/base/files/file_path.cc
@@ -552,7 +552,7 @@ string16 FilePath::LossyDisplayName() const {
 std::string FilePath::MaybeAsASCII() const {
   if (IsStringASCII(path_))
     return path_;
-  return std::string();
+  return "";
 }
 
 std::string FilePath::AsUTF8Unsafe() const {
diff --git a/base/i18n/char_iterator_unittest.cc b/base/i18n/char_iterator_unittest.cc
index 509e27c..6d1294e 100644
--- a/base/i18n/char_iterator_unittest.cc
+++ b/base/i18n/char_iterator_unittest.cc
@@ -11,7 +11,7 @@ namespace base {
 namespace i18n {
 
 TEST(CharIteratorsTest, TestUTF8) {
-  std::string empty;
+  std::string empty("");
   UTF8CharIterator empty_iter(&empty);
   ASSERT_TRUE(empty_iter.end());
   ASSERT_EQ(0, empty_iter.array_pos());
diff --git a/base/json/json_value_serializer_unittest.cc b/base/json/json_value_serializer_unittest.cc
index 9df0435..e510500 100644
--- a/base/json/json_value_serializer_unittest.cc
+++ b/base/json/json_value_serializer_unittest.cc
@@ -196,7 +196,7 @@ TEST(JSONValueSerializerTest, Roundtrip) {
   // initialized with a const string.
   ASSERT_FALSE(serializer.Serialize(*root_dict));
 
-  std::string test_serialization;
+  std::string test_serialization = "";
   JSONStringValueSerializer mutable_serializer(&test_serialization);
   ASSERT_TRUE(mutable_serializer.Serialize(*root_dict));
   ASSERT_EQ(original_serialization, test_serialization);
diff --git a/base/metrics/field_trial.cc b/base/metrics/field_trial.cc
index 1f4f9ae..4ab5ff9 100644
--- a/base/metrics/field_trial.cc
+++ b/base/metrics/field_trial.cc
@@ -318,7 +318,7 @@ std::string FieldTrialList::FindFullName(const std::string& name) {
   FieldTrial* field_trial = Find(name);
   if (field_trial)
     return field_trial->group_name();
-  return std::string();
+  return "";
 }
 
 // static
diff --git a/base/metrics/field_trial_unittest.cc b/base/metrics/field_trial_unittest.cc
index bb2c39f..81c4f37 100644
--- a/base/metrics/field_trial_unittest.cc
+++ b/base/metrics/field_trial_unittest.cc
@@ -86,7 +86,7 @@ TEST_F(FieldTrialTest, Registration) {
   EXPECT_EQ(name1, trial1->trial_name());
   EXPECT_EQ("", trial1->group_name_internal());
 
-  trial1->AppendGroup(std::string(), 7);
+  trial1->AppendGroup("", 7);
 
   EXPECT_EQ(trial1, FieldTrialList::Find(name1));
   EXPECT_FALSE(FieldTrialList::Find(name2));
@@ -221,7 +221,7 @@ TEST_F(FieldTrialTest, OneWinner) {
   std::string winner_name;
 
   for (int i = 1; i <= group_count; ++i) {
-    int might_win = trial->AppendGroup(std::string(), 1);
+    int might_win = trial->AppendGroup("", 1);
 
     // Because we keep appending groups, we want to see if the last group that
     // was added has been assigned or not.
diff --git a/base/metrics/statistics_recorder.cc b/base/metrics/statistics_recorder.cc
index 13aeeb7..f6174f3 100644
--- a/base/metrics/statistics_recorder.cc
+++ b/base/metrics/statistics_recorder.cc
@@ -308,7 +308,7 @@ StatisticsRecorder::~StatisticsRecorder() {
   DCHECK(histograms_ && ranges_ && lock_);
   if (dump_on_exit_) {
     string output;
-    WriteGraph(std::string(), &output);
+    WriteGraph("", &output);
     DLOG(INFO) << output;
   }
 
diff --git a/base/metrics/stats_counters.cc b/base/metrics/stats_counters.cc
index 12416d9..f763220 100644
--- a/base/metrics/stats_counters.cc
+++ b/base/metrics/stats_counters.cc
@@ -45,7 +45,7 @@ int* StatsCounter::GetPtr() {
   if (counter_id_ == -1) {
     counter_id_ = table->FindCounter(name_);
     if (table->GetSlot() == 0) {
-      if (!table->RegisterThread(std::string())) {
+      if (!table->RegisterThread("")) {
         // There is no room for this thread.  This thread
         // cannot use counters.
         counter_id_ = 0;
diff --git a/base/metrics/stats_table.cc b/base/metrics/stats_table.cc
index 9585863..dede1e4 100644
--- a/base/metrics/stats_table.cc
+++ b/base/metrics/stats_table.cc
@@ -431,8 +431,8 @@ int* StatsTable::FindLocation(const char* name) {
   // Get the slot for this thread.  Try to register
   // it if none exists.
   int slot = table->GetSlot();
-  if (!slot && !(slot = table->RegisterThread(std::string())))
-    return NULL;
+  if (!slot && !(slot = table->RegisterThread("")))
+      return NULL;
 
   // Find the counter id for the counter.
   std::string str_name(name);
diff --git a/base/nix/mime_util_xdg.cc b/base/nix/mime_util_xdg.cc
index 5794b6d..00dcafa 100644
--- a/base/nix/mime_util_xdg.cc
+++ b/base/nix/mime_util_xdg.cc
@@ -344,9 +344,9 @@ size_t IconTheme::MatchesSize(SubDirInfo* info, size_t size) {
 
 std::string IconTheme::ReadLine(FILE* fp) {
   if (!fp)
-    return std::string();
+    return "";
 
-  std::string result;
+  std::string result = "";
   const size_t kBufferSize = 100;
   char buffer[kBufferSize];
   while ((fgets(buffer, kBufferSize - 1, fp)) != NULL) {
diff --git a/base/pickle_unittest.cc b/base/pickle_unittest.cc
index d252dae..d418fdf 100644
--- a/base/pickle_unittest.cc
+++ b/base/pickle_unittest.cc
@@ -134,7 +134,7 @@ TEST(PickleTest, UnalignedSize) {
 
 TEST(PickleTest, ZeroLenStr) {
   Pickle pickle;
-  EXPECT_TRUE(pickle.WriteString(std::string()));
+  EXPECT_TRUE(pickle.WriteString(""));
 
   PickleIterator iter(pickle);
   std::string outstr;
@@ -144,7 +144,7 @@ TEST(PickleTest, ZeroLenStr) {
 
 TEST(PickleTest, ZeroLenWStr) {
   Pickle pickle;
-  EXPECT_TRUE(pickle.WriteWString(std::wstring()));
+  EXPECT_TRUE(pickle.WriteWString(L""));
 
   PickleIterator iter(pickle);
   std::string outstr;
diff --git a/base/prefs/pref_change_registrar_unittest.cc b/base/prefs/pref_change_registrar_unittest.cc
index f353a8f..49da721 100644
--- a/base/prefs/pref_change_registrar_unittest.cc
+++ b/base/prefs/pref_change_registrar_unittest.cc
@@ -132,7 +132,7 @@ class ObserveSetOfPreferencesTest : public testing::Test {
     PrefRegistrySimple* registry = pref_service_->registry();
     registry->RegisterStringPref(kHomePage, "http://google.com");
     registry->RegisterBooleanPref(kHomePageIsNewTabPage, false);
-    registry->RegisterStringPref(kApplicationLocale, std::string());
+    registry->RegisterStringPref(kApplicationLocale, "");
   }
 
   PrefChangeRegistrar* CreatePrefChangeRegistrar() {
diff --git a/base/prefs/pref_service_unittest.cc b/base/prefs/pref_service_unittest.cc
index 927f2f7..26fe19a 100644
--- a/base/prefs/pref_service_unittest.cc
+++ b/base/prefs/pref_service_unittest.cc
@@ -45,7 +45,7 @@ TEST(PrefServiceTest, NoObserverFire) {
   Mock::VerifyAndClearExpectations(&obs);
 
   // Clearing the pref should cause the pref to fire.
-  const StringValue expected_default_value((std::string()));
+  const StringValue expected_default_value("");
   obs.Expect(pref_name, &expected_default_value);
   prefs.ClearPref(pref_name);
   Mock::VerifyAndClearExpectations(&obs);
diff --git a/base/process_util_linux.cc b/base/process_util_linux.cc
index e06d99c..2af9227 100644
--- a/base/process_util_linux.cc
+++ b/base/process_util_linux.cc
@@ -161,7 +161,7 @@ std::string GetProcStatsFieldAsString(
     ProcStatsFields field_num) {
   if (field_num < VM_COMM || field_num > VM_STATE) {
     NOTREACHED();
-    return std::string();
+    return "";
   }
 
   if (proc_stats.size() > static_cast<size_t>(field_num))
diff --git a/base/process_util_unittest.cc b/base/process_util_unittest.cc
index 3ce9942..265a2df 100644
--- a/base/process_util_unittest.cc
+++ b/base/process_util_unittest.cc
@@ -758,8 +758,8 @@ TEST_F(ProcessUtilTest, LaunchProcess) {
   EXPECT_EQ(0, setenv("BASE_TEST", "testing", 1 /* override */));
   EXPECT_EQ("testing\n", TestLaunchProcess(env_changes, no_clone_flags));
 
-  env_changes.push_back(
-      std::make_pair(std::string("BASE_TEST"), std::string()));
+  env_changes.push_back(std::make_pair(std::string("BASE_TEST"),
+                                       std::string("")));
   EXPECT_EQ("\n", TestLaunchProcess(env_changes, no_clone_flags));
 
   env_changes[0].second = "foo";
@@ -800,7 +800,7 @@ TEST_F(ProcessUtilTest, AlterEnvironment) {
   delete[] e;
 
   changes.clear();
-  changes.push_back(std::make_pair(std::string("A"), std::string()));
+  changes.push_back(std::make_pair(std::string("A"), std::string("")));
   e = base::AlterEnvironment(changes, empty);
   EXPECT_TRUE(e[0] == NULL);
   delete[] e;
@@ -819,7 +819,7 @@ TEST_F(ProcessUtilTest, AlterEnvironment) {
   delete[] e;
 
   changes.clear();
-  changes.push_back(std::make_pair(std::string("A"), std::string()));
+  changes.push_back(std::make_pair(std::string("A"), std::string("")));
   e = base::AlterEnvironment(changes, a2);
   EXPECT_TRUE(e[0] == NULL);
   delete[] e;
diff --git a/base/string_util_unittest.cc b/base/string_util_unittest.cc
index d580fba..d36b955 100644
--- a/base/string_util_unittest.cc
+++ b/base/string_util_unittest.cc
@@ -70,7 +70,7 @@ TEST(StringUtilTest, TruncateUTF8ToByteSize) {
   std::string output;
 
   // Empty strings and invalid byte_size arguments
-  EXPECT_FALSE(Truncated(std::string(), 0, &output));
+  EXPECT_FALSE(Truncated("", 0, &output));
   EXPECT_EQ(output, "");
   EXPECT_TRUE(Truncated("\xe1\x80\xbf", 0, &output));
   EXPECT_EQ(output, "");
@@ -319,7 +319,7 @@ TEST(StringUtilTest, CollapseWhitespaceASCII) {
 }
 
 TEST(StringUtilTest, ContainsOnlyWhitespaceASCII) {
-  EXPECT_TRUE(ContainsOnlyWhitespaceASCII(std::string()));
+  EXPECT_TRUE(ContainsOnlyWhitespaceASCII(""));
   EXPECT_TRUE(ContainsOnlyWhitespaceASCII(" "));
   EXPECT_TRUE(ContainsOnlyWhitespaceASCII("\t"));
   EXPECT_TRUE(ContainsOnlyWhitespaceASCII("\t \r \n  "));
@@ -712,7 +712,7 @@ void TokenizeTest() {
   EXPECT_EQ(r[2], STR(" three"));
   r.clear();
 
-  size = Tokenize(STR(), STR(","), &r);
+  size = Tokenize(STR(""), STR(","), &r);
   EXPECT_EQ(0U, size);
   ASSERT_EQ(0U, r.size());
   r.clear();
@@ -761,7 +761,7 @@ TEST(StringUtilTest, JoinString) {
   in.push_back("c");
   EXPECT_EQ("a,b,c", JoinString(in, ','));
 
-  in.push_back(std::string());
+  in.push_back("");
   EXPECT_EQ("a,b,c,", JoinString(in, ','));
   in.push_back(" ");
   EXPECT_EQ("a|b|c|| ", JoinString(in, '|'));
@@ -780,7 +780,7 @@ TEST(StringUtilTest, JoinStringWithString) {
   parts.push_back("c");
   EXPECT_EQ("a, b, c", JoinString(parts, separator));
 
-  parts.push_back(std::string());
+  parts.push_back("");
   EXPECT_EQ("a, b, c, ", JoinString(parts, separator));
   parts.push_back(" ");
   EXPECT_EQ("a|b|c|| ", JoinString(parts, "|"));
@@ -812,10 +812,10 @@ TEST(StringUtilTest, StartsWith) {
   EXPECT_TRUE(StartsWithASCII("JavaScript:url", "javascript", false));
   EXPECT_FALSE(StartsWithASCII("java", "javascript", true));
   EXPECT_FALSE(StartsWithASCII("java", "javascript", false));
-  EXPECT_FALSE(StartsWithASCII(std::string(), "javascript", false));
-  EXPECT_FALSE(StartsWithASCII(std::string(), "javascript", true));
-  EXPECT_TRUE(StartsWithASCII("java", std::string(), false));
-  EXPECT_TRUE(StartsWithASCII("java", std::string(), true));
+  EXPECT_FALSE(StartsWithASCII("", "javascript", false));
+  EXPECT_FALSE(StartsWithASCII("", "javascript", true));
+  EXPECT_TRUE(StartsWithASCII("java", "", false));
+  EXPECT_TRUE(StartsWithASCII("java", "", true));
 
   EXPECT_TRUE(StartsWith(L"javascript:url", L"javascript", true));
   EXPECT_FALSE(StartsWith(L"JavaScript:url", L"javascript", true));
@@ -823,10 +823,10 @@ TEST(StringUtilTest, StartsWith) {
   EXPECT_TRUE(StartsWith(L"JavaScript:url", L"javascript", false));
   EXPECT_FALSE(StartsWith(L"java", L"javascript", true));
   EXPECT_FALSE(StartsWith(L"java", L"javascript", false));
-  EXPECT_FALSE(StartsWith(std::wstring(), L"javascript", false));
-  EXPECT_FALSE(StartsWith(std::wstring(), L"javascript", true));
-  EXPECT_TRUE(StartsWith(L"java", std::wstring(), false));
-  EXPECT_TRUE(StartsWith(L"java", std::wstring(), true));
+  EXPECT_FALSE(StartsWith(L"", L"javascript", false));
+  EXPECT_FALSE(StartsWith(L"", L"javascript", true));
+  EXPECT_TRUE(StartsWith(L"java", L"", false));
+  EXPECT_TRUE(StartsWith(L"java", L"", true));
 }
 
 TEST(StringUtilTest, EndsWith) {
@@ -838,14 +838,14 @@ TEST(StringUtilTest, EndsWith) {
   EXPECT_FALSE(EndsWith(L".plug", L".plugin", false));
   EXPECT_FALSE(EndsWith(L"Foo.plugin Bar", L".plugin", true));
   EXPECT_FALSE(EndsWith(L"Foo.plugin Bar", L".plugin", false));
-  EXPECT_FALSE(EndsWith(std::wstring(), L".plugin", false));
-  EXPECT_FALSE(EndsWith(std::wstring(), L".plugin", true));
-  EXPECT_TRUE(EndsWith(L"Foo.plugin", std::wstring(), false));
-  EXPECT_TRUE(EndsWith(L"Foo.plugin", std::wstring(), true));
+  EXPECT_FALSE(EndsWith(L"", L".plugin", false));
+  EXPECT_FALSE(EndsWith(L"", L".plugin", true));
+  EXPECT_TRUE(EndsWith(L"Foo.plugin", L"", false));
+  EXPECT_TRUE(EndsWith(L"Foo.plugin", L"", true));
   EXPECT_TRUE(EndsWith(L".plugin", L".plugin", false));
   EXPECT_TRUE(EndsWith(L".plugin", L".plugin", true));
-  EXPECT_TRUE(EndsWith(std::wstring(), std::wstring(), false));
-  EXPECT_TRUE(EndsWith(std::wstring(), std::wstring(), true));
+  EXPECT_TRUE(EndsWith(L"", L"", false));
+  EXPECT_TRUE(EndsWith(L"", L"", true));
 }
 
 TEST(StringUtilTest, GetStringFWithOffsets) {
@@ -1142,10 +1142,10 @@ TEST(StringUtilTest, ReplaceChars) {
 TEST(StringUtilTest, ContainsOnlyChars) {
   // Providing an empty list of characters should return false but for the empty
   // string.
-  EXPECT_TRUE(ContainsOnlyChars(std::string(), std::string()));
-  EXPECT_FALSE(ContainsOnlyChars("Hello", std::string()));
+  EXPECT_TRUE(ContainsOnlyChars("", ""));
+  EXPECT_FALSE(ContainsOnlyChars("Hello", ""));
 
-  EXPECT_TRUE(ContainsOnlyChars(std::string(), "1234"));
+  EXPECT_TRUE(ContainsOnlyChars("", "1234"));
   EXPECT_TRUE(ContainsOnlyChars("1", "1234"));
   EXPECT_TRUE(ContainsOnlyChars("1", "4321"));
   EXPECT_TRUE(ContainsOnlyChars("123", "4321"));
diff --git a/base/strings/string_split.cc b/base/strings/string_split.cc
index 819fdba..f5f19e9 100644
--- a/base/strings/string_split.cc
+++ b/base/strings/string_split.cc
@@ -107,8 +107,7 @@ bool SplitStringIntoKeyValuePairs(
       success = false;
     }
     DCHECK_LE(value.size(), 1U);
-    kv_pairs->push_back(
-        make_pair(key, value.empty() ? std::string() : value[0]));
+    kv_pairs->push_back(make_pair(key, value.empty()? "" : value[0]));
   }
   return success;
 }
diff --git a/base/strings/string_split_unittest.cc b/base/strings/string_split_unittest.cc
index 6729497..a950cac 100644
--- a/base/strings/string_split_unittest.cc
+++ b/base/strings/string_split_unittest.cc
@@ -36,10 +36,9 @@ class SplitStringIntoKeyValuesTest : public testing::Test {
 };
 
 TEST_F(SplitStringIntoKeyValuesTest, EmptyInputMultipleValues) {
-  EXPECT_FALSE(SplitStringIntoKeyValues(std::string(),  // Empty input
-                                        '\t',           // Key separators
-                                        &key,
-                                        &values));
+  EXPECT_FALSE(SplitStringIntoKeyValues("",     // Empty input
+                                        '\t',   // Key separators
+                                        &key, &values));
   EXPECT_TRUE(key.empty());
   EXPECT_TRUE(values.empty());
 }
@@ -70,10 +69,9 @@ TEST_F(SplitStringIntoKeyValuesTest, KeyWithMultipleValues) {
 }
 
 TEST_F(SplitStringIntoKeyValuesTest, EmptyInputSingleValue) {
-  EXPECT_FALSE(SplitStringIntoKeyValues(std::string(),  // Empty input
-                                        '\t',           // Key separators
-                                        &key,
-                                        &values));
+  EXPECT_FALSE(SplitStringIntoKeyValues("",     // Empty input
+                                        '\t',   // Key separators
+                                        &key, &values));
   EXPECT_TRUE(key.empty());
   EXPECT_TRUE(values.empty());
 }
@@ -110,9 +108,9 @@ class SplitStringIntoKeyValuePairsTest : public testing::Test {
 };
 
 TEST_F(SplitStringIntoKeyValuePairsTest, EmptyString) {
-  EXPECT_TRUE(SplitStringIntoKeyValuePairs(std::string(),
-                                           ':',  // Key-value delimiters
-                                           ',',  // Key-value pair delims
+  EXPECT_TRUE(SplitStringIntoKeyValuePairs("",
+                                           ':',   // Key-value delimiters
+                                           ',',   // Key-value pair delims
                                            &kv_pairs));
   EXPECT_TRUE(kv_pairs.empty());
 }
@@ -155,7 +153,7 @@ TEST_F(SplitStringIntoKeyValuePairsTest, DelimiterInValue) {
 
 TEST(SplitStringUsingSubstrTest, EmptyString) {
   std::vector<std::string> results;
-  SplitStringUsingSubstr(std::string(), "DELIMITER", &results);
+  SplitStringUsingSubstr("", "DELIMITER", &results);
   ASSERT_EQ(1u, results.size());
   EXPECT_THAT(results, ElementsAre(""));
 }
@@ -164,7 +162,7 @@ TEST(SplitStringUsingSubstrTest, EmptyString) {
 TEST(StringUtilTest, SplitString) {
   std::vector<std::wstring> r;
 
-  SplitString(std::wstring(), L',', &r);
+  SplitString(L"", L',', &r);
   EXPECT_EQ(0U, r.size());
   r.clear();
 
diff --git a/base/sys_info_posix.cc b/base/sys_info_posix.cc
index 57b7af6..854f123 100644
--- a/base/sys_info_posix.cc
+++ b/base/sys_info_posix.cc
@@ -55,7 +55,7 @@ std::string SysInfo::OperatingSystemName() {
   struct utsname info;
   if (uname(&info) < 0) {
     NOTREACHED();
-    return std::string();
+    return "";
   }
   return std::string(info.sysname);
 }
@@ -67,7 +67,7 @@ std::string SysInfo::OperatingSystemVersion() {
   struct utsname info;
   if (uname(&info) < 0) {
     NOTREACHED();
-    return std::string();
+    return "";
   }
   return std::string(info.release);
 }
@@ -78,7 +78,7 @@ std::string SysInfo::OperatingSystemArchitecture() {
   struct utsname info;
   if (uname(&info) < 0) {
     NOTREACHED();
-    return std::string();
+    return "";
   }
   std::string arch(info.machine);
   if (arch == "i386" || arch == "i486" || arch == "i586" || arch == "i686") {
diff --git a/base/test/trace_event_analyzer.cc b/base/test/trace_event_analyzer.cc
index 8457ce9..431945b 100644
--- a/base/test/trace_event_analyzer.cc
+++ b/base/test/trace_event_analyzer.cc
@@ -140,7 +140,7 @@ std::string TraceEvent::GetKnownArgAsString(const std::string& name) const {
   if (GetArgAsString(name, &arg_string))
     return arg_string;
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 double TraceEvent::GetKnownArgAsDouble(const std::string& name) const {
diff --git a/base/test/trace_event_analyzer_unittest.cc b/base/test/trace_event_analyzer_unittest.cc
index 52926fd..33cacbf 100644
--- a/base/test/trace_event_analyzer_unittest.cc
+++ b/base/test/trace_event_analyzer_unittest.cc
@@ -786,7 +786,7 @@ TEST_F(TraceEventAnalyzerTest, FindClosest) {
   events[0].name = "one";
   events[2].name = "two";
   events[4].name = "three";
-  Query query_named = Query::EventName() != Query::String(std::string());
+  Query query_named = Query::EventName() != Query::String("");
   Query query_one = Query::EventName() == Query::String("one");
 
   // Only one event matches query_one, so two closest can't be found.
@@ -822,7 +822,7 @@ TEST_F(TraceEventAnalyzerTest, CountMatches) {
   events[0].name = "one";
   events[2].name = "two";
   events[4].name = "three";
-  Query query_named = Query::EventName() != Query::String(std::string());
+  Query query_named = Query::EventName() != Query::String("");
   Query query_one = Query::EventName() == Query::String("one");
 
   EXPECT_EQ(0u, CountMatches(event_ptrs, Query::Bool(false)));
diff --git a/base/values_unittest.cc b/base/values_unittest.cc
index bad83fa..98bc73c 100644
--- a/base/values_unittest.cc
+++ b/base/values_unittest.cc
@@ -599,7 +599,7 @@ TEST(ValuesTest, RemoveEmptyChildren) {
   // Make sure we don't prune too much.
   root->SetBoolean("bool", true);
   root->Set("empty_dict", new DictionaryValue);
-  root->SetString("empty_string", std::string());
+  root->SetString("empty_string", "");
   root.reset(root->DeepCopyWithoutEmptyChildren());
   EXPECT_EQ(2U, root->size());
 
diff --git a/base/vlog_unittest.cc b/base/vlog_unittest.cc
index 3a508f4..ef7247f 100644
--- a/base/vlog_unittest.cc
+++ b/base/vlog_unittest.cc
@@ -16,20 +16,12 @@ namespace {
 
 TEST(VlogTest, NoVmodule) {
   int min_log_level = 0;
-  EXPECT_EQ(0,
-            VlogInfo(std::string(), std::string(), &min_log_level)
-                .GetVlogLevel("test1"));
-  EXPECT_EQ(0,
-            VlogInfo("0", std::string(), &min_log_level).GetVlogLevel("test2"));
-  EXPECT_EQ(
-      0, VlogInfo("blah", std::string(), &min_log_level).GetVlogLevel("test3"));
-  EXPECT_EQ(
-      0,
-      VlogInfo("0blah1", std::string(), &min_log_level).GetVlogLevel("test4"));
-  EXPECT_EQ(1,
-            VlogInfo("1", std::string(), &min_log_level).GetVlogLevel("test5"));
-  EXPECT_EQ(5,
-            VlogInfo("5", std::string(), &min_log_level).GetVlogLevel("test6"));
+  EXPECT_EQ(0, VlogInfo("", "", &min_log_level).GetVlogLevel("test1"));
+  EXPECT_EQ(0, VlogInfo("0", "", &min_log_level).GetVlogLevel("test2"));
+  EXPECT_EQ(0, VlogInfo("blah", "", &min_log_level).GetVlogLevel("test3"));
+  EXPECT_EQ(0, VlogInfo("0blah1", "", &min_log_level).GetVlogLevel("test4"));
+  EXPECT_EQ(1, VlogInfo("1", "", &min_log_level).GetVlogLevel("test5"));
+  EXPECT_EQ(5, VlogInfo("5", "", &min_log_level).GetVlogLevel("test6"));
 }
 
 TEST(VlogTest, MatchVlogPattern) {
@@ -100,7 +92,7 @@ TEST(VlogTest, VmoduleDirs) {
   const char kVModuleSwitch[] =
       "foo/bar.cc=1,baz\\*\\qux.cc=2,*quux/*=3,*/*-inl.h=4";
   int min_log_level = 0;
-  VlogInfo vlog_info(std::string(), kVModuleSwitch, &min_log_level);
+  VlogInfo vlog_info("", kVModuleSwitch, &min_log_level);
   EXPECT_EQ(0, vlog_info.GetVlogLevel("/foo/bar.cc"));
   EXPECT_EQ(0, vlog_info.GetVlogLevel("bar.cc"));
   EXPECT_EQ(1, vlog_info.GetVlogLevel("foo/bar.cc"));
diff --git a/chrome/browser/about_flags_unittest.cc b/chrome/browser/about_flags_unittest.cc
index 1f6ef04..4720ce6 100644
--- a/chrome/browser/about_flags_unittest.cc
+++ b/chrome/browser/about_flags_unittest.cc
@@ -285,7 +285,7 @@ TEST_F(AboutFlagsTest, CheckValues) {
   // Convert the flags to switches.
   ConvertFlagsToSwitches(&prefs_, &command_line);
   EXPECT_TRUE(command_line.HasSwitch(kSwitch1));
-  EXPECT_EQ(std::string(), command_line.GetSwitchValueASCII(kSwitch1));
+  EXPECT_EQ(std::string(""), command_line.GetSwitchValueASCII(kSwitch1));
   EXPECT_TRUE(command_line.HasSwitch(kSwitch2));
   EXPECT_EQ(std::string(kValueForSwitch2),
             command_line.GetSwitchValueASCII(kSwitch2));
diff --git a/chrome/browser/accessibility/accessibility_events.cc b/chrome/browser/accessibility/accessibility_events.cc
index 9a46ef6..65cf111 100644
--- a/chrome/browser/accessibility/accessibility_events.cc
+++ b/chrome/browser/accessibility/accessibility_events.cc
@@ -166,6 +166,7 @@ AccessibilityTextBoxInfo::AccessibilityTextBoxInfo(Profile* profile,
                                                    const std::string& context,
                                                    bool password)
     : AccessibilityControlInfo(profile, name),
+      value_(""),
       password_(password),
       selection_start_(0),
       selection_end_(0) {
diff --git a/chrome/browser/autofill/autofill_browsertest.cc b/chrome/browser/autofill/autofill_browsertest.cc
index b3d6f54..af63f86 100644
--- a/chrome/browser/autofill/autofill_browsertest.cc
+++ b/chrome/browser/autofill/autofill_browsertest.cc
@@ -505,14 +505,14 @@ class AutofillTest : public InProcessBrowserTest {
 
     // The previewed values should not be accessible to JavaScript.
     ExpectFieldValue("firstname", "M");
-    ExpectFieldValue("lastname", std::string());
-    ExpectFieldValue("address1", std::string());
-    ExpectFieldValue("address2", std::string());
-    ExpectFieldValue("city", std::string());
-    ExpectFieldValue("state", std::string());
-    ExpectFieldValue("zip", std::string());
-    ExpectFieldValue("country", std::string());
-    ExpectFieldValue("phone", std::string());
+    ExpectFieldValue("lastname", "");
+    ExpectFieldValue("address1", "");
+    ExpectFieldValue("address2", "");
+    ExpectFieldValue("city", "");
+    ExpectFieldValue("state", "");
+    ExpectFieldValue("zip", "");
+    ExpectFieldValue("country", "");
+    ExpectFieldValue("phone", "");
     // TODO(isherman): It would be nice to test that the previewed values are
     // displayed: http://crbug.com/57220
 
@@ -742,7 +742,7 @@ IN_PROC_BROWSER_TEST_F(AutofillTest, DISABLED_AutofillFormWithRepeatedField) {
 
   // Invoke Autofill.
   TryBasicFormFill();
-  ExpectFieldValue("state_freeform", std::string());
+  ExpectFieldValue("state_freeform", "");
 }
 
 // http://crbug.com/150084
@@ -1307,8 +1307,8 @@ IN_PROC_BROWSER_TEST_F(AutofillTest, MAYBE_ComparePhoneNumbers) {
   ExpectFieldValue("PHONE_HOME_NUMBER_3-2", "555");
   ExpectFieldValue("PHONE_HOME_NUMBER_4-1", "4567");
   ExpectFieldValue("PHONE_HOME_NUMBER_4-2", "4567");
-  ExpectFieldValue("PHONE_HOME_EXT-1", std::string());
-  ExpectFieldValue("PHONE_HOME_EXT-2", std::string());
+  ExpectFieldValue("PHONE_HOME_EXT-1", "");
+  ExpectFieldValue("PHONE_HOME_EXT-2", "");
   ExpectFieldValue("PHONE_HOME_COUNTRY_CODE-1", "1");
 }
 
@@ -1447,7 +1447,7 @@ IN_PROC_BROWSER_TEST_F(AutofillTest, MAYBE_NoAutofillForReadOnlyFields) {
   ui_test_utils::NavigateToURL(browser(), url);
   PopulateForm("firstname");
 
-  ExpectFieldValue("email", std::string());
+  ExpectFieldValue("email", "");
   ExpectFieldValue("address", addr_line1);
 }
 
diff --git a/chrome/browser/automation/automation_misc_browsertest.cc b/chrome/browser/automation/automation_misc_browsertest.cc
index 11ce614..97efd95 100644
--- a/chrome/browser/automation/automation_misc_browsertest.cc
+++ b/chrome/browser/automation/automation_misc_browsertest.cc
@@ -82,8 +82,8 @@ IN_PROC_BROWSER_TEST_F(AutomationMiscBrowserTest, ProcessMouseEvent) {
       "  window.didClick = true;"
       "}, true);"));
   AutomationMouseEvent automation_event;
-  automation_event.location_script_chain
-      .push_back(ScriptEvaluationRequest("{'x': 5, 'y': 10}", std::string()));
+  automation_event.location_script_chain.push_back(
+      ScriptEvaluationRequest("{'x': 5, 'y': 10}", ""));
   WebKit::WebMouseEvent& mouse_event = automation_event.mouse_event;
   mouse_event.type = WebKit::WebInputEvent::MouseDown;
   mouse_event.button = WebKit::WebMouseEvent::ButtonLeft;
diff --git a/chrome/browser/automation/testing_automation_provider.cc b/chrome/browser/automation/testing_automation_provider.cc
index e176eec..ae9f48c 100644
--- a/chrome/browser/automation/testing_automation_provider.cc
+++ b/chrome/browser/automation/testing_automation_provider.cc
@@ -991,7 +991,7 @@ void TestingAutomationProvider::GetTabTitle(int handle,
     NavigationController* tab = tab_tracker_->GetResource(handle);
     NavigationEntry* entry = tab->GetActiveEntry();
     if (entry != NULL) {
-      *title = UTF16ToWideHack(entry->GetTitleForDisplay(std::string()));
+      *title = UTF16ToWideHack(entry->GetTitleForDisplay(""));
     } else {
       *title = std::wstring();
     }
@@ -3414,7 +3414,7 @@ void TestingAutomationProvider::RemoveSavedPassword(
   // This observer will delete itself.
   PasswordStoreLoginsChangedObserver* observer =
       new PasswordStoreLoginsChangedObserver(
-          this, reply_message, PasswordStoreChange::REMOVE, std::string());
+          this, reply_message, PasswordStoreChange::REMOVE, "");
   observer->Init();
 
   password_store->RemoveLogin(to_remove);
@@ -5353,7 +5353,7 @@ void TestingAutomationProvider::GetTabInfo(
       return;
     }
     DictionaryValue dict;
-    dict.SetString("title", entry->GetTitleForDisplay(std::string()));
+    dict.SetString("title", entry->GetTitleForDisplay(""));
     dict.SetString("url", entry->GetVirtualURL().spec());
     reply.SendSuccess(&dict);
   } else {
diff --git a/chrome/browser/bookmarks/bookmark_utils_unittest.cc b/chrome/browser/bookmarks/bookmark_utils_unittest.cc
index a5f253d..f71645e 100644
--- a/chrome/browser/bookmarks/bookmark_utils_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_utils_unittest.cc
@@ -166,31 +166,22 @@ TEST_F(BookmarkUtilsTest, ApplyEditsWithNoFolderChange) {
   {
     BookmarkEditor::EditDetails detail(
         BookmarkEditor::EditDetails::AddFolder(bookmarkbar, 1));
-    ApplyEditsWithNoFolderChange(&model,
-                                 bookmarkbar,
-                                 detail,
-                                 ASCIIToUTF16("folder0"),
-                                 GURL(std::string()));
+    ApplyEditsWithNoFolderChange(&model, bookmarkbar, detail,
+                                 ASCIIToUTF16("folder0"), GURL(""));
     EXPECT_EQ(ASCIIToUTF16("folder0"), bookmarkbar->GetChild(1)->GetTitle());
   }
   {
     BookmarkEditor::EditDetails detail(
         BookmarkEditor::EditDetails::AddFolder(bookmarkbar, -1));
-    ApplyEditsWithNoFolderChange(&model,
-                                 bookmarkbar,
-                                 detail,
-                                 ASCIIToUTF16("folder1"),
-                                 GURL(std::string()));
+    ApplyEditsWithNoFolderChange(&model, bookmarkbar, detail,
+                                 ASCIIToUTF16("folder1"), GURL(""));
     EXPECT_EQ(ASCIIToUTF16("folder1"), bookmarkbar->GetChild(3)->GetTitle());
   }
   {
     BookmarkEditor::EditDetails detail(
         BookmarkEditor::EditDetails::AddFolder(bookmarkbar, 10));
-    ApplyEditsWithNoFolderChange(&model,
-                                 bookmarkbar,
-                                 detail,
-                                 ASCIIToUTF16("folder2"),
-                                 GURL(std::string()));
+    ApplyEditsWithNoFolderChange(&model, bookmarkbar, detail,
+                                 ASCIIToUTF16("folder2"), GURL(""));
     EXPECT_EQ(ASCIIToUTF16("folder2"), bookmarkbar->GetChild(4)->GetTitle());
   }
 }
diff --git a/chrome/browser/browsing_data/browsing_data_cookie_helper_unittest.cc b/chrome/browser/browsing_data/browsing_data_cookie_helper_unittest.cc
index be0879b..94df56c 100644
--- a/chrome/browser/browsing_data/browsing_data_cookie_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_cookie_helper_unittest.cc
@@ -277,10 +277,8 @@ TEST_F(BrowsingDataCookieHelperTest, CannedDomainCookie) {
   helper->AddChangedCookie(origin, origin, "A=1; Domain=.www.google.com",
                            net::CookieOptions());
   // Try adding invalid cookies that will be ignored.
-  helper->AddChangedCookie(origin, origin, std::string(), net::CookieOptions());
-  helper->AddChangedCookie(origin,
-                           origin,
-                           "C=bad guy; Domain=wrongdomain.com",
+  helper->AddChangedCookie(origin, origin, "", net::CookieOptions());
+  helper->AddChangedCookie(origin, origin, "C=bad guy; Domain=wrongdomain.com",
                            net::CookieOptions());
 
   helper->StartFetching(
diff --git a/chrome/browser/browsing_data/browsing_data_database_helper_browsertest.cc b/chrome/browser/browsing_data/browsing_data_database_helper_browsertest.cc
index 019a45b..8c29d07 100644
--- a/chrome/browser/browsing_data/browsing_data_database_helper_browsertest.cc
+++ b/chrome/browser/browsing_data/browsing_data_database_helper_browsertest.cc
@@ -104,9 +104,9 @@ IN_PROC_BROWSER_TEST_F(BrowsingDataDatabaseHelperTest, CannedAddDatabase) {
 
   scoped_refptr<CannedBrowsingDataDatabaseHelper> helper(
       new CannedBrowsingDataDatabaseHelper(browser()->profile()));
-  helper->AddDatabase(origin1, db1, std::string());
-  helper->AddDatabase(origin1, db2, std::string());
-  helper->AddDatabase(origin2, db3, std::string());
+  helper->AddDatabase(origin1, db1, "");
+  helper->AddDatabase(origin1, db2, "");
+  helper->AddDatabase(origin2, db3, "");
 
   TestCompletionCallback callback;
   helper->StartFetching(
@@ -136,8 +136,8 @@ IN_PROC_BROWSER_TEST_F(BrowsingDataDatabaseHelperTest, CannedUnique) {
 
   scoped_refptr<CannedBrowsingDataDatabaseHelper> helper(
       new CannedBrowsingDataDatabaseHelper(browser()->profile()));
-  helper->AddDatabase(origin, db, std::string());
-  helper->AddDatabase(origin, db, std::string());
+  helper->AddDatabase(origin, db, "");
+  helper->AddDatabase(origin, db, "");
 
   TestCompletionCallback callback;
   helper->StartFetching(
diff --git a/chrome/browser/browsing_data/browsing_data_database_helper_unittest.cc b/chrome/browser/browsing_data/browsing_data_database_helper_unittest.cc
index 89c290d..2a2b474 100644
--- a/chrome/browser/browsing_data/browsing_data_database_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_database_helper_unittest.cc
@@ -35,7 +35,7 @@ TEST_F(CannedBrowsingDataDatabaseHelperTest, Empty) {
       new CannedBrowsingDataDatabaseHelper(&profile));
 
   ASSERT_TRUE(helper->empty());
-  helper->AddDatabase(origin, db, std::string());
+  helper->AddDatabase(origin, db, "");
   ASSERT_FALSE(helper->empty());
   helper->Reset();
   ASSERT_TRUE(helper->empty());
@@ -52,9 +52,9 @@ TEST_F(CannedBrowsingDataDatabaseHelperTest, IgnoreExtensionsAndDevTools) {
       new CannedBrowsingDataDatabaseHelper(&profile));
 
   ASSERT_TRUE(helper->empty());
-  helper->AddDatabase(origin1, db, std::string());
+  helper->AddDatabase(origin1, db, "");
   ASSERT_TRUE(helper->empty());
-  helper->AddDatabase(origin2, db, std::string());
+  helper->AddDatabase(origin2, db, "");
   ASSERT_TRUE(helper->empty());
   helper->Reset();
   ASSERT_TRUE(helper->empty());
diff --git a/chrome/browser/browsing_data/cookies_tree_model_unittest.cc b/chrome/browser/browsing_data/cookies_tree_model_unittest.cc
index 9699414..58b1dd5 100644
--- a/chrome/browser/browsing_data/cookies_tree_model_unittest.cc
+++ b/chrome/browser/browsing_data/cookies_tree_model_unittest.cc
@@ -416,7 +416,7 @@ TEST_F(CookiesTreeModelTest, RemoveAll) {
     SCOPED_TRACE("After removing");
     EXPECT_EQ(1, cookies_model->GetRoot()->GetTotalNodeCount());
     EXPECT_EQ(0, cookies_model->GetRoot()->child_count());
-    EXPECT_EQ(std::string(), GetDisplayedCookies(cookies_model.get()));
+    EXPECT_EQ(std::string(""), GetDisplayedCookies(cookies_model.get()));
     EXPECT_TRUE(mock_browsing_data_cookie_helper_->AllDeleted());
     EXPECT_TRUE(mock_browsing_data_database_helper_->AllDeleted());
     EXPECT_TRUE(mock_browsing_data_local_storage_helper_->AllDeleted());
diff --git a/chrome/browser/certificate_manager_model.cc b/chrome/browser/certificate_manager_model.cc
index aecd3a3..f519a0d 100644
--- a/chrome/browser/certificate_manager_model.cc
+++ b/chrome/browser/certificate_manager_model.cc
@@ -38,7 +38,7 @@ void CertificateManagerModel::Refresh() {
   chrome::UnlockSlotsIfNecessary(
       modules,
       chrome::kCryptoModulePasswordListCerts,
-      std::string(),  // unused.
+      "",  // unused.
       base::Bind(&CertificateManagerModel::RefreshSlotsUnlocked,
                  base::Unretained(this)));
 }
@@ -95,8 +95,9 @@ string16 CertificateManagerModel::GetColumnText(
           x509_certificate_model::GetTokenName(cert.os_cert_handle()));
       break;
     case COL_SERIAL_NUMBER:
-      rv = ASCIIToUTF16(x509_certificate_model::GetSerialNumberHexified(
-          cert.os_cert_handle(), std::string()));
+      rv = ASCIIToUTF16(
+          x509_certificate_model::GetSerialNumberHexified(
+              cert.os_cert_handle(), ""));
       break;
     case COL_EXPIRES_ON:
       if (!cert.valid_expiry().is_null())
diff --git a/chrome/browser/content_settings/content_settings_browsertest.cc b/chrome/browser/content_settings/content_settings_browsertest.cc
index f4105ad..88c664c 100644
--- a/chrome/browser/content_settings/content_settings_browsertest.cc
+++ b/chrome/browser/content_settings/content_settings_browsertest.cc
@@ -338,12 +338,12 @@ IN_PROC_BROWSER_TEST_F(ClickToPlayPluginTest, AllowException) {
 
   browser()->profile()->GetHostContentSettingsMap()->SetDefaultContentSetting(
       CONTENT_SETTINGS_TYPE_PLUGINS, CONTENT_SETTING_BLOCK);
-  browser()->profile()->GetHostContentSettingsMap()
-      ->SetContentSetting(ContentSettingsPattern::FromURL(url),
-                          ContentSettingsPattern::Wildcard(),
-                          CONTENT_SETTINGS_TYPE_PLUGINS,
-                          std::string(),
-                          CONTENT_SETTING_ALLOW);
+  browser()->profile()->GetHostContentSettingsMap()->SetContentSetting(
+      ContentSettingsPattern::FromURL(url),
+      ContentSettingsPattern::Wildcard(),
+      CONTENT_SETTINGS_TYPE_PLUGINS,
+      "",
+      CONTENT_SETTING_ALLOW);
 
   string16 expected_title(ASCIIToUTF16("OK"));
   content::TitleWatcher title_watcher(
@@ -357,12 +357,12 @@ IN_PROC_BROWSER_TEST_F(ClickToPlayPluginTest, BlockException) {
   GURL url = ui_test_utils::GetTestUrl(
       base::FilePath(), base::FilePath().AppendASCII("clicktoplay.html"));
 
-  browser()->profile()->GetHostContentSettingsMap()
-      ->SetContentSetting(ContentSettingsPattern::FromURL(url),
-                          ContentSettingsPattern::Wildcard(),
-                          CONTENT_SETTINGS_TYPE_PLUGINS,
-                          std::string(),
-                          CONTENT_SETTING_BLOCK);
+  browser()->profile()->GetHostContentSettingsMap()->SetContentSetting(
+      ContentSettingsPattern::FromURL(url),
+      ContentSettingsPattern::Wildcard(),
+      CONTENT_SETTINGS_TYPE_PLUGINS,
+      "",
+      CONTENT_SETTING_BLOCK);
 
   string16 expected_title(ASCIIToUTF16("Click To Play"));
   content::TitleWatcher title_watcher(
diff --git a/chrome/browser/content_settings/content_settings_internal_extension_provider.cc b/chrome/browser/content_settings/content_settings_internal_extension_provider.cc
index 56dd993..815d037 100644
--- a/chrome/browser/content_settings/content_settings_internal_extension_provider.cc
+++ b/chrome/browser/content_settings/content_settings_internal_extension_provider.cc
@@ -117,19 +117,19 @@ void InternalExtensionProvider::SetContentSettingForExtension(
       value_map_.DeleteValue(primary_pattern,
                              secondary_pattern,
                              CONTENT_SETTINGS_TYPE_PLUGINS,
-                             ResourceIdentifier());
+                             ResourceIdentifier(""));
     } else {
       value_map_.SetValue(primary_pattern,
                           secondary_pattern,
                           CONTENT_SETTINGS_TYPE_PLUGINS,
-                          ResourceIdentifier(),
+                          ResourceIdentifier(""),
                           Value::CreateIntegerValue(setting));
     }
   }
   NotifyObservers(primary_pattern,
                   secondary_pattern,
                   CONTENT_SETTINGS_TYPE_PLUGINS,
-                  ResourceIdentifier());
+                  ResourceIdentifier(""));
 }
 
 }  // namespace content_settings
diff --git a/chrome/browser/content_settings/content_settings_origin_identifier_value_map_unittest.cc b/chrome/browser/content_settings/content_settings_origin_identifier_value_map_unittest.cc
index b8612a5..21089fb 100644
--- a/chrome/browser/content_settings/content_settings_origin_identifier_value_map_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_origin_identifier_value_map_unittest.cc
@@ -14,40 +14,38 @@
 TEST(OriginIdentifierValueMapTest, SetGetValue) {
   content_settings::OriginIdentifierValueMap map;
 
-  EXPECT_EQ(NULL,
-            map.GetValue(GURL("http://www.google.com"),
-                         GURL("http://www.google.com"),
-                         CONTENT_SETTINGS_TYPE_COOKIES,
-                         std::string()));
-  map.SetValue(ContentSettingsPattern::FromString("[*.]google.com"),
-               ContentSettingsPattern::FromString("[*.]google.com"),
-               CONTENT_SETTINGS_TYPE_COOKIES,
-               std::string(),
-               Value::CreateIntegerValue(1));
+  EXPECT_EQ(NULL, map.GetValue(GURL("http://www.google.com"),
+                               GURL("http://www.google.com"),
+                               CONTENT_SETTINGS_TYPE_COOKIES,
+                               ""));
+  map.SetValue(
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      Value::CreateIntegerValue(1));
 
   scoped_ptr<Value> expected_value(Value::CreateIntegerValue(1));
-  EXPECT_TRUE(expected_value->Equals(map.GetValue(GURL("http://www.google.com"),
-                                                  GURL("http://www.google.com"),
-                                                  CONTENT_SETTINGS_TYPE_COOKIES,
-                                                  std::string())));
-
-  EXPECT_EQ(NULL,
-            map.GetValue(GURL("http://www.google.com"),
-                         GURL("http://www.youtube.com"),
-                         CONTENT_SETTINGS_TYPE_COOKIES,
-                         std::string()));
-
-  EXPECT_EQ(NULL,
-            map.GetValue(GURL("http://www.youtube.com"),
-                         GURL("http://www.google.com"),
-                         CONTENT_SETTINGS_TYPE_COOKIES,
-                         std::string()));
-
-  EXPECT_EQ(NULL,
-            map.GetValue(GURL("http://www.google.com"),
-                         GURL("http://www.google.com"),
-                         CONTENT_SETTINGS_TYPE_POPUPS,
-                         std::string()));
+  EXPECT_TRUE(expected_value->Equals(
+      map.GetValue(GURL("http://www.google.com"),
+                   GURL("http://www.google.com"),
+                   CONTENT_SETTINGS_TYPE_COOKIES,
+                   "")));
+
+  EXPECT_EQ(NULL, map.GetValue(GURL("http://www.google.com"),
+                               GURL("http://www.youtube.com"),
+                               CONTENT_SETTINGS_TYPE_COOKIES,
+                               ""));
+
+  EXPECT_EQ(NULL, map.GetValue(GURL("http://www.youtube.com"),
+                               GURL("http://www.google.com"),
+                               CONTENT_SETTINGS_TYPE_COOKIES,
+                               ""));
+
+  EXPECT_EQ(NULL, map.GetValue(GURL("http://www.google.com"),
+                               GURL("http://www.google.com"),
+                               CONTENT_SETTINGS_TYPE_POPUPS,
+                               ""));
 
   EXPECT_EQ(NULL, map.GetValue(GURL("http://www.google.com"),
                                GURL("http://www.google.com"),
@@ -121,11 +119,12 @@ TEST(OriginIdentifierValueMapTest, Clear) {
       CONTENT_SETTINGS_TYPE_PLUGINS,
       "java-plugin",
       Value::CreateIntegerValue(1));
-  map.SetValue(ContentSettingsPattern::FromString("[*.]google.com"),
-               ContentSettingsPattern::FromString("[*.]google.com"),
-               CONTENT_SETTINGS_TYPE_COOKIES,
-               std::string(),
-               Value::CreateIntegerValue(1));
+  map.SetValue(
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      Value::CreateIntegerValue(1));
   EXPECT_FALSE(map.empty());
   int actual_value;
   EXPECT_TRUE(map.GetValue(GURL("http://www.google.com"),
@@ -146,36 +145,38 @@ TEST(OriginIdentifierValueMapTest, Clear) {
 TEST(OriginIdentifierValueMapTest, ListEntryPrecedences) {
   content_settings::OriginIdentifierValueMap map;
 
-  map.SetValue(ContentSettingsPattern::FromString("[*.]google.com"),
-               ContentSettingsPattern::FromString("[*.]google.com"),
-               CONTENT_SETTINGS_TYPE_COOKIES,
-               std::string(),
-               Value::CreateIntegerValue(1));
+  map.SetValue(
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      Value::CreateIntegerValue(1));
 
-  map.SetValue(ContentSettingsPattern::FromString("www.google.com"),
-               ContentSettingsPattern::FromString("[*.]google.com"),
-               CONTENT_SETTINGS_TYPE_COOKIES,
-               std::string(),
-               Value::CreateIntegerValue(2));
+  map.SetValue(
+      ContentSettingsPattern::FromString("www.google.com"),
+      ContentSettingsPattern::FromString("[*.]google.com"),
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      Value::CreateIntegerValue(2));
 
   int actual_value;
   EXPECT_TRUE(map.GetValue(GURL("http://mail.google.com"),
                            GURL("http://www.google.com"),
                            CONTENT_SETTINGS_TYPE_COOKIES,
-                           std::string())->GetAsInteger(&actual_value));
+                           "")->GetAsInteger(&actual_value));
   EXPECT_EQ(1, actual_value);
 
   EXPECT_TRUE(map.GetValue(GURL("http://www.google.com"),
                            GURL("http://www.google.com"),
                            CONTENT_SETTINGS_TYPE_COOKIES,
-                           std::string())->GetAsInteger(&actual_value));
+                           "")->GetAsInteger(&actual_value));
   EXPECT_EQ(2, actual_value);
 }
 
 TEST(OriginIdentifierValueMapTest, IterateEmpty) {
   content_settings::OriginIdentifierValueMap map;
   scoped_ptr<content_settings::RuleIterator> rule_iterator(
-      map.GetRuleIterator(CONTENT_SETTINGS_TYPE_COOKIES, std::string(), NULL));
+      map.GetRuleIterator(CONTENT_SETTINGS_TYPE_COOKIES, "", NULL));
   EXPECT_FALSE(rule_iterator->HasNext());
 }
 
@@ -186,19 +187,21 @@ TEST(OriginIdentifierValueMapTest, IterateNonempty) {
       ContentSettingsPattern::FromString("[*.]google.com");
   ContentSettingsPattern sub_pattern =
       ContentSettingsPattern::FromString("sub.google.com");
-  map.SetValue(pattern,
-               ContentSettingsPattern::Wildcard(),
-               CONTENT_SETTINGS_TYPE_COOKIES,
-               std::string(),
-               Value::CreateIntegerValue(1));
-  map.SetValue(sub_pattern,
-               ContentSettingsPattern::Wildcard(),
-               CONTENT_SETTINGS_TYPE_COOKIES,
-               std::string(),
-               Value::CreateIntegerValue(2));
+  map.SetValue(
+      pattern,
+      ContentSettingsPattern::Wildcard(),
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      Value::CreateIntegerValue(1));
+  map.SetValue(
+      sub_pattern,
+      ContentSettingsPattern::Wildcard(),
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      Value::CreateIntegerValue(2));
 
   scoped_ptr<content_settings::RuleIterator> rule_iterator(
-      map.GetRuleIterator(CONTENT_SETTINGS_TYPE_COOKIES, std::string(), NULL));
+      map.GetRuleIterator(CONTENT_SETTINGS_TYPE_COOKIES, "", NULL));
   ASSERT_TRUE(rule_iterator->HasNext());
   content_settings::Rule rule = rule_iterator->Next();
   EXPECT_EQ(sub_pattern, rule.primary_pattern);
diff --git a/chrome/browser/content_settings/content_settings_policy_provider.cc b/chrome/browser/content_settings/content_settings_policy_provider.cc
index f1e40fb..b112db0 100644
--- a/chrome/browser/content_settings/content_settings_policy_provider.cc
+++ b/chrome/browser/content_settings/content_settings_policy_provider.cc
@@ -276,7 +276,7 @@ void PolicyProvider::GetContentSettingsFromPreferences(
           pattern_pair.first,
           secondary_pattern,
           content_type,
-          NO_RESOURCE_IDENTIFIER,
+          ResourceIdentifier(NO_RESOURCE_IDENTIFIER),
           base::Value::CreateIntegerValue(
               kPrefsForManagedContentSettingsMap[i].setting));
     }
diff --git a/chrome/browser/content_settings/content_settings_policy_provider_unittest.cc b/chrome/browser/content_settings/content_settings_policy_provider_unittest.cc
index 37b718c..23c43f8 100644
--- a/chrome/browser/content_settings/content_settings_policy_provider_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_policy_provider_unittest.cc
@@ -150,34 +150,22 @@ TEST_F(PolicyProviderTest, GettingManagedContentSettings) {
   GURL google_url("http://mail.google.com");
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSetting(&provider,
-                              youtube_url,
-                              youtube_url,
-                              CONTENT_SETTINGS_TYPE_COOKIES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &provider, youtube_url, youtube_url,
+                CONTENT_SETTINGS_TYPE_COOKIES, "", false));
   EXPECT_EQ(NULL,
-            GetContentSettingValue(&provider,
-                                   youtube_url,
-                                   youtube_url,
-                                   CONTENT_SETTINGS_TYPE_COOKIES,
-                                   std::string(),
-                                   false));
+            GetContentSettingValue(
+                &provider, youtube_url, youtube_url,
+                CONTENT_SETTINGS_TYPE_COOKIES, "", false));
 
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSetting(&provider,
-                              google_url,
-                              google_url,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &provider, google_url, google_url,
+                CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   scoped_ptr<Value> value_ptr(
-      GetContentSettingValue(&provider,
-                             google_url,
-                             google_url,
-                             CONTENT_SETTINGS_TYPE_IMAGES,
-                             std::string(),
-                             false));
+      GetContentSettingValue(
+          &provider, google_url, google_url,
+          CONTENT_SETTINGS_TYPE_IMAGES, "", false));
 
   int int_value = -1;
   value_ptr->GetAsInteger(&int_value);
@@ -188,19 +176,17 @@ TEST_F(PolicyProviderTest, GettingManagedContentSettings) {
   // SetWebsiteSetting does nothing.
   scoped_ptr<base::Value> value_block(
       Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
-  bool owned = provider.SetWebsiteSetting(yt_url_pattern,
-                                          yt_url_pattern,
-                                          CONTENT_SETTINGS_TYPE_COOKIES,
-                                          std::string(),
-                                          value_block.get());
+  bool owned = provider.SetWebsiteSetting(
+      yt_url_pattern,
+      yt_url_pattern,
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      value_block.get());
   EXPECT_FALSE(owned);
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSetting(&provider,
-                              youtube_url,
-                              youtube_url,
-                              CONTENT_SETTINGS_TYPE_COOKIES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &provider, youtube_url, youtube_url,
+                CONTENT_SETTINGS_TYPE_COOKIES, "", false));
 
   provider.ShutdownOnUIThread();
 }
@@ -227,12 +213,9 @@ TEST_F(PolicyProviderTest, ResourceIdentifier) {
   // There is currently no policy support for resource content settings.
   // Resource identifiers are simply ignored by the PolicyProvider.
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
-            GetContentSetting(&provider,
-                              google_url,
-                              google_url,
-                              CONTENT_SETTINGS_TYPE_PLUGINS,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &provider, google_url, google_url,
+                CONTENT_SETTINGS_TYPE_PLUGINS, "", false));
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
             GetContentSetting(
@@ -249,14 +232,10 @@ TEST_F(PolicyProviderTest, AutoSelectCertificateList) {
   PolicyProvider provider(prefs);
   GURL google_url("https://mail.google.com");
   // Tests the default setting for auto selecting certificates
-  EXPECT_EQ(
-      NULL,
-      GetContentSettingValue(&provider,
-                             google_url,
-                             google_url,
-                             CONTENT_SETTINGS_TYPE_AUTO_SELECT_CERTIFICATE,
-                             std::string(),
-                             false));
+  EXPECT_EQ(NULL,
+            GetContentSettingValue(
+                &provider, google_url, google_url,
+                CONTENT_SETTINGS_TYPE_AUTO_SELECT_CERTIFICATE, "", false));
 
   // Set the content settings pattern list for origins to auto select
   // certificates.
@@ -268,21 +247,13 @@ TEST_F(PolicyProviderTest, AutoSelectCertificateList) {
   prefs->SetManagedPref(prefs::kManagedAutoSelectCertificateForUrls,
                         value);
   GURL youtube_url("https://www.youtube.com");
-  EXPECT_EQ(
-      NULL,
-      GetContentSettingValue(&provider,
-                             youtube_url,
-                             youtube_url,
-                             CONTENT_SETTINGS_TYPE_AUTO_SELECT_CERTIFICATE,
-                             std::string(),
-                             false));
-  scoped_ptr<Value> cert_filter(
-      GetContentSettingValue(&provider,
-                             google_url,
-                             google_url,
-                             CONTENT_SETTINGS_TYPE_AUTO_SELECT_CERTIFICATE,
-                             std::string(),
-                             false));
+  EXPECT_EQ(NULL,
+            GetContentSettingValue(
+                &provider, youtube_url, youtube_url,
+                CONTENT_SETTINGS_TYPE_AUTO_SELECT_CERTIFICATE, "", false));
+  scoped_ptr<Value> cert_filter(GetContentSettingValue(
+      &provider, google_url, google_url,
+      CONTENT_SETTINGS_TYPE_AUTO_SELECT_CERTIFICATE, "", false));
 
   ASSERT_EQ(Value::TYPE_DICTIONARY, cert_filter->GetType());
   DictionaryValue* dict_value =
diff --git a/chrome/browser/content_settings/content_settings_pref_provider.cc b/chrome/browser/content_settings/content_settings_pref_provider.cc
index 4690f2f..a92315e 100644
--- a/chrome/browser/content_settings/content_settings_pref_provider.cc
+++ b/chrome/browser/content_settings/content_settings_pref_provider.cc
@@ -188,21 +188,22 @@ void PrefProvider::ClearAllContentSettingsRules(
   {
     base::AutoLock auto_lock(lock_);
     scoped_ptr<RuleIterator> rule_iterator(
-        map_to_modify->GetRuleIterator(content_type, std::string(), NULL));
+        map_to_modify->GetRuleIterator(content_type, "", NULL));
     // Copy the rules; we cannot call |UpdatePref| while holding |lock_|.
     while (rule_iterator->HasNext())
       rules_to_delete.push_back(rule_iterator->Next());
 
-    map_to_modify->DeleteValues(content_type, std::string());
+    map_to_modify->DeleteValues(content_type, "");
   }
 
   for (std::vector<Rule>::const_iterator it = rules_to_delete.begin();
        it != rules_to_delete.end(); ++it) {
-    UpdatePref(it->primary_pattern,
-               it->secondary_pattern,
-               content_type,
-               std::string(),
-               NULL);
+    UpdatePref(
+        it->primary_pattern,
+        it->secondary_pattern,
+        content_type,
+        "",
+        NULL);
   }
   NotifyObservers(ContentSettingsPattern(),
                   ContentSettingsPattern(),
@@ -306,8 +307,8 @@ void PrefProvider::UpdatePref(
 void PrefProvider::MigrateObsoleteMediaContentSetting() {
   std::vector<Rule> rules_to_delete;
   {
-    scoped_ptr<RuleIterator> rule_iterator(GetRuleIterator(
-        CONTENT_SETTINGS_TYPE_MEDIASTREAM, std::string(), false));
+    scoped_ptr<RuleIterator> rule_iterator(
+        GetRuleIterator(CONTENT_SETTINGS_TYPE_MEDIASTREAM, "", false));
     while (rule_iterator->HasNext()) {
       // Skip default setting and rules without a value.
       const content_settings::Rule& rule = rule_iterator->Next();
@@ -332,7 +333,7 @@ void PrefProvider::MigrateObsoleteMediaContentSetting() {
       SetWebsiteSetting(it->primary_pattern,
                         it->secondary_pattern,
                         CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC,
-                        std::string(),
+                        "",
                         Value::CreateIntegerValue(CONTENT_SETTING_ALLOW));
     }
     // Add the exception to the new camera content setting.
@@ -340,7 +341,7 @@ void PrefProvider::MigrateObsoleteMediaContentSetting() {
       SetWebsiteSetting(it->primary_pattern,
                         it->secondary_pattern,
                         CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA,
-                        std::string(),
+                        "",
                         Value::CreateIntegerValue(CONTENT_SETTING_ALLOW));
     }
 
@@ -348,7 +349,7 @@ void PrefProvider::MigrateObsoleteMediaContentSetting() {
     SetWebsiteSetting(it->primary_pattern,
                       it->secondary_pattern,
                       CONTENT_SETTINGS_TYPE_MEDIASTREAM,
-                      std::string(),
+                      "",
                       NULL);
   }
 }
@@ -454,7 +455,7 @@ void PrefProvider::ReadContentSettingsFromPref(bool overwrite) {
         value_map_.SetValue(pattern_pair.first,
                             pattern_pair.second,
                             content_type,
-                            ResourceIdentifier(),
+                            ResourceIdentifier(""),
                             value);
         if (content_type == CONTENT_SETTINGS_TYPE_COOKIES) {
           ContentSetting s = ValueToContentSetting(value);
diff --git a/chrome/browser/content_settings/content_settings_pref_provider_unittest.cc b/chrome/browser/content_settings/content_settings_pref_provider_unittest.cc
index 1ddc6d0..f951829 100644
--- a/chrome/browser/content_settings/content_settings_pref_provider_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_pref_provider_unittest.cc
@@ -121,7 +121,7 @@ TEST_F(PrefProviderTest, Observer) {
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       Value::CreateIntegerValue(CONTENT_SETTING_ALLOW));
 
   pref_content_settings_provider.ShutdownOnUIThread();
@@ -166,26 +166,20 @@ TEST_F(PrefProviderTest, Incognito) {
       pattern,
       pattern,
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       Value::CreateIntegerValue(CONTENT_SETTING_ALLOW));
 
   GURL host("http://example.com/");
   // The value should of course be visible in the regular PrefProvider.
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
-            GetContentSetting(&pref_content_settings_provider,
-                              host,
-                              host,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   // And also in the OTR version.
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
-            GetContentSetting(&pref_content_settings_provider_incognito,
-                              host,
-                              host,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider_incognito,
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   // But the value should not be overridden in the OTR user prefs accidentally.
   EXPECT_FALSE(otr_user_prefs->IsSetInOverlay(
       prefs::kContentSettingsPatternPairs));
@@ -203,40 +197,26 @@ TEST_F(PrefProviderTest, GetContentSettingsValue) {
       ContentSettingsPattern::FromString("[*.]example.com");
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSetting(&provider,
-                              primary_url,
-                              primary_url,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(&provider, primary_url, primary_url,
+                              CONTENT_SETTINGS_TYPE_IMAGES, "", false));
 
   EXPECT_EQ(NULL,
-            GetContentSettingValue(&provider,
-                                   primary_url,
-                                   primary_url,
-                                   CONTENT_SETTINGS_TYPE_IMAGES,
-                                   std::string(),
-                                   false));
+            GetContentSettingValue(
+                &provider, primary_url, primary_url,
+                CONTENT_SETTINGS_TYPE_IMAGES, "", false));
 
-  provider.SetWebsiteSetting(primary_pattern,
-                             primary_pattern,
-                             CONTENT_SETTINGS_TYPE_IMAGES,
-                             std::string(),
-                             Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
+  provider.SetWebsiteSetting(
+      primary_pattern,
+      primary_pattern,
+      CONTENT_SETTINGS_TYPE_IMAGES,
+      "",
+      Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSetting(&provider,
-                              primary_url,
-                              primary_url,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(&provider, primary_url, primary_url,
+                              CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   scoped_ptr<Value> value_ptr(
-      GetContentSettingValue(&provider,
-                             primary_url,
-                             primary_url,
-                             CONTENT_SETTINGS_TYPE_IMAGES,
-                             std::string(),
-                             false));
+      GetContentSettingValue(&provider, primary_url, primary_url,
+                             CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   int int_value = -1;
   value_ptr->GetAsInteger(&int_value);
   EXPECT_EQ(CONTENT_SETTING_BLOCK, IntToContentSetting(int_value));
@@ -244,15 +224,12 @@ TEST_F(PrefProviderTest, GetContentSettingsValue) {
   provider.SetWebsiteSetting(primary_pattern,
                              primary_pattern,
                              CONTENT_SETTINGS_TYPE_IMAGES,
-                             std::string(),
+                             "",
                              NULL);
   EXPECT_EQ(NULL,
-            GetContentSettingValue(&provider,
-                                   primary_url,
-                                   primary_url,
-                                   CONTENT_SETTINGS_TYPE_IMAGES,
-                                   std::string(),
-                                   false));
+            GetContentSettingValue(
+                &provider, primary_url, primary_url,
+                CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   provider.ShutdownOnUIThread();
 }
 
@@ -273,74 +250,53 @@ TEST_F(PrefProviderTest, Patterns) {
       ContentSettingsPattern::FromString("file:///tmp/test.html");
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSetting(&pref_content_settings_provider,
-                              host1,
-                              host1,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host1, host1, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   pref_content_settings_provider.SetWebsiteSetting(
       pattern1,
       pattern1,
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSetting(&pref_content_settings_provider,
-                              host1,
-                              host1,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host1, host1, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSetting(&pref_content_settings_provider,
-                              host2,
-                              host2,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host2, host2, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSetting(&pref_content_settings_provider,
-                              host3,
-                              host3,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host3, host3, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
   pref_content_settings_provider.SetWebsiteSetting(
       pattern2,
       pattern2,
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSetting(&pref_content_settings_provider,
-                              host3,
-                              host3,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host3, host3, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
             GetContentSetting(&pref_content_settings_provider,
-                              host4,
-                              host4,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
+                              host4, host4, CONTENT_SETTINGS_TYPE_IMAGES, "",
                               false));
   pref_content_settings_provider.SetWebsiteSetting(
       pattern3,
       pattern3,
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSetting(&pref_content_settings_provider,
-                              host4,
-                              host4,
-                              CONTENT_SETTINGS_TYPE_IMAGES,
-                              std::string(),
-                              false));
+            GetContentSetting(
+                &pref_content_settings_provider,
+                host4, host4, CONTENT_SETTINGS_TYPE_IMAGES, "", false));
 
   pref_content_settings_provider.ShutdownOnUIThread();
 }
diff --git a/chrome/browser/content_settings/content_settings_provider.h b/chrome/browser/content_settings/content_settings_provider.h
index 6bc64de..fefa226 100644
--- a/chrome/browser/content_settings/content_settings_provider.h
+++ b/chrome/browser/content_settings/content_settings_provider.h
@@ -7,7 +7,7 @@
 #ifndef CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_PROVIDER_H_
 #define CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_PROVIDER_H_
 
-#define NO_RESOURCE_IDENTIFIER std::string()
+#define NO_RESOURCE_IDENTIFIER ""
 
 #include <string>
 #include <vector>
diff --git a/chrome/browser/content_settings/content_settings_provider_unittest.cc b/chrome/browser/content_settings/content_settings_provider_unittest.cc
index 0832a1c..e0857b3 100644
--- a/chrome/browser/content_settings/content_settings_provider_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_provider_unittest.cc
@@ -46,18 +46,11 @@ TEST(ContentSettingsProviderTest, Mock) {
                                    CONTENT_SETTINGS_TYPE_PLUGINS,
                                    "flash_plugin", false));
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSetting(&mock_provider,
-                              url,
-                              url,
-                              CONTENT_SETTINGS_TYPE_GEOLOCATION,
-                              std::string(),
-                              false));
+            GetContentSetting(&mock_provider, url, url,
+                              CONTENT_SETTINGS_TYPE_GEOLOCATION, "", false));
   EXPECT_EQ(NULL,
-            GetContentSettingValue(&mock_provider,
-                                   url,
-                                   url,
-                                   CONTENT_SETTINGS_TYPE_GEOLOCATION,
-                                   std::string(),
+            GetContentSettingValue(&mock_provider, url, url,
+                                   CONTENT_SETTINGS_TYPE_GEOLOCATION, "",
                                    false));
 
   bool owned = mock_provider.SetWebsiteSetting(
diff --git a/chrome/browser/content_settings/content_settings_utils.cc b/chrome/browser/content_settings/content_settings_utils.cc
index 9754ba1..d3a2869 100644
--- a/chrome/browser/content_settings/content_settings_utils.cc
+++ b/chrome/browser/content_settings/content_settings_utils.cc
@@ -190,10 +190,10 @@ ContentSetting GetContentSetting(const ProviderInterface* provider,
 
 void GetRendererContentSettingRules(const HostContentSettingsMap* map,
                                     RendererContentSettingRules* rules) {
-  map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_IMAGES, std::string(), &(rules->image_rules));
-  map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string(), &(rules->script_rules));
+  map->GetSettingsForOneType(CONTENT_SETTINGS_TYPE_IMAGES, "",
+                             &(rules->image_rules));
+  map->GetSettingsForOneType(CONTENT_SETTINGS_TYPE_JAVASCRIPT, "",
+                             &(rules->script_rules));
 }
 
 }  // namespace content_settings
diff --git a/chrome/browser/content_settings/content_settings_utils_unittest.cc b/chrome/browser/content_settings/content_settings_utils_unittest.cc
index d5eeeca..69f88c1 100644
--- a/chrome/browser/content_settings/content_settings_utils_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_utils_unittest.cc
@@ -11,7 +11,7 @@
 TEST(ContentSettingsUtilsTest, ParsePatternString) {
   content_settings::PatternPair pattern_pair;
 
-  pattern_pair = content_settings::ParsePatternString(std::string());
+  pattern_pair = content_settings::ParsePatternString("");
   EXPECT_FALSE(pattern_pair.first.IsValid());
   EXPECT_FALSE(pattern_pair.second.IsValid());
 
diff --git a/chrome/browser/content_settings/cookie_settings.cc b/chrome/browser/content_settings/cookie_settings.cc
index e0b1ff6..e34a56e 100644
--- a/chrome/browser/content_settings/cookie_settings.cc
+++ b/chrome/browser/content_settings/cookie_settings.cc
@@ -130,7 +130,7 @@ bool CookieSettings::IsCookieSessionOnly(const GURL& origin) const {
 void CookieSettings::GetCookieSettings(
     ContentSettingsForOneType* settings) const {
   return host_content_settings_map_->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_COOKIES, std::string(), settings);
+      CONTENT_SETTINGS_TYPE_COOKIES, "", settings);
 }
 
 void CookieSettings::SetDefaultCookieSetting(ContentSetting setting) {
@@ -147,21 +147,17 @@ void CookieSettings::SetCookieSetting(
   if (setting == CONTENT_SETTING_SESSION_ONLY) {
     DCHECK(secondary_pattern == ContentSettingsPattern::Wildcard());
   }
-  host_content_settings_map_->SetContentSetting(primary_pattern,
-                                                secondary_pattern,
-                                                CONTENT_SETTINGS_TYPE_COOKIES,
-                                                std::string(),
-                                                setting);
+  host_content_settings_map_->SetContentSetting(
+      primary_pattern, secondary_pattern, CONTENT_SETTINGS_TYPE_COOKIES, "",
+      setting);
 }
 
 void CookieSettings::ResetCookieSetting(
     const ContentSettingsPattern& primary_pattern,
     const ContentSettingsPattern& secondary_pattern) {
-  host_content_settings_map_->SetContentSetting(primary_pattern,
-                                                secondary_pattern,
-                                                CONTENT_SETTINGS_TYPE_COOKIES,
-                                                std::string(),
-                                                CONTENT_SETTING_DEFAULT);
+  host_content_settings_map_->SetContentSetting(
+      primary_pattern, secondary_pattern, CONTENT_SETTINGS_TYPE_COOKIES, "",
+      CONTENT_SETTING_DEFAULT);
 }
 
 void CookieSettings::ShutdownOnUIThread() {
@@ -180,12 +176,9 @@ ContentSetting CookieSettings::GetCookieSetting(
 
   // First get any host-specific settings.
   content_settings::SettingInfo info;
-  scoped_ptr<base::Value> value(host_content_settings_map_->GetWebsiteSetting(
-      url,
-      first_party_url,
-      CONTENT_SETTINGS_TYPE_COOKIES,
-      std::string(),
-      &info));
+  scoped_ptr<base::Value> value(
+      host_content_settings_map_->GetWebsiteSetting(
+          url, first_party_url, CONTENT_SETTINGS_TYPE_COOKIES, "", &info));
   if (source)
     *source = info.source;
 
diff --git a/chrome/browser/content_settings/host_content_settings_map.cc b/chrome/browser/content_settings/host_content_settings_map.cc
index 777203d..8749d6f 100644
--- a/chrome/browser/content_settings/host_content_settings_map.cc
+++ b/chrome/browser/content_settings/host_content_settings_map.cc
@@ -133,7 +133,7 @@ void HostContentSettingsMap::RegisterExtensionService(
   OnContentSettingChanged(ContentSettingsPattern(),
                           ContentSettingsPattern(),
                           CONTENT_SETTINGS_TYPE_DEFAULT,
-                          std::string());
+                          "");
 }
 #endif
 
@@ -159,7 +159,7 @@ ContentSetting HostContentSettingsMap::GetDefaultContentSettingFromProvider(
     ContentSettingsType content_type,
     content_settings::ProviderInterface* provider) const {
   scoped_ptr<content_settings::RuleIterator> rule_iterator(
-      provider->GetRuleIterator(content_type, std::string(), false));
+      provider->GetRuleIterator(content_type, "", false));
 
   ContentSettingsPattern wildcard = ContentSettingsPattern::Wildcard();
   while (rule_iterator->HasNext()) {
@@ -460,18 +460,19 @@ void HostContentSettingsMap::MigrateObsoleteClearOnExitPref() {
   AddSettingsForOneType(content_settings_providers_[PREF_PROVIDER],
                         PREF_PROVIDER,
                         CONTENT_SETTINGS_TYPE_COOKIES,
-                        std::string(),
+                        "",
                         &exceptions,
                         false);
   for (ContentSettingsForOneType::iterator it = exceptions.begin();
        it != exceptions.end(); ++it) {
     if (it->setting != CONTENT_SETTING_ALLOW)
       continue;
-    SetWebsiteSetting(it->primary_pattern,
-                      it->secondary_pattern,
-                      CONTENT_SETTINGS_TYPE_COOKIES,
-                      std::string(),
-                      Value::CreateIntegerValue(CONTENT_SETTING_SESSION_ONLY));
+    SetWebsiteSetting(
+        it->primary_pattern,
+        it->secondary_pattern,
+        CONTENT_SETTINGS_TYPE_COOKIES,
+        "",
+        Value::CreateIntegerValue(CONTENT_SETTING_SESSION_ONLY));
   }
 
   prefs_->SetBoolean(prefs::kContentSettingsClearOnExitMigrated, true);
diff --git a/chrome/browser/content_settings/host_content_settings_map_unittest.cc b/chrome/browser/content_settings/host_content_settings_map_unittest.cc
index bba4336..57fd929 100644
--- a/chrome/browser/content_settings/host_content_settings_map_unittest.cc
+++ b/chrome/browser/content_settings/host_content_settings_map_unittest.cc
@@ -81,16 +81,16 @@ TEST_F(HostContentSettingsMapTest, IndividualSettings) {
        ContentSettingsPattern::FromString("[*.]example.com");
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       CONTENT_SETTING_DEFAULT);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
@@ -99,10 +99,10 @@ TEST_F(HostContentSettingsMapTest, IndividualSettings) {
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, ""));
 
   // Check returning all settings for a host.
   host_content_settings_map->SetContentSetting(
@@ -113,7 +113,7 @@ TEST_F(HostContentSettingsMapTest, IndividualSettings) {
       CONTENT_SETTING_DEFAULT);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
@@ -122,7 +122,7 @@ TEST_F(HostContentSettingsMapTest, IndividualSettings) {
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
@@ -131,23 +131,22 @@ TEST_F(HostContentSettingsMapTest, IndividualSettings) {
       CONTENT_SETTING_ALLOW);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_POPUPS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_POPUPS, ""));
+  EXPECT_EQ(CONTENT_SETTING_ASK,
+            host_content_settings_map->GetContentSetting(
+                host, host, CONTENT_SETTINGS_TYPE_GEOLOCATION, ""));
   EXPECT_EQ(CONTENT_SETTING_ASK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_GEOLOCATION, std::string()));
-  EXPECT_EQ(
-      CONTENT_SETTING_ASK,
-      host_content_settings_map->GetContentSetting(
-          host, host, CONTENT_SETTINGS_TYPE_NOTIFICATIONS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_NOTIFICATIONS, ""));
   EXPECT_EQ(CONTENT_SETTING_ASK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_FULLSCREEN, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_FULLSCREEN, ""));
   EXPECT_EQ(CONTENT_SETTING_ASK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_MOUSELOCK, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_MOUSELOCK, ""));
 
   // Check returning all hosts for a setting.
   ContentSettingsPattern pattern2 =
@@ -165,16 +164,18 @@ TEST_F(HostContentSettingsMapTest, IndividualSettings) {
       std::string(),
       CONTENT_SETTING_BLOCK);
   ContentSettingsForOneType host_settings;
-  host_content_settings_map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_IMAGES, std::string(), &host_settings);
+  host_content_settings_map->GetSettingsForOneType(CONTENT_SETTINGS_TYPE_IMAGES,
+                                                   "",
+                                                   &host_settings);
   // |host_settings| contains the default setting and an exception.
   EXPECT_EQ(2U, host_settings.size());
   host_content_settings_map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_PLUGINS, std::string(), &host_settings);
+      CONTENT_SETTINGS_TYPE_PLUGINS, "", &host_settings);
   // |host_settings| contains the default setting and 2 exceptions.
   EXPECT_EQ(3U, host_settings.size());
-  host_content_settings_map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_POPUPS, std::string(), &host_settings);
+  host_content_settings_map->GetSettingsForOneType(CONTENT_SETTINGS_TYPE_POPUPS,
+                                                   "",
+                                                   &host_settings);
   // |host_settings| contains only the default setting.
   EXPECT_EQ(1U, host_settings.size());
 }
@@ -216,12 +217,13 @@ TEST_F(HostContentSettingsMapTest, Clear) {
   host_content_settings_map->ClearSettingsForOneType(
       CONTENT_SETTINGS_TYPE_IMAGES);
   ContentSettingsForOneType host_settings;
-  host_content_settings_map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_IMAGES, std::string(), &host_settings);
+  host_content_settings_map->GetSettingsForOneType(CONTENT_SETTINGS_TYPE_IMAGES,
+                                                   "",
+                                                   &host_settings);
   // |host_settings| contains only the default setting.
   EXPECT_EQ(1U, host_settings.size());
   host_content_settings_map->GetSettingsForOneType(
-      CONTENT_SETTINGS_TYPE_PLUGINS, std::string(), &host_settings);
+      CONTENT_SETTINGS_TYPE_PLUGINS, "", &host_settings);
   // |host_settings| contains the default setting and an exception.
   EXPECT_EQ(2U, host_settings.size());
 }
@@ -240,7 +242,7 @@ TEST_F(HostContentSettingsMapTest, Patterns) {
        ContentSettingsPattern::FromString("example.org");
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host1, host1, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host1, host1, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   host_content_settings_map->SetContentSetting(
       pattern1,
       ContentSettingsPattern::Wildcard(),
@@ -249,13 +251,13 @@ TEST_F(HostContentSettingsMapTest, Patterns) {
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host1, host1, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host1, host1, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host2, host2, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host2, host2, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host3, host3, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host3, host3, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   host_content_settings_map->SetContentSetting(
       pattern2,
       ContentSettingsPattern::Wildcard(),
@@ -264,7 +266,7 @@ TEST_F(HostContentSettingsMapTest, Patterns) {
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host3, host3, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host3, host3, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 }
 
 TEST_F(HostContentSettingsMapTest, Observer) {
@@ -325,7 +327,7 @@ TEST_F(HostContentSettingsMapTest, ObserveDefaultPref) {
       CONTENT_SETTINGS_TYPE_IMAGES, CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   // Make a copy of the pref's new value so we can reset it later.
   scoped_ptr<Value> new_value(prefs->FindPreference(
@@ -335,13 +337,13 @@ TEST_F(HostContentSettingsMapTest, ObserveDefaultPref) {
   prefs->Set(prefs::kDefaultContentSettings, *default_value);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   // Reseting the pref to its previous value should update the cache.
   prefs->Set(prefs::kDefaultContentSettings, *new_value);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 }
 
 TEST_F(HostContentSettingsMapTest, ObserveExceptionPref) {
@@ -361,7 +363,7 @@ TEST_F(HostContentSettingsMapTest, ObserveExceptionPref) {
 
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   host_content_settings_map->SetContentSetting(
       pattern,
@@ -371,7 +373,7 @@ TEST_F(HostContentSettingsMapTest, ObserveExceptionPref) {
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   // Make a copy of the pref's new value so we can reset it later.
   scoped_ptr<Value> new_value(prefs->FindPreference(
@@ -381,13 +383,13 @@ TEST_F(HostContentSettingsMapTest, ObserveExceptionPref) {
   prefs->Set(prefs::kContentSettingsPatternPairs, *default_value);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   // Reseting the pref to its previous value should update the cache.
   prefs->Set(prefs::kContentSettingsPatternPairs, *new_value);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 }
 
 TEST_F(HostContentSettingsMapTest, HostTrimEndingDotCheck) {
@@ -411,26 +413,26 @@ TEST_F(HostContentSettingsMapTest, HostTrimEndingDotCheck) {
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       CONTENT_SETTING_DEFAULT);
-  EXPECT_EQ(
-      CONTENT_SETTING_ALLOW,
-      host_content_settings_map->GetContentSetting(host_ending_with_dot,
-                                                   host_ending_with_dot,
-                                                   CONTENT_SETTINGS_TYPE_IMAGES,
-                                                   std::string()));
+  EXPECT_EQ(CONTENT_SETTING_ALLOW,
+            host_content_settings_map->GetContentSetting(
+                host_ending_with_dot,
+                host_ending_with_dot,
+                CONTENT_SETTINGS_TYPE_IMAGES,
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
-  EXPECT_EQ(
-      CONTENT_SETTING_BLOCK,
-      host_content_settings_map->GetContentSetting(host_ending_with_dot,
-                                                   host_ending_with_dot,
-                                                   CONTENT_SETTINGS_TYPE_IMAGES,
-                                                   std::string()));
+  EXPECT_EQ(CONTENT_SETTING_BLOCK,
+            host_content_settings_map->GetContentSetting(
+                host_ending_with_dot,
+                host_ending_with_dot,
+                CONTENT_SETTINGS_TYPE_IMAGES,
+                ""));
 
   EXPECT_TRUE(cookie_settings->IsSettingCookieAllowed(
       host_ending_with_dot, host_ending_with_dot));
@@ -438,7 +440,7 @@ TEST_F(HostContentSettingsMapTest, HostTrimEndingDotCheck) {
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_COOKIES,
-      std::string(),
+      "",
       CONTENT_SETTING_DEFAULT);
   EXPECT_TRUE(cookie_settings->IsSettingCookieAllowed(
       host_ending_with_dot, host_ending_with_dot));
@@ -446,7 +448,7 @@ TEST_F(HostContentSettingsMapTest, HostTrimEndingDotCheck) {
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_COOKIES,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
   EXPECT_FALSE(cookie_settings->IsSettingCookieAllowed(
       host_ending_with_dot, host_ending_with_dot));
@@ -456,93 +458,93 @@ TEST_F(HostContentSettingsMapTest, HostTrimEndingDotCheck) {
                 host_ending_with_dot,
                 host_ending_with_dot,
                 CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-                std::string()));
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-      std::string(),
+      "",
       CONTENT_SETTING_DEFAULT);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
                 host_ending_with_dot,
                 host_ending_with_dot,
                 CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-                std::string()));
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
                 host_ending_with_dot,
                 host_ending_with_dot,
                 CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-                std::string()));
+                ""));
 
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
                 host_ending_with_dot,
                 host_ending_with_dot,
                 CONTENT_SETTINGS_TYPE_PLUGINS,
-                std::string()));
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_PLUGINS,
-      std::string(),
+      "",
       CONTENT_SETTING_DEFAULT);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
                 host_ending_with_dot,
                 host_ending_with_dot,
                 CONTENT_SETTINGS_TYPE_PLUGINS,
-                std::string()));
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_PLUGINS,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
                 host_ending_with_dot,
                 host_ending_with_dot,
                 CONTENT_SETTINGS_TYPE_PLUGINS,
-                std::string()));
+                ""));
 
-  EXPECT_EQ(
-      CONTENT_SETTING_BLOCK,
-      host_content_settings_map->GetContentSetting(host_ending_with_dot,
-                                                   host_ending_with_dot,
-                                                   CONTENT_SETTINGS_TYPE_POPUPS,
-                                                   std::string()));
+  EXPECT_EQ(CONTENT_SETTING_BLOCK,
+            host_content_settings_map->GetContentSetting(
+                host_ending_with_dot,
+                host_ending_with_dot,
+                CONTENT_SETTINGS_TYPE_POPUPS,
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_POPUPS,
-      std::string(),
+      "",
       CONTENT_SETTING_DEFAULT);
-  EXPECT_EQ(
-      CONTENT_SETTING_BLOCK,
-      host_content_settings_map->GetContentSetting(host_ending_with_dot,
-                                                   host_ending_with_dot,
-                                                   CONTENT_SETTINGS_TYPE_POPUPS,
-                                                   std::string()));
+  EXPECT_EQ(CONTENT_SETTING_BLOCK,
+            host_content_settings_map->GetContentSetting(
+                host_ending_with_dot,
+                host_ending_with_dot,
+                CONTENT_SETTINGS_TYPE_POPUPS,
+                ""));
   host_content_settings_map->SetContentSetting(
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_POPUPS,
-      std::string(),
+      "",
       CONTENT_SETTING_ALLOW);
-  EXPECT_EQ(
-      CONTENT_SETTING_ALLOW,
-      host_content_settings_map->GetContentSetting(host_ending_with_dot,
-                                                   host_ending_with_dot,
-                                                   CONTENT_SETTINGS_TYPE_POPUPS,
-                                                   std::string()));
+  EXPECT_EQ(CONTENT_SETTING_ALLOW,
+            host_content_settings_map->GetContentSetting(
+                host_ending_with_dot,
+                host_ending_with_dot,
+                CONTENT_SETTINGS_TYPE_POPUPS,
+                ""));
 }
 
 TEST_F(HostContentSettingsMapTest, NestedSettings) {
@@ -562,53 +564,52 @@ TEST_F(HostContentSettingsMapTest, NestedSettings) {
       pattern1,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
 
   host_content_settings_map->SetContentSetting(
       pattern2,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_COOKIES,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
 
   host_content_settings_map->SetContentSetting(
       pattern3,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_PLUGINS,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
   host_content_settings_map->SetDefaultContentSetting(
       CONTENT_SETTINGS_TYPE_JAVASCRIPT, CONTENT_SETTING_BLOCK);
 
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_COOKIES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_COOKIES, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_POPUPS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_POPUPS, ""));
   EXPECT_EQ(CONTENT_SETTING_ASK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_GEOLOCATION, std::string()));
-  EXPECT_EQ(
-      CONTENT_SETTING_ASK,
-      host_content_settings_map->GetContentSetting(
-          host, host, CONTENT_SETTINGS_TYPE_NOTIFICATIONS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_GEOLOCATION, ""));
   EXPECT_EQ(CONTENT_SETTING_ASK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_FULLSCREEN, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_NOTIFICATIONS, ""));
   EXPECT_EQ(CONTENT_SETTING_ASK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_MOUSELOCK, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_FULLSCREEN, ""));
+  EXPECT_EQ(CONTENT_SETTING_ASK,
+            host_content_settings_map->GetContentSetting(
+                host, host, CONTENT_SETTINGS_TYPE_MOUSELOCK, ""));
 }
 
 TEST_F(HostContentSettingsMapTest, OffTheRecord) {
@@ -625,10 +626,10 @@ TEST_F(HostContentSettingsMapTest, OffTheRecord) {
 
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             otr_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   // Changing content settings on the main map should also affect the
   // incognito map.
@@ -636,28 +637,27 @@ TEST_F(HostContentSettingsMapTest, OffTheRecord) {
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_IMAGES,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             otr_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   // Changing content settings on the incognito map should NOT affect the
   // main map.
-  otr_map->SetContentSetting(pattern,
-                             ContentSettingsPattern::Wildcard(),
-                             CONTENT_SETTINGS_TYPE_IMAGES,
-                             std::string(),
-                             CONTENT_SETTING_ALLOW);
+  otr_map->SetContentSetting(
+      pattern,
+      ContentSettingsPattern::Wildcard(),
+      CONTENT_SETTINGS_TYPE_IMAGES, "", CONTENT_SETTING_ALLOW);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             otr_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 
   otr_map->ShutdownOnUIThread();
 }
@@ -738,7 +738,7 @@ TEST_F(HostContentSettingsMapTest, ResourceIdentifier) {
           CONTENT_SETTINGS_TYPE_PLUGINS, NULL);
   EXPECT_EQ(default_plugin_setting,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_PLUGINS, ""));
 
   // If no resource-specific content settings are defined, the setting should be
   // DEFAULT.
@@ -865,7 +865,7 @@ TEST_F(HostContentSettingsMapTest,
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-      std::string(),
+      "",
       CONTENT_SETTING_BLOCK);
 
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
@@ -875,14 +875,14 @@ TEST_F(HostContentSettingsMapTest,
   GURL host("http://example.com/");
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
 
   // Set managed-default-content-setting for content-settings-type JavaScript.
   prefs->SetManagedPref(prefs::kManagedDefaultJavaScriptSetting,
                         Value::CreateIntegerValue(CONTENT_SETTING_ALLOW));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
 }
 
 // Managed default content setting should have higher priority
@@ -906,7 +906,7 @@ TEST_F(HostContentSettingsMapTest,
       pattern,
       ContentSettingsPattern::Wildcard(),
       CONTENT_SETTINGS_TYPE_JAVASCRIPT,
-      std::string(),
+      "",
       CONTENT_SETTING_ALLOW);
 
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
@@ -915,20 +915,20 @@ TEST_F(HostContentSettingsMapTest,
   GURL host("http://example.com/");
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
 
   // Set managed-default-content-settings-preferences.
   prefs->SetManagedPref(prefs::kManagedDefaultJavaScriptSetting,
                         Value::CreateIntegerValue(CONTENT_SETTING_BLOCK));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
 
   // Remove managed-default-content-settings-preferences.
   prefs->RemoveManagedPref(prefs::kManagedDefaultJavaScriptSetting);
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
 }
 
 // If a default-content-setting is set to managed setting, the user defined
@@ -1004,10 +1004,10 @@ TEST_F(HostContentSettingsMapTest, GetContentSetting) {
       CONTENT_SETTING_BLOCK);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             host_content_settings_map->GetContentSetting(
-                host, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                host, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             host_content_settings_map->GetContentSetting(
-                embedder, host, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                embedder, host, CONTENT_SETTINGS_TYPE_IMAGES, ""));
 }
 
 TEST_F(HostContentSettingsMapTest, ShouldAllowAllContent) {
diff --git a/chrome/browser/content_settings/mock_settings_observer.cc b/chrome/browser/content_settings/mock_settings_observer.cc
index c8de7fa..a281a1d 100644
--- a/chrome/browser/content_settings/mock_settings_observer.cc
+++ b/chrome/browser/content_settings/mock_settings_observer.cc
@@ -35,5 +35,5 @@ void MockSettingsObserver::Observe(
   // This checks that calling a Get function from an observer doesn't
   // deadlock.
   GURL url("http://random-hostname.com/");
-  map->GetContentSetting(url, url, CONTENT_SETTINGS_TYPE_IMAGES, std::string());
+  map->GetContentSetting(url, url, CONTENT_SETTINGS_TYPE_IMAGES, "");
 }
diff --git a/chrome/browser/devtools/browser_list_tabcontents_provider.cc b/chrome/browser/devtools/browser_list_tabcontents_provider.cc
index 2edc6bf..aca4bac 100644
--- a/chrome/browser/devtools/browser_list_tabcontents_provider.cc
+++ b/chrome/browser/devtools/browser_list_tabcontents_provider.cc
@@ -116,19 +116,19 @@ std::string BrowserListTabContentsProvider::GetViewDescription(
   content::WebContents* web_contents =
       content::WebContents::FromRenderViewHost(rvh);
   if (!web_contents)
-    return std::string();
+    return "";
 
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
   if (!profile)
-    return std::string();
+    return "";
 
   extensions::ExtensionHost* extension_host =
       extensions::ExtensionSystem::Get(profile)->process_manager()->
           GetBackgroundHostForExtension(web_contents->GetURL().host());
 
   if (!extension_host || extension_host->host_contents() != web_contents)
-    return std::string();
+    return "";
 
   return extension_host->extension()->name();
 }
diff --git a/chrome/browser/devtools/devtools_file_helper.cc b/chrome/browser/devtools/devtools_file_helper.cc
index d1f2888..d485a52 100644
--- a/chrome/browser/devtools/devtools_file_helper.cc
+++ b/chrome/browser/devtools/devtools_file_helper.cc
@@ -77,7 +77,7 @@ class SelectFileDialog : public ui::SelectFileDialog::Listener,
                                     default_path,
                                     NULL,
                                     0,
-                                    base::FilePath::StringType(),
+                                    FILE_PATH_LITERAL(""),
                                     NULL,
                                     NULL);
   }
@@ -346,7 +346,7 @@ void DevToolsFileHelper::AddValidatedFileSystem(
                                                  file_system_id,
                                                  registered_name,
                                                  file_system_path);
-  callback.Run(std::string(), filesystem);
+  callback.Run("", filesystem);
 }
 
 void DevToolsFileHelper::RequestFileSystems(
diff --git a/chrome/browser/devtools/devtools_sanity_browsertest.cc b/chrome/browser/devtools/devtools_sanity_browsertest.cc
index 4f832f7..6a8b30c 100644
--- a/chrome/browser/devtools/devtools_sanity_browsertest.cc
+++ b/chrome/browser/devtools/devtools_sanity_browsertest.cc
@@ -441,7 +441,7 @@ IN_PROC_BROWSER_TEST_F(
 IN_PROC_BROWSER_TEST_F(DevToolsExtensionTest,
                        TestDevToolsExtensionAPI) {
   LoadExtension("devtools_extension");
-  RunTest("waitForTestResultsInConsole", std::string());
+  RunTest("waitForTestResultsInConsole", "");
 }
 
 // Tests that chrome.devtools extension can communicate with background page
@@ -449,7 +449,7 @@ IN_PROC_BROWSER_TEST_F(DevToolsExtensionTest,
 IN_PROC_BROWSER_TEST_F(DevToolsExtensionTest,
                        TestDevToolsExtensionMessaging) {
   LoadExtension("devtools_messaging");
-  RunTest("waitForTestResultsInConsole", std::string());
+  RunTest("waitForTestResultsInConsole", "");
 }
 
 // Tests that chrome.experimental.devtools extension is correctly exposed
@@ -457,7 +457,7 @@ IN_PROC_BROWSER_TEST_F(DevToolsExtensionTest,
 IN_PROC_BROWSER_TEST_F(DevToolsExperimentalExtensionTest,
                        TestDevToolsExperimentalExtensionAPI) {
   LoadExtension("devtools_experimental");
-  RunTest("waitForTestResultsInConsole", std::string());
+  RunTest("waitForTestResultsInConsole", "");
 }
 
 // Tests that a content script is in the scripts list.
@@ -478,7 +478,7 @@ IN_PROC_BROWSER_TEST_F(DevToolsExtensionTest,
 
 IN_PROC_BROWSER_TEST_F(DevToolsSanityTest,
                        MAYBE_TestRendererProcessNativeMemorySize) {
-  RunTest("testRendererProcessNativeMemorySize", std::string());
+  RunTest("testRendererProcessNativeMemorySize", "");
 }
 
 // Tests that scripts are not duplicated after Scripts Panel switch.
diff --git a/chrome/browser/download/download_browsertest.cc b/chrome/browser/download/download_browsertest.cc
index 5ec91a2..7c63cb7 100644
--- a/chrome/browser/download/download_browsertest.cc
+++ b/chrome/browser/download/download_browsertest.cc
@@ -1655,12 +1655,7 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, NewWindow) {
 
 IN_PROC_BROWSER_TEST_F(DownloadTest, DownloadHistoryCheck) {
   GURL download_url(URLRequestSlowDownloadJob::kKnownSizeUrl);
-  base::FilePath file(net::GenerateFileName(download_url,
-                                            std::string(),
-                                            std::string(),
-                                            std::string(),
-                                            std::string(),
-                                            std::string()));
+  base::FilePath file(net::GenerateFileName(download_url, "", "", "", "", ""));
 
   // We use the server so that we can get a redirect and test url_chain
   // persistence.
@@ -2632,7 +2627,7 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, LoadURLExternallyReferrerPolicy) {
 
   // Check that the file contains the expected referrer.
   base::FilePath file(download_items[0]->GetFullPath());
-  std::string expected_contents = test_server()->GetURL(std::string()).spec();
+  std::string expected_contents = test_server()->GetURL("").spec();
   ASSERT_TRUE(VerifyFile(file, expected_contents, expected_contents.length()));
 }
 
diff --git a/chrome/browser/download/download_file_picker.cc b/chrome/browser/download/download_file_picker.cc
index a968b06..29a1573 100644
--- a/chrome/browser/download/download_file_picker.cc
+++ b/chrome/browser/download/download_file_picker.cc
@@ -86,14 +86,15 @@ void DownloadFilePicker::Init(
       platform_util::GetTopLevel(web_contents->GetView()->GetNativeView()) :
       NULL;
 
-  select_file_dialog_->SelectFile(ui::SelectFileDialog::SELECT_SAVEAS_FILE,
-                                  string16(),
-                                  suggested_path_,
-                                  &file_type_info,
-                                  0,
-                                  base::FilePath::StringType(),
-                                  owning_window,
-                                  NULL);
+  select_file_dialog_->SelectFile(
+      ui::SelectFileDialog::SELECT_SAVEAS_FILE,
+      string16(),
+      suggested_path_,
+      &file_type_info,
+      0,
+      FILE_PATH_LITERAL(""),
+      owning_window,
+      NULL);
 }
 
 DownloadFilePicker::~DownloadFilePicker() {
diff --git a/chrome/browser/download/download_prefs.cc b/chrome/browser/download/download_prefs.cc
index 4aba528..2bfb792 100644
--- a/chrome/browser/download/download_prefs.cc
+++ b/chrome/browser/download/download_prefs.cc
@@ -86,7 +86,7 @@ void DownloadPrefs::RegisterUserPrefs(PrefRegistrySyncable* registry) {
                                 false,
                                 PrefRegistrySyncable::SYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kDownloadExtensionsToOpen,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterBooleanPref(prefs::kDownloadDirUpgraded,
                                 false,
diff --git a/chrome/browser/extensions/activity_log.cc b/chrome/browser/extensions/activity_log.cc
index dcf8e8f..34f820b 100644
--- a/chrome/browser/extensions/activity_log.cc
+++ b/chrome/browser/extensions/activity_log.cc
@@ -27,7 +27,7 @@ namespace {
 
 // Concatenate arguments.
 std::string MakeArgList(const ListValue* args) {
-  std::string call_signature;
+  std::string call_signature = "";
   ListValue::const_iterator it = args->begin();
   for (; it != args->end(); ++it) {
     std::string arg;
@@ -395,10 +395,9 @@ void ActivityLog::OnScriptsExecuted(
     // of content scripts will be empty.  We don't want to log it because
     // the call to tabs.executeScript will have already been logged anyway.
     if (!it->second.empty()) {
-      std::string ext_scripts_str;
+      std::string ext_scripts_str = "";
       for (std::set<std::string>::const_iterator it2 = it->second.begin();
-           it2 != it->second.end();
-           ++it2) {
+           it2 != it->second.end(); ++it2) {
         ext_scripts_str += *it2;
         ext_scripts_str += " ";
       }
@@ -407,9 +406,9 @@ void ActivityLog::OnScriptsExecuted(
       LogDOMActionInternal(extension,
                            on_url,
                            web_contents->GetTitle(),
-                           std::string(),  // no api call here
+                           "",   // no api call here
                            script_names.get(),
-                           std::string(),  // no extras either
+                           "",   // no extras either
                            DOMAction::INSERTED);
     }
   }
diff --git a/chrome/browser/extensions/activity_log_unittest.cc b/chrome/browser/extensions/activity_log_unittest.cc
index a5ecc95..f678d7b 100644
--- a/chrome/browser/extensions/activity_log_unittest.cc
+++ b/chrome/browser/extensions/activity_log_unittest.cc
@@ -93,8 +93,10 @@ TEST_F(ActivityLogTest, Construct) {
   extension_service_->AddExtension(extension);
   scoped_ptr<ListValue> args(new ListValue());
   ASSERT_TRUE(ActivityLog::IsLogEnabled());
-  activity_log->LogAPIAction(
-      extension, std::string("tabs.testMethod"), args.get(), std::string());
+  activity_log->LogAPIAction(extension,
+                             std::string("tabs.testMethod"),
+                             args.get(),
+                             "");
 }
 
 TEST_F(ActivityLogTest, LogAndFetchActions) {
@@ -111,8 +113,10 @@ TEST_F(ActivityLogTest, LogAndFetchActions) {
   ASSERT_TRUE(ActivityLog::IsLogEnabled());
 
   // Write some API calls
-  activity_log->LogAPIAction(
-      extension, std::string("tabs.testMethod"), args.get(), std::string());
+  activity_log->LogAPIAction(extension,
+                             std::string("tabs.testMethod"),
+                             args.get(),
+                             "");
   activity_log->LogDOMAction(extension,
                              GURL("http://www.google.com"),
                              string16(),
@@ -140,10 +144,14 @@ TEST_F(ActivityLogTest, LogWithoutArguments) {
   scoped_ptr<ListValue> args(new ListValue());
   args->Set(0, new base::StringValue("hello"));
   args->Set(1, new base::StringValue("world"));
-  activity_log->LogAPIAction(
-      extension, std::string("tabs.testMethod"), args.get(), std::string());
+  activity_log->LogAPIAction(extension,
+                             std::string("tabs.testMethod"),
+                             args.get(),
+                             "");
   activity_log->GetActions(
-      extension->id(), 0, base::Bind(ActivityLogTest::Arguments_Missing));
+      extension->id(),
+      0,
+      base::Bind(ActivityLogTest::Arguments_Missing));
 }
 
 TEST_F(ActivityLogTest, LogWithArguments) {
@@ -161,10 +169,14 @@ TEST_F(ActivityLogTest, LogWithArguments) {
   scoped_ptr<ListValue> args(new ListValue());
   args->Set(0, new base::StringValue("hello"));
   args->Set(1, new base::StringValue("world"));
-  activity_log->LogAPIAction(
-      extension, std::string("extension.connect"), args.get(), std::string());
+  activity_log->LogAPIAction(extension,
+                            std::string("extension.connect"),
+                            args.get(),
+                            "");
   activity_log->GetActions(
-      extension->id(), 0, base::Bind(ActivityLogTest::Arguments_Present));
+      extension->id(),
+      0,
+      base::Bind(ActivityLogTest::Arguments_Present));
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc b/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc
index 34b4187..60c367a 100644
--- a/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc
+++ b/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc
@@ -151,7 +151,7 @@ TEST_F(ExtensionAlarmsTest, Create) {
   CreateAlarm("[null, {\"delayInMinutes\": 0}]");
 
   const Alarm* alarm =
-      alarm_manager_->GetAlarm(extension_->id(), std::string());
+      alarm_manager_->GetAlarm(extension_->id(), "");
   ASSERT_TRUE(alarm);
   EXPECT_EQ("", alarm->js_alarm->name);
   EXPECT_DOUBLE_EQ(10000, alarm->js_alarm->scheduled_time);
@@ -179,7 +179,7 @@ TEST_F(ExtensionAlarmsTest, CreateRepeating) {
   CreateAlarm("[null, {\"periodInMinutes\": 0.001}]");
 
   const Alarm* alarm =
-      alarm_manager_->GetAlarm(extension_->id(), std::string());
+      alarm_manager_->GetAlarm(extension_->id(), "");
   ASSERT_TRUE(alarm);
   EXPECT_EQ("", alarm->js_alarm->name);
   EXPECT_DOUBLE_EQ(10060, alarm->js_alarm->scheduled_time);
@@ -205,7 +205,7 @@ TEST_F(ExtensionAlarmsTest, CreateAbsolute) {
   CreateAlarm("[null, {\"when\": 10001}]");
 
   const Alarm* alarm =
-      alarm_manager_->GetAlarm(extension_->id(), std::string());
+      alarm_manager_->GetAlarm(extension_->id(), "");
   ASSERT_TRUE(alarm);
   EXPECT_EQ("", alarm->js_alarm->name);
   EXPECT_DOUBLE_EQ(10001, alarm->js_alarm->scheduled_time);
@@ -217,7 +217,7 @@ TEST_F(ExtensionAlarmsTest, CreateAbsolute) {
   // MessageLoop when that happens.
   MessageLoop::current()->Run();
 
-  ASSERT_FALSE(alarm_manager_->GetAlarm(extension_->id(), std::string()));
+  ASSERT_FALSE(alarm_manager_->GetAlarm(extension_->id(), ""));
 
   ASSERT_EQ(1u, alarm_delegate_->alarms_seen.size());
   EXPECT_EQ("", alarm_delegate_->alarms_seen[0]);
@@ -228,7 +228,7 @@ TEST_F(ExtensionAlarmsTest, CreateRepeatingWithQuickFirstCall) {
   CreateAlarm("[null, {\"when\": 10001, \"periodInMinutes\": 0.001}]");
 
   const Alarm* alarm =
-      alarm_manager_->GetAlarm(extension_->id(), std::string());
+      alarm_manager_->GetAlarm(extension_->id(), "");
   ASSERT_TRUE(alarm);
   EXPECT_EQ("", alarm->js_alarm->name);
   EXPECT_DOUBLE_EQ(10001, alarm->js_alarm->scheduled_time);
@@ -240,13 +240,13 @@ TEST_F(ExtensionAlarmsTest, CreateRepeatingWithQuickFirstCall) {
   // MessageLoop when that happens.
   MessageLoop::current()->Run();
 
-  ASSERT_TRUE(alarm_manager_->GetAlarm(extension_->id(), std::string()));
+  ASSERT_TRUE(alarm_manager_->GetAlarm(extension_->id(), ""));
   EXPECT_THAT(alarm_delegate_->alarms_seen, testing::ElementsAre(""));
 
   test_clock_.SetNow(base::Time::FromDoubleT(10.7));
   MessageLoop::current()->Run();
 
-  ASSERT_TRUE(alarm_manager_->GetAlarm(extension_->id(), std::string()));
+  ASSERT_TRUE(alarm_manager_->GetAlarm(extension_->id(), ""));
   EXPECT_THAT(alarm_delegate_->alarms_seen, testing::ElementsAre("", ""));
 }
 
diff --git a/chrome/browser/extensions/api/bookmarks/bookmarks_api.cc b/chrome/browser/extensions/api/bookmarks/bookmarks_api.cc
index 754eeee..0470b78 100644
--- a/chrome/browser/extensions/api/bookmarks/bookmarks_api.cc
+++ b/chrome/browser/extensions/api/bookmarks/bookmarks_api.cc
@@ -946,7 +946,7 @@ void BookmarksIOFunction::ShowSelectFileDialog(
                                   default_path,
                                   &file_type_info,
                                   0,
-                                  base::FilePath::StringType(),
+                                  FILE_PATH_LITERAL(""),
                                   NULL,
                                   NULL);
 }
diff --git a/chrome/browser/extensions/api/content_settings/content_settings_apitest.cc b/chrome/browser/extensions/api/content_settings/content_settings_apitest.cc
index dd20fba1..a424f83 100644
--- a/chrome/browser/extensions/api/content_settings/content_settings_apitest.cc
+++ b/chrome/browser/extensions/api/content_settings/content_settings_apitest.cc
@@ -74,16 +74,16 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentSettings) {
   EXPECT_FALSE(cookie_settings->IsReadingCookieAllowed(url, url));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             map->GetContentSetting(
-                url, url, CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
+                url, url, CONTENT_SETTINGS_TYPE_IMAGES, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             map->GetContentSetting(
-                url, url, CONTENT_SETTINGS_TYPE_JAVASCRIPT, std::string()));
+                url, url, CONTENT_SETTINGS_TYPE_JAVASCRIPT, ""));
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             map->GetContentSetting(
-                url, url, CONTENT_SETTINGS_TYPE_PLUGINS, std::string()));
+                url, url, CONTENT_SETTINGS_TYPE_PLUGINS, ""));
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
             map->GetContentSetting(
-                url, url, CONTENT_SETTINGS_TYPE_POPUPS, std::string()));
+                url, url, CONTENT_SETTINGS_TYPE_POPUPS, ""));
 #if 0
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             map->GetContentSetting(
@@ -91,7 +91,7 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentSettings) {
 #endif
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
             map->GetContentSetting(
-                url, url, CONTENT_SETTINGS_TYPE_NOTIFICATIONS, std::string()));
+                url, url, CONTENT_SETTINGS_TYPE_NOTIFICATIONS, ""));
 }
 
 // Flaky on the trybots. See http://crbug.com/96725.
diff --git a/chrome/browser/extensions/api/content_settings/content_settings_helpers.cc b/chrome/browser/extensions/api/content_settings/content_settings_helpers.cc
index 537d08f..8ee0fbf 100644
--- a/chrome/browser/extensions/api/content_settings/content_settings_helpers.cc
+++ b/chrome/browser/extensions/api/content_settings/content_settings_helpers.cc
@@ -48,7 +48,7 @@ std::string GetDefaultPort(const std::string& scheme) {
   if (scheme == chrome::kHttpsScheme)
     return "443";
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 }  // namespace
diff --git a/chrome/browser/extensions/api/content_settings/content_settings_store_unittest.cc b/chrome/browser/extensions/api/content_settings/content_settings_store_unittest.cc
index bedd2ea..5e13633 100644
--- a/chrome/browser/extensions/api/content_settings/content_settings_store_unittest.cc
+++ b/chrome/browser/extensions/api/content_settings/content_settings_store_unittest.cc
@@ -101,76 +101,73 @@ TEST_F(ContentSettingsStoreTest, RegisterUnregister) {
   GURL url("http://www.youtube.com");
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSettingFromStore(store(),
-                                       url,
-                                       url,
-                                       CONTENT_SETTINGS_TYPE_COOKIES,
-                                       std::string(),
-                                       false));
+            GetContentSettingFromStore(
+                store(), url, url, CONTENT_SETTINGS_TYPE_COOKIES, "", false));
 
   // Register first extension
   std::string ext_id("my_extension");
   RegisterExtension(ext_id);
 
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSettingFromStore(store(),
-                                       url,
-                                       url,
-                                       CONTENT_SETTINGS_TYPE_COOKIES,
-                                       std::string(),
-                                       false));
+            GetContentSettingFromStore(
+                store(), url, url, CONTENT_SETTINGS_TYPE_COOKIES, "", false));
 
   // Set setting
   ContentSettingsPattern pattern =
       ContentSettingsPattern::FromURL(GURL("http://www.youtube.com"));
   EXPECT_CALL(observer, OnContentSettingChanged(ext_id, false));
-  store()->SetExtensionContentSetting(ext_id,
-                                      pattern,
-                                      pattern,
-                                      CONTENT_SETTINGS_TYPE_COOKIES,
-                                      std::string(),
-                                      CONTENT_SETTING_ALLOW,
-                                      kExtensionPrefsScopeRegular);
+  store()->SetExtensionContentSetting(
+      ext_id,
+      pattern,
+      pattern,
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      CONTENT_SETTING_ALLOW,
+      kExtensionPrefsScopeRegular);
   Mock::VerifyAndClear(&observer);
 
   EXPECT_EQ(CONTENT_SETTING_ALLOW,
-            GetContentSettingFromStore(store(),
-                                       url,
-                                       url,
-                                       CONTENT_SETTINGS_TYPE_COOKIES,
-                                       std::string(),
-                                       false));
+            GetContentSettingFromStore(
+                store(),
+                url,
+                url,
+                CONTENT_SETTINGS_TYPE_COOKIES,
+                "",
+                false));
 
   // Register second extension.
   std::string ext_id_2("my_second_extension");
   RegisterExtension(ext_id_2);
   EXPECT_CALL(observer, OnContentSettingChanged(ext_id_2, false));
-  store()->SetExtensionContentSetting(ext_id_2,
-                                      pattern,
-                                      pattern,
-                                      CONTENT_SETTINGS_TYPE_COOKIES,
-                                      std::string(),
-                                      CONTENT_SETTING_BLOCK,
-                                      kExtensionPrefsScopeRegular);
+  store()->SetExtensionContentSetting(
+      ext_id_2,
+      pattern,
+      pattern,
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      CONTENT_SETTING_BLOCK,
+      kExtensionPrefsScopeRegular);
 
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSettingFromStore(store(),
-                                       url,
-                                       url,
-                                       CONTENT_SETTINGS_TYPE_COOKIES,
-                                       std::string(),
-                                       false));
+            GetContentSettingFromStore(
+                store(),
+                url,
+                url,
+                CONTENT_SETTINGS_TYPE_COOKIES,
+                "",
+                false));
 
   // Unregister first extension. This shouldn't change the setting.
   EXPECT_CALL(observer, OnContentSettingChanged(ext_id, false));
   store()->UnregisterExtension(ext_id);
   EXPECT_EQ(CONTENT_SETTING_BLOCK,
-            GetContentSettingFromStore(store(),
-                                       url,
-                                       url,
-                                       CONTENT_SETTINGS_TYPE_COOKIES,
-                                       std::string(),
-                                       false));
+            GetContentSettingFromStore(
+                store(),
+                url,
+                url,
+                CONTENT_SETTINGS_TYPE_COOKIES,
+                "",
+                false));
   Mock::VerifyAndClear(&observer);
 
   // Unregister second extension. This should reset the setting to its default
@@ -178,12 +175,13 @@ TEST_F(ContentSettingsStoreTest, RegisterUnregister) {
   EXPECT_CALL(observer, OnContentSettingChanged(ext_id_2, false));
   store()->UnregisterExtension(ext_id_2);
   EXPECT_EQ(CONTENT_SETTING_DEFAULT,
-            GetContentSettingFromStore(store(),
-                                       url,
-                                       url,
-                                       CONTENT_SETTINGS_TYPE_COOKIES,
-                                       std::string(),
-                                       false));
+            GetContentSettingFromStore(
+                store(),
+                url,
+                url,
+                CONTENT_SETTINGS_TYPE_COOKIES,
+                "",
+                false));
 
   store()->RemoveObserver(&observer);
 }
@@ -192,7 +190,7 @@ TEST_F(ContentSettingsStoreTest, GetAllSettings) {
   bool incognito = false;
   std::vector<content_settings::Rule> rules;
   GetSettingsForOneTypeFromStore(
-      store(), CONTENT_SETTINGS_TYPE_COOKIES, std::string(), incognito, &rules);
+      store(), CONTENT_SETTINGS_TYPE_COOKIES, "", incognito, &rules);
   ASSERT_EQ(0u, rules.size());
 
   // Register first extension.
@@ -200,16 +198,17 @@ TEST_F(ContentSettingsStoreTest, GetAllSettings) {
   RegisterExtension(ext_id);
   ContentSettingsPattern pattern =
       ContentSettingsPattern::FromURL(GURL("http://www.youtube.com"));
-  store()->SetExtensionContentSetting(ext_id,
-                                      pattern,
-                                      pattern,
-                                      CONTENT_SETTINGS_TYPE_COOKIES,
-                                      std::string(),
-                                      CONTENT_SETTING_ALLOW,
-                                      kExtensionPrefsScopeRegular);
+  store()->SetExtensionContentSetting(
+      ext_id,
+      pattern,
+      pattern,
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      CONTENT_SETTING_ALLOW,
+      kExtensionPrefsScopeRegular);
 
   GetSettingsForOneTypeFromStore(
-      store(), CONTENT_SETTINGS_TYPE_COOKIES, std::string(), incognito, &rules);
+      store(), CONTENT_SETTINGS_TYPE_COOKIES, "", incognito, &rules);
   ASSERT_EQ(1u, rules.size());
   CheckRule(rules[0], pattern, pattern, CONTENT_SETTING_ALLOW);
 
@@ -218,16 +217,20 @@ TEST_F(ContentSettingsStoreTest, GetAllSettings) {
   RegisterExtension(ext_id_2);
   ContentSettingsPattern pattern_2 =
       ContentSettingsPattern::FromURL(GURL("http://www.example.com"));
-  store()->SetExtensionContentSetting(ext_id_2,
-                                      pattern_2,
-                                      pattern_2,
-                                      CONTENT_SETTINGS_TYPE_COOKIES,
-                                      std::string(),
-                                      CONTENT_SETTING_BLOCK,
-                                      kExtensionPrefsScopeRegular);
-
-  GetSettingsForOneTypeFromStore(
-      store(), CONTENT_SETTINGS_TYPE_COOKIES, std::string(), incognito, &rules);
+  store()->SetExtensionContentSetting(
+      ext_id_2,
+      pattern_2,
+      pattern_2,
+      CONTENT_SETTINGS_TYPE_COOKIES,
+      "",
+      CONTENT_SETTING_BLOCK,
+      kExtensionPrefsScopeRegular);
+
+  GetSettingsForOneTypeFromStore(store(),
+                                 CONTENT_SETTINGS_TYPE_COOKIES,
+                                 "",
+                                 incognito,
+                                 &rules);
   ASSERT_EQ(2u, rules.size());
   // Rules appear in the reverse installation order of the extensions.
   CheckRule(rules[0], pattern_2, pattern_2, CONTENT_SETTING_BLOCK);
@@ -237,7 +240,7 @@ TEST_F(ContentSettingsStoreTest, GetAllSettings) {
   store()->SetExtensionState(ext_id, false);
 
   GetSettingsForOneTypeFromStore(
-      store(), CONTENT_SETTINGS_TYPE_COOKIES, std::string(), incognito, &rules);
+      store(), CONTENT_SETTINGS_TYPE_COOKIES, "", incognito, &rules);
   ASSERT_EQ(1u, rules.size());
   CheckRule(rules[0], pattern_2, pattern_2, CONTENT_SETTING_BLOCK);
 
@@ -245,7 +248,7 @@ TEST_F(ContentSettingsStoreTest, GetAllSettings) {
   store()->UnregisterExtension(ext_id_2);
 
   GetSettingsForOneTypeFromStore(
-      store(), CONTENT_SETTINGS_TYPE_COOKIES, std::string(), incognito, &rules);
+      store(), CONTENT_SETTINGS_TYPE_COOKIES, "", incognito, &rules);
   ASSERT_EQ(0u, rules.size());
 }
 
diff --git a/chrome/browser/extensions/api/cookies/cookies_api.cc b/chrome/browser/extensions/api/cookies/cookies_api.cc
index c35b830..f3a4a35 100644
--- a/chrome/browser/extensions/api/cookies/cookies_api.cc
+++ b/chrome/browser/extensions/api/cookies/cookies_api.cc
@@ -203,9 +203,8 @@ bool CookiesGetFunction::RunImpl() {
   if (!ParseUrl(parsed_args_->details.url, &url_, true))
     return false;
 
-  std::string store_id =
-      parsed_args_->details.store_id.get() ? *parsed_args_->details.store_id
-                                           : std::string();
+  std::string store_id = parsed_args_->details.store_id.get() ?
+      *parsed_args_->details.store_id : "";
   net::URLRequestContextGetter* store_context = NULL;
   if (!ParseStoreContext(&store_id, &store_context))
     return false;
@@ -277,9 +276,8 @@ bool CookiesGetAllFunction::RunImpl() {
     return false;
   }
 
-  std::string store_id =
-      parsed_args_->details.store_id.get() ? *parsed_args_->details.store_id
-                                           : std::string();
+  std::string store_id = parsed_args_->details.store_id.get() ?
+      *parsed_args_->details.store_id : "";
   net::URLRequestContextGetter* store_context = NULL;
   if (!ParseStoreContext(&store_id, &store_context))
     return false;
@@ -341,9 +339,8 @@ bool CookiesSetFunction::RunImpl() {
   if (!ParseUrl(parsed_args_->details.url, &url_, true))
       return false;
 
-  std::string store_id =
-      parsed_args_->details.store_id.get() ? *parsed_args_->details.store_id
-                                           : std::string();
+  std::string store_id = parsed_args_->details.store_id.get() ?
+      *parsed_args_->details.store_id : "";
   net::URLRequestContextGetter* store_context = NULL;
   if (!ParseStoreContext(&store_id, &store_context))
     return false;
@@ -377,19 +374,17 @@ void CookiesSetFunction::SetCookieOnIOThread() {
 
   cookie_monster->SetCookieWithDetailsAsync(
       url_,
-      parsed_args_->details.name.get() ? *parsed_args_->details.name
-                                       : std::string(),
-      parsed_args_->details.value.get() ? *parsed_args_->details.value
-                                        : std::string(),
-      parsed_args_->details.domain.get() ? *parsed_args_->details.domain
-                                         : std::string(),
-      parsed_args_->details.path.get() ? *parsed_args_->details.path
-                                       : std::string(),
+      parsed_args_->details.name.get() ? *parsed_args_->details.name : "",
+      parsed_args_->details.value.get() ? *parsed_args_->details.value : "",
+      parsed_args_->details.domain.get() ? *parsed_args_->details.domain : "",
+      parsed_args_->details.path.get() ? *parsed_args_->details.path : "",
       expiration_time,
-      parsed_args_->details.secure.get() ? *parsed_args_->details.secure.get()
-                                         : false,
-      parsed_args_->details.http_only.get() ? *parsed_args_->details.http_only
-                                            : false,
+      parsed_args_->details.secure.get() ?
+          *parsed_args_->details.secure.get() :
+          false,
+      parsed_args_->details.http_only.get() ?
+          *parsed_args_->details.http_only :
+          false,
       base::Bind(&CookiesSetFunction::PullCookie, this));
 }
 
@@ -411,9 +406,8 @@ void CookiesSetFunction::PullCookieCallback(
     // Return the first matching cookie. Relies on the fact that the
     // CookieMonster returns them in canonical order (longest path, then
     // earliest creation time).
-    std::string name =
-        parsed_args_->details.name.get() ? *parsed_args_->details.name
-                                         : std::string();
+    std::string name = parsed_args_->details.name.get() ?
+        *parsed_args_->details.name : "";
     if (it->Name() == name) {
       scoped_ptr<Cookie> cookie(
           cookies_helpers::CreateCookie(*it, *parsed_args_->details.store_id));
@@ -431,10 +425,10 @@ void CookiesSetFunction::PullCookieCallback(
 void CookiesSetFunction::RespondOnUIThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (!success_) {
-    std::string name =
-        parsed_args_->details.name.get() ? *parsed_args_->details.name
-                                         : std::string();
-    error_ = ErrorUtils::FormatErrorMessage(keys::kCookieSetFailedError, name);
+    std::string name = parsed_args_->details.name.get() ?
+        *parsed_args_->details.name : "";
+    error_ = ErrorUtils::FormatErrorMessage(
+        keys::kCookieSetFailedError, name);
   }
   SendResponse(success_);
 }
@@ -453,9 +447,8 @@ bool CookiesRemoveFunction::RunImpl() {
   if (!ParseUrl(parsed_args_->details.url, &url_, true))
     return false;
 
-  std::string store_id =
-      parsed_args_->details.store_id.get() ? *parsed_args_->details.store_id
-                                           : std::string();
+  std::string store_id = parsed_args_->details.store_id.get() ?
+      *parsed_args_->details.store_id : "";
   net::URLRequestContextGetter* store_context = NULL;
   if (!ParseStoreContext(&store_id, &store_context))
     return false;
diff --git a/chrome/browser/extensions/api/cookies/cookies_helpers.cc b/chrome/browser/extensions/api/cookies/cookies_helpers.cc
index c61e729..d9866f2 100644
--- a/chrome/browser/extensions/api/cookies/cookies_helpers.cc
+++ b/chrome/browser/extensions/api/cookies/cookies_helpers.cc
@@ -74,8 +74,8 @@ scoped_ptr<Cookie> CreateCookie(
   cookie->host_only = net::cookie_util::DomainIsHostOnly(
       canonical_cookie.Domain());
   // A non-UTF8 path is invalid, so we just replace it with an empty string.
-  cookie->path = IsStringUTF8(canonical_cookie.Path()) ? canonical_cookie.Path()
-                                                       : std::string();
+  cookie->path = IsStringUTF8(canonical_cookie.Path()) ?
+      canonical_cookie.Path() : "";
   cookie->secure = canonical_cookie.IsSecure();
   cookie->http_only = canonical_cookie.IsHttpOnly();
   cookie->session = !canonical_cookie.IsPersistent();
diff --git a/chrome/browser/extensions/api/cookies/cookies_unittest.cc b/chrome/browser/extensions/api/cookies/cookies_unittest.cc
index 0844b83..f1bd93d 100644
--- a/chrome/browser/extensions/api/cookies/cookies_unittest.cc
+++ b/chrome/browser/extensions/api/cookies/cookies_unittest.cc
@@ -195,36 +195,22 @@ TEST_F(ExtensionCookiesTest, DomainMatching) {
     scoped_ptr<GetAll::Params> params(GetAll::Params::Create(args));
 
     cookies_helpers::MatchFilter filter(&params->details);
-    net::CanonicalCookie cookie(GURL(),
-                                std::string(),
-                                std::string(),
-                                tests[i].domain,
-                                std::string(),
-                                base::Time(),
-                                base::Time(),
-                                base::Time(),
-                                false,
-                                false);
+    net::CanonicalCookie cookie(GURL(), "", "", tests[i].domain,"",
+                                base::Time(), base::Time(), base::Time(),
+                                false, false);
     EXPECT_EQ(tests[i].matches, filter.MatchesCookie(cookie));
   }
 }
 
 TEST_F(ExtensionCookiesTest, DecodeUTF8WithErrorHandling) {
-  net::CanonicalCookie canonical_cookie(GURL(),
-                                        std::string(),
-                                        "011Q255bNX_1!yd\203e+",
-                                        "test.com",
-                                        "/path\203",
-                                        base::Time(),
-                                        base::Time(),
-                                        base::Time(),
-                                        false,
-                                        false);
+  net::CanonicalCookie canonical_cookie(
+      GURL(), "", "011Q255bNX_1!yd\203e+", "test.com", "/path\203",
+      base::Time(), base::Time(), base::Time(), false, false);
   scoped_ptr<Cookie> cookie(
       cookies_helpers::CreateCookie(
           canonical_cookie, "some cookie store"));
   EXPECT_EQ(std::string("011Q255bNX_1!yd\xEF\xBF\xBD" "e+"), cookie->value);
-  EXPECT_EQ(std::string(), cookie->path);
+  EXPECT_EQ(std::string(""), cookie->path);
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/declarative/initializing_rules_registry.cc b/chrome/browser/extensions/api/declarative/initializing_rules_registry.cc
index d209bed..0074233 100644
--- a/chrome/browser/extensions/api/declarative/initializing_rules_registry.cc
+++ b/chrome/browser/extensions/api/declarative/initializing_rules_registry.cc
@@ -39,7 +39,7 @@ std::string InitializingRulesRegistry::RemoveRules(
   if (!error.empty())
     return error;
   RemoveUsedRuleIdentifiers(extension_id, rule_identifiers);
-  return std::string();
+  return "";
 }
 
 std::string InitializingRulesRegistry::RemoveAllRules(
@@ -48,7 +48,7 @@ std::string InitializingRulesRegistry::RemoveAllRules(
   if (!error.empty())
     return error;
   RemoveAllUsedRuleIdentifiers(extension_id);
-  return std::string();
+  return "";
 }
 
 std::string InitializingRulesRegistry::GetRules(
@@ -122,7 +122,7 @@ std::string InitializingRulesRegistry::CheckAndFillInOptionalRules(
       used_rule_identifiers_[extension_id].insert(*(rule->id));
     }
   }
-  return std::string();
+  return "";
 }
 
 void InitializingRulesRegistry::FillInOptionalPriorities(
diff --git a/chrome/browser/extensions/api/declarative/rules_registry_with_cache_unittest.cc b/chrome/browser/extensions/api/declarative/rules_registry_with_cache_unittest.cc
index 1be1983..4f49f36 100644
--- a/chrome/browser/extensions/api/declarative/rules_registry_with_cache_unittest.cc
+++ b/chrome/browser/extensions/api/declarative/rules_registry_with_cache_unittest.cc
@@ -69,7 +69,7 @@ TEST_F(RulesRegistryWithCacheTest, AddRules) {
   registry_->SetResult("Error");
   EXPECT_EQ("Error", AddRule(extension_id, rule_id));
   EXPECT_EQ(0, GetNumberOfRules(extension_id));
-  registry_->SetResult(std::string());
+  registry_->SetResult("");
 
   // Check that rules can be inserted.
   EXPECT_EQ("", AddRule(extension_id, rule_id));
@@ -97,7 +97,7 @@ TEST_F(RulesRegistryWithCacheTest, RemoveRules) {
   registry_->SetResult("Error");
   EXPECT_EQ("Error", RemoveRule(extension_id, rule_id));
   EXPECT_EQ(1, GetNumberOfRules(extension_id));
-  registry_->SetResult(std::string());
+  registry_->SetResult("");
 
   // Check that nothing happens if a rule does not exist.
   EXPECT_EQ("", RemoveRule(extension_id, "unknown_rule"));
@@ -122,7 +122,7 @@ TEST_F(RulesRegistryWithCacheTest, RemoveAllRules) {
   registry_->SetResult("Error");
   EXPECT_EQ("Error", registry_->RemoveAllRules(extension_id));
   EXPECT_EQ(2, GetNumberOfRules(extension_id));
-  registry_->SetResult(std::string());
+  registry_->SetResult("");
 
   // Check that rules may be removed and only for the correct extension.
   EXPECT_EQ("", registry_->RemoveAllRules(extension_id));
diff --git a/chrome/browser/extensions/api/declarative_content/content_condition.cc b/chrome/browser/extensions/api/declarative_content/content_condition.cc
index 6c00b80..4a88e17 100644
--- a/chrome/browser/extensions/api/declarative_content/content_condition.cc
+++ b/chrome/browser/extensions/api/declarative_content/content_condition.cc
@@ -129,8 +129,7 @@ scoped_ptr<ContentCondition> ContentCondition::Create(
   if (!url_matcher_condition_set) {
     URLMatcherConditionSet::Conditions url_matcher_conditions;
     url_matcher_conditions.insert(
-        url_matcher_condition_factory->CreateHostPrefixCondition(
-            std::string()));
+        url_matcher_condition_factory->CreateHostPrefixCondition(""));
     url_matcher_condition_set =
         new URLMatcherConditionSet(++g_next_id, url_matcher_conditions);
   }
diff --git a/chrome/browser/extensions/api/declarative_content/content_rules_registry.cc b/chrome/browser/extensions/api/declarative_content/content_rules_registry.cc
index eb95b47..c9ed31e 100644
--- a/chrome/browser/extensions/api/declarative_content/content_rules_registry.cc
+++ b/chrome/browser/extensions/api/declarative_content/content_rules_registry.cc
@@ -176,7 +176,7 @@ std::string ContentRulesRegistry::AddRulesImpl(
 
   UpdateConditionCache();
 
-  return std::string();
+  return "";
 }
 
 std::string ContentRulesRegistry::RemoveRulesImpl(
@@ -221,7 +221,7 @@ std::string ContentRulesRegistry::RemoveRulesImpl(
 
   UpdateConditionCache();
 
-  return std::string();
+  return "";
 }
 
 std::string ContentRulesRegistry::RemoveAllRulesImpl(
diff --git a/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc b/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
index dc3bead..813b6b9 100644
--- a/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
+++ b/chrome/browser/extensions/api/declarative_content/declarative_content_apitest.cc
@@ -56,7 +56,7 @@ IN_PROC_BROWSER_TEST_F(DeclarativeContentApiTest, Overview) {
       tab, "document.body.innerHTML = '<input type=\"password\">';"));
   // Give the mutation observer a chance to run and send back the
   // matching-selector update.
-  ASSERT_TRUE(content::ExecuteScript(tab, std::string()));
+  ASSERT_TRUE(content::ExecuteScript(tab, ""));
   EXPECT_TRUE(page_action->GetIsVisible(tab_id));
 
   // Remove it again to make sure that reverts the action.
@@ -64,7 +64,7 @@ IN_PROC_BROWSER_TEST_F(DeclarativeContentApiTest, Overview) {
       tab, "document.body.innerHTML = 'Hello world';"));
   // Give the mutation observer a chance to run and send back the
   // matching-selector update.
-  ASSERT_TRUE(content::ExecuteScript(tab, std::string()));
+  ASSERT_TRUE(content::ExecuteScript(tab, ""));
   EXPECT_FALSE(page_action->GetIsVisible(tab_id));
 }
 
diff --git a/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry.cc b/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry.cc
index 695edac..c8cae51 100644
--- a/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry.cc
+++ b/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry.cc
@@ -184,7 +184,7 @@ std::string WebRequestRulesRegistry::AddRulesImpl(
 
   ClearCacheOnNavigation();
 
-  return std::string();
+  return "";
 }
 
 std::string WebRequestRulesRegistry::RemoveRulesImpl(
@@ -223,7 +223,7 @@ std::string WebRequestRulesRegistry::RemoveRulesImpl(
 
   ClearCacheOnNavigation();
 
-  return std::string();
+  return "";
 }
 
 std::string WebRequestRulesRegistry::RemoveAllRulesImpl(
diff --git a/chrome/browser/extensions/api/developer_private/entry_picker.cc b/chrome/browser/extensions/api/developer_private/entry_picker.cc
index 12a2994..c2b3d78 100644
--- a/chrome/browser/extensions/api/developer_private/entry_picker.cc
+++ b/chrome/browser/extensions/api/developer_private/entry_picker.cc
@@ -64,9 +64,8 @@ EntryPicker::EntryPicker(EntryPickerClient* client,
                                   last_directory,
                                   &info,
                                   file_type_index,
-                                  base::FilePath::StringType(),
-                                  owning_window,
-                                  NULL);
+                                  FILE_PATH_LITERAL(""),
+                                  owning_window, NULL);
 }
 
 EntryPicker::~EntryPicker() {}
diff --git a/chrome/browser/extensions/api/dial/dial_device_data_unittest.cc b/chrome/browser/extensions/api/dial/dial_device_data_unittest.cc
index 4ccc470..447efca 100644
--- a/chrome/browser/extensions/api/dial/dial_device_data_unittest.cc
+++ b/chrome/browser/extensions/api/dial/dial_device_data_unittest.cc
@@ -96,9 +96,9 @@ TEST(DialDeviceDataTest, TestIsDeviceDescriptionUrl) {
       GURL("https://192.168.1.1:1234/dd.xml")));
 
   EXPECT_FALSE(DialDeviceData::IsDeviceDescriptionUrl(GURL()));
-  EXPECT_FALSE(DialDeviceData::IsDeviceDescriptionUrl(GURL(std::string())));
-  EXPECT_FALSE(
-      DialDeviceData::IsDeviceDescriptionUrl(GURL("file://path/to/file")));
+  EXPECT_FALSE(DialDeviceData::IsDeviceDescriptionUrl(GURL("")));
+  EXPECT_FALSE(DialDeviceData::IsDeviceDescriptionUrl(
+      GURL("file://path/to/file")));
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/dial/dial_service_unittest.cc b/chrome/browser/extensions/api/dial/dial_service_unittest.cc
index b378589..da1cc7b 100644
--- a/chrome/browser/extensions/api/dial/dial_service_unittest.cc
+++ b/chrome/browser/extensions/api/dial/dial_service_unittest.cc
@@ -116,7 +116,9 @@ TEST_F(DialServiceTest, TestResponseParsing) {
   DialDeviceData not_parsed;
 
   // Empty, garbage
-  EXPECT_FALSE(DialServiceImpl::ParseResponse(std::string(), now, &not_parsed));
+  EXPECT_FALSE(DialServiceImpl::ParseResponse(
+    "",
+    now, &not_parsed));
   EXPECT_FALSE(DialServiceImpl::ParseResponse(
     "\r\n\r\n",
     now, &not_parsed));
diff --git a/chrome/browser/extensions/api/downloads/downloads_api.cc b/chrome/browser/extensions/api/downloads/downloads_api.cc
index 6a126aa..44e7f29 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api.cc
@@ -218,9 +218,9 @@ scoped_ptr<base::DictionaryValue> DownloadItemToJSON(
   json->SetBoolean(kExistsKey, !download_item->GetFileExternallyRemoved());
   json->SetInteger(kIdKey, download_item->GetId());
   const GURL& url = download_item->GetOriginalUrl();
-  json->SetString(kUrlKey, (url.is_valid() ? url.spec() : std::string()));
-  json->SetString(kFilenameKey,
-                  download_item->GetFullPath().LossyDisplayName());
+  json->SetString(kUrlKey, (url.is_valid() ? url.spec() : ""));
+  json->SetString(
+      kFilenameKey, download_item->GetFullPath().LossyDisplayName());
   json->SetString(kDangerKey, DangerString(download_item->GetDangerType()));
   if (download_item->GetDangerType() !=
       content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS)
diff --git a/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc b/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
index e403cd5..23a1131 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
@@ -737,8 +737,7 @@ class HTML5FileWriter {
   ~HTML5FileWriter() {
     CHECK(BrowserThread::PostTask(BrowserThread::IO, FROM_HERE, base::Bind(
         &HTML5FileWriter::TearDownURLRequestContext, base::Unretained(this))));
-    events_listener_->WaitFor(
-        profile_, kURLRequestContextToreDown, std::string());
+    events_listener_->WaitFor(profile_, kURLRequestContextToreDown, "");
   }
 
   bool WriteFile() {
@@ -1072,10 +1071,8 @@ IN_PROC_BROWSER_TEST_F(DownloadExtensionTest,
 
   // Simulate an error during icon load by invoking the mock with an empty
   // result string.
-  std::string error = RunFunctionAndReturnError(
-      MockedGetFileIconFunction(download_item->GetTargetFilePath(),
-                                IconLoader::NORMAL,
-                                std::string()),
+  std::string error = RunFunctionAndReturnError(MockedGetFileIconFunction(
+        download_item->GetTargetFilePath(), IconLoader::NORMAL, ""),
       args32);
   EXPECT_STREQ(download_extension_errors::kIconNotFoundError, error.c_str());
 
diff --git a/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc b/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
index 07845e4..0a5497f 100644
--- a/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
+++ b/chrome/browser/extensions/api/extension_action/browser_action_apitest.cc
@@ -692,9 +692,11 @@ IN_PROC_BROWSER_TEST_F(BrowserActionApiTest, TestTriggerBrowserAction) {
       "window.domAutomationController.send(document.body.style."
       "backgroundColor);";
   std::string result;
-  const std::string frame_xpath;
-  EXPECT_TRUE(content::ExecuteScriptInFrameAndExtractString(
-      tab, frame_xpath, script, &result));
+  const std::string frame_xpath = "";
+  EXPECT_TRUE(content::ExecuteScriptInFrameAndExtractString(tab,
+                                                            frame_xpath,
+                                                            script,
+                                                            &result));
   EXPECT_EQ(result, "red");
 }
 
diff --git a/chrome/browser/extensions/api/extension_action/page_action_apitest.cc b/chrome/browser/extensions/api/extension_action/page_action_apitest.cc
index cad5250..232280a 100644
--- a/chrome/browser/extensions/api/extension_action/page_action_apitest.cc
+++ b/chrome/browser/extensions/api/extension_action/page_action_apitest.cc
@@ -63,7 +63,7 @@ IN_PROC_BROWSER_TEST_F(PageActionApiTest, Basic) {
     ExtensionService* service = extensions::ExtensionSystem::Get(
         browser()->profile())->extension_service();
     service->browser_event_router()->PageActionExecuted(
-        browser()->profile(), *action, tab_id, std::string(), 0);
+        browser()->profile(), *action, tab_id, "", 0);
     EXPECT_TRUE(catcher.GetNextResult());
   }
 
@@ -108,7 +108,7 @@ IN_PROC_BROWSER_TEST_F(PageActionApiTest, AddPopup) {
     ExtensionService* service = extensions::ExtensionSystem::Get(
         browser()->profile())->extension_service();
     service->browser_event_router()->PageActionExecuted(
-        browser()->profile(), *page_action, tab_id, std::string(), 1);
+        browser()->profile(), *page_action, tab_id, "", 1);
     ASSERT_TRUE(catcher.GetNextResult());
   }
 
@@ -188,7 +188,7 @@ IN_PROC_BROWSER_TEST_F(PageActionApiTest, OldPageActions) {
         browser()->profile())->extension_service();
     ExtensionAction* page_action = GetPageAction(*extension);
     service->browser_event_router()->PageActionExecuted(
-        browser()->profile(), *page_action, tab_id, std::string(), 1);
+        browser()->profile(), *page_action, tab_id, "", 1);
     EXPECT_TRUE(catcher.GetNextResult());
   }
 }
@@ -260,7 +260,7 @@ IN_PROC_BROWSER_TEST_F(PageActionApiTest, TestTriggerPageAction) {
     ExtensionService* service = extensions::ExtensionSystem::Get(
         browser()->profile())->extension_service();
     service->browser_event_router()->PageActionExecuted(
-        browser()->profile(), *page_action, tab_id, std::string(), 0);
+        browser()->profile(), *page_action, tab_id, "", 0);
     EXPECT_TRUE(catcher.GetNextResult());
   }
 
@@ -273,9 +273,11 @@ IN_PROC_BROWSER_TEST_F(PageActionApiTest, TestTriggerPageAction) {
       "window.domAutomationController.send(document.body.style."
       "backgroundColor);";
   std::string result;
-  const std::string frame_xpath;
-  EXPECT_TRUE(content::ExecuteScriptInFrameAndExtractString(
-      tab, frame_xpath, script, &result));
+  const std::string frame_xpath = "";
+  EXPECT_TRUE(content::ExecuteScriptInFrameAndExtractString(tab,
+                                                            frame_xpath,
+                                                            script,
+                                                            &result));
   EXPECT_EQ(result, "red");
 }
 
diff --git a/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc b/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc
index ff7fae7..fd32e96 100644
--- a/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc
+++ b/chrome/browser/extensions/api/extension_action/script_badge_apitest.cc
@@ -88,8 +88,7 @@ IN_PROC_BROWSER_TEST_F(ScriptBadgeApiTest, Basics) {
     ResultCatcher catcher;
     // Visit a non-extension page so the extension can run a content script and
     // cause the script badge to be animated in.
-    ui_test_utils::NavigateToURL(browser(),
-                                 test_server()->GetURL(std::string()));
+    ui_test_utils::NavigateToURL(browser(), test_server()->GetURL(""));
     ASSERT_TRUE(catcher.GetNextResult());
   }
   EXPECT_TRUE(script_badge->GetIsVisible(tab_id));
diff --git a/chrome/browser/extensions/api/file_system/file_system_api.cc b/chrome/browser/extensions/api/file_system/file_system_api.cc
index e849e3cc..3bb588a 100644
--- a/chrome/browser/extensions/api/file_system/file_system_api.cc
+++ b/chrome/browser/extensions/api/file_system/file_system_api.cc
@@ -435,11 +435,8 @@ class FileSystemChooseEntryFunction::FilePicker
     select_file_dialog_->SelectFile(picker_type,
                                     string16(),
                                     suggested_name,
-                                    &file_type_info,
-                                    0,
-                                    base::FilePath::StringType(),
-                                    owning_window,
-                                    NULL);
+                                    &file_type_info, 0, FILE_PATH_LITERAL(""),
+                                    owning_window, NULL);
   }
 
   virtual ~FilePicker() {}
diff --git a/chrome/browser/extensions/api/file_system/file_system_api_unittest.cc b/chrome/browser/extensions/api/file_system/file_system_api_unittest.cc
index 570c0fb..96da293 100644
--- a/chrome/browser/extensions/api/file_system/file_system_api_unittest.cc
+++ b/chrome/browser/extensions/api/file_system/file_system_api_unittest.cc
@@ -70,8 +70,8 @@ TEST_F(FileSystemApiUnitTest, FileSystemChooseEntryFunctionFileTypeInfoTest) {
   // Test grouping of multiple types.
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   std::vector<linked_ptr<AcceptOption> > options;
-  options.push_back(linked_ptr<AcceptOption>(BuildAcceptOption(
-      std::string(), "application/x-chrome-extension", "jso")));
+  options.push_back(linked_ptr<AcceptOption>(
+      BuildAcceptOption("", "application/x-chrome-extension", "jso")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       base::FilePath::StringType(), &options, &acceptsAllTypes);
@@ -90,7 +90,7 @@ TEST_F(FileSystemApiUnitTest, FileSystemChooseEntryFunctionFileTypeInfoTest) {
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   options.clear();
   options.push_back(linked_ptr<AcceptOption>(
-      BuildAcceptOption(std::string(), std::string(), "unrelated")));
+      BuildAcceptOption("", "", "unrelated")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       ToStringType(".jso"), &options, &acceptsAllTypes);
@@ -100,9 +100,9 @@ TEST_F(FileSystemApiUnitTest, FileSystemChooseEntryFunctionFileTypeInfoTest) {
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   options.clear();
   options.push_back(linked_ptr<AcceptOption>(
-      BuildAcceptOption(std::string(), std::string(), "jso,js")));
+      BuildAcceptOption("", "", "jso,js")));
   options.push_back(linked_ptr<AcceptOption>(
-      BuildAcceptOption(std::string(), std::string(), "cpp,cc")));
+      BuildAcceptOption("", "", "cpp,cc")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       base::FilePath::StringType(), &options, &acceptsAllTypes);
@@ -122,7 +122,7 @@ TEST_F(FileSystemApiUnitTest, FileSystemChooseEntryFunctionFileTypeInfoTest) {
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   options.clear();
   options.push_back(linked_ptr<AcceptOption>(
-      BuildAcceptOption(std::string(), "image/*", "html")));
+      BuildAcceptOption("", "image/*", "html")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       base::FilePath::StringType(), &options, &acceptsAllTypes);
@@ -134,8 +134,8 @@ TEST_F(FileSystemApiUnitTest, FileSystemChooseEntryFunctionFileTypeInfoTest) {
   // still present the default.
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   options.clear();
-  options.push_back(linked_ptr<AcceptOption>(BuildAcceptOption(
-      std::string(), "image/*,audio/*,video/*", std::string())));
+  options.push_back(linked_ptr<AcceptOption>(
+      BuildAcceptOption("", "image/*,audio/*,video/*", "")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       base::FilePath::StringType(), &options, &acceptsAllTypes);
@@ -146,7 +146,7 @@ TEST_F(FileSystemApiUnitTest, FileSystemChooseEntryFunctionFileTypeInfoTest) {
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   options.clear();
   options.push_back(linked_ptr<AcceptOption>(
-      BuildAcceptOption("File Types 101", "image/jpeg", std::string())));
+      BuildAcceptOption("File Types 101", "image/jpeg", "")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       base::FilePath::StringType(), &options, &acceptsAllTypes);
diff --git a/chrome/browser/extensions/api/identity/identity_apitest.cc b/chrome/browser/extensions/api/identity/identity_apitest.cc
index 174f922..b6fec79d 100644
--- a/chrome/browser/extensions/api/identity/identity_apitest.cc
+++ b/chrome/browser/extensions/api/identity/identity_apitest.cc
@@ -508,7 +508,7 @@ class LaunchWebAuthFlowFunctionTest : public ExtensionBrowserTest {
 };
 
 IN_PROC_BROWSER_TEST_F(LaunchWebAuthFlowFunctionTest, Bounds) {
-  RunAndCheckBounds(std::string(), 0, 0, 0, 0);
+  RunAndCheckBounds("", 0, 0, 0, 0);
   RunAndCheckBounds("\"width\": 100, \"height\": 200", 0, 0, 100, 200);
   RunAndCheckBounds("\"left\": 100, \"top\": 200", 100, 200, 0, 0);
   RunAndCheckBounds(
diff --git a/chrome/browser/extensions/api/management/management_api_browsertest.cc b/chrome/browser/extensions/api/management/management_api_browsertest.cc
index 5b6b04d..f475e81 100644
--- a/chrome/browser/extensions/api/management/management_api_browsertest.cc
+++ b/chrome/browser/extensions/api/management/management_api_browsertest.cc
@@ -257,15 +257,15 @@ IN_PROC_BROWSER_TEST_F(ExtensionManagementApiEscalationTest,
   // This should succeed when user accepts dialog.
   CommandLine::ForCurrentProcess()->AppendSwitchASCII(
       switches::kAppsGalleryInstallAutoConfirmForTests, "accept");
-  SetEnabled(true, true, std::string());
+  SetEnabled(true, true, "");
 
   // Crash the extension. Mock a reload by disabling and then enabling. The
   // extension should be reloaded and enabled.
   ASSERT_TRUE(CrashEnabledExtension(kId));
-  SetEnabled(false, true, std::string());
-  SetEnabled(true, true, std::string());
-  const Extension* extension = ExtensionSystem::Get(browser()->profile())
-      ->extension_service()->GetExtensionById(kId, false);
+  SetEnabled(false, true, "");
+  SetEnabled(true, true, "");
+  const Extension* extension = ExtensionSystem::Get(browser()->profile())->
+      extension_service()->GetExtensionById(kId, false);
   EXPECT_TRUE(extension);
 }
 
diff --git a/chrome/browser/extensions/api/messaging/message_service.cc b/chrome/browser/extensions/api/messaging/message_service.cc
index e3075f9..aae6a25 100644
--- a/chrome/browser/extensions/api/messaging/message_service.cc
+++ b/chrome/browser/extensions/api/messaging/message_service.cc
@@ -216,7 +216,7 @@ void MessageService::OpenChannelToNativeApp(
   }
 
   if (!has_permission) {
-    ExtensionMessagePort port(source, MSG_ROUTING_CONTROL, std::string());
+    ExtensionMessagePort port(source, MSG_ROUTING_CONTROL, "");
     port.DispatchOnDisconnect(GET_OPPOSITE_PORT_ID(receiver_port_id),
                               kMissingPermissionError);
     return;
@@ -247,7 +247,7 @@ void MessageService::OpenChannelToNativeApp(
   if (!native_process.get()) {
     LOG(ERROR) << "Failed to create native process.";
     // Treat it as a disconnect.
-    ExtensionMessagePort port(source, MSG_ROUTING_CONTROL, std::string());
+    ExtensionMessagePort port(source, MSG_ROUTING_CONTROL, "");
     port.DispatchOnDisconnect(GET_OPPOSITE_PORT_ID(receiver_port_id),
                               kReceivingEndDoesntExistError);
     return;
@@ -320,8 +320,7 @@ bool MessageService::OpenChannelImpl(scoped_ptr<OpenChannelParams> params) {
 
   if (!params->receiver.get() || !params->receiver->GetRenderProcessHost()) {
     // Treat it as a disconnect.
-    ExtensionMessagePort port(
-        params->source, MSG_ROUTING_CONTROL, std::string());
+    ExtensionMessagePort port(params->source, MSG_ROUTING_CONTROL, "");
     port.DispatchOnDisconnect(GET_OPPOSITE_PORT_ID(params->receiver_port_id),
                               kReceivingEndDoesntExistError);
     return false;
diff --git a/chrome/browser/extensions/api/proxy/proxy_api.cc b/chrome/browser/extensions/api/proxy/proxy_api.cc
index 5e811bd..ff945d3 100644
--- a/chrome/browser/extensions/api/proxy/proxy_api.cc
+++ b/chrome/browser/extensions/api/proxy/proxy_api.cc
@@ -41,7 +41,7 @@ void ProxyEventRouter::OnProxyError(
   DictionaryValue* dict = new DictionaryValue();
   dict->SetBoolean(keys::kProxyEventFatal, true);
   dict->SetString(keys::kProxyEventError, net::ErrorToString(error_code));
-  dict->SetString(keys::kProxyEventDetails, std::string());
+  dict->SetString(keys::kProxyEventDetails, "");
   args->Append(dict);
 
   if (profile) {
diff --git a/chrome/browser/extensions/api/proxy/proxy_api_helpers_unittest.cc b/chrome/browser/extensions/api/proxy/proxy_api_helpers_unittest.cc
index ff3cd32..116f85a 100644
--- a/chrome/browser/extensions/api/proxy/proxy_api_helpers_unittest.cc
+++ b/chrome/browser/extensions/api/proxy/proxy_api_helpers_unittest.cc
@@ -222,71 +222,41 @@ TEST(ExtensionProxyApiHelpers, CreateProxyConfigDict) {
   std::string error;
   scoped_ptr<DictionaryValue> exp_direct(ProxyConfigDictionary::CreateDirect());
   scoped_ptr<DictionaryValue> out_direct(
-      CreateProxyConfigDict(ProxyPrefs::MODE_DIRECT,
-                            false,
-                            std::string(),
-                            std::string(),
-                            std::string(),
-                            std::string(),
+      CreateProxyConfigDict(ProxyPrefs::MODE_DIRECT, false, "", "", "", "",
                             &error));
   EXPECT_TRUE(Value::Equals(exp_direct.get(), out_direct.get()));
 
   scoped_ptr<DictionaryValue> exp_auto(
       ProxyConfigDictionary::CreateAutoDetect());
   scoped_ptr<DictionaryValue> out_auto(
-      CreateProxyConfigDict(ProxyPrefs::MODE_AUTO_DETECT,
-                            false,
-                            std::string(),
-                            std::string(),
-                            std::string(),
-                            std::string(),
+      CreateProxyConfigDict(ProxyPrefs::MODE_AUTO_DETECT, false, "", "", "", "",
                             &error));
   EXPECT_TRUE(Value::Equals(exp_auto.get(), out_auto.get()));
 
   scoped_ptr<DictionaryValue> exp_pac_url(
       ProxyConfigDictionary::CreatePacScript(kSamplePacScriptUrl, false));
   scoped_ptr<DictionaryValue> out_pac_url(
-      CreateProxyConfigDict(ProxyPrefs::MODE_PAC_SCRIPT,
-                            false,
-                            kSamplePacScriptUrl,
-                            std::string(),
-                            std::string(),
-                            std::string(),
-                            &error));
+        CreateProxyConfigDict(ProxyPrefs::MODE_PAC_SCRIPT, false,
+                              kSamplePacScriptUrl, "", "", "", &error));
   EXPECT_TRUE(Value::Equals(exp_pac_url.get(), out_pac_url.get()));
 
   scoped_ptr<DictionaryValue> exp_pac_data(
       ProxyConfigDictionary::CreatePacScript(kSamplePacScriptAsDataUrl, false));
   scoped_ptr<DictionaryValue> out_pac_data(
-      CreateProxyConfigDict(ProxyPrefs::MODE_PAC_SCRIPT,
-                            false,
-                            std::string(),
-                            kSamplePacScript,
-                            std::string(),
-                            std::string(),
-                            &error));
+          CreateProxyConfigDict(ProxyPrefs::MODE_PAC_SCRIPT, false, "",
+                                kSamplePacScript, "", "", &error));
   EXPECT_TRUE(Value::Equals(exp_pac_data.get(), out_pac_data.get()));
 
   scoped_ptr<DictionaryValue> exp_fixed(
       ProxyConfigDictionary::CreateFixedServers("foo:80", "localhost"));
   scoped_ptr<DictionaryValue> out_fixed(
-      CreateProxyConfigDict(ProxyPrefs::MODE_FIXED_SERVERS,
-                            false,
-                            std::string(),
-                            std::string(),
-                            "foo:80",
-                            "localhost",
-                            &error));
+          CreateProxyConfigDict(ProxyPrefs::MODE_FIXED_SERVERS, false, "", "",
+                                "foo:80", "localhost", &error));
   EXPECT_TRUE(Value::Equals(exp_fixed.get(), out_fixed.get()));
 
   scoped_ptr<DictionaryValue> exp_system(ProxyConfigDictionary::CreateSystem());
   scoped_ptr<DictionaryValue> out_system(
-      CreateProxyConfigDict(ProxyPrefs::MODE_SYSTEM,
-                            false,
-                            std::string(),
-                            std::string(),
-                            std::string(),
-                            std::string(),
+      CreateProxyConfigDict(ProxyPrefs::MODE_SYSTEM, false, "", "", "", "",
                             &error));
   EXPECT_TRUE(Value::Equals(exp_system.get(), out_system.get()));
 
diff --git a/chrome/browser/extensions/api/socket/udp_socket.cc b/chrome/browser/extensions/api/socket/udp_socket.cc
index b9a804c..a2b5f97 100644
--- a/chrome/browser/extensions/api/socket/udp_socket.cc
+++ b/chrome/browser/extensions/api/socket/udp_socket.cc
@@ -108,7 +108,7 @@ void UDPSocket::RecvFrom(int count,
   DCHECK(!callback.is_null());
 
   if (!recv_from_callback_.is_null()) {
-    callback.Run(net::ERR_IO_PENDING, NULL, std::string(), 0);
+    callback.Run(net::ERR_IO_PENDING, NULL, "", 0);
     return;
   } else {
     recv_from_callback_ = callback;
diff --git a/chrome/browser/extensions/api/storage/settings_sync_unittest.cc b/chrome/browser/extensions/api/storage/settings_sync_unittest.cc
index fcfcdc8..ec530e8 100644
--- a/chrome/browser/extensions/api/storage/settings_sync_unittest.cc
+++ b/chrome/browser/extensions/api/storage/settings_sync_unittest.cc
@@ -130,10 +130,9 @@ class MockSyncChangeProcessor : public syncer::SyncChangeProcessor {
     if (matching_changes.empty()) {
       ADD_FAILURE() << "No matching changes for " << extension_id << "/" <<
           key << " (out of " << changes_.size() << ")";
-      return SettingSyncData(syncer::SyncChange::ACTION_INVALID,
-                             std::string(),
-                             std::string(),
-                             scoped_ptr<Value>(new DictionaryValue()));
+      return SettingSyncData(
+          syncer::SyncChange::ACTION_INVALID, "", "",
+          scoped_ptr<Value>(new DictionaryValue()));
     }
     if (matching_changes.size() != 1u) {
       ADD_FAILURE() << matching_changes.size() << " matching changes for " <<
diff --git a/chrome/browser/extensions/api/web_request/web_request_api.cc b/chrome/browser/extensions/api/web_request/web_request_api.cc
index 56a8403..a17684e 100644
--- a/chrome/browser/extensions/api/web_request/web_request_api.cc
+++ b/chrome/browser/extensions/api/web_request/web_request_api.cc
@@ -316,7 +316,7 @@ ListValue* GetRequestHeadersList(const net::HttpRequestHeaders& headers) {
 // Creates a StringValue with the status line of |headers|. If |headers| is
 // NULL, an empty string is returned.  Ownership is passed to the caller.
 StringValue* GetStatusLine(net::HttpResponseHeaders* headers) {
-  return new StringValue(headers ? headers->GetStatusLine() : std::string());
+  return new StringValue(headers ? headers->GetStatusLine() : "");
 }
 
 void NotifyWebRequestAPIUsed(void* profile_id, const Extension* extension) {
diff --git a/chrome/browser/extensions/api/web_request/web_request_api_helpers.cc b/chrome/browser/extensions/api/web_request/web_request_api_helpers.cc
index 0d2a3d6..a9f1319 100644
--- a/chrome/browser/extensions/api/web_request/web_request_api_helpers.cc
+++ b/chrome/browser/extensions/api/web_request/web_request_api_helpers.cc
@@ -621,7 +621,7 @@ static std::string FindSetRequestHeader(
         return (*delta)->extension_id;
     }
   }
-  return std::string();
+  return "";
 }
 
 // Returns the extension ID of the first extension in |deltas| that removes the
@@ -639,7 +639,7 @@ static std::string FindRemoveRequestHeader(
         return (*delta)->extension_id;
     }
   }
-  return std::string();
+  return "";
 }
 
 void MergeOnBeforeSendHeadersResponses(
@@ -816,26 +816,22 @@ static bool DoesResponseCookieMatchFilter(net::ParsedCookie* cookie,
   if (filter->name.get() && cookie->Name() != *filter->name) return false;
   if (filter->value.get() && cookie->Value() != *filter->value) return false;
   if (filter->expires.get()) {
-    std::string actual_value =
-        cookie->HasExpires() ? cookie->Expires() : std::string();
+    std::string actual_value = cookie->HasExpires() ? cookie->Expires() : "";
     if (actual_value != *filter->expires)
       return false;
   }
   if (filter->max_age.get()) {
-    std::string actual_value =
-        cookie->HasMaxAge() ? cookie->MaxAge() : std::string();
+    std::string actual_value = cookie->HasMaxAge() ? cookie->MaxAge() : "";
     if (actual_value != base::IntToString(*filter->max_age))
       return false;
   }
   if (filter->domain.get()) {
-    std::string actual_value =
-        cookie->HasDomain() ? cookie->Domain() : std::string();
+    std::string actual_value = cookie->HasDomain() ? cookie->Domain() : "";
     if (actual_value != *filter->domain)
       return false;
   }
   if (filter->path.get()) {
-    std::string actual_value =
-        cookie->HasPath() ? cookie->Path() : std::string();
+    std::string actual_value = cookie->HasPath() ? cookie->Path() : "";
     if (actual_value != *filter->path)
       return false;
   }
@@ -884,8 +880,7 @@ static bool MergeAddResponseCookieModifications(
         continue;
       // Cookie names are not unique in response cookies so we always append
       // and never override.
-      linked_ptr<net::ParsedCookie> cookie(
-          new net::ParsedCookie(std::string()));
+      linked_ptr<net::ParsedCookie> cookie(new net::ParsedCookie(""));
       ApplyResponseCookieModification((*mod)->modification.get(), cookie.get());
       cookies->push_back(cookie);
       modified = true;
@@ -1013,7 +1008,7 @@ static std::string FindRemoveResponseHeader(
         return (*delta)->extension_id;
     }
   }
-  return std::string();
+  return "";
 }
 
 void MergeOnHeadersReceivedResponses(
diff --git a/chrome/browser/extensions/api/web_request/web_request_api_unittest.cc b/chrome/browser/extensions/api/web_request/web_request_api_unittest.cc
index fc78860..91e3dd9 100644
--- a/chrome/browser/extensions/api/web_request/web_request_api_unittest.cc
+++ b/chrome/browser/extensions/api/web_request/web_request_api_unittest.cc
@@ -574,10 +574,9 @@ TEST_F(ExtensionWebRequestTest, AccessRequestBodyData) {
       keys::kRequestBodyRawBytesKey,
       BinaryValue::CreateWithCopiedBuffer(kPlainBlock1, kPlainBlock1Length),
       &raw);
-  extensions::subtle::AppendKeyValuePair(
-      keys::kRequestBodyRawFileKey,
-      Value::CreateStringValue(std::string()),
-      &raw);
+  extensions::subtle::AppendKeyValuePair(keys::kRequestBodyRawFileKey,
+                                         Value::CreateStringValue(""),
+                                         &raw);
   extensions::subtle::AppendKeyValuePair(
       keys::kRequestBodyRawBytesKey,
       BinaryValue::CreateWithCopiedBuffer(kPlainBlock2, kPlainBlock2Length),
@@ -963,7 +962,7 @@ void TestInitFromValue(const std::string& values, bool expected_return_code,
 
 }
 TEST_F(ExtensionWebRequestTest, InitFromValue) {
-  TestInitFromValue(std::string(), true, 0);
+  TestInitFromValue("", true, 0);
 
   // Single valid values.
   TestInitFromValue(
diff --git a/chrome/browser/extensions/api/web_socket_proxy_private/web_socket_proxy_private_api.cc b/chrome/browser/extensions/api/web_socket_proxy_private/web_socket_proxy_private_api.cc
index 91483c5..237941c 100644
--- a/chrome/browser/extensions/api/web_socket_proxy_private/web_socket_proxy_private_api.cc
+++ b/chrome/browser/extensions/api/web_socket_proxy_private/web_socket_proxy_private_api.cc
@@ -95,7 +95,7 @@ void WebSocketProxyPrivate::ResolveHostIOPart(IOThread* io_thread) {
 
 bool WebSocketProxyPrivate::RunImpl() {
   AddRef();
-  SetResult(Value::CreateStringValue(std::string()));
+  SetResult(Value::CreateStringValue(""));
 
 #if defined(OS_CHROMEOS)
   bool delay_response = false;
diff --git a/chrome/browser/extensions/api/webstore_private/webstore_private_api.cc b/chrome/browser/extensions/api/webstore_private/webstore_private_api.cc
index 8cb59aa..0264c36 100644
--- a/chrome/browser/extensions/api/webstore_private/webstore_private_api.cc
+++ b/chrome/browser/extensions/api/webstore_private/webstore_private_api.cc
@@ -295,7 +295,7 @@ bool BeginInstallWithManifestFunction::RunImpl() {
 void BeginInstallWithManifestFunction::SetResultCode(ResultCode code) {
   switch (code) {
     case ERROR_NONE:
-      SetResult(Value::CreateStringValue(std::string()));
+      SetResult(Value::CreateStringValue(""));
       break;
     case UNKNOWN_ERROR:
       SetResult(Value::CreateStringValue("unknown_error"));
@@ -338,7 +338,7 @@ void BeginInstallWithManifestFunction::OnWebstoreParseSuccess(
       Extension::FROM_WEBSTORE,
       id,
       localized_name_,
-      std::string(),
+      "",
       &error);
 
   if (!dummy_extension_) {
diff --git a/chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc b/chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc
index 1a39317..81a63d1 100644
--- a/chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc
+++ b/chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc
@@ -248,7 +248,7 @@ class ExtensionWebstoreGetWebGLStatusTest : public InProcessBrowserTest {
             function.get(), kEmptyArgs, browser()));
     ASSERT_TRUE(result);
     EXPECT_EQ(base::Value::TYPE_STRING, result->GetType());
-    std::string webgl_status;
+    std::string webgl_status = "";
     EXPECT_TRUE(result->GetAsString(&webgl_status));
     EXPECT_STREQ(webgl_allowed ? kWebGLStatusAllowed : kWebGLStatusBlocked,
                  webgl_status.c_str());
diff --git a/chrome/browser/extensions/bundle_installer.cc b/chrome/browser/extensions/bundle_installer.cc
index 7cf66d3..97005be 100644
--- a/chrome/browser/extensions/bundle_installer.cc
+++ b/chrome/browser/extensions/bundle_installer.cc
@@ -215,7 +215,7 @@ void BundleInstaller::ParseManifests() {
 
   for (ItemMap::iterator i = items_.begin(); i != items_.end(); ++i) {
     scoped_refptr<WebstoreInstallHelper> helper = new WebstoreInstallHelper(
-        this, i->first, i->second.manifest, std::string(), GURL(), NULL);
+        this, i->first, i->second.manifest, "", GURL(), NULL);
     helper->Start();
   }
 }
diff --git a/chrome/browser/extensions/component_loader.cc b/chrome/browser/extensions/component_loader.cc
index 82a6883..58c53b7 100644
--- a/chrome/browser/extensions/component_loader.cc
+++ b/chrome/browser/extensions/component_loader.cc
@@ -137,7 +137,7 @@ std::string ComponentLoader::Add(const std::string& manifest_contents,
   DictionaryValue* manifest = ParseManifest(manifest_contents);
   if (manifest)
     return Add(manifest, root_directory);
-  return std::string();
+  return "";
 }
 
 std::string ComponentLoader::Add(const DictionaryValue* parsed_manifest,
diff --git a/chrome/browser/extensions/component_loader_unittest.cc b/chrome/browser/extensions/component_loader_unittest.cc
index 4b2b52a..bedcfee 100644
--- a/chrome/browser/extensions/component_loader_unittest.cc
+++ b/chrome/browser/extensions/component_loader_unittest.cc
@@ -141,7 +141,7 @@ TEST_F(ComponentLoaderTest, ParseManifest) {
   // Test manifests that are valid JSON, but don't have an object literal
   // at the root. ParseManifest() should always return NULL.
 
-  manifest.reset(component_loader_.ParseManifest(std::string()));
+  manifest.reset(component_loader_.ParseManifest(""));
   EXPECT_FALSE(manifest.get());
 
   manifest.reset(component_loader_.ParseManifest("[{ \"foo\": 3 }]"));
diff --git a/chrome/browser/extensions/event_router.cc b/chrome/browser/extensions/event_router.cc
index 72e0f52..4a75636 100644
--- a/chrome/browser/extensions/event_router.cc
+++ b/chrome/browser/extensions/event_router.cc
@@ -119,7 +119,7 @@ void EventRouter::LogExtensionEventMessage(void* profile_id,
         LOG(WARNING) << "Extension " << extension_id << " not found!";
       } else {
         extensions::ActivityLog::GetInstance(profile)->LogEventAction(
-            extension, event_name, event_args.get(), std::string());
+            extension, event_name, event_args.get(), "");
       }
     }
   }
@@ -243,8 +243,10 @@ void EventRouter::OnListenerAdded(const EventListener* listener) {
     scoped_ptr<ListValue> args(new ListValue());
     if (listener->filter)
       args->Append(listener->filter->DeepCopy());
-    activity_log_->LogAPIAction(
-        extension, event_name + ".addListener", args.get(), std::string());
+    activity_log_->LogAPIAction(extension,
+                                event_name + ".addListener",
+                                args.get(),
+                                "");
   }
 }
 
@@ -269,8 +271,10 @@ void EventRouter::OnListenerRemoved(const EventListener* listener) {
                                             ExtensionService::INCLUDE_ENABLED);
   if (extension) {
     scoped_ptr<ListValue> args(new ListValue());
-    activity_log_->LogAPIAction(
-        extension, event_name + ".removeListener", args.get(), std::string());
+    activity_log_->LogAPIAction(extension,
+                                event_name + ".removeListener",
+                                args.get(),
+                                "");
   }
 }
 
@@ -380,7 +384,7 @@ bool EventRouter::HasEventListenerImpl(const ListenerMap& listener_map,
 }
 
 void EventRouter::BroadcastEvent(scoped_ptr<Event> event) {
-  DispatchEventImpl(std::string(), linked_ptr<Event>(event.release()));
+  DispatchEventImpl("", linked_ptr<Event>(event.release()));
 }
 
 void EventRouter::DispatchEventToExtension(const std::string& extension_id,
diff --git a/chrome/browser/extensions/event_router_forwarder.cc b/chrome/browser/extensions/event_router_forwarder.cc
index f094608..15b7e97 100644
--- a/chrome/browser/extensions/event_router_forwarder.cc
+++ b/chrome/browser/extensions/event_router_forwarder.cc
@@ -26,7 +26,7 @@ void EventRouterForwarder::BroadcastEventToRenderers(
     const std::string& event_name,
     scoped_ptr<base::ListValue> event_args,
     const GURL& event_url) {
-  HandleEvent(std::string(), event_name, event_args.Pass(), 0, true, event_url);
+  HandleEvent("", event_name, event_args.Pass(), 0, true, event_url);
 }
 
 void EventRouterForwarder::DispatchEventToRenderers(
@@ -37,12 +37,8 @@ void EventRouterForwarder::DispatchEventToRenderers(
     const GURL& event_url) {
   if (!profile)
     return;
-  HandleEvent(std::string(),
-              event_name,
-              event_args.Pass(),
-              profile,
-              use_profile_to_restrict_events,
-              event_url);
+  HandleEvent("", event_name, event_args.Pass(), profile,
+              use_profile_to_restrict_events, event_url);
 }
 
 void EventRouterForwarder::BroadcastEventToExtension(
diff --git a/chrome/browser/extensions/extension_action_unittest.cc b/chrome/browser/extensions/extension_action_unittest.cc
index 6c2ca63..9a5c3ff 100644
--- a/chrome/browser/extensions/extension_action_unittest.cc
+++ b/chrome/browser/extensions/extension_action_unittest.cc
@@ -15,7 +15,7 @@ using extensions::ActionInfo;
 TEST(ExtensionActionTest, Title) {
   ActionInfo action_info;
   action_info.default_title = "Initial Title";
-  ExtensionAction action(std::string(), ActionInfo::TYPE_PAGE, action_info);
+  ExtensionAction action("", ActionInfo::TYPE_PAGE, action_info);
 
   ASSERT_EQ("Initial Title", action.GetTitle(1));
   action.SetTitle(ExtensionAction::kDefaultTabId, "foo");
@@ -31,7 +31,8 @@ TEST(ExtensionActionTest, Title) {
 }
 
 TEST(ExtensionActionTest, Visibility) {
-  ExtensionAction action(std::string(), ActionInfo::TYPE_PAGE, ActionInfo());
+  ExtensionAction action("", ActionInfo::TYPE_PAGE,
+                         ActionInfo());
 
   ASSERT_FALSE(action.GetIsVisible(1));
   action.SetAppearance(ExtensionAction::kDefaultTabId, ExtensionAction::ACTIVE);
@@ -52,8 +53,8 @@ TEST(ExtensionActionTest, Visibility) {
   ASSERT_FALSE(action.GetIsVisible(1));
   ASSERT_FALSE(action.GetIsVisible(100));
 
-  ExtensionAction browser_action(
-      std::string(), ActionInfo::TYPE_BROWSER, ActionInfo());
+  ExtensionAction browser_action("", ActionInfo::TYPE_BROWSER,
+                                 ActionInfo());
   ASSERT_TRUE(browser_action.GetIsVisible(1));
 }
 
@@ -61,8 +62,8 @@ TEST(ExtensionActionTest, ScriptBadgeAnimation) {
   // Supports the icon animation.
   MessageLoop message_loop;
 
-  ExtensionAction script_badge(
-      std::string(), ActionInfo::TYPE_SCRIPT_BADGE, ActionInfo());
+  ExtensionAction script_badge("", ActionInfo::TYPE_SCRIPT_BADGE,
+                               ActionInfo());
   EXPECT_FALSE(script_badge.GetIconAnimation(ExtensionAction::kDefaultTabId));
   script_badge.SetAppearance(ExtensionAction::kDefaultTabId,
                              ExtensionAction::ACTIVE);
@@ -85,8 +86,8 @@ TEST(ExtensionActionTest, GetAttention) {
   // Supports the icon animation.
   scoped_ptr<MessageLoop> message_loop(new MessageLoop);
 
-  ExtensionAction script_badge(
-      std::string(), ActionInfo::TYPE_SCRIPT_BADGE, ActionInfo());
+  ExtensionAction script_badge("", ActionInfo::TYPE_SCRIPT_BADGE,
+                               ActionInfo());
   EXPECT_FALSE(script_badge.GetIsVisible(1));
   EXPECT_FALSE(script_badge.GetIconAnimation(1));
   script_badge.SetAppearance(1, ExtensionAction::WANTS_ATTENTION);
@@ -106,8 +107,8 @@ TEST(ExtensionActionTest, GetAttention) {
 TEST(ExtensionActionTest, Icon) {
   ActionInfo action_info;
   action_info.default_icon.Add(16, "icon16.png");
-  ExtensionAction page_action(
-      std::string(), ActionInfo::TYPE_PAGE, action_info);
+  ExtensionAction page_action("", ActionInfo::TYPE_PAGE,
+                              action_info);
   ASSERT_TRUE(page_action.default_icon());
   EXPECT_EQ("icon16.png",
             page_action.default_icon()->Get(
@@ -118,7 +119,8 @@ TEST(ExtensionActionTest, Icon) {
 }
 
 TEST(ExtensionActionTest, Badge) {
-  ExtensionAction action(std::string(), ActionInfo::TYPE_PAGE, ActionInfo());
+  ExtensionAction action("", ActionInfo::TYPE_PAGE,
+                         ActionInfo());
   ASSERT_EQ("", action.GetBadgeText(1));
   action.SetBadgeText(ExtensionAction::kDefaultTabId, "foo");
   ASSERT_EQ("foo", action.GetBadgeText(1));
@@ -133,7 +135,8 @@ TEST(ExtensionActionTest, Badge) {
 }
 
 TEST(ExtensionActionTest, BadgeTextColor) {
-  ExtensionAction action(std::string(), ActionInfo::TYPE_PAGE, ActionInfo());
+  ExtensionAction action("", ActionInfo::TYPE_PAGE,
+                         ActionInfo());
   ASSERT_EQ(0x00000000u, action.GetBadgeTextColor(1));
   action.SetBadgeTextColor(ExtensionAction::kDefaultTabId, 0xFFFF0000u);
   ASSERT_EQ(0xFFFF0000u, action.GetBadgeTextColor(1));
@@ -148,7 +151,8 @@ TEST(ExtensionActionTest, BadgeTextColor) {
 }
 
 TEST(ExtensionActionTest, BadgeBackgroundColor) {
-  ExtensionAction action(std::string(), ActionInfo::TYPE_PAGE, ActionInfo());
+  ExtensionAction action("", ActionInfo::TYPE_PAGE,
+                         ActionInfo());
   ASSERT_EQ(0x00000000u, action.GetBadgeBackgroundColor(1));
   action.SetBadgeBackgroundColor(ExtensionAction::kDefaultTabId,
                                  0xFFFF0000u);
@@ -172,7 +176,7 @@ TEST(ExtensionActionTest, PopupUrl) {
 
   ActionInfo action_info;
   action_info.default_popup_url = url_foo;
-  ExtensionAction action(std::string(), ActionInfo::TYPE_PAGE, action_info);
+  ExtensionAction action("", ActionInfo::TYPE_PAGE, action_info);
 
   ASSERT_EQ(url_foo, action.GetPopupUrl(1));
   ASSERT_EQ(url_foo, action.GetPopupUrl(100));
diff --git a/chrome/browser/extensions/extension_apitest.cc b/chrome/browser/extensions/extension_apitest.cc
index 8d072ae..e3534e4 100644
--- a/chrome/browser/extensions/extension_apitest.cc
+++ b/chrome/browser/extensions/extension_apitest.cc
@@ -80,7 +80,7 @@ void ExtensionApiTest::ResultCatcher::Observe(
     case chrome::NOTIFICATION_EXTENSION_TEST_PASSED:
       VLOG(1) << "Got EXTENSION_TEST_PASSED notification.";
       results_.push_back(true);
-      messages_.push_back(std::string());
+      messages_.push_back("");
       if (waiting_)
         MessageLoopForUI::current()->Quit();
       break;
@@ -114,45 +114,41 @@ void ExtensionApiTest::TearDownInProcessBrowserTestFixture() {
 }
 
 bool ExtensionApiTest::RunExtensionTest(const char* extension_name) {
-  return RunExtensionTestImpl(
-      extension_name, std::string(), kFlagEnableFileAccess);
+  return RunExtensionTestImpl(extension_name, "", kFlagEnableFileAccess);
 }
 
 bool ExtensionApiTest::RunExtensionTestIncognito(const char* extension_name) {
-  return RunExtensionTestImpl(extension_name,
-                              std::string(),
-                              kFlagEnableIncognito | kFlagEnableFileAccess);
+  return RunExtensionTestImpl(
+      extension_name, "", kFlagEnableIncognito | kFlagEnableFileAccess);
 }
 
 bool ExtensionApiTest::RunExtensionTestIgnoreManifestWarnings(
     const char* extension_name) {
   return RunExtensionTestImpl(
-      extension_name, std::string(), kFlagIgnoreManifestWarnings);
+      extension_name, "", kFlagIgnoreManifestWarnings);
 }
 
 bool ExtensionApiTest::RunExtensionTestAllowOldManifestVersion(
     const char* extension_name) {
   return RunExtensionTestImpl(
       extension_name,
-      std::string(),
+      "",
       kFlagEnableFileAccess | kFlagAllowOldManifestVersions);
 }
 
 bool ExtensionApiTest::RunComponentExtensionTest(const char* extension_name) {
-  return RunExtensionTestImpl(extension_name,
-                              std::string(),
-                              kFlagEnableFileAccess | kFlagLoadAsComponent);
+  return RunExtensionTestImpl(
+      extension_name, "", kFlagEnableFileAccess | kFlagLoadAsComponent);
 }
 
 bool ExtensionApiTest::RunExtensionTestNoFileAccess(
     const char* extension_name) {
-  return RunExtensionTestImpl(extension_name, std::string(), kFlagNone);
+  return RunExtensionTestImpl(extension_name, "", kFlagNone);
 }
 
 bool ExtensionApiTest::RunExtensionTestIncognitoNoFileAccess(
     const char* extension_name) {
-  return RunExtensionTestImpl(
-      extension_name, std::string(), kFlagEnableIncognito);
+  return RunExtensionTestImpl(extension_name, "", kFlagEnableIncognito);
 }
 
 bool ExtensionApiTest::RunExtensionSubtest(const char* extension_name,
@@ -178,8 +174,7 @@ bool ExtensionApiTest::RunPageTest(const std::string& page_url,
 }
 
 bool ExtensionApiTest::RunPlatformAppTest(const char* extension_name) {
-  return RunExtensionTestImpl(
-      extension_name, std::string(), kFlagLaunchPlatformApp);
+  return RunExtensionTestImpl(extension_name, "", kFlagLaunchPlatformApp);
 }
 
 // Load |extension_name| extension and/or |page_url| and wait for
diff --git a/chrome/browser/extensions/extension_browsertest.cc b/chrome/browser/extensions/extension_browsertest.cc
index cfad60e..b051df9 100644
--- a/chrome/browser/extensions/extension_browsertest.cc
+++ b/chrome/browser/extensions/extension_browsertest.cc
@@ -337,13 +337,9 @@ class MockAutoConfirmExtensionInstallPrompt : public ExtensionInstallPrompt {
 const Extension* ExtensionBrowserTest::InstallExtensionFromWebstore(
     const base::FilePath& path,
     int expected_change) {
-  return InstallOrUpdateExtension(std::string(),
-                                  path,
-                                  INSTALL_UI_TYPE_NONE,
-                                  expected_change,
-                                  Manifest::INTERNAL,
-                                  browser(),
-                                  true);
+  return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NONE,
+                                  expected_change, Manifest::INTERNAL,
+                                  browser(), true);
 }
 
 const Extension* ExtensionBrowserTest::InstallOrUpdateExtension(
diff --git a/chrome/browser/extensions/extension_browsertest.h b/chrome/browser/extensions/extension_browsertest.h
index 9d79f56..9d1203c 100644
--- a/chrome/browser/extensions/extension_browsertest.h
+++ b/chrome/browser/extensions/extension_browsertest.h
@@ -112,8 +112,8 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
   // you expect a failed upgrade.
   const extensions::Extension* InstallExtension(const base::FilePath& path,
                                                 int expected_change) {
-    return InstallOrUpdateExtension(
-        std::string(), path, INSTALL_UI_TYPE_NONE, expected_change);
+    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NONE,
+                                    expected_change);
   }
 
   // Same as above, but an install source other than Manifest::INTERNAL can be
@@ -122,11 +122,8 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
       const base::FilePath& path,
       int expected_change,
       extensions::Manifest::Location install_source) {
-    return InstallOrUpdateExtension(std::string(),
-                                    path,
-                                    INSTALL_UI_TYPE_NONE,
-                                    expected_change,
-                                    install_source);
+    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NONE,
+                                    expected_change, install_source);
   }
 
   // Installs extension as if it came from the Chrome Webstore.
@@ -147,27 +144,22 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
   const extensions::Extension* InstallExtensionWithUI(
       const base::FilePath& path,
       int expected_change) {
-    return InstallOrUpdateExtension(
-        std::string(), path, INSTALL_UI_TYPE_NORMAL, expected_change);
+    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_NORMAL,
+                                    expected_change);
   }
 
   const extensions::Extension* InstallExtensionWithUIAutoConfirm(
       const base::FilePath& path,
       int expected_change,
       Browser* browser) {
-    return InstallOrUpdateExtension(std::string(),
-                                    path,
-                                    INSTALL_UI_TYPE_AUTO_CONFIRM,
-                                    expected_change,
-                                    browser,
-                                    false);
+    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_AUTO_CONFIRM,
+                                    expected_change, browser, false);
   }
 
   // Begins install process but simulates a user cancel.
   const extensions::Extension* StartInstallButCancel(
       const base::FilePath& path) {
-    return InstallOrUpdateExtension(
-        std::string(), path, INSTALL_UI_TYPE_CANCEL, 0);
+    return InstallOrUpdateExtension("", path, INSTALL_UI_TYPE_CANCEL, 0);
   }
 
   void ReloadExtension(const std::string& extension_id);
diff --git a/chrome/browser/extensions/extension_function_dispatcher.cc b/chrome/browser/extensions/extension_function_dispatcher.cc
index c15ba6f..00a1f39 100644
--- a/chrome/browser/extensions/extension_function_dispatcher.cc
+++ b/chrome/browser/extensions/extension_function_dispatcher.cc
@@ -63,7 +63,7 @@ void LogSuccess(const Extension* extension,
   } else {
     extensions::ActivityLog* activity_log =
         extensions::ActivityLog::GetInstance(profile);
-    activity_log->LogAPIAction(extension, api_name, args.get(), std::string());
+    activity_log->LogAPIAction(extension, api_name, args.get(), "");
   }
 }
 
@@ -86,8 +86,11 @@ void LogFailure(const Extension* extension,
   } else {
     extensions::ActivityLog* activity_log =
         extensions::ActivityLog::GetInstance(profile);
-    activity_log->LogBlockedAction(
-        extension, api_name, args.get(), reason, std::string());
+    activity_log->LogBlockedAction(extension,
+                                   api_name,
+                                   args.get(),
+                                   reason,
+                                   "");
   }
 }
 
diff --git a/chrome/browser/extensions/extension_pref_value_map_unittest.cc b/chrome/browser/extensions/extension_pref_value_map_unittest.cc
index 7f1b2d5..bfa573f 100644
--- a/chrome/browser/extensions/extension_pref_value_map_unittest.cc
+++ b/chrome/browser/extensions/extension_pref_value_map_unittest.cc
@@ -45,7 +45,7 @@ class ExtensionPrefValueMapTestBase : public BASECLASS {
   // Returns an empty string if the key is not set.
   std::string GetValue(const char * key, bool incognito) const {
     const Value *value = epvm_.GetEffectivePrefValue(key, incognito, NULL);
-    std::string string_value;
+    std::string string_value = "";
     if (value)
       value->GetAsString(&string_value);
     return string_value;
diff --git a/chrome/browser/extensions/extension_prefs.cc b/chrome/browser/extensions/extension_prefs.cc
index b24e0e7..0f1d743 100644
--- a/chrome/browser/extensions/extension_prefs.cc
+++ b/chrome/browser/extensions/extension_prefs.cc
@@ -1670,8 +1670,7 @@ void ExtensionPrefs::SetDelayedInstallInfo(
   if (extension->RequiresSortOrdinal()) {
     extension_dict->SetString(
         kPrefSuggestedPageOrdinal,
-        page_ordinal.IsValid() ? page_ordinal.ToInternalValue()
-                               : std::string());
+        page_ordinal.IsValid() ? page_ordinal.ToInternalValue() : "");
   }
 
   UpdateExtensionPref(extension->id(), kDelayedInstallInfo, extension_dict);
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index 09fc245..a4cb67f 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -63,7 +63,7 @@ std::string GetExtensionID(RenderViewHost* render_view_host) {
   // This works for both apps and extensions because the site has been
   // normalized to the extension URL for apps.
   if (!render_view_host->GetSiteInstance())
-    return std::string();
+    return "";
 
   return render_view_host->GetSiteInstance()->GetSiteURL().host();
 }
diff --git a/chrome/browser/extensions/extension_protocols.cc b/chrome/browser/extensions/extension_protocols.cc
index 503b2ad..049d813 100644
--- a/chrome/browser/extensions/extension_protocols.cc
+++ b/chrome/browser/extensions/extension_protocols.cc
@@ -320,8 +320,7 @@ bool AllowExtensionResourceLoad(net::URLRequest* request,
   // some extensions want to be able to do things like create their own
   // launchers.
   std::string resource_root_relative_path =
-      request->url().path().empty() ? std::string()
-                                    : request->url().path().substr(1);
+      request->url().path().empty() ? "" : request->url().path().substr(1);
   if (extension->is_hosted_app() &&
       !extensions::IconsInfo::GetIcons(extension)
           .ContainsPath(resource_root_relative_path)) {
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index 368d048..a6068b5 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -1192,7 +1192,7 @@ TEST_F(ExtensionServiceTest, LoadAllExtensionsFromDirectorySuccess) {
 
   EXPECT_EQ(std::string(good1), loaded_[1]->id());
   EXPECT_EQ(std::string("My extension 2"), loaded_[1]->name());
-  EXPECT_EQ(std::string(), loaded_[1]->description());
+  EXPECT_EQ(std::string(""), loaded_[1]->description());
   EXPECT_EQ(loaded_[1]->GetResourceURL("background.html"),
             extensions::BackgroundInfo::GetBackgroundURL(loaded_[1]));
   EXPECT_EQ(
@@ -1220,7 +1220,7 @@ TEST_F(ExtensionServiceTest, LoadAllExtensionsFromDirectorySuccess) {
   int index = expected_num_extensions - 1;
   EXPECT_EQ(std::string(good2), loaded_[index]->id());
   EXPECT_EQ(std::string("My extension 3"), loaded_[index]->name());
-  EXPECT_EQ(std::string(), loaded_[index]->description());
+  EXPECT_EQ(std::string(""), loaded_[index]->description());
   EXPECT_EQ(
       0u,
       extensions::ContentScriptsInfo::GetContentScripts(loaded_[index]).size());
@@ -3313,8 +3313,8 @@ TEST_F(ExtensionServiceTest, ManagementPolicyProhibitsLoadFromPrefs) {
   // UNPACKED is for extensions loaded from a directory. We use it here, even
   // though we're testing loading from prefs, so that we don't need to provide
   // an extension key.
-  extensions::ExtensionInfo extension_info(
-      &manifest, std::string(), path, Manifest::UNPACKED);
+  extensions::ExtensionInfo extension_info(&manifest, "", path,
+                                           Manifest::UNPACKED);
 
   // Ensure we can load it with no management policy in place.
   management_policy_->UnregisterAllProviders();
diff --git a/chrome/browser/extensions/extension_test_message_listener.cc b/chrome/browser/extensions/extension_test_message_listener.cc
index e892ba1..90aa01a 100644
--- a/chrome/browser/extensions/extension_test_message_listener.cc
+++ b/chrome/browser/extensions/extension_test_message_listener.cc
@@ -17,6 +17,7 @@ ExtensionTestMessageListener::ExtensionTestMessageListener(
       satisfied_(false),
       waiting_(false),
       will_reply_(will_reply),
+      failure_message_(""),
       failed_(false) {
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_TEST_MESSAGE,
                  content::NotificationService::AllSources());
@@ -58,7 +59,7 @@ void ExtensionTestMessageListener::Observe(
     satisfied_ = true;
     registrar_.RemoveAll();  // Stop listening for more messages.
     if (!will_reply_) {
-      function_->Reply(std::string());
+      function_->Reply("");
       function_ = NULL;
     }
     if (waiting_) {
diff --git a/chrome/browser/extensions/extensions_quota_service.cc b/chrome/browser/extensions/extensions_quota_service.cc
index 6b267a5..c01b9e3 100644
--- a/chrome/browser/extensions/extensions_quota_service.cc
+++ b/chrome/browser/extensions/extensions_quota_service.cc
@@ -42,7 +42,7 @@ std::string ExtensionsQuotaService::Assess(
   DCHECK(CalledOnValidThread());
 
   if (function->ShouldSkipQuotaLimiting())
-    return std::string();
+    return "";
 
   // Lookup function list for extension.
   FunctionHeuristicsMap& functions = function_heuristics_[extension_id];
@@ -53,7 +53,7 @@ std::string ExtensionsQuotaService::Assess(
     function->GetQuotaLimitHeuristics(&heuristics);
 
   if (heuristics.empty())
-    return std::string();  // No heuristic implies no limit.
+    return "";  // No heuristic implies no limit.
 
   ViolationErrorMap::iterator violation_error =
       violation_errors_.find(extension_id);
@@ -71,7 +71,7 @@ std::string ExtensionsQuotaService::Assess(
   }
 
   if (!failed_heuristic)
-    return std::string();
+    return "";
 
   std::string error = failed_heuristic->GetError();
   DCHECK_GT(error.length(), 0u);
diff --git a/chrome/browser/extensions/external_policy_loader_unittest.cc b/chrome/browser/extensions/external_policy_loader_unittest.cc
index 75bd788..5f8943c 100644
--- a/chrome/browser/extensions/external_policy_loader_unittest.cc
+++ b/chrome/browser/extensions/external_policy_loader_unittest.cc
@@ -139,8 +139,7 @@ TEST_F(ExternalPolicyLoaderTest, InvalidEntriesIgnored) {
 
   // Add invalid entries.
   forced_extensions.SetString("invalid", "http://www.example.com/crx");
-  forced_extensions.SetString("dddddddddddddddddddddddddddddddd",
-                              std::string());
+  forced_extensions.SetString("dddddddddddddddddddddddddddddddd", "");
   forced_extensions.SetString("invalid", "bad");
 
   MockExternalPolicyProviderVisitor mv;
diff --git a/chrome/browser/extensions/isolated_app_browsertest.cc b/chrome/browser/extensions/isolated_app_browsertest.cc
index ec55a4c..b7717bb 100644
--- a/chrome/browser/extensions/isolated_app_browsertest.cc
+++ b/chrome/browser/extensions/isolated_app_browsertest.cc
@@ -328,7 +328,7 @@ IN_PROC_BROWSER_TEST_F(IsolatedAppTest, MAYBE_SubresourceCookieIsolation) {
 
   // The app under test acts on URLs whose host is "localhost",
   // so the URLs we navigate to must have host "localhost".
-  GURL root_url = test_server()->GetURL(std::string());
+  GURL root_url = test_server()->GetURL("");
   GURL base_url = test_server()->GetURL("files/extensions/isolated_apps/");
   GURL::Replacements replace_host;
   std::string host_str("localhost");  // Must stay in scope with replace_host.
diff --git a/chrome/browser/extensions/menu_manager.cc b/chrome/browser/extensions/menu_manager.cc
index 4256c61..0335866 100644
--- a/chrome/browser/extensions/menu_manager.cc
+++ b/chrome/browser/extensions/menu_manager.cc
@@ -833,10 +833,14 @@ void MenuManager::RemoveAllIncognitoContextItems() {
     RemoveContextMenuItem(*remove_iter);
 }
 
-MenuItem::Id::Id() : incognito(false), uid(0) {}
+MenuItem::Id::Id()
+    : incognito(false), extension_id(""), uid(0), string_uid("") {
+}
 
 MenuItem::Id::Id(bool incognito, const std::string& extension_id)
-    : incognito(incognito), extension_id(extension_id), uid(0) {}
+    : incognito(incognito), extension_id(extension_id), uid(0),
+      string_uid("") {
+}
 
 MenuItem::Id::~Id() {
 }
diff --git a/chrome/browser/extensions/pending_extension_info.cc b/chrome/browser/extensions/pending_extension_info.cc
index a1e93d8..6fc0adc 100644
--- a/chrome/browser/extensions/pending_extension_info.cc
+++ b/chrome/browser/extensions/pending_extension_info.cc
@@ -25,7 +25,8 @@ PendingExtensionInfo::PendingExtensionInfo(
       install_source_(install_source) {}
 
 PendingExtensionInfo::PendingExtensionInfo()
-    : update_url_(),
+    : id_(""),
+      update_url_(),
       should_allow_install_(NULL),
       is_from_sync_(true),
       install_silently_(false),
diff --git a/chrome/browser/extensions/platform_app_browsertest_util.cc b/chrome/browser/extensions/platform_app_browsertest_util.cc
index 58c2548..62f8545 100644
--- a/chrome/browser/extensions/platform_app_browsertest_util.cc
+++ b/chrome/browser/extensions/platform_app_browsertest_util.cc
@@ -142,13 +142,13 @@ ShellWindow* PlatformAppBrowserTest::CreateShellWindow(
     const Extension* extension) {
   ShellWindow::CreateParams params;
   return ShellWindow::Create(
-      browser()->profile(), extension, GURL(std::string()), params);
+      browser()->profile(), extension, GURL(""), params);
 }
 
 ShellWindow* PlatformAppBrowserTest::CreateShellWindowFromParams(
     const Extension* extension, const ShellWindow::CreateParams& params) {
   return ShellWindow::Create(
-      browser()->profile(), extension, GURL(std::string()), params);
+      browser()->profile(), extension, GURL(""), params);
 }
 
 void PlatformAppBrowserTest::CloseShellWindow(ShellWindow* window) {
diff --git a/chrome/browser/extensions/platform_app_launcher.cc b/chrome/browser/extensions/platform_app_launcher.cc
index 46daa89..a883e66 100644
--- a/chrome/browser/extensions/platform_app_launcher.cc
+++ b/chrome/browser/extensions/platform_app_launcher.cc
@@ -107,7 +107,10 @@ class PlatformAppPathLauncher
   PlatformAppPathLauncher(Profile* profile,
                           const Extension* extension,
                           const base::FilePath& file_path)
-      : profile_(profile), extension_(extension), file_path_(file_path) {}
+      : profile_(profile),
+        extension_(extension),
+        file_path_(file_path),
+        handler_id_("") {}
 
   void Launch() {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
diff --git a/chrome/browser/extensions/script_badge_controller_unittest.cc b/chrome/browser/extensions/script_badge_controller_unittest.cc
index cb773f8..d2cf6bc 100644
--- a/chrome/browser/extensions/script_badge_controller_unittest.cc
+++ b/chrome/browser/extensions/script_badge_controller_unittest.cc
@@ -138,7 +138,7 @@ TEST_F(ScriptBadgeControllerTest, ExecutionMakesBadgeVisible) {
       web_contents(),
       id_map,
       web_contents()->GetController().GetActiveEntry()->GetPageID(),
-      GURL(std::string()));
+      GURL(""));
   EXPECT_THAT(script_badge_controller_->GetCurrentActions(),
               testing::ElementsAre(GetScriptBadge(*extension)));
   EXPECT_THAT(location_bar_updated.events, testing::Gt(0));
@@ -167,7 +167,7 @@ TEST_F(ScriptBadgeControllerTest, FragmentNavigation) {
         web_contents(),
         id_map,
         web_contents()->GetController().GetActiveEntry()->GetPageID(),
-        GURL(std::string()));
+        GURL(""));
 
     EXPECT_THAT(script_badge_controller_->GetCurrentActions(),
                 testing::ElementsAre(GetScriptBadge(*extension)));
diff --git a/chrome/browser/extensions/script_executor.cc b/chrome/browser/extensions/script_executor.cc
index b35b776..c5ed09f 100644
--- a/chrome/browser/extensions/script_executor.cc
+++ b/chrome/browser/extensions/script_executor.cc
@@ -66,7 +66,7 @@ class Handler : public content::WebContentsObserver {
 
   virtual void WebContentsDestroyed(content::WebContents* tab) OVERRIDE {
     base::ListValue val;
-    callback_.Run(kRendererDestroyed, -1, GURL(std::string()), val);
+    callback_.Run(kRendererDestroyed, -1, GURL(""), val);
     delete this;
   }
 
diff --git a/chrome/browser/extensions/subscribe_page_action_browsertest.cc b/chrome/browser/extensions/subscribe_page_action_browsertest.cc
index 02449a1..471ad5c 100644
--- a/chrome/browser/extensions/subscribe_page_action_browsertest.cc
+++ b/chrome/browser/extensions/subscribe_page_action_browsertest.cc
@@ -114,8 +114,10 @@ void NavigateToFeedAndValidate(net::TestServer* server,
                                GetFeedUrl(server, url, true, extension_id));
 
   WebContents* tab = browser->tab_strip_model()->GetActiveWebContents();
-  ASSERT_TRUE(ValidatePageElement(
-      tab, std::string(), kScriptFeedTitle, expected_feed_title));
+  ASSERT_TRUE(ValidatePageElement(tab,
+                                  "",
+                                  kScriptFeedTitle,
+                                  expected_feed_title));
   ASSERT_TRUE(ValidatePageElement(tab,
                                   "//html/body/div/iframe[1]",
                                   kScriptAnchor,
diff --git a/chrome/browser/extensions/tab_helper.cc b/chrome/browser/extensions/tab_helper.cc
index cd420ad..cdcec02 100644
--- a/chrome/browser/extensions/tab_helper.cc
+++ b/chrome/browser/extensions/tab_helper.cc
@@ -413,7 +413,7 @@ void TabHelper::OnInlineInstallComplete(int install_id,
                                         const std::string& error) {
   if (success) {
     Send(new ExtensionMsg_InlineWebstoreInstallResponse(
-        return_route_id, install_id, true, std::string()));
+        return_route_id, install_id, true, ""));
   } else {
     Send(new ExtensionMsg_InlineWebstoreInstallResponse(
         return_route_id, install_id, false, error));
diff --git a/chrome/browser/extensions/updater/extension_downloader.cc b/chrome/browser/extensions/updater/extension_downloader.cc
index f165732..0c04a89 100644
--- a/chrome/browser/extensions/updater/extension_downloader.cc
+++ b/chrome/browser/extensions/updater/extension_downloader.cc
@@ -153,7 +153,12 @@ UpdateDetails::UpdateDetails(const std::string& id, const Version& version)
 
 UpdateDetails::~UpdateDetails() {}
 
-ExtensionDownloader::ExtensionFetch::ExtensionFetch() : url() {}
+
+ExtensionDownloader::ExtensionFetch::ExtensionFetch()
+    : id(""),
+      url(),
+      package_hash(""),
+      version("") {}
 
 ExtensionDownloader::ExtensionFetch::ExtensionFetch(
     const std::string& id,
@@ -215,11 +220,7 @@ bool ExtensionDownloader::AddPendingExtension(const std::string& id,
   Version version("0.0.0.0");
   DCHECK(version.IsValid());
 
-  return AddExtensionData(id,
-                          version,
-                          Manifest::TYPE_UNKNOWN,
-                          update_url,
-                          std::string(),
+  return AddExtensionData(id, version, Manifest::TYPE_UNKNOWN, update_url, "",
                           request_id);
 }
 
@@ -248,10 +249,7 @@ void ExtensionDownloader::StartBlacklistUpdate(
       new ManifestFetchData(extension_urls::GetWebstoreUpdateUrl(),
                             request_id));
   DCHECK(blacklist_fetch->base_url().SchemeIsSecure());
-  blacklist_fetch->AddExtension(kBlacklistAppID,
-                                version,
-                                &ping_data,
-                                std::string(),
+  blacklist_fetch->AddExtension(kBlacklistAppID, version, &ping_data, "",
                                 kDefaultInstallSource);
   StartUpdateCheck(blacklist_fetch.Pass());
 }
diff --git a/chrome/browser/extensions/updater/extension_updater.cc b/chrome/browser/extensions/updater/extension_updater.cc
index 130da8f..feadf5a 100644
--- a/chrome/browser/extensions/updater/extension_updater.cc
+++ b/chrome/browser/extensions/updater/extension_updater.cc
@@ -106,7 +106,10 @@ ExtensionUpdater::FetchedCRXFile::FetchedCRXFile(
       download_url(u),
       request_ids(request_ids) {}
 
-ExtensionUpdater::FetchedCRXFile::FetchedCRXFile() : path(), download_url() {}
+ExtensionUpdater::FetchedCRXFile::FetchedCRXFile()
+    : extension_id(""),
+      path(),
+      download_url() {}
 
 ExtensionUpdater::FetchedCRXFile::~FetchedCRXFile() {}
 
diff --git a/chrome/browser/extensions/updater/extension_updater_unittest.cc b/chrome/browser/extensions/updater/extension_updater_unittest.cc
index 3481c0c..4921d9e 100644
--- a/chrome/browser/extensions/updater/extension_updater_unittest.cc
+++ b/chrome/browser/extensions/updater/extension_updater_unittest.cc
@@ -432,7 +432,7 @@ static void ExtractParameters(const std::string& params,
     if (!key_val.empty()) {
       std::string key = key_val[0];
       EXPECT_TRUE(result->find(key) == result->end());
-      (*result)[key] = (key_val.size() == 2) ? key_val[1] : std::string();
+      (*result)[key] = (key_val.size() == 2) ? key_val[1] : "";
     } else {
       NOTREACHED();
     }
@@ -637,8 +637,7 @@ class ExtensionUpdaterTest : public testing::Test {
     // Make sure that an empty update URL data string does not cause a ap=
     // option to appear in the x= parameter.
     ManifestFetchData fetch_data(GURL("http://localhost/foo"), 0);
-    fetch_data.AddExtension(
-        id, version, &kNeverPingedData, std::string(), std::string());
+    fetch_data.AddExtension(id, version, &kNeverPingedData, "", "");
 
     std::map<std::string, std::string> params;
     VerifyQueryAndExtractParameters(fetch_data.full_url().query(), &params);
@@ -654,8 +653,7 @@ class ExtensionUpdaterTest : public testing::Test {
     // Make sure that an update URL data string causes an appropriate ap=
     // option to appear in the x= parameter.
     ManifestFetchData fetch_data(GURL("http://localhost/foo"), 0);
-    fetch_data.AddExtension(
-        id, version, &kNeverPingedData, "bar", std::string());
+    fetch_data.AddExtension(id, version, &kNeverPingedData, "bar", "");
     std::map<std::string, std::string> params;
     VerifyQueryAndExtractParameters(fetch_data.full_url().query(), &params);
     EXPECT_EQ(id, params["id"]);
@@ -670,8 +668,7 @@ class ExtensionUpdaterTest : public testing::Test {
     // Make sure that an update URL data string causes an appropriate ap=
     // option to appear in the x= parameter.
     ManifestFetchData fetch_data(GURL("http://localhost/foo"), 0);
-    fetch_data.AddExtension(
-        id, version, &kNeverPingedData, "a=1&b=2&c", std::string());
+    fetch_data.AddExtension(id, version, &kNeverPingedData, "a=1&b=2&c", "");
     std::map<std::string, std::string> params;
     VerifyQueryAndExtractParameters(fetch_data.full_url().query(), &params);
     EXPECT_EQ(id, params["id"]);
@@ -741,12 +738,14 @@ class ExtensionUpdaterTest : public testing::Test {
     // installed and available at v2.0).
     const std::string id1 = id_util::GenerateId("1");
     const std::string id2 = id_util::GenerateId("2");
-    fetch_data.AddExtension(
-        id1, "1.0.0.0", &kNeverPingedData, kEmptyUpdateUrlData, std::string());
-    AddParseResult(id1, "1.1", "http://localhost/e1_1.1.crx", &updates);
-    fetch_data.AddExtension(
-        id2, "2.0.0.0", &kNeverPingedData, kEmptyUpdateUrlData, std::string());
-    AddParseResult(id2, "2.0.0.0", "http://localhost/e2_2.0.crx", &updates);
+    fetch_data.AddExtension(id1, "1.0.0.0",
+                            &kNeverPingedData, kEmptyUpdateUrlData, "");
+    AddParseResult(id1, "1.1",
+                   "http://localhost/e1_1.1.crx", &updates);
+    fetch_data.AddExtension(id2, "2.0.0.0",
+                            &kNeverPingedData, kEmptyUpdateUrlData, "");
+    AddParseResult(id2, "2.0.0.0",
+                   "http://localhost/e2_2.0.crx", &updates);
 
     EXPECT_CALL(delegate, IsExtensionPending(_)).WillRepeatedly(Return(false));
     EXPECT_CALL(delegate, GetExtensionExistingVersion(id1, _))
@@ -783,11 +782,8 @@ class ExtensionUpdaterTest : public testing::Test {
     std::list<std::string>::const_iterator it;
     for (it = ids_for_update_check.begin();
          it != ids_for_update_check.end(); ++it) {
-      fetch_data.AddExtension(*it,
-                              "1.0.0.0",
-                              &kNeverPingedData,
-                              kEmptyUpdateUrlData,
-                              std::string());
+      fetch_data.AddExtension(*it, "1.0.0.0",
+                              &kNeverPingedData, kEmptyUpdateUrlData, "");
       AddParseResult(*it, "1.1", "http://localhost/e1_1.1.crx", &updates);
     }
 
@@ -820,14 +816,10 @@ class ExtensionUpdaterTest : public testing::Test {
     scoped_ptr<ManifestFetchData> fetch3(new ManifestFetchData(kUpdateUrl, 0));
     scoped_ptr<ManifestFetchData> fetch4(new ManifestFetchData(kUpdateUrl, 0));
     ManifestFetchData::PingData zeroDays(0, 0, true);
-    fetch1->AddExtension(
-        "1111", "1.0", &zeroDays, kEmptyUpdateUrlData, std::string());
-    fetch2->AddExtension(
-        "2222", "2.0", &zeroDays, kEmptyUpdateUrlData, std::string());
-    fetch3->AddExtension(
-        "3333", "3.0", &zeroDays, kEmptyUpdateUrlData, std::string());
-    fetch4->AddExtension(
-        "4444", "4.0", &zeroDays, kEmptyUpdateUrlData, std::string());
+    fetch1->AddExtension("1111", "1.0", &zeroDays, kEmptyUpdateUrlData, "");
+    fetch2->AddExtension("2222", "2.0", &zeroDays, kEmptyUpdateUrlData, "");
+    fetch3->AddExtension("3333", "3.0", &zeroDays, kEmptyUpdateUrlData, "");
+    fetch4->AddExtension("4444", "4.0", &zeroDays, kEmptyUpdateUrlData, "");
 
     // This will start the first fetcher and queue the others. The next in queue
     // is started as each fetcher receives its response.
@@ -935,8 +927,7 @@ class ExtensionUpdaterTest : public testing::Test {
 
     scoped_ptr<ManifestFetchData> fetch(new ManifestFetchData(kUpdateUrl, 0));
     ManifestFetchData::PingData zeroDays(0, 0, true);
-    fetch->AddExtension(
-        "1111", "1.0", &zeroDays, kEmptyUpdateUrlData, std::string());
+    fetch->AddExtension("1111", "1.0", &zeroDays, kEmptyUpdateUrlData, "");
 
     // This will start the first fetcher.
     downloader.StartUpdateCheck(fetch.Pass());
@@ -963,8 +954,7 @@ class ExtensionUpdaterTest : public testing::Test {
     // For response codes that are not in the 5xx range ExtensionDownloader
     // should not retry.
     fetch.reset(new ManifestFetchData(kUpdateUrl, 0));
-    fetch->AddExtension(
-        "1111", "1.0", &zeroDays, kEmptyUpdateUrlData, std::string());
+    fetch->AddExtension("1111", "1.0", &zeroDays, kEmptyUpdateUrlData, "");
 
     // This will start the first fetcher.
     downloader.StartUpdateCheck(fetch.Pass());
@@ -1016,7 +1006,7 @@ class ExtensionUpdaterTest : public testing::Test {
     GURL test_url("http://localhost/extension.crx");
 
     std::string id = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
-    std::string hash;
+    std::string hash = "";
     Version version("0.0.1");
     std::set<int> requests;
     requests.insert(0);
@@ -1152,8 +1142,8 @@ class ExtensionUpdaterTest : public testing::Test {
     std::string id1 = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
     std::string id2 = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
 
-    std::string hash1;
-    std::string hash2;
+    std::string hash1 = "";
+    std::string hash2 = "";
 
     std::string version1 = "0.1";
     std::string version2 = "0.1";
@@ -1367,7 +1357,7 @@ class ExtensionUpdaterTest : public testing::Test {
     fetcher->set_url(fetched_urls[0]);
     fetcher->set_status(net::URLRequestStatus());
     fetcher->set_response_code(500);
-    fetcher->SetResponseString(std::string());
+    fetcher->SetResponseString("");
     fetcher->delegate()->OnURLFetchComplete(fetcher);
 
     fetcher = factory.GetFetcherByID(ExtensionDownloader::kManifestFetcherId);
@@ -1452,11 +1442,8 @@ class ExtensionUpdaterTest : public testing::Test {
 
     ManifestFetchData fetch_data(update_url, 0);
     const Extension* extension = tmp[0];
-    fetch_data.AddExtension(extension->id(),
-                            extension->VersionString(),
-                            &kNeverPingedData,
-                            kEmptyUpdateUrlData,
-                            std::string());
+    fetch_data.AddExtension(extension->id(), extension->VersionString(),
+                            &kNeverPingedData, kEmptyUpdateUrlData, "");
     UpdateManifest::Results results;
     results.daystart_elapsed_seconds = 750;
 
@@ -1660,7 +1647,7 @@ TEST_F(ExtensionUpdaterTest, TestManifestFetchesBuilderAddExtension) {
   EXPECT_EQ(1u, ManifestFetchersCount(downloader.get()));
 
   // Extensions with empty IDs should be rejected.
-  EXPECT_FALSE(downloader->AddPendingExtension(std::string(), GURL(), 0));
+  EXPECT_FALSE(downloader->AddPendingExtension("", GURL(), 0));
   downloader->StartAllPending();
   EXPECT_EQ(1u, ManifestFetchersCount(downloader.get()));
 
diff --git a/chrome/browser/extensions/webstore_installer.cc b/chrome/browser/extensions/webstore_installer.cc
index 09b7f8e..81db7ed 100644
--- a/chrome/browser/extensions/webstore_installer.cc
+++ b/chrome/browser/extensions/webstore_installer.cc
@@ -125,8 +125,7 @@ void GetDownloadFilePath(
   base::FilePath file =
       directory.AppendASCII(id + "_" + random_number + ".crx");
 
-  int uniquifier =
-      file_util::GetUniquePathNumber(file, base::FilePath::StringType());
+  int uniquifier = file_util::GetUniquePathNumber(file, FILE_PATH_LITERAL(""));
   if (uniquifier > 0) {
     file = file.InsertBeforeExtensionASCII(
         base::StringPrintf(" (%d)", uniquifier));
diff --git a/chrome/browser/extensions/webstore_standalone_installer.cc b/chrome/browser/extensions/webstore_standalone_installer.cc
index 7df550f..cadce50 100644
--- a/chrome/browser/extensions/webstore_standalone_installer.cc
+++ b/chrome/browser/extensions/webstore_standalone_installer.cc
@@ -80,7 +80,7 @@ void WebstoreStandaloneInstaller::OnWebstoreRequestFailure() {
 void WebstoreStandaloneInstaller::OnWebstoreResponseParseSuccess(
     DictionaryValue* webstore_data) {
   if (!CheckRequestorAlive()) {
-    CompleteInstall(std::string());
+    CompleteInstall("");
     return;
   }
 
@@ -141,13 +141,13 @@ void WebstoreStandaloneInstaller::OnWebstoreResponseParseSuccess(
   // Assume ownership of webstore_data.
   webstore_data_.reset(webstore_data);
 
-  scoped_refptr<WebstoreInstallHelper> helper =
-      new WebstoreInstallHelper(this,
-                                id_,
-                                manifest,
-                                std::string(),  // We don't have any icon data.
-                                icon_url,
-                                profile_->GetRequestContext());
+  scoped_refptr<WebstoreInstallHelper> helper = new WebstoreInstallHelper(
+      this,
+      id_,
+      manifest,
+      "",  // We don't have any icon data.
+      icon_url,
+      profile_->GetRequestContext());
   // The helper will call us back via OnWebstoreParseSucces or
   // OnWebstoreParseFailure.
   helper->Start();
@@ -165,7 +165,7 @@ void WebstoreStandaloneInstaller::OnWebstoreParseSuccess(
   CHECK_EQ(id_, id);
 
   if (!CheckRequestorAlive()) {
-    CompleteInstall(std::string());
+    CompleteInstall("");
     return;
   }
 
@@ -190,7 +190,7 @@ void WebstoreStandaloneInstaller::OnWebstoreParseFailure(
 
 void WebstoreStandaloneInstaller::InstallUIProceed() {
   if (!CheckRequestorAlive()) {
-    CompleteInstall(std::string());
+    CompleteInstall("");
     return;
   }
 
@@ -219,7 +219,7 @@ void WebstoreStandaloneInstaller::InstallUIAbort(bool user_initiated) {
 void WebstoreStandaloneInstaller::OnExtensionInstallSuccess(
     const std::string& id) {
   CHECK_EQ(id_, id);
-  CompleteInstall(std::string());
+  CompleteInstall("");
 }
 
 void WebstoreStandaloneInstaller::OnExtensionInstallFailure(
diff --git a/chrome/browser/feedback/feedback_util.cc b/chrome/browser/feedback/feedback_util.cc
index f892a87..7133c60 100644
--- a/chrome/browser/feedback/feedback_util.cc
+++ b/chrome/browser/feedback/feedback_util.cc
@@ -283,7 +283,7 @@ void FeedbackUtil::SendReport(scoped_refptr<FeedbackData> data) {
   // CHROMEOS_RELEASE_VERSION from /etc/lsb-release
 #if !defined(OS_CHROMEOS)
   // Add OS version (eg, for WinXP SP2: "5.1.2600 Service Pack 2").
-  std::string os_version;
+  std::string os_version = "";
   SetOSVersion(&os_version);
   AddFeedbackData(&feedback_data, std::string(kOsVersionTag), os_version);
 #endif
diff --git a/chrome/browser/file_select_helper.cc b/chrome/browser/file_select_helper.cc
index 48cf490..15e4a05 100644
--- a/chrome/browser/file_select_helper.cc
+++ b/chrome/browser/file_select_helper.cc
@@ -423,10 +423,9 @@ void FileSelectHelper::RunFileChooserOnUIThread(
       params.title,
       default_file_name,
       select_file_types_.get(),
-      select_file_types_.get() && !select_file_types_->extensions.empty()
-          ? 1
-          : 0,  // 1-based index of default extension to show.
-      base::FilePath::StringType(),
+      select_file_types_.get() && !select_file_types_->extensions.empty() ?
+          1 : 0,  // 1-based index of default extension to show.
+      FILE_PATH_LITERAL(""),
       owning_window,
 #if defined(OS_ANDROID)
       &accept_types);
diff --git a/chrome/browser/google/google_util.cc b/chrome/browser/google/google_util.cc
index 50900bd..d66a585 100644
--- a/chrome/browser/google/google_util.cc
+++ b/chrome/browser/google/google_util.cc
@@ -32,7 +32,7 @@
 #endif
 
 #ifndef LINKDOCTOR_SERVER_REQUEST_URL
-#define LINKDOCTOR_SERVER_REQUEST_URL std::string()
+#define LINKDOCTOR_SERVER_REQUEST_URL ""
 #endif
 
 namespace {
diff --git a/chrome/browser/google/google_util_unittest.cc b/chrome/browser/google/google_util_unittest.cc
index 75b7067..cf4c610 100644
--- a/chrome/browser/google/google_util_unittest.cc
+++ b/chrome/browser/google/google_util_unittest.cc
@@ -53,7 +53,7 @@ TEST(GoogleUtilTest, GoodHomePagesSecure) {
 }
 
 TEST(GoogleUtilTest, BadHomePages) {
-  EXPECT_FALSE(IsGoogleHomePageUrl(std::string()));
+  EXPECT_FALSE(IsGoogleHomePageUrl(""));
 
   // If specified, only the "www" subdomain is OK.
   EXPECT_FALSE(IsGoogleHomePageUrl("http://maps.google.com"));
@@ -237,7 +237,7 @@ TEST(GoogleUtilTest, BadSearches) {
       "http://www.google.com/search/nogood?q=something"));
   EXPECT_FALSE(IsGoogleSearchUrl(
       "http://www.google.com/webhp/nogood#q=something"));
-  EXPECT_FALSE(IsGoogleSearchUrl(std::string()));
+  EXPECT_FALSE(IsGoogleSearchUrl(""));
 
   // Case sensitive paths.
   EXPECT_FALSE(IsGoogleSearchUrl(
diff --git a/chrome/browser/google_apis/base_operations.cc b/chrome/browser/google_apis/base_operations.cc
index 6692a8a..c6f425c 100644
--- a/chrome/browser/google_apis/base_operations.cc
+++ b/chrome/browser/google_apis/base_operations.cc
@@ -186,7 +186,7 @@ void UrlFetchOperationBase::Start(const std::string& access_token,
         request_type == URLFetcher::PATCH) {
       // Set empty upload content-type and upload content, so that
       // the request will have no "Content-type: " header and no content.
-      url_fetcher_->SetUploadData(std::string(), std::string());
+      url_fetcher_->SetUploadData("", "");
     }
   }
 
diff --git a/chrome/browser/google_apis/base_operations_unittest.cc b/chrome/browser/google_apis/base_operations_unittest.cc
index 047e5c2..2f7e01a 100644
--- a/chrome/browser/google_apis/base_operations_unittest.cc
+++ b/chrome/browser/google_apis/base_operations_unittest.cc
@@ -66,9 +66,9 @@ class BaseOperationsTest : public testing::Test {
   virtual void SetUp() OVERRIDE {
     profile_.reset(new TestingProfile);
     runner_.reset(new OperationRunner(profile_.get(),
-                                      NULL /* url_request_context_getter */,
-                                      std::vector<std::string>() /* scopes */,
-                                      std::string() /* custom user agent */));
+                                      NULL  /* url_request_context_getter */,
+                                      std::vector<std::string>()  /* scopes */,
+                                      ""  /* custom user agent */));
     runner_->Initialize();
     LOG(ERROR) << "Initialized.";
   }
diff --git a/chrome/browser/google_apis/drive_api_operations.cc b/chrome/browser/google_apis/drive_api_operations.cc
index 1206743..7bab455 100644
--- a/chrome/browser/google_apis/drive_api_operations.cc
+++ b/chrome/browser/google_apis/drive_api_operations.cc
@@ -200,7 +200,7 @@ GURL CreateDirectoryOperation::GetURL() const {
   if (parent_resource_id_.empty() || directory_name_.empty()) {
     return GURL();
   }
-  return url_generator_.GetFilelistUrl(GURL(), std::string());
+  return url_generator_.GetFilelistUrl(GURL(), "");
 }
 
 net::URLFetcher::RequestType CreateDirectoryOperation::GetRequestType() const {
diff --git a/chrome/browser/google_apis/drive_api_operations_unittest.cc b/chrome/browser/google_apis/drive_api_operations_unittest.cc
index b6a0f61..36c2c89 100644
--- a/chrome/browser/google_apis/drive_api_operations_unittest.cc
+++ b/chrome/browser/google_apis/drive_api_operations_unittest.cc
@@ -867,7 +867,7 @@ TEST_F(DriveApiOperationsTest, UploadExistingFileOperation) {
           kTestContentType,
           kTestContent.size(),
           "resource_id",  // The resource id of the file to be overwritten.
-          std::string(),  // No etag.
+          "",  // No etag.
           CreateComposedCallback(
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
diff --git a/chrome/browser/google_apis/drive_api_url_generator_unittest.cc b/chrome/browser/google_apis/drive_api_url_generator_unittest.cc
index bcb6c6d..818fb2d 100644
--- a/chrome/browser/google_apis/drive_api_url_generator_unittest.cc
+++ b/chrome/browser/google_apis/drive_api_url_generator_unittest.cc
@@ -69,7 +69,7 @@ TEST_F(DriveApiUrlGeneratorTest, GetFilelistUrl) {
   // Use default URL, if |override_url| is empty.
   // Do not add q parameter if |search_string| is empty.
   EXPECT_EQ("https://www.googleapis.com/drive/v2/files",
-            url_generator_.GetFilelistUrl(GURL(), std::string()).spec());
+            url_generator_.GetFilelistUrl(GURL(), "").spec());
 
   // Set q parameter if non-empty |search_string| is given.
   EXPECT_EQ("https://www.googleapis.com/drive/v2/files?q=query",
@@ -77,10 +77,9 @@ TEST_F(DriveApiUrlGeneratorTest, GetFilelistUrl) {
 
   // Use the |override_url| for the base URL if given.
   // The behavior for the |search_string| should be as same as above cases.
-  EXPECT_EQ(
-      "https://localhost/drive/v2/files",
-      url_generator_.GetFilelistUrl(GURL("https://localhost/drive/v2/files"),
-                                    std::string()).spec());
+  EXPECT_EQ("https://localhost/drive/v2/files",
+            url_generator_.GetFilelistUrl(
+                GURL("https://localhost/drive/v2/files"), "").spec());
   EXPECT_EQ("https://localhost/drive/v2/files?q=query",
             url_generator_.GetFilelistUrl(
                 GURL("https://localhost/drive/v2/files"), "query").spec());
diff --git a/chrome/browser/google_apis/drive_uploader_unittest.cc b/chrome/browser/google_apis/drive_uploader_unittest.cc
index f522a87..5f3bb62 100644
--- a/chrome/browser/google_apis/drive_uploader_unittest.cc
+++ b/chrome/browser/google_apis/drive_uploader_unittest.cc
@@ -298,7 +298,7 @@ TEST_F(DriveUploaderTest, UploadExisting0KB) {
       base::FilePath::FromUTF8Unsafe(kTestDrivePath),
       local_path,
       kTestMimeType,
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(
           &error, &drive_path, &file_path, &resource_entry));
   test_util::RunBlockingPoolTask();
@@ -330,7 +330,7 @@ TEST_F(DriveUploaderTest, UploadExisting512KB) {
       base::FilePath::FromUTF8Unsafe(kTestDrivePath),
       local_path,
       kTestMimeType,
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(
           &error, &drive_path, &file_path, &resource_entry));
   test_util::RunBlockingPoolTask();
@@ -363,7 +363,7 @@ TEST_F(DriveUploaderTest, UploadExisting1234KB) {
       base::FilePath::FromUTF8Unsafe(kTestDrivePath),
       local_path,
       kTestMimeType,
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(
           &error, &drive_path, &file_path, &resource_entry));
   test_util::RunBlockingPoolTask();
@@ -429,7 +429,7 @@ TEST_F(DriveUploaderTest, InitiateUploadFail) {
       base::FilePath::FromUTF8Unsafe(kTestDrivePath),
       local_path,
       kTestMimeType,
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(
           &error, &drive_path, &file_path, &resource_entry));
   test_util::RunBlockingPoolTask();
@@ -508,7 +508,7 @@ TEST_F(DriveUploaderTest, ResumeUploadFail) {
       base::FilePath::FromUTF8Unsafe(kTestDrivePath),
       local_path,
       kTestMimeType,
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(
           &error, &drive_path, &file_path, &resource_entry));
   test_util::RunBlockingPoolTask();
@@ -528,7 +528,7 @@ TEST_F(DriveUploaderTest, NonExistingSourceFile) {
       base::FilePath::FromUTF8Unsafe(kTestDrivePath),
       temp_dir_.path().AppendASCII("_this_path_should_not_exist_"),
       kTestMimeType,
-      std::string(),             // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(
           &error, &drive_path, &file_path, &resource_entry));
   test_util::RunBlockingPoolTask();
diff --git a/chrome/browser/google_apis/fake_drive_service.cc b/chrome/browser/google_apis/fake_drive_service.cc
index d5cb4ad..d91aced 100644
--- a/chrome/browser/google_apis/fake_drive_service.cc
+++ b/chrome/browser/google_apis/fake_drive_service.cc
@@ -340,10 +340,10 @@ void FakeDriveService::GetAllResourceList(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
-  GetResourceList(GURL(),         // no next feed
-                  0,              // start changestamp
-                  std::string(),  // empty search query
-                  std::string(),  // no directory resource id,
+  GetResourceList(GURL(),  // no next feed
+                  0,  // start changestamp
+                  "",  // empty search query
+                  "",  // no directory resource id,
                   callback);
 }
 
@@ -354,9 +354,9 @@ void FakeDriveService::GetResourceListInDirectory(
   DCHECK(!directory_resource_id.empty());
   DCHECK(!callback.is_null());
 
-  GetResourceList(GURL(),         // no next feed
-                  0,              // start changestamp
-                  std::string(),  // empty search query
+  GetResourceList(GURL(),  // no next feed
+                  0,  // start changestamp
+                  "",  // empty search query
                   directory_resource_id,
                   callback);
 }
@@ -367,10 +367,10 @@ void FakeDriveService::Search(const std::string& search_query,
   DCHECK(!search_query.empty());
   DCHECK(!callback.is_null());
 
-  GetResourceList(GURL(),         // no next feed
-                  0,              // start changestamp
+  GetResourceList(GURL(),  // no next feed
+                  0,  // start changestamp
                   search_query,
-                  std::string(),  // no directory resource id,
+                  "",  // no directory resource id,
                   callback);
 }
 
@@ -395,10 +395,10 @@ void FakeDriveService::GetChangeList(int64 start_changestamp,
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
-  GetResourceList(GURL(),         // no next feed
+  GetResourceList(GURL(),  // no next feed
                   start_changestamp,
-                  std::string(),  // empty search query
-                  std::string(),  // no directory resource id,
+                  "",  // empty search query
+                  "",  // no directory resource id,
                   callback);
 }
 
diff --git a/chrome/browser/google_apis/fake_drive_service_unittest.cc b/chrome/browser/google_apis/fake_drive_service_unittest.cc
index 2f94ba5..e89ed15 100644
--- a/chrome/browser/google_apis/fake_drive_service_unittest.cc
+++ b/chrome/browser/google_apis/fake_drive_service_unittest.cc
@@ -96,9 +96,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_All) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,              // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      0,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -117,9 +117,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_WithStartIndex) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL("http://dummyurl/?start-offset=2"),
-      0,              // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      0,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -139,9 +139,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_WithStartIndexAndMaxResults) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL("http://localhost/?start-offset=2&max-results=5"),
-      0,              // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      0,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -168,9 +168,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_WithDefaultMaxResultsChanged) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,              // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      0,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -196,8 +196,8 @@ TEST_F(FakeDriveServiceTest, GetResourceList_InRootDirectory) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,                                  // start_changestamp
-      std::string(),                      // search_query
+      0,  // start_changestamp
+      "",  // search_query
       fake_service_.GetRootResourceId(),  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
@@ -217,9 +217,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_Search) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,              // start_changestamp
-      "File",         // search_query
-      std::string(),  // directory_resource_id
+      0,  // start_changestamp
+      "File",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -239,9 +239,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_SearchWithAttribute) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,              // start_changestamp
+      0,  // start_changestamp
       "title:1.txt",  // search_query
-      std::string(),  // directory_resource_id
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -261,9 +261,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_SearchMultipleQueries) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,              // start_changestamp
+      0,  // start_changestamp
       "Directory 1",  // search_query
-      std::string(),  // directory_resource_id
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -274,9 +274,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_SearchMultipleQueries) {
 
   fake_service_.GetResourceList(
       GURL(),
-      0,                  // start_changestamp
+      0,  // start_changestamp
       "\"Directory 1\"",  // search_query
-      std::string(),      // directory_resource_id
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -299,9 +299,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_NoNewEntries) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      654321 + 1,     // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      654321 + 1,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -331,9 +331,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_WithNewEntry) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      654321 + 1,     // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      654321 + 1,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -354,9 +354,9 @@ TEST_F(FakeDriveServiceTest, GetResourceList_Offline) {
   scoped_ptr<ResourceList> resource_list;
   fake_service_.GetResourceList(
       GURL(),
-      0,              // start_changestamp
-      std::string(),  // search_query
-      std::string(),  // directory_resource_id
+      0,  // start_changestamp
+      "",  // search_query
+      "",  // directory_resource_id
       test_util::CreateCopyResultCallback(&error, &resource_list));
   message_loop_.RunUntilIdle();
 
@@ -845,7 +845,7 @@ TEST_F(FakeDriveServiceTest, DeleteResource_ExistingFile) {
 
   GDataErrorCode error = GDATA_OTHER_ERROR;
   fake_service_.DeleteResource("file:2_file_resource_id",
-                               std::string(),  // etag
+                               "",  // etag
                                test_util::CreateCopyResultCallback(&error));
   message_loop_.RunUntilIdle();
 
@@ -860,7 +860,7 @@ TEST_F(FakeDriveServiceTest, DeleteResource_NonexistingFile) {
 
   GDataErrorCode error = GDATA_OTHER_ERROR;
   fake_service_.DeleteResource("file:nonexisting_resource_id",
-                               std::string(),  // etag
+                               "",  // etag
                                test_util::CreateCopyResultCallback(&error));
   message_loop_.RunUntilIdle();
 
@@ -874,7 +874,7 @@ TEST_F(FakeDriveServiceTest, DeleteResource_Offline) {
 
   GDataErrorCode error = GDATA_OTHER_ERROR;
   fake_service_.DeleteResource("file:2_file_resource_id",
-                               std::string(),  // etag
+                               "",  // etag
                                test_util::CreateCopyResultCallback(&error));
   message_loop_.RunUntilIdle();
 
@@ -1506,7 +1506,7 @@ TEST_F(FakeDriveServiceTest, InitiateUploadExistingFile_Offline) {
       "test/foo",
       13,
       "file:2_file_resource_id",
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(&error, &upload_location));
   message_loop_.RunUntilIdle();
 
@@ -1525,7 +1525,7 @@ TEST_F(FakeDriveServiceTest, InitiateUploadExistingFile_NotFound) {
       "test/foo",
       13,
       "non_existent",
-      std::string(),  // etag
+      "",  // etag
       test_util::CreateCopyResultCallback(&error, &upload_location));
   message_loop_.RunUntilIdle();
 
diff --git a/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc b/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc
index 7f2395d..1a15c62 100644
--- a/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc
+++ b/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc
@@ -325,10 +325,10 @@ TEST_F(GDataWapiOperationsTest, GetResourceListOperation_DefaultFeed) {
       &operation_registry_,
       request_context_getter_.get(),
       *url_generator_,
-      GURL(),         // Pass an empty URL to use the default feed
-      0,              // start changestamp
-      std::string(),  // search string
-      std::string(),  // directory resource ID
+      GURL(),  // Pass an empty URL to use the default feed
+      0,  // start changestamp
+      "",  // search string
+      "",  // directory resource ID
       CreateComposedCallback(
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
@@ -360,9 +360,9 @@ TEST_F(GDataWapiOperationsTest, GetResourceListOperation_ValidFeed) {
       request_context_getter_.get(),
       *url_generator_,
       test_server_.GetURL("/files/chromeos/gdata/root_feed.json"),
-      0,              // start changestamp
-      std::string(),  // search string
-      std::string(),  // directory resource ID
+      0,  // start changestamp
+      "",  // search string
+      "",  // directory resource ID
       CreateComposedCallback(
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
@@ -395,9 +395,9 @@ TEST_F(GDataWapiOperationsTest, GetResourceListOperation_InvalidFeed) {
       request_context_getter_.get(),
       *url_generator_,
       test_server_.GetURL("/files/chromeos/gdata/testfile.txt"),
-      0,              // start changestamp
-      std::string(),  // search string
-      std::string(),  // directory resource ID
+      0,  // start changestamp
+      "",  // search string
+      "",  // directory resource ID
       CreateComposedCallback(
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
@@ -548,10 +548,11 @@ TEST_F(GDataWapiOperationsTest, DeleteResourceOperation) {
       &operation_registry_,
       request_context_getter_.get(),
       *url_generator_,
-      CreateComposedCallback(base::Bind(&test_util::RunAndQuit),
-                             test_util::CreateCopyResultCallback(&result_code)),
+      CreateComposedCallback(
+          base::Bind(&test_util::RunAndQuit),
+          test_util::CreateCopyResultCallback(&result_code)),
       "file:2_file_resource_id",
-      std::string());
+      "");
 
   operation->Start(kTestGDataAuthToken, kTestUserAgent,
                    base::Bind(&test_util::DoNothingForReAuthenticateCallback));
@@ -1134,7 +1135,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewLargeFile) {
 // The test is almost identical to UploadNewFile. The only difference is the
 // expectation for the Content-Range header.
 TEST_F(GDataWapiOperationsTest, UploadNewEmptyFile) {
-  const std::string kUploadContent;
+  const std::string kUploadContent = "";
   GDataErrorCode result_code = GDATA_OTHER_ERROR;
   GURL upload_url;
 
@@ -1243,7 +1244,7 @@ TEST_F(GDataWapiOperationsTest, UploadExistingFile) {
           "text/plain",
           kUploadContent.size(),
           "file:foo",
-          std::string() /* etag */);
+          "" /* etag */);
 
   initiate_operation->Start(
       kTestGDataAuthToken, kTestUserAgent,
diff --git a/chrome/browser/google_apis/gdata_wapi_parser_unittest.cc b/chrome/browser/google_apis/gdata_wapi_parser_unittest.cc
index 1356cf6..f85d325 100644
--- a/chrome/browser/google_apis/gdata_wapi_parser_unittest.cc
+++ b/chrome/browser/google_apis/gdata_wapi_parser_unittest.cc
@@ -324,7 +324,7 @@ TEST(GDataWAPIParserTest, ResourceEntryHasDocumentExtension) {
   EXPECT_FALSE(ResourceEntry::HasHostedDocumentExtension(
       base::FilePath(FILE_PATH_LITERAL("Test"))));
   EXPECT_FALSE(ResourceEntry::HasHostedDocumentExtension(
-      base::FilePath()));
+      base::FilePath(FILE_PATH_LITERAL(""))));
 }
 
 TEST(GDataWAPIParserTest, ResourceEntryClassifyEntryKind) {
diff --git a/chrome/browser/google_apis/gdata_wapi_service.cc b/chrome/browser/google_apis/gdata_wapi_service.cc
index 2649049..47edcf6 100644
--- a/chrome/browser/google_apis/gdata_wapi_service.cc
+++ b/chrome/browser/google_apis/gdata_wapi_service.cc
@@ -199,14 +199,15 @@ void GDataWapiService::GetAllResourceList(
   DCHECK(!callback.is_null());
 
   runner_->StartOperationWithRetry(
-      new GetResourceListOperation(operation_registry(),
-                                   url_request_context_getter_,
-                                   url_generator_,
-                                   GURL(),         // No override url
-                                   0,              // start changestamp
-                                   std::string(),  // empty search query
-                                   std::string(),  // no directory resource id
-                                   callback));
+      new GetResourceListOperation(
+          operation_registry(),
+          url_request_context_getter_,
+          url_generator_,
+          GURL(),  // No override url
+          0,  // start changestamp
+          "",  // empty search query
+          "",  // no directory resource id
+          callback));
 }
 
 void GDataWapiService::GetResourceListInDirectory(
@@ -217,14 +218,15 @@ void GDataWapiService::GetResourceListInDirectory(
   DCHECK(!callback.is_null());
 
   runner_->StartOperationWithRetry(
-      new GetResourceListOperation(operation_registry(),
-                                   url_request_context_getter_,
-                                   url_generator_,
-                                   GURL(),         // No override url
-                                   0,              // start changestamp
-                                   std::string(),  // empty search query
-                                   directory_resource_id,
-                                   callback));
+      new GetResourceListOperation(
+          operation_registry(),
+          url_request_context_getter_,
+          url_generator_,
+          GURL(),  // No override url
+          0,  // start changestamp
+          "",  // empty search query
+          directory_resource_id,
+          callback));
 }
 
 void GDataWapiService::Search(const std::string& search_query,
@@ -234,14 +236,15 @@ void GDataWapiService::Search(const std::string& search_query,
   DCHECK(!callback.is_null());
 
   runner_->StartOperationWithRetry(
-      new GetResourceListOperation(operation_registry(),
-                                   url_request_context_getter_,
-                                   url_generator_,
-                                   GURL(),         // No override url
-                                   0,              // start changestamp
-                                   search_query,
-                                   std::string(),  // no directory resource id
-                                   callback));
+      new GetResourceListOperation(
+          operation_registry(),
+          url_request_context_getter_,
+          url_generator_,
+          GURL(),  // No override url
+          0,  // start changestamp
+          search_query,
+          "",  // no directory resource id
+          callback));
 }
 
 void GDataWapiService::SearchInDirectory(
@@ -271,14 +274,15 @@ void GDataWapiService::GetChangeList(int64 start_changestamp,
   DCHECK(!callback.is_null());
 
   runner_->StartOperationWithRetry(
-      new GetResourceListOperation(operation_registry(),
-                                   url_request_context_getter_,
-                                   url_generator_,
-                                   GURL(),         // No override url
-                                   start_changestamp,
-                                   std::string(),  // empty search query
-                                   std::string(),  // no directory resource id
-                                   callback));
+      new GetResourceListOperation(
+          operation_registry(),
+          url_request_context_getter_,
+          url_generator_,
+          GURL(),  // No override url
+          start_changestamp,
+          "",  // empty search query
+          "",  // no directory resource id
+          callback));
 }
 
 void GDataWapiService::ContinueGetResourceList(
@@ -289,14 +293,15 @@ void GDataWapiService::ContinueGetResourceList(
   DCHECK(!callback.is_null());
 
   runner_->StartOperationWithRetry(
-      new GetResourceListOperation(operation_registry(),
-                                   url_request_context_getter_,
-                                   url_generator_,
-                                   override_url,
-                                   0,              // start changestamp
-                                   std::string(),  // empty search query
-                                   std::string(),  // no directory resource id
-                                   callback));
+      new GetResourceListOperation(
+          operation_registry(),
+          url_request_context_getter_,
+          url_generator_,
+          override_url,
+          0,  // start changestamp
+          "",  // empty search query
+          "",  // no directory resource id
+          callback));
 }
 
 void GDataWapiService::GetResourceEntry(
diff --git a/chrome/browser/google_apis/gdata_wapi_url_generator_unittest.cc b/chrome/browser/google_apis/gdata_wapi_url_generator_unittest.cc
index de80699..571a661 100644
--- a/chrome/browser/google_apis/gdata_wapi_url_generator_unittest.cc
+++ b/chrome/browser/google_apis/gdata_wapi_url_generator_unittest.cc
@@ -32,29 +32,29 @@ TEST_F(GDataWapiUrlGeneratorTest, AddInitiateUploadUrlParams) {
 }
 
 TEST_F(GDataWapiUrlGeneratorTest, AddFeedUrlParams) {
-  EXPECT_EQ(
-      "http://www.example.com/?v=3&alt=json&showroot=true&"
-      "showfolders=true"
-      "&include-shared=true"
-      "&max-results=100"
-      "&include-installed-apps=true",
-      GDataWapiUrlGenerator::AddFeedUrlParams(GURL("http://www.example.com"),
-                                              100,  // num_items_to_fetch
-                                              0,    // changestamp
-                                              std::string()  // search_string
-                                              ).spec());
-  EXPECT_EQ(
-      "http://www.example.com/?v=3&alt=json&showroot=true&"
-      "showfolders=true"
-      "&include-shared=true"
-      "&max-results=100"
-      "&include-installed-apps=true"
-      "&start-index=123",
-      GDataWapiUrlGenerator::AddFeedUrlParams(GURL("http://www.example.com"),
-                                              100,  // num_items_to_fetch
-                                              123,  // changestamp
-                                              std::string()  // search_string
-                                              ).spec());
+  EXPECT_EQ("http://www.example.com/?v=3&alt=json&showroot=true&"
+            "showfolders=true"
+            "&include-shared=true"
+            "&max-results=100"
+            "&include-installed-apps=true",
+            GDataWapiUrlGenerator::AddFeedUrlParams(
+                GURL("http://www.example.com"),
+                100,  // num_items_to_fetch
+                0,  // changestamp
+                ""  // search_string
+                                                 ).spec());
+  EXPECT_EQ("http://www.example.com/?v=3&alt=json&showroot=true&"
+            "showfolders=true"
+            "&include-shared=true"
+            "&max-results=100"
+            "&include-installed-apps=true"
+            "&start-index=123",
+            GDataWapiUrlGenerator::AddFeedUrlParams(
+                GURL("http://www.example.com"),
+                100,  // num_items_to_fetch
+                123,  // changestamp
+                ""  // search_string
+                                                 ).spec());
   EXPECT_EQ("http://www.example.com/?v=3&alt=json&showroot=true&"
             "showfolders=true"
             "&include-shared=true"
@@ -72,52 +72,53 @@ TEST_F(GDataWapiUrlGeneratorTest, AddFeedUrlParams) {
 
 TEST_F(GDataWapiUrlGeneratorTest, GenerateResourceListUrl) {
   // This is the very basic URL for the GetResourceList operation.
-  EXPECT_EQ("https://docs.google.com/feeds/default/private/full"
-            "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
-            "&max-results=500&include-installed-apps=true",
-            url_generator_.GenerateResourceListUrl(
-                GURL(),         // override_url,
-                0,              // start_changestamp,
-                std::string(),  // search_string,
-                std::string()   // directory resource ID
-                ).spec());
+  EXPECT_EQ(
+      "https://docs.google.com/feeds/default/private/full"
+      "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
+      "&max-results=500&include-installed-apps=true",
+      url_generator_.GenerateResourceListUrl(GURL(),  // override_url,
+                                             0,  // start_changestamp,
+                                             "",  // search_string,
+                                             ""  // directory resource ID
+                                             ).spec());
 
   // With an override URL provided, the base URL is changed, but the default
   // parameters remain as-is.
-  EXPECT_EQ("http://localhost/"
-            "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
-            "&max-results=500&include-installed-apps=true",
-            url_generator_.GenerateResourceListUrl(
-                GURL("http://localhost/"),  // override_url,
-                0,                          // start_changestamp,
-                std::string(),              // search_string,
-                std::string()               // directory resource ID
-                ).spec());
+  EXPECT_EQ(
+      "http://localhost/"
+      "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
+      "&max-results=500&include-installed-apps=true",
+      url_generator_.GenerateResourceListUrl(
+          GURL("http://localhost/"),  // override_url,
+          0,  // start_changestamp,
+          "",  // search_string,
+          ""  // directory resource ID
+          ).spec());
 
   // With a non-zero start_changestamp provided, the base URL is changed from
   // "full" to "changes", and "start-index" parameter is added.
-  EXPECT_EQ("https://docs.google.com/feeds/default/private/changes"
-            "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
-            "&max-results=500&include-installed-apps=true"
-            "&start-index=100",
-            url_generator_.GenerateResourceListUrl(
-                GURL(),         // override_url,
-                100,            // start_changestamp,
-                std::string(),  // search_string,
-                std::string()   // directory resource ID
-                ).spec());
+  EXPECT_EQ(
+      "https://docs.google.com/feeds/default/private/changes"
+      "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
+      "&max-results=500&include-installed-apps=true"
+      "&start-index=100",
+      url_generator_.GenerateResourceListUrl(GURL(),  // override_url,
+                                             100,  // start_changestamp,
+                                             "",  // search_string,
+                                             ""  // directory resource ID
+                                             ).spec());
 
   // With a non-empty search string provided, "max-results" value is changed,
   // and "q" parameter is added.
-  EXPECT_EQ("https://docs.google.com/feeds/default/private/full"
-            "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
-            "&max-results=50&include-installed-apps=true&q=foo",
-            url_generator_.GenerateResourceListUrl(
-                GURL(),        // override_url,
-                0,             // start_changestamp,
-                "foo",         // search_string,
-                std::string()  // directory resource ID
-                ).spec());
+  EXPECT_EQ(
+      "https://docs.google.com/feeds/default/private/full"
+      "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
+      "&max-results=50&include-installed-apps=true&q=foo",
+      url_generator_.GenerateResourceListUrl(GURL(),  // override_url,
+                                             0,  // start_changestamp,
+                                             "foo",  // search_string,
+                                             ""  // directory resource ID
+                                             ).spec());
 
   // With a non-empty directory resource ID provided, the base URL is
   // changed, but the default parameters remain.
@@ -126,23 +127,24 @@ TEST_F(GDataWapiUrlGeneratorTest, GenerateResourceListUrl) {
       "?v=3&alt=json&showroot=true&showfolders=true&include-shared=true"
       "&max-results=500&include-installed-apps=true",
       url_generator_.GenerateResourceListUrl(GURL(),  // override_url,
-                                             0,       // start_changestamp,
-                                             std::string(),  // search_string,
+                                             0,  // start_changestamp,
+                                             "",  // search_string,
                                              "XXX"  // directory resource ID
                                              ).spec());
 
   // With a non-empty override_url provided, the base URL is changed, but
   // the default parameters remain. Note that start-index should not be
   // overridden.
-  EXPECT_EQ("http://example.com/"
-            "?start-index=123&v=3&alt=json&showroot=true&showfolders=true"
-            "&include-shared=true&max-results=500&include-installed-apps=true",
-            url_generator_.GenerateResourceListUrl(
-                GURL("http://example.com/?start-index=123"),  // override_url,
-                100,            // start_changestamp,
-                std::string(),  // search_string,
-                "XXX"           // directory resource ID
-                ).spec());
+  EXPECT_EQ(
+      "http://example.com/"
+      "?start-index=123&v=3&alt=json&showroot=true&showfolders=true"
+      "&include-shared=true&max-results=500&include-installed-apps=true",
+      url_generator_.GenerateResourceListUrl(
+          GURL("http://example.com/?start-index=123"),  // override_url,
+          100,  // start_changestamp,
+          "",  // search_string,
+          "XXX"  // directory resource ID
+          ).spec());
 }
 
 TEST_F(GDataWapiUrlGeneratorTest, GenerateEditUrl) {
diff --git a/chrome/browser/google_apis/operation_util_unittest.cc b/chrome/browser/google_apis/operation_util_unittest.cc
index 14e4c5dd..8a8ffe4 100644
--- a/chrome/browser/google_apis/operation_util_unittest.cc
+++ b/chrome/browser/google_apis/operation_util_unittest.cc
@@ -11,7 +11,7 @@ namespace util {
 
 TEST(GenerateIfMatchHeaderTest, GenerateIfMatchHeader) {
   // The header matched to all etag should be returned for empty etag.
-  EXPECT_EQ("If-Match: *", GenerateIfMatchHeader(std::string()));
+  EXPECT_EQ("If-Match: *", GenerateIfMatchHeader(""));
 
   // Otherwise, the returned header should be matched to the given etag.
   EXPECT_EQ("If-Match: abcde", GenerateIfMatchHeader("abcde"));
diff --git a/chrome/browser/google_apis/test_server/http_server_unittest.cc b/chrome/browser/google_apis/test_server/http_server_unittest.cc
index d837baf..e242098 100644
--- a/chrome/browser/google_apis/test_server/http_server_unittest.cc
+++ b/chrome/browser/google_apis/test_server/http_server_unittest.cc
@@ -38,7 +38,7 @@ std::string GetContentTypeFromFetcher(const net::URLFetcher& fetcher) {
     if (headers->GetMimeType(&content_type))
       return content_type;
   }
-  return std::string();
+  return "";
 }
 
 }  // namespace
diff --git a/chrome/browser/history/history_querying_unittest.cc b/chrome/browser/history/history_querying_unittest.cc
index ed138e8..c1355dd 100644
--- a/chrome/browser/history/history_querying_unittest.cc
+++ b/chrome/browser/history/history_querying_unittest.cc
@@ -468,7 +468,7 @@ TEST_F(HistoryQueryTest, Paging) {
   // Since results are fetched 1 and 2 at a time, entry #0 and #6 will not
   // be de-duplicated.
   int expected_results[] = { 4, 2, 3, 1, 7, 6, 5, 0 };
-  TestPaging(std::string(), expected_results, arraysize(expected_results));
+  TestPaging("", expected_results, arraysize(expected_results));
 }
 
 TEST_F(HistoryQueryTest, FTSPaging) {
diff --git a/chrome/browser/history/history_tab_helper.cc b/chrome/browser/history/history_tab_helper.cc
index 5438b97..a984557 100644
--- a/chrome/browser/history/history_tab_helper.cc
+++ b/chrome/browser/history/history_tab_helper.cc
@@ -53,8 +53,7 @@ void HistoryTabHelper::UpdateHistoryForNavigation(
 void HistoryTabHelper::UpdateHistoryPageTitle(const NavigationEntry& entry) {
   HistoryService* hs = GetHistoryService();
   if (hs)
-    hs->SetPageTitle(entry.GetVirtualURL(),
-                     entry.GetTitleForDisplay(std::string()));
+    hs->SetPageTitle(entry.GetVirtualURL(), entry.GetTitleForDisplay(""));
 }
 
 history::HistoryAddPageArgs
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index c988e55..e465a80 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -164,19 +164,20 @@ class HistoryBackendDBTest : public HistoryUnitTestBase {
     std::vector<GURL> url_chain;
     url_chain.push_back(GURL("foo-url"));
 
-    DownloadRow download(base::FilePath(FILE_PATH_LITERAL("foo-path")),
-                         base::FilePath(FILE_PATH_LITERAL("foo-path")),
-                         url_chain,
-                         GURL(std::string()),
-                         time,
-                         time,
-                         0,
-                         512,
-                         state,
-                         content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
-                         content::DOWNLOAD_INTERRUPT_REASON_NONE,
-                         0,
-                         0);
+    DownloadRow download(
+        base::FilePath(FILE_PATH_LITERAL("foo-path")),
+        base::FilePath(FILE_PATH_LITERAL("foo-path")),
+        url_chain,
+        GURL(""),
+        time,
+        time,
+        0,
+        512,
+        state,
+        content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
+        content::DOWNLOAD_INTERRUPT_REASON_NONE,
+        0,
+        0);
     return db_->CreateDownload(download);
   }
 
@@ -316,7 +317,7 @@ TEST_F(HistoryBackendDBTest, MigrateDownloadsReasonPathsAndDangerType) {
     int64 db_handle = 0;
     // Null path.
     s.BindInt64(0, ++db_handle);
-    s.BindString(1, std::string());
+    s.BindString(1, "");
     s.BindString(2, "http://whatever.com/index.html");
     s.BindInt64(3, now.ToTimeT());
     s.BindInt64(4, 100);
@@ -463,19 +464,20 @@ TEST_F(HistoryBackendDBTest, DownloadNukeRecordsMissingURLs) {
   CreateBackendAndDatabase();
   base::Time now(base::Time::Now());
   std::vector<GURL> url_chain;
-  DownloadRow download(base::FilePath(FILE_PATH_LITERAL("foo-path")),
-                       base::FilePath(FILE_PATH_LITERAL("foo-path")),
-                       url_chain,
-                       GURL(std::string()),
-                       now,
-                       now,
-                       0,
-                       512,
-                       DownloadItem::COMPLETE,
-                       content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
-                       content::DOWNLOAD_INTERRUPT_REASON_NONE,
-                       0,
-                       0);
+  DownloadRow download(
+      base::FilePath(FILE_PATH_LITERAL("foo-path")),
+      base::FilePath(FILE_PATH_LITERAL("foo-path")),
+      url_chain,
+      GURL(""),
+      now,
+      now,
+      0,
+      512,
+      DownloadItem::COMPLETE,
+      content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
+      content::DOWNLOAD_INTERRUPT_REASON_NONE,
+      0,
+      0);
 
   // Creating records without any urls should fail.
   EXPECT_EQ(DownloadDatabase::kUninitializedHandle,
diff --git a/chrome/browser/history/thumbnail_database_unittest.cc b/chrome/browser/history/thumbnail_database_unittest.cc
index de3bd33..fc92feb 100644
--- a/chrome/browser/history/thumbnail_database_unittest.cc
+++ b/chrome/browser/history/thumbnail_database_unittest.cc
@@ -414,7 +414,7 @@ TEST_F(ThumbnailDatabaseTest, UpgradeToVersion6) {
   EXPECT_EQ(url, GURL(statement.ColumnString(1)));
   EXPECT_EQ(TOUCH_ICON, statement.ColumnInt(2));
   // Any previous data in sizes should be cleared.
-  EXPECT_EQ(std::string(), statement.ColumnString(3));
+  EXPECT_EQ(std::string(""), statement.ColumnString(3));
 
   statement.Assign(db.db_.GetCachedStatement(SQL_FROM_HERE,
       "SELECT icon_id, last_updated, image_data, width, height "
@@ -854,7 +854,7 @@ TEST_F(ThumbnailDatabaseTest, FaviconSizesToAndFromString) {
 
   // Valid input.
   FaviconSizes sizes_empty;
-  ThumbnailDatabase::DatabaseStringToFaviconSizes(std::string(), &sizes_empty);
+  ThumbnailDatabase::DatabaseStringToFaviconSizes("", &sizes_empty);
   EXPECT_EQ(0u, sizes_empty.size());
 
   FaviconSizes sizes_valid;
diff --git a/chrome/browser/importer/firefox_importer_utils.cc b/chrome/browser/importer/firefox_importer_utils.cc
index 8ffe8f2..0535cf6 100644
--- a/chrome/browser/importer/firefox_importer_utils.cc
+++ b/chrome/browser/importer/firefox_importer_utils.cc
@@ -255,12 +255,12 @@ std::string ReadBrowserConfigProp(const base::FilePath& app_path,
                                   const std::string& pref_key) {
   std::string content;
   if (!ReadPrefFile(app_path.AppendASCII("browserconfig.properties"), &content))
-    return std::string();
+    return "";
 
   // This file has the syntax: key=value.
   size_t prop_index = content.find(pref_key + "=");
   if (prop_index == std::string::npos)
-    return std::string();
+    return "";
 
   size_t start = prop_index + pref_key.length();
   size_t stop = std::string::npos;
@@ -270,7 +270,7 @@ std::string ReadBrowserConfigProp(const base::FilePath& app_path,
   if (start == std::string::npos ||
       stop == std::string::npos || (start == stop)) {
     LOG(WARNING) << "Firefox property " << pref_key << " could not be parsed.";
-    return std::string();
+    return "";
   }
 
   return content.substr(start + 1, stop - start - 1);
@@ -280,7 +280,7 @@ std::string ReadPrefsJsValue(const base::FilePath& profile_path,
                              const std::string& pref_key) {
   std::string content;
   if (!ReadPrefFile(profile_path.AppendASCII("prefs.js"), &content))
-    return std::string();
+    return "";
 
   return GetPrefsJsValue(content, pref_key);
 }
@@ -411,7 +411,7 @@ std::string GetPrefsJsValue(const std::string& content,
   if (start == std::string::npos || stop == std::string::npos ||
       stop < start) {
     LOG(WARNING) << "Firefox property " << pref_key << " could not be parsed.";
-    return std::string();
+    return "";
   }
 
   // String values have double quotes we don't need to return to the caller.
diff --git a/chrome/browser/internal_auth_unittest.cc b/chrome/browser/internal_auth_unittest.cc
index da8954e..42080cd 100644
--- a/chrome/browser/internal_auth_unittest.cc
+++ b/chrome/browser/internal_auth_unittest.cc
@@ -69,10 +69,9 @@ TEST_F(InternalAuthTest, BadGeneration) {
       token, long_string_, map));
 
   // Trying empty domain.
-  token = InternalAuthGeneration::GeneratePassport(std::string(), map);
+  token = InternalAuthGeneration::GeneratePassport("", map);
   ASSERT_TRUE(token.empty());
-  ASSERT_FALSE(
-      InternalAuthVerification::VerifyPassport(token, std::string(), map));
+  ASSERT_FALSE(InternalAuthVerification::VerifyPassport(token, "", map));
 
   std::string dummy("abcdefghij");
   for (size_t i = 1000; i--;) {
@@ -88,7 +87,7 @@ TEST_F(InternalAuthTest, BadGeneration) {
   ASSERT_FALSE(InternalAuthVerification::VerifyPassport(token, "zapata", map));
 
   map.clear();
-  map[std::string()] = "value";
+  map[""] = "value";
   // Trying empty key.
   token = InternalAuthGeneration::GeneratePassport("zapata", map);
   ASSERT_TRUE(token.empty());
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index b0c5010..76d5df7 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -691,10 +691,8 @@ void IOThread::EnableSpdy(const std::string& mode) {
     const std::string& element = *it;
     std::vector<std::string> name_value;
     base::SplitString(element, '=', &name_value);
-    const std::string& option =
-        name_value.size() > 0 ? name_value[0] : std::string();
-    const std::string value =
-        name_value.size() > 1 ? name_value[1] : std::string();
+    const std::string& option = name_value.size() > 0 ? name_value[0] : "";
+    const std::string value = name_value.size() > 1 ? name_value[1] : "";
 
     if (option == kOff) {
       net::HttpStreamFactory::set_spdy_enabled(false);
@@ -741,11 +739,10 @@ void IOThread::RegisterPrefs(PrefRegistrySimple* registry) {
                                "spdyproxy");
   registry->RegisterBooleanPref(prefs::kDisableAuthNegotiateCnameLookup, false);
   registry->RegisterBooleanPref(prefs::kEnableAuthNegotiatePort, false);
-  registry->RegisterStringPref(prefs::kAuthServerWhitelist, std::string());
-  registry->RegisterStringPref(prefs::kAuthNegotiateDelegateWhitelist,
-                               std::string());
-  registry->RegisterStringPref(prefs::kGSSAPILibraryName, std::string());
-  registry->RegisterStringPref(prefs::kSpdyProxyAuthOrigin, std::string());
+  registry->RegisterStringPref(prefs::kAuthServerWhitelist, "");
+  registry->RegisterStringPref(prefs::kAuthNegotiateDelegateWhitelist, "");
+  registry->RegisterStringPref(prefs::kGSSAPILibraryName, "");
+  registry->RegisterStringPref(prefs::kSpdyProxyAuthOrigin, "");
   registry->RegisterBooleanPref(prefs::kEnableReferrers, true);
   registry->RegisterInt64Pref(prefs::kHttpReceivedContentLength, 0);
   registry->RegisterInt64Pref(prefs::kHttpOriginalContentLength, 0);
diff --git a/chrome/browser/language_usage_metrics_unittest.cc b/chrome/browser/language_usage_metrics_unittest.cc
index e007e70..db6e987 100644
--- a/chrome/browser/language_usage_metrics_unittest.cc
+++ b/chrome/browser/language_usage_metrics_unittest.cc
@@ -16,7 +16,7 @@ TEST(LanguageUsageMetricsTest, ParseAcceptLanguages) {
   EXPECT_EQ(JAPANESE, *language_set.begin());
 
   // Empty language.
-  LanguageUsageMetrics::ParseAcceptLanguages(std::string(), &language_set);
+  LanguageUsageMetrics::ParseAcceptLanguages("", &language_set);
   EXPECT_EQ(0U, language_set.size());
 
   // Country code is ignored.
@@ -86,6 +86,6 @@ TEST(LanguageUsageMetricsTest, ToLanguage) {
   EXPECT_EQ(JAPANESE, LanguageUsageMetrics::ToLanguage("ja-JP"));
 
   // Invalid locales are considered as unknown language.
-  EXPECT_EQ(UNKNOWN_LANGUAGE, LanguageUsageMetrics::ToLanguage(std::string()));
+  EXPECT_EQ(UNKNOWN_LANGUAGE, LanguageUsageMetrics::ToLanguage(""));
   EXPECT_EQ(UNKNOWN_LANGUAGE, LanguageUsageMetrics::ToLanguage("xx"));
 }
diff --git a/chrome/browser/logging_chrome_browsertest.cc b/chrome/browser/logging_chrome_browsertest.cc
index df32456..9728fd3 100644
--- a/chrome/browser/logging_chrome_browsertest.cc
+++ b/chrome/browser/logging_chrome_browsertest.cc
@@ -44,7 +44,7 @@ class ChromeLoggingTest : public testing::Test {
 
 // Tests the log file name getter without an environment variable.
 TEST_F(ChromeLoggingTest, LogFileName) {
-  SaveEnvironmentVariable(std::string());
+  SaveEnvironmentVariable("");
 
   base::FilePath filename = logging::GetLogFileName();
   ASSERT_NE(base::FilePath::StringType::npos,
diff --git a/chrome/browser/managed_mode/managed_user_service.cc b/chrome/browser/managed_mode/managed_user_service.cc
index 80b2bc8..0cc29f5 100644
--- a/chrome/browser/managed_mode/managed_user_service.cc
+++ b/chrome/browser/managed_mode/managed_user_service.cc
@@ -154,10 +154,10 @@ void ManagedUserService::RegisterUserPrefs(PrefRegistrySyncable* registry) {
                                 ManagedModeURLFilter::BLOCK,
                                 PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kManagedModeLocalPassphrase,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kManagedModeLocalSalt,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
 
@@ -203,7 +203,7 @@ bool ManagedUserService::UserMayLoad(const extensions::Extension* extension,
                                      string16* error) const {
   string16 tmp_error;
   // |extension| can be NULL in unit tests.
-  if (ExtensionManagementPolicyImpl(extension ? extension->id() : std::string(),
+  if (ExtensionManagementPolicyImpl(extension ? extension->id() : "",
                                     &tmp_error))
     return true;
 
@@ -244,8 +244,7 @@ bool ManagedUserService::UserMayModifySettings(
     const extensions::Extension* extension,
     string16* error) const {
   // |extension| can be NULL in unit tests.
-  return ExtensionManagementPolicyImpl(
-      extension ? extension->id() : std::string(), error);
+  return ExtensionManagementPolicyImpl(extension ? extension->id() : "", error);
 }
 
 void ManagedUserService::Observe(int type,
diff --git a/chrome/browser/media/media_stream_devices_controller.cc b/chrome/browser/media/media_stream_devices_controller.cc
index 2d844a4..c83e74d 100644
--- a/chrome/browser/media/media_stream_devices_controller.cc
+++ b/chrome/browser/media/media_stream_devices_controller.cc
@@ -279,11 +279,11 @@ void MediaStreamDevicesController::HandleTabMediaRequest() {
 
     if (request_.audio_type == content::MEDIA_TAB_AUDIO_CAPTURE) {
       devices.push_back(content::MediaStreamDevice(
-          content::MEDIA_TAB_AUDIO_CAPTURE, std::string(), std::string()));
+          content::MEDIA_TAB_AUDIO_CAPTURE, "", ""));
     }
     if (request_.video_type == content::MEDIA_TAB_VIDEO_CAPTURE) {
       devices.push_back(content::MediaStreamDevice(
-          content::MEDIA_TAB_VIDEO_CAPTURE, std::string(), std::string()));
+          content::MEDIA_TAB_VIDEO_CAPTURE, "", ""));
     }
 
     callback_.Run(devices);
diff --git a/chrome/browser/media_galleries/media_galleries_dialog_controller.cc b/chrome/browser/media_galleries/media_galleries_dialog_controller.cc
index bcd3ae3..98ba8da 100644
--- a/chrome/browser/media_galleries/media_galleries_dialog_controller.cc
+++ b/chrome/browser/media_galleries/media_galleries_dialog_controller.cc
@@ -147,7 +147,7 @@ string16 MediaGalleriesDialogController::GetHeader() const {
 }
 
 string16 MediaGalleriesDialogController::GetSubtext() const {
-  std::string extension_name(extension_ ? extension_->name() : std::string());
+  std::string extension_name(extension_ ? extension_->name() : "");
   return l10n_util::GetStringFUTF16(IDS_MEDIA_GALLERIES_DIALOG_SUBTEXT,
                                     UTF8ToUTF16(extension_name));
 }
@@ -184,9 +184,7 @@ void MediaGalleriesDialogController::OnAddFolderClicked() {
       ui::SelectFileDialog::SELECT_FOLDER,
       l10n_util::GetStringUTF16(IDS_MEDIA_GALLERIES_DIALOG_ADD_GALLERY_TITLE),
       user_data_dir,
-      NULL,
-      0,
-      base::FilePath::StringType(),
+      NULL, 0, FILE_PATH_LITERAL(""),
       web_contents_->GetView()->GetTopLevelNativeWindow(),
       NULL);
 }
diff --git a/chrome/browser/media_galleries/media_galleries_preferences.cc b/chrome/browser/media_galleries/media_galleries_preferences.cc
index 48689ee..78316ef 100644
--- a/chrome/browser/media_galleries/media_galleries_preferences.cc
+++ b/chrome/browser/media_galleries/media_galleries_preferences.cc
@@ -258,7 +258,7 @@ void MediaGalleriesPreferences::InitFromPrefs(bool notify_observers) {
     }
   }
   if (notify_observers)
-    NotifyChangeObservers(std::string());
+    NotifyChangeObservers("");
 }
 
 void MediaGalleriesPreferences::NotifyChangeObservers(
diff --git a/chrome/browser/metrics/metrics_log.cc b/chrome/browser/metrics/metrics_log.cc
index ec39326..72fff96 100644
--- a/chrome/browser/metrics/metrics_log.cc
+++ b/chrome/browser/metrics/metrics_log.cc
@@ -969,7 +969,7 @@ void MetricsLog::RecordOmniboxOpenedURL(const AutocompleteLog& log) {
   // Write the XML version.
   OPEN_ELEMENT_FOR_SCOPE("uielement");
   WriteAttribute("action", "autocomplete");
-  WriteAttribute("targetidhash", std::string());
+  WriteAttribute("targetidhash", "");
   // TODO(kochi): Properly track windows.
   WriteIntAttribute("window", 0);
   if (log.tab_id != -1) {
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index c25c8e6..e68d7bf 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -391,13 +391,13 @@ class MetricsMemoryDetails : public MemoryDetails {
 // static
 void MetricsService::RegisterPrefs(PrefRegistrySimple* registry) {
   DCHECK(IsSingleThreaded());
-  registry->RegisterStringPref(prefs::kMetricsClientID, std::string());
+  registry->RegisterStringPref(prefs::kMetricsClientID, "");
   registry->RegisterIntegerPref(prefs::kMetricsLowEntropySource,
                                 kLowEntropySourceNotSet);
   registry->RegisterInt64Pref(prefs::kMetricsClientIDTimestamp, 0);
   registry->RegisterInt64Pref(prefs::kStabilityLaunchTimeSec, 0);
   registry->RegisterInt64Pref(prefs::kStabilityLastTimestampSec, 0);
-  registry->RegisterStringPref(prefs::kStabilityStatsVersion, std::string());
+  registry->RegisterStringPref(prefs::kStabilityStatsVersion, "");
   registry->RegisterInt64Pref(prefs::kStabilityStatsBuildTime, 0);
   registry->RegisterBooleanPref(prefs::kStabilityExitedCleanly, true);
   registry->RegisterBooleanPref(prefs::kStabilitySessionEndCompleted, true);
diff --git a/chrome/browser/nacl_host/pnacl_file_host_unittest.cc b/chrome/browser/nacl_host/pnacl_file_host_unittest.cc
index 6e30c29..eb2a74a 100644
--- a/chrome/browser/nacl_host/pnacl_file_host_unittest.cc
+++ b/chrome/browser/nacl_host/pnacl_file_host_unittest.cc
@@ -57,7 +57,7 @@ TEST(PnaclFileHostTest, TestFilenamesWithPnaclPath) {
                                 &out_path));
 
   // Other bad files.
-  EXPECT_FALSE(PnaclCanOpenFile(std::string(), &out_path));
+  EXPECT_FALSE(PnaclCanOpenFile("", &out_path));
   EXPECT_FALSE(PnaclCanOpenFile(".", &out_path));
   EXPECT_FALSE(PnaclCanOpenFile("..", &out_path));
 #if defined(OS_WIN)
diff --git a/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc b/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc
index f1d1714..4326fb9 100644
--- a/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc
+++ b/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc
@@ -123,7 +123,8 @@ class NotSendingTestReporter : public TestReporter {
 class MockURLRequest : public net::URLRequest {
  public:
   explicit MockURLRequest(net::URLRequestContext* context)
-      : net::URLRequest(GURL(std::string()), NULL, context) {}
+      : net::URLRequest(GURL(""), NULL, context) {
+  }
 
  private:
 };
diff --git a/chrome/browser/net/chrome_network_delegate_unittest.cc b/chrome/browser/net/chrome_network_delegate_unittest.cc
index b5c8151..f822195 100644
--- a/chrome/browser/net/chrome_network_delegate_unittest.cc
+++ b/chrome/browser/net/chrome_network_delegate_unittest.cc
@@ -234,7 +234,7 @@ TEST_F(ChromeNetworkDelegateSafeSearchTest, SafeSearchOn) {
                        "q=goog&" + kBothParameters);
 
   // Test that another website is not affected, without parameters.
-  CheckAddedParameters("http://google.com/finance", std::string());
+  CheckAddedParameters("http://google.com/finance", "");
 
   // Test that another website is not affected, with parameters.
   CheckAddedParameters("http://google.com/finance?q=goog", "q=goog");
@@ -255,10 +255,10 @@ TEST_F(ChromeNetworkDelegateSafeSearchTest, SafeSearchOff) {
   SetDelegate(delegate.get());
 
   // Test the home page.
-  CheckAddedParameters("http://google.com/", std::string());
+  CheckAddedParameters("http://google.com/", "");
 
   // Test the search home page.
-  CheckAddedParameters("http://google.com/webhp", std::string());
+  CheckAddedParameters("http://google.com/webhp", "");
 
   // Test the home page with parameters.
   CheckAddedParameters("http://google.com/search?q=google",
diff --git a/chrome/browser/net/dns_probe_job_unittest.cc b/chrome/browser/net/dns_probe_job_unittest.cc
index 1fe8766..06d6965 100644
--- a/chrome/browser/net/dns_probe_job_unittest.cc
+++ b/chrome/browser/net/dns_probe_job_unittest.cc
@@ -54,7 +54,7 @@ void DnsProbeJobTest::RunProbe(MockDnsClientRule::Result good_result,
   const uint16 kTypeA = net::dns_protocol::kTypeA;
   MockDnsClientRuleList rules;
   rules.push_back(MockDnsClientRule("google.com", kTypeA, good_result));
-  rules.push_back(MockDnsClientRule(std::string(), kTypeA, bad_result));
+  rules.push_back(MockDnsClientRule("", kTypeA, bad_result));
 
   scoped_ptr<DnsClient> dns_client = CreateMockDnsClient(config, rules);
   dns_client->SetConfig(config);
diff --git a/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc b/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc
index f582d1b..7f33790 100644
--- a/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc
+++ b/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc
@@ -118,10 +118,8 @@ class HttpPipeliningCompatibilityClientTest : public testing::Test {
       HttpPipeliningCompatibilityClient::Options options) {
     HttpPipeliningCompatibilityClient client(NULL);
     net::TestCompletionCallback callback;
-    client.Start(test_server_.GetURL(std::string()).spec(),
-                 requests,
-                 options,
-                 callback.callback(),
+    client.Start(test_server_.GetURL("").spec(),
+                 requests, options, callback.callback(),
                  context_->GetURLRequestContext());
     callback.WaitForResult();
   }
diff --git a/chrome/browser/net/pref_proxy_config_tracker_impl_unittest.cc b/chrome/browser/net/pref_proxy_config_tracker_impl_unittest.cc
index c69fc93..3ab5d69 100644
--- a/chrome/browser/net/pref_proxy_config_tracker_impl_unittest.cc
+++ b/chrome/browser/net/pref_proxy_config_tracker_impl_unittest.cc
@@ -135,9 +135,9 @@ TEST_F(PrefProxyConfigTrackerImplTest, BaseConfiguration) {
 }
 
 TEST_F(PrefProxyConfigTrackerImplTest, DynamicPrefOverrides) {
-  pref_service_->SetManagedPref(prefs::kProxy,
-                                ProxyConfigDictionary::CreateFixedServers(
-                                    "http://example.com:3128", std::string()));
+  pref_service_->SetManagedPref(
+      prefs::kProxy,
+      ProxyConfigDictionary::CreateFixedServers("http://example.com:3128", ""));
   loop_.RunUntilIdle();
 
   net::ProxyConfig actual_config;
diff --git a/chrome/browser/net/url_info.cc b/chrome/browser/net/url_info.cc
index 1046827..ddba658 100644
--- a/chrome/browser/net/url_info.cc
+++ b/chrome/browser/net/url_info.cc
@@ -361,7 +361,7 @@ std::string UrlInfo::GetAsciiMotivation() const {
       return RemoveJs(referring_url_.spec());
 
     default:
-      return std::string();
+      return "";
   }
 }
 
diff --git a/chrome/browser/page_cycler/page_cycler.cc b/chrome/browser/page_cycler/page_cycler.cc
index b78e1fe..04086d2 100644
--- a/chrome/browser/page_cycler/page_cycler.cc
+++ b/chrome/browser/page_cycler/page_cycler.cc
@@ -192,12 +192,10 @@ void PageCycler::PrepareResultsOnBackgroundThread() {
     base::ProcessId pid = base::GetCurrentProcId();
 #endif  // OS_WIN
     ChromeProcessList chrome_processes(GetRunningChromeProcesses(pid));
-    output += perf_test::MemoryUsageInfoToString(
-        std::string(), chrome_processes, pid);
-    output +=
-        perf_test::IOPerfInfoToString(std::string(), chrome_processes, pid);
-    output += perf_test::SystemCommitChargeToString(
-        std::string(), base::GetSystemCommitCharge(), false);
+    output += perf_test::MemoryUsageInfoToString("", chrome_processes, pid);
+    output += perf_test::IOPerfInfoToString("", chrome_processes, pid);
+    output += perf_test::SystemCommitChargeToString("",
+              base::GetSystemCommitCharge(), false);
     output.append("Pages: [" + urls_string_ + "]\n");
     output.append("*RESULT times: t_ref= [" + timings_string_ + "] ms\n");
   }
diff --git a/chrome/browser/password_manager/native_backend_kwallet_x.cc b/chrome/browser/password_manager/native_backend_kwallet_x.cc
index 9c6003d..74d6bb9 100644
--- a/chrome/browser/password_manager/native_backend_kwallet_x.cc
+++ b/chrome/browser/password_manager/native_backend_kwallet_x.cc
@@ -186,7 +186,7 @@ bool NativeBackendKWallet::StartKWalletd() {
   builder.AppendString("kwalletd");     // serviceName
   builder.AppendArrayOfStrings(empty);  // urls
   builder.AppendArrayOfStrings(empty);  // envs
-  builder.AppendString(std::string());  // startup_id
+  builder.AppendString("");             // startup_id
   builder.AppendBool(false);            // blind
   scoped_ptr<dbus::Response> response(
       klauncher->CallMethodAndBlock(
diff --git a/chrome/browser/password_manager/native_backend_kwallet_x_unittest.cc b/chrome/browser/password_manager/native_backend_kwallet_x_unittest.cc
index 11af55a..ad00e11 100644
--- a/chrome/browser/password_manager/native_backend_kwallet_x_unittest.cc
+++ b/chrome/browser/password_manager/native_backend_kwallet_x_unittest.cc
@@ -315,7 +315,7 @@ dbus::Response* NativeBackendKWalletTest::KLauncherMethodCall(
   scoped_ptr<dbus::Response> response(dbus::Response::CreateEmpty());
   dbus::MessageWriter writer(response.get());
   writer.AppendInt32(klauncher_ret_);
-  writer.AppendString(std::string());  // dbus_name
+  writer.AppendString("");   // dbus_name
   writer.AppendString(klauncher_error_);
   writer.AppendInt32(1234);  // pid
   return response.release();
diff --git a/chrome/browser/plugins/plugin_finder.cc b/chrome/browser/plugins/plugin_finder.cc
index 0070387..32ad157 100644
--- a/chrome/browser/plugins/plugin_finder.cc
+++ b/chrome/browser/plugins/plugin_finder.cc
@@ -292,11 +292,9 @@ scoped_ptr<PluginMetadata> PluginFinder::GetPluginMetadata(
   std::string identifier = GetIdentifier(plugin);
   PluginMetadata* metadata = new PluginMetadata(identifier,
                                                 GetGroupName(plugin),
-                                                false,
-                                                GURL(),
-                                                GURL(),
+                                                false, GURL(), GURL(),
                                                 plugin.name,
-                                                std::string());
+                                                "");
   for (size_t i = 0; i < plugin.mime_types.size(); ++i)
     metadata->AddMatchingMimeType(plugin.mime_types[i].mime_type);
 
diff --git a/chrome/browser/plugins/plugin_metadata_unittest.cc b/chrome/browser/plugins/plugin_metadata_unittest.cc
index b542b1b..3e3bf99 100644
--- a/chrome/browser/plugins/plugin_metadata_unittest.cc
+++ b/chrome/browser/plugins/plugin_metadata_unittest.cc
@@ -34,11 +34,9 @@ TEST(PluginMetadataTest, SecurityStatus) {
 
   PluginMetadata plugin_metadata("claybrick-writer",
                                  ASCIIToUTF16("ClayBrick Writer"),
-                                 true,
-                                 GURL(),
-                                 GURL(),
+                                 true, GURL(), GURL(),
                                  ASCIIToUTF16("ClayBrick"),
-                                 std::string());
+                                 "");
 #if defined(OS_LINUX)
   EXPECT_EQ(kRequiresAuthorization,
             GetSecurityStatus(&plugin_metadata, "1.2.3"));
diff --git a/chrome/browser/policy/cloud/cloud_policy_refresh_scheduler_unittest.cc b/chrome/browser/policy/cloud/cloud_policy_refresh_scheduler_unittest.cc
index 9f3c403..269ca75 100644
--- a/chrome/browser/policy/cloud/cloud_policy_refresh_scheduler_unittest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_refresh_scheduler_unittest.cc
@@ -127,7 +127,7 @@ TEST_F(CloudPolicyRefreshSchedulerTest, InitialRefreshManagedAlreadyFetched) {
 }
 
 TEST_F(CloudPolicyRefreshSchedulerTest, Unregistered) {
-  client_.SetDMToken(std::string());
+  client_.SetDMToken("");
   scoped_ptr<CloudPolicyRefreshScheduler> scheduler(CreateRefreshScheduler());
   client_.NotifyPolicyFetched();
   client_.NotifyRegistrationStateChanged();
@@ -182,7 +182,7 @@ TEST_F(CloudPolicyRefreshSchedulerSteadyStateTest, OnRegistrationStateChanged) {
   EXPECT_EQ(GetLastDelay(), base::TimeDelta());
 
   task_runner_->ClearPendingTasks();
-  client_.SetDMToken(std::string());
+  client_.SetDMToken("");
   client_.NotifyRegistrationStateChanged();
   EXPECT_TRUE(task_runner_->GetPendingTasks().empty());
 }
diff --git a/chrome/browser/policy/cloud/cloud_policy_service_unittest.cc b/chrome/browser/policy/cloud/cloud_policy_service_unittest.cc
index b1c7ccb..90b344b 100644
--- a/chrome/browser/policy/cloud/cloud_policy_service_unittest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_service_unittest.cc
@@ -118,7 +118,7 @@ TEST_F(CloudPolicyServiceTest, RefreshPolicySuccess) {
 
 TEST_F(CloudPolicyServiceTest, RefreshPolicyNotRegistered) {
   // Clear the token so the client is not registered.
-  client_.SetDMToken(std::string());
+  client_.SetDMToken("");
 
   EXPECT_CALL(client_, FetchPolicy()).Times(0);
   EXPECT_CALL(*this, OnPolicyRefresh(false)).Times(1);
diff --git a/chrome/browser/policy/cloud/device_management_service_unittest.cc b/chrome/browser/policy/cloud/device_management_service_unittest.cc
index b83ca80..ae84965 100644
--- a/chrome/browser/policy/cloud/device_management_service_unittest.cc
+++ b/chrome/browser/policy/cloud/device_management_service_unittest.cc
@@ -513,7 +513,7 @@ TEST_F(DeviceManagementServiceTest, CancelDuringCallback) {
 
   // Generate a callback.
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, 0);
-  SendResponse(fetcher, status, 500, std::string());
+  SendResponse(fetcher, status, 500, "");
 
   // Job should have been reset.
   EXPECT_FALSE(request_job.get());
@@ -534,7 +534,7 @@ TEST_F(DeviceManagementServiceTest, RetryOnProxyError) {
   // Generate a callback with a proxy failure.
   net::URLRequestStatus status(net::URLRequestStatus::FAILED,
                                net::ERR_PROXY_CONNECTION_FAILED);
-  SendResponse(fetcher, status, 200, std::string());
+  SendResponse(fetcher, status, 200, "");
 
   // Verify that a new URLFetcher was started that bypasses the proxy.
   fetcher = GetFetcher();
@@ -564,7 +564,7 @@ TEST_F(DeviceManagementServiceTest, RetryOnBadResponseFromProxy) {
   // Generate a callback with a valid http response, that was generated by
   // a bad/wrong proxy.
   net::URLRequestStatus status;
-  SendResponse(fetcher, status, 200, std::string());
+  SendResponse(fetcher, status, 200, "");
 
   // Verify that a new URLFetcher was started that bypasses the proxy.
   fetcher = GetFetcher();
diff --git a/chrome/browser/policy/cloud/mock_cloud_policy_client.cc b/chrome/browser/policy/cloud/mock_cloud_policy_client.cc
index 92b67e7..7008ec3 100644
--- a/chrome/browser/policy/cloud/mock_cloud_policy_client.cc
+++ b/chrome/browser/policy/cloud/mock_cloud_policy_client.cc
@@ -10,11 +10,7 @@ namespace em = enterprise_management;
 namespace policy {
 
 MockCloudPolicyClient::MockCloudPolicyClient()
-    : CloudPolicyClient(std::string(),
-                        std::string(),
-                        USER_AFFILIATION_NONE,
-                        NULL,
-                        NULL) {}
+    : CloudPolicyClient("", "", USER_AFFILIATION_NONE, NULL, NULL) {}
 
 MockCloudPolicyClient::~MockCloudPolicyClient() {}
 
diff --git a/chrome/browser/policy/cloud/mock_device_management_service.cc b/chrome/browser/policy/cloud/mock_device_management_service.cc
index f7836ce..987cf62 100644
--- a/chrome/browser/policy/cloud/mock_device_management_service.cc
+++ b/chrome/browser/policy/cloud/mock_device_management_service.cc
@@ -116,7 +116,7 @@ ACTION_P2(CreateAsyncMockDeviceManagementJob, service, mock_job) {
 MockDeviceManagementJob::~MockDeviceManagementJob() {}
 
 MockDeviceManagementService::MockDeviceManagementService()
-    : DeviceManagementService(std::string()) {}
+    : DeviceManagementService("") {}
 
 MockDeviceManagementService::~MockDeviceManagementService() {}
 
diff --git a/chrome/browser/policy/configuration_policy_pref_store_unittest.cc b/chrome/browser/policy/configuration_policy_pref_store_unittest.cc
index 321b3732..a801f83 100644
--- a/chrome/browser/policy/configuration_policy_pref_store_unittest.cc
+++ b/chrome/browser/policy/configuration_policy_pref_store_unittest.cc
@@ -409,10 +409,9 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, ManualOptions) {
           ProxyPolicyHandler::PROXY_MANUALLY_CONFIGURED_PROXY_SERVER_MODE));
   UpdateProviderPolicy(policy);
 
-  VerifyProxyPrefs("chromium.org",
-                   std::string(),
-                   "http://chromium.org/override",
-                   ProxyPrefs::MODE_FIXED_SERVERS);
+  VerifyProxyPrefs(
+      "chromium.org", "", "http://chromium.org/override",
+      ProxyPrefs::MODE_FIXED_SERVERS);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, ManualOptionsReversedApplyOrder) {
@@ -427,10 +426,9 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, ManualOptionsReversedApplyOrder) {
              base::Value::CreateStringValue("chromium.org"));
   UpdateProviderPolicy(policy);
 
-  VerifyProxyPrefs("chromium.org",
-                   std::string(),
-                   "http://chromium.org/override",
-                   ProxyPrefs::MODE_FIXED_SERVERS);
+  VerifyProxyPrefs(
+      "chromium.org", "", "http://chromium.org/override",
+      ProxyPrefs::MODE_FIXED_SERVERS);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, ManualOptionsInvalid) {
@@ -452,8 +450,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, NoProxyServerMode) {
              base::Value::CreateIntegerValue(
                  ProxyPolicyHandler::PROXY_SERVER_MODE));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(
-      std::string(), std::string(), std::string(), ProxyPrefs::MODE_DIRECT);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_DIRECT);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, NoProxyModeName) {
@@ -461,8 +458,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, NoProxyModeName) {
   policy.Set(key::kProxyMode, POLICY_LEVEL_MANDATORY, POLICY_SCOPE_USER,
              base::Value::CreateStringValue(ProxyPrefs::kDirectProxyModeName));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(
-      std::string(), std::string(), std::string(), ProxyPrefs::MODE_DIRECT);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_DIRECT);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, AutoDetectProxyServerMode) {
@@ -472,10 +468,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, AutoDetectProxyServerMode) {
       base::Value::CreateIntegerValue(
           ProxyPolicyHandler::PROXY_AUTO_DETECT_PROXY_SERVER_MODE));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(std::string(),
-                   std::string(),
-                   std::string(),
-                   ProxyPrefs::MODE_AUTO_DETECT);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_AUTO_DETECT);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, AutoDetectProxyModeName) {
@@ -484,10 +477,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, AutoDetectProxyModeName) {
              base::Value::CreateStringValue(
                  ProxyPrefs::kAutoDetectProxyModeName));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(std::string(),
-                   std::string(),
-                   std::string(),
-                   ProxyPrefs::MODE_AUTO_DETECT);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_AUTO_DETECT);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, PacScriptProxyMode) {
@@ -498,9 +488,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, PacScriptProxyMode) {
              base::Value::CreateStringValue(
                  ProxyPrefs::kPacScriptProxyModeName));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(std::string(),
-                   "http://short.org/proxy.pac",
-                   std::string(),
+  VerifyProxyPrefs("", "http://short.org/proxy.pac", "",
                    ProxyPrefs::MODE_PAC_SCRIPT);
 }
 
@@ -518,21 +506,15 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, PacScriptProxyModeInvalid) {
 // for unset properties.
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, PacScriptProxyModeBug78016) {
   PolicyMap policy;
-  policy.Set(key::kProxyServer,
-             POLICY_LEVEL_MANDATORY,
-             POLICY_SCOPE_USER,
-             base::Value::CreateStringValue(std::string()));
-  policy.Set(key::kProxyPacUrl,
-             POLICY_LEVEL_MANDATORY,
-             POLICY_SCOPE_USER,
+  policy.Set(key::kProxyServer, POLICY_LEVEL_MANDATORY, POLICY_SCOPE_USER,
+             base::Value::CreateStringValue(""));
+  policy.Set(key::kProxyPacUrl, POLICY_LEVEL_MANDATORY, POLICY_SCOPE_USER,
              base::Value::CreateStringValue("http://short.org/proxy.pac"));
   policy.Set(key::kProxyMode, POLICY_LEVEL_MANDATORY, POLICY_SCOPE_USER,
              base::Value::CreateStringValue(
                  ProxyPrefs::kPacScriptProxyModeName));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(std::string(),
-                   "http://short.org/proxy.pac",
-                   std::string(),
+  VerifyProxyPrefs("", "http://short.org/proxy.pac", "",
                    ProxyPrefs::MODE_PAC_SCRIPT);
 }
 
@@ -542,8 +524,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, UseSystemProxyServerMode) {
       base::Value::CreateIntegerValue(
           ProxyPolicyHandler::PROXY_USE_SYSTEM_PROXY_SERVER_MODE));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(
-      std::string(), std::string(), std::string(), ProxyPrefs::MODE_SYSTEM);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_SYSTEM);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, UseSystemProxyMode) {
@@ -551,8 +532,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest, UseSystemProxyMode) {
   policy.Set(key::kProxyMode, POLICY_LEVEL_MANDATORY, POLICY_SCOPE_USER,
              base::Value::CreateStringValue(ProxyPrefs::kSystemProxyModeName));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(
-      std::string(), std::string(), std::string(), ProxyPrefs::MODE_SYSTEM);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_SYSTEM);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest,
@@ -565,10 +545,7 @@ TEST_F(ConfigurationPolicyPrefStoreProxyTest,
              base::Value::CreateStringValue(
                  ProxyPrefs::kAutoDetectProxyModeName));
   UpdateProviderPolicy(policy);
-  VerifyProxyPrefs(std::string(),
-                   std::string(),
-                   std::string(),
-                   ProxyPrefs::MODE_AUTO_DETECT);
+  VerifyProxyPrefs("", "", "", ProxyPrefs::MODE_AUTO_DETECT);
 }
 
 TEST_F(ConfigurationPolicyPrefStoreProxyTest, ProxyInvalid) {
@@ -791,7 +768,7 @@ TEST_F(ConfigurationPolicyPrefStoreDefaultSearchTest, Disabled) {
   base::FundamentalValue expected_enabled(false);
   EXPECT_TRUE(base::Value::Equals(&expected_enabled, value));
   EXPECT_TRUE(store_->GetValue(prefs::kDefaultSearchProviderSearchURL, &value));
-  base::StringValue expected_search_url((std::string()));
+  base::StringValue expected_search_url("");
   EXPECT_TRUE(base::Value::Equals(&expected_search_url, value));
 }
 
@@ -931,10 +908,8 @@ TEST_F(ConfigurationPolicyPrefStorePromptDownloadTest, Default) {
 TEST_F(ConfigurationPolicyPrefStorePromptDownloadTest, SetDownloadDirectory) {
   PolicyMap policy;
   EXPECT_FALSE(store_->GetValue(prefs::kPromptForDownload, NULL));
-  policy.Set(key::kDownloadDirectory,
-             POLICY_LEVEL_MANDATORY,
-             POLICY_SCOPE_USER,
-             base::Value::CreateStringValue(std::string()));
+  policy.Set(key::kDownloadDirectory, POLICY_LEVEL_MANDATORY,
+             POLICY_SCOPE_USER, base::Value::CreateStringValue(""));
   UpdateProviderPolicy(policy);
 
   // Setting a DownloadDirectory should disable the PromptForDownload pref.
diff --git a/chrome/browser/policy/policy_map_unittest.cc b/chrome/browser/policy/policy_map_unittest.cc
index 367ce06..a2f6207 100644
--- a/chrome/browser/policy/policy_map_unittest.cc
+++ b/chrome/browser/policy/policy_map_unittest.cc
@@ -103,13 +103,9 @@ TEST(PolicyMapTest, MergeFrom) {
         Value::CreateBooleanValue(false));
   b.Set(key::kBookmarkBarEnabled, POLICY_LEVEL_RECOMMENDED,
         POLICY_SCOPE_MACHINE, Value::CreateBooleanValue(true));
-  b.Set(key::kDefaultSearchProviderSearchURL,
-        POLICY_LEVEL_MANDATORY,
-        POLICY_SCOPE_MACHINE,
-        Value::CreateStringValue(std::string()));
-  b.Set(key::kDisableSpdy,
-        POLICY_LEVEL_RECOMMENDED,
-        POLICY_SCOPE_USER,
+  b.Set(key::kDefaultSearchProviderSearchURL, POLICY_LEVEL_MANDATORY,
+        POLICY_SCOPE_MACHINE, Value::CreateStringValue(""));
+  b.Set(key::kDisableSpdy, POLICY_LEVEL_RECOMMENDED, POLICY_SCOPE_USER,
         Value::CreateBooleanValue(true));
 
   a.MergeFrom(b);
@@ -125,10 +121,8 @@ TEST(PolicyMapTest, MergeFrom) {
   c.Set(key::kBookmarkBarEnabled, POLICY_LEVEL_RECOMMENDED,
         POLICY_SCOPE_MACHINE, Value::CreateBooleanValue(true));
   // POLICY_LEVEL_MANDATORY over POLICY_LEVEL_RECOMMENDED.
-  c.Set(key::kDefaultSearchProviderSearchURL,
-        POLICY_LEVEL_MANDATORY,
-        POLICY_SCOPE_MACHINE,
-        Value::CreateStringValue(std::string()));
+  c.Set(key::kDefaultSearchProviderSearchURL, POLICY_LEVEL_MANDATORY,
+        POLICY_SCOPE_MACHINE, Value::CreateStringValue(""));
   // Merge new ones.
   c.Set(key::kDisableSpdy, POLICY_LEVEL_RECOMMENDED, POLICY_SCOPE_USER,
         Value::CreateBooleanValue(true));
diff --git a/chrome/browser/policy/policy_prefs_browsertest.cc b/chrome/browser/policy/policy_prefs_browsertest.cc
index 23173bc..bce4fe0 100644
--- a/chrome/browser/policy/policy_prefs_browsertest.cc
+++ b/chrome/browser/policy/policy_prefs_browsertest.cc
@@ -519,8 +519,8 @@ IN_PROC_BROWSER_TEST_P(PolicyPrefsTest, CheckPolicyIndicators) {
       // set by policy.
       PolicyMap policies;
       UpdateProviderPolicy(policies);
-      VerifyControlledSettingIndicators(
-          browser(), indicator_selector, std::string(), std::string(), false);
+      VerifyControlledSettingIndicators(browser(), indicator_selector,
+                                        "", "", false);
       // Check that the appropriate controlled setting indicator is shown when a
       // value is enforced by policy.
       policies.LoadFrom(&(*indicator_test_case)->policy(),
diff --git a/chrome/browser/policy/url_blacklist_manager_unittest.cc b/chrome/browser/policy/url_blacklist_manager_unittest.cc
index b1f69d1..3e5ac0f 100644
--- a/chrome/browser/policy/url_blacklist_manager_unittest.cc
+++ b/chrome/browser/policy/url_blacklist_manager_unittest.cc
@@ -240,83 +240,31 @@ INSTANTIATE_TEST_CASE_P(
     URLBlacklistFilterToComponentsTest,
     testing::Values(
         FilterTestParams("google.com",
-                         std::string(),
-                         ".google.com",
-                         true,
-                         0u,
-                         std::string()),
+                         "", ".google.com", true, 0u, ""),
         FilterTestParams(".google.com",
-                         std::string(),
-                         "google.com",
-                         false,
-                         0u,
-                         std::string()),
+                         "", "google.com", false, 0u, ""),
         FilterTestParams("http://google.com",
-                         "http",
-                         ".google.com",
-                         true,
-                         0u,
-                         std::string()),
+                         "http", ".google.com", true, 0u, ""),
         FilterTestParams("google.com/",
-                         std::string(),
-                         ".google.com",
-                         true,
-                         0u,
-                         "/"),
+                         "", ".google.com", true, 0u, "/"),
         FilterTestParams("http://google.com:8080/whatever",
-                         "http",
-                         ".google.com",
-                         true,
-                         8080u,
-                         "/whatever"),
+                         "http", ".google.com", true, 8080u, "/whatever"),
         FilterTestParams("http://user:pass@google.com:8080/whatever",
-                         "http",
-                         ".google.com",
-                         true,
-                         8080u,
-                         "/whatever"),
+                         "http", ".google.com", true, 8080u, "/whatever"),
         FilterTestParams("123.123.123.123",
-                         std::string(),
-                         "123.123.123.123",
-                         false,
-                         0u,
-                         std::string()),
+                         "", "123.123.123.123", false, 0u, ""),
         FilterTestParams("https://123.123.123.123",
-                         "https",
-                         "123.123.123.123",
-                         false,
-                         0u,
-                         std::string()),
+                         "https", "123.123.123.123", false, 0u, ""),
         FilterTestParams("123.123.123.123/",
-                         std::string(),
-                         "123.123.123.123",
-                         false,
-                         0u,
-                         "/"),
+                         "", "123.123.123.123", false, 0u, "/"),
         FilterTestParams("http://123.123.123.123:123/whatever",
-                         "http",
-                         "123.123.123.123",
-                         false,
-                         123u,
-                         "/whatever"),
+                         "http", "123.123.123.123", false, 123u, "/whatever"),
         FilterTestParams("*",
-                         std::string(),
-                         std::string(),
-                         true,
-                         0u,
-                         std::string()),
+                         "", "", true, 0u, ""),
         FilterTestParams("ftp://*",
-                         "ftp",
-                         std::string(),
-                         true,
-                         0u,
-                         std::string()),
+                         "ftp", "", true, 0u, ""),
         FilterTestParams("http://*/whatever",
-                         "http",
-                         std::string(),
-                         true,
-                         0u,
-                         "/whatever")));
+                         "http", "", true, 0u, "/whatever")));
 
 TEST_F(URLBlacklistManagerTest, Filtering) {
   URLBlacklist blacklist;
diff --git a/chrome/browser/popup_blocker_browsertest.cc b/chrome/browser/popup_blocker_browsertest.cc
index aacbbef..c2e3ede 100644
--- a/chrome/browser/popup_blocker_browsertest.cc
+++ b/chrome/browser/popup_blocker_browsertest.cc
@@ -55,7 +55,7 @@ class PopupBlockerBrowserTest : public InProcessBrowserTest {
     // Do a round trip to the renderer first to flush any in-flight IPCs to
     // create a to-be-blocked window.
     WebContents* tab = browser->tab_strip_model()->GetActiveWebContents();
-    CHECK(content::ExecuteScript(tab, std::string()));
+    CHECK(content::ExecuteScript(tab, ""));
     BlockedContentTabHelper* blocked_content_tab_helper =
         BlockedContentTabHelper::FromWebContents(tab);
     std::vector<WebContents*> blocked_contents;
@@ -127,12 +127,12 @@ IN_PROC_BROWSER_TEST_F(PopupBlockerBrowserTest, MultiplePopups) {
 IN_PROC_BROWSER_TEST_F(PopupBlockerBrowserTest,
                        AllowPopupThroughContentSetting) {
   GURL url(GetTestURL());
-  browser()->profile()->GetHostContentSettingsMap()
-      ->SetContentSetting(ContentSettingsPattern::FromURL(url),
-                          ContentSettingsPattern::Wildcard(),
-                          CONTENT_SETTINGS_TYPE_POPUPS,
-                          std::string(),
-                          CONTENT_SETTING_ALLOW);
+  browser()->profile()->GetHostContentSettingsMap()->SetContentSetting(
+      ContentSettingsPattern::FromURL(url),
+      ContentSettingsPattern::Wildcard(),
+      CONTENT_SETTINGS_TYPE_POPUPS,
+      "",
+      CONTENT_SETTING_ALLOW);
 
   NavigateAndCheckPopupShown(browser(), url);
 }
diff --git a/chrome/browser/predictors/autocomplete_action_predictor.cc b/chrome/browser/predictors/autocomplete_action_predictor.cc
index 184e7a7..cc183c36 100644
--- a/chrome/browser/predictors/autocomplete_action_predictor.cc
+++ b/chrome/browser/predictors/autocomplete_action_predictor.cc
@@ -148,7 +148,7 @@ void AutocompleteActionPredictor::StartPrerendering(
           prerender::PrerenderManagerFactory::GetForProfile(profile_)) {
     content::SessionStorageNamespace* session_storage_namespace = NULL;
     content::SessionStorageNamespaceMap::const_iterator it =
-        session_storage_namespace_map.find(std::string());
+        session_storage_namespace_map.find("");
     if (it != session_storage_namespace_map.end())
       session_storage_namespace = it->second;
     prerender_handle_.reset(
diff --git a/chrome/browser/predictors/resource_prefetch_predictor.cc b/chrome/browser/predictors/resource_prefetch_predictor.cc
index b37f3a1..a6d7cbd 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor.cc
@@ -1012,8 +1012,7 @@ void ResourcePrefetchPredictor::LearnNavigation(
   } else {
     bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
     PrefetchData empty_data(
-        !is_host ? PREFETCH_KEY_TYPE_HOST : PREFETCH_KEY_TYPE_URL,
-        std::string());
+        !is_host ? PREFETCH_KEY_TYPE_HOST : PREFETCH_KEY_TYPE_URL , "");
     const PrefetchData& host_data = is_host ? cache_entry->second : empty_data;
     const PrefetchData& url_data = is_host ? empty_data : cache_entry->second;
     BrowserThread::PostTask(
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc b/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc
index fa5be14..d39e892 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc
@@ -167,45 +167,34 @@ void ResourcePrefetchPredictorTablesTest::TestDeleteSingleDataPoint() {
 void ResourcePrefetchPredictorTablesTest::TestUpdateData() {
   PrefetchData google(PREFETCH_KEY_TYPE_URL, "http://www.google.com");
   google.last_visit = base::Time::FromInternalValue(10);
-  google.resources.push_back(ResourceRow(std::string(),
-                                         "http://www.google.com/style.css",
-                                         ResourceType::STYLESHEET,
-                                         6,
-                                         2,
-                                         0,
-                                         1.0));
-  google.resources.push_back(ResourceRow(std::string(),
-                                         "http://www.google.com/image.png",
-                                         ResourceType::IMAGE,
-                                         6,
-                                         4,
-                                         1,
-                                         4.2));
-  google.resources.push_back(ResourceRow(std::string(),
-                                         "http://www.google.com/a.xml",
-                                         ResourceType::LAST_TYPE,
-                                         1,
-                                         0,
-                                         0,
-                                         6.1));
-  google.resources
-      .push_back(ResourceRow(std::string(),
-                             "http://www.resources.google.com/script.js",
-                             ResourceType::SCRIPT,
-                             12,
-                             0,
-                             0,
-                             8.5));
+  google.resources.push_back(ResourceRow(
+      "",
+      "http://www.google.com/style.css",
+      ResourceType::STYLESHEET,
+      6, 2, 0, 1.0));
+  google.resources.push_back(ResourceRow(
+      "",
+      "http://www.google.com/image.png",
+      ResourceType::IMAGE,
+      6, 4, 1, 4.2));
+  google.resources.push_back(ResourceRow(
+      "",
+      "http://www.google.com/a.xml",
+      ResourceType::LAST_TYPE,
+      1, 0, 0, 6.1));
+  google.resources.push_back(ResourceRow(
+      "",
+      "http://www.resources.google.com/script.js",
+      ResourceType::SCRIPT,
+      12, 0, 0, 8.5));
 
   PrefetchData yahoo(PREFETCH_KEY_TYPE_HOST, "www.yahoo.com");
   yahoo.last_visit = base::Time::FromInternalValue(7);
-  yahoo.resources.push_back(ResourceRow(std::string(),
-                                        "http://www.yahoo.com/image.png",
-                                        ResourceType::IMAGE,
-                                        120,
-                                        1,
-                                        1,
-                                        10.0));
+  yahoo.resources.push_back(ResourceRow(
+      "",
+      "http://www.yahoo.com/image.png",
+      ResourceType::IMAGE,
+      120, 1, 1, 10.0));
 
   tables_->UpdateData(google, yahoo);
 
@@ -287,78 +276,59 @@ void ResourcePrefetchPredictorTablesTest::InitializeSampleData() {
   {  // Url data.
     PrefetchData google(PREFETCH_KEY_TYPE_URL, "http://www.google.com");
     google.last_visit = base::Time::FromInternalValue(1);
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://www.google.com/style.css",
-                                           ResourceType::STYLESHEET,
-                                           5,
-                                           2,
-                                           1,
-                                           1.1));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://www.google.com/script.js",
-                                           ResourceType::SCRIPT,
-                                           4,
-                                           0,
-                                           1,
-                                           2.1));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://www.google.com/image.png",
-                                           ResourceType::IMAGE,
-                                           6,
-                                           3,
-                                           0,
-                                           2.2));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://www.google.com/a.font",
-                                           ResourceType::LAST_TYPE,
-                                           2,
-                                           0,
-                                           0,
-                                           5.1));
-    google.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.resources.google.com/script.js",
-                               ResourceType::SCRIPT,
-                               11,
-                               0,
-                               0,
-                               8.5));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://www.google.com/style.css",
+        ResourceType::STYLESHEET,
+        5, 2, 1, 1.1));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://www.google.com/script.js",
+        ResourceType::SCRIPT,
+        4, 0, 1, 2.1));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://www.google.com/image.png",
+        ResourceType::IMAGE,
+        6, 3, 0, 2.2));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://www.google.com/a.font",
+        ResourceType::LAST_TYPE,
+        2, 0, 0, 5.1));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://www.resources.google.com/script.js",
+        ResourceType::SCRIPT,
+        11, 0, 0, 8.5));
 
     PrefetchData reddit(PREFETCH_KEY_TYPE_URL, "http://www.reddit.com");
     reddit.last_visit = base::Time::FromInternalValue(2);
-    reddit.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://reddit-resource.com/script1.js",
-                               ResourceType::SCRIPT,
-                               4,
-                               0,
-                               1,
-                               1.0));
-    reddit.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://reddit-resource.com/script2.js",
-                               ResourceType::SCRIPT,
-                               2,
-                               0,
-                               0,
-                               2.1));
+    reddit.resources.push_back(ResourceRow(
+        "",
+        "http://reddit-resource.com/script1.js",
+        ResourceType::SCRIPT,
+        4, 0, 1, 1.0));
+    reddit.resources.push_back(ResourceRow(
+        "",
+        "http://reddit-resource.com/script2.js",
+        ResourceType::SCRIPT,
+        2, 0, 0, 2.1));
 
     PrefetchData yahoo(PREFETCH_KEY_TYPE_URL, "http://www.yahoo.com");
     yahoo.last_visit = base::Time::FromInternalValue(3);
-    yahoo.resources.push_back(ResourceRow(std::string(),
-                                          "http://www.google.com/image.png",
-                                          ResourceType::IMAGE,
-                                          20,
-                                          1,
-                                          0,
-                                          10.0));
+    yahoo.resources.push_back(ResourceRow(
+        "",
+        "http://www.google.com/image.png",
+        ResourceType::IMAGE,
+        20, 1, 0, 10.0));
 
     test_url_data_.clear();
     test_url_data_.insert(std::make_pair("http://www.google.com", google));
     test_url_data_.insert(std::make_pair("http://www.reddit.com", reddit));
     test_url_data_.insert(std::make_pair("http://www.yahoo.com", yahoo));
 
-    PrefetchData empty_host_data(PREFETCH_KEY_TYPE_HOST, std::string());
+    PrefetchData empty_host_data(PREFETCH_KEY_TYPE_HOST, "");
     tables_->UpdateData(google, empty_host_data);
     tables_->UpdateData(reddit, empty_host_data);
     tables_->UpdateData(yahoo, empty_host_data);
@@ -367,61 +337,45 @@ void ResourcePrefetchPredictorTablesTest::InitializeSampleData() {
   {  // Host data.
     PrefetchData facebook(PREFETCH_KEY_TYPE_HOST, "www.facebook.com");
     facebook.last_visit = base::Time::FromInternalValue(4);
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.facebook.com/style.css",
-                               ResourceType::STYLESHEET,
-                               5,
-                               2,
-                               1,
-                               1.1));
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.facebook.com/script.js",
-                               ResourceType::SCRIPT,
-                               4,
-                               0,
-                               1,
-                               2.1));
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.facebook.com/image.png",
-                               ResourceType::IMAGE,
-                               6,
-                               3,
-                               0,
-                               2.2));
-    facebook.resources.push_back(ResourceRow(std::string(),
-                                             "http://www.facebook.com/a.font",
-                                             ResourceType::LAST_TYPE,
-                                             2,
-                                             0,
-                                             0,
-                                             5.1));
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.resources.facebook.com/script.js",
-                               ResourceType::SCRIPT,
-                               11,
-                               0,
-                               0,
-                               8.5));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/style.css",
+        ResourceType::STYLESHEET,
+        5, 2, 1, 1.1));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/script.js",
+        ResourceType::SCRIPT,
+        4, 0, 1, 2.1));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/image.png",
+        ResourceType::IMAGE,
+        6, 3, 0, 2.2));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/a.font",
+        ResourceType::LAST_TYPE,
+        2, 0, 0, 5.1));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.resources.facebook.com/script.js",
+        ResourceType::SCRIPT,
+        11, 0, 0, 8.5));
 
     PrefetchData yahoo(PREFETCH_KEY_TYPE_HOST, "www.yahoo.com");
     yahoo.last_visit = base::Time::FromInternalValue(5);
-    yahoo.resources.push_back(ResourceRow(std::string(),
-                                          "http://www.google.com/image.png",
-                                          ResourceType::IMAGE,
-                                          20,
-                                          1,
-                                          0,
-                                          10.0));
+    yahoo.resources.push_back(ResourceRow(
+        "",
+        "http://www.google.com/image.png",
+        ResourceType::IMAGE,
+        20, 1, 0, 10.0));
 
     test_host_data_.clear();
     test_host_data_.insert(std::make_pair("www.facebook.com", facebook));
     test_host_data_.insert(std::make_pair("www.yahoo.com", yahoo));
 
-    PrefetchData empty_url_data(PREFETCH_KEY_TYPE_URL, std::string());
+    PrefetchData empty_url_data(PREFETCH_KEY_TYPE_URL, "");
     tables_->UpdateData(empty_url_data, facebook);
     tables_->UpdateData(empty_url_data, yahoo);
   }
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc b/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc
index b6203da..891b70c 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc
@@ -176,8 +176,9 @@ ResourcePrefetchPredictorTest::ResourcePrefetchPredictorTest()
       profile_(new TestingProfile()),
       predictor_(NULL),
       mock_tables_(new StrictMock<MockResourcePrefetchPredictorTables>()),
-      empty_url_data_(PREFETCH_KEY_TYPE_URL, std::string()),
-      empty_host_data_(PREFETCH_KEY_TYPE_HOST, std::string()) {}
+      empty_url_data_(PREFETCH_KEY_TYPE_URL, ""),
+      empty_host_data_(PREFETCH_KEY_TYPE_HOST, "") {
+}
 
 ResourcePrefetchPredictorTest::~ResourcePrefetchPredictorTest() {
   profile_.reset(NULL);
@@ -213,70 +214,52 @@ void ResourcePrefetchPredictorTest::InitializeSampleData() {
   {  // Url data.
     PrefetchData google(PREFETCH_KEY_TYPE_URL, "http://www.google.com/");
     google.last_visit = base::Time::FromInternalValue(1);
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/style1.css",
-                                           ResourceType::STYLESHEET,
-                                           3,
-                                           2,
-                                           1,
-                                           1.0));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script3.js",
-                                           ResourceType::SCRIPT,
-                                           4,
-                                           0,
-                                           1,
-                                           2.1));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script4.js",
-                                           ResourceType::SCRIPT,
-                                           11,
-                                           0,
-                                           0,
-                                           2.1));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/image1.png",
-                                           ResourceType::IMAGE,
-                                           6,
-                                           3,
-                                           0,
-                                           2.2));
-    google.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/a.font",
-                                           ResourceType::LAST_TYPE,
-                                           2,
-                                           0,
-                                           0,
-                                           5.1));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/style1.css",
+        ResourceType::STYLESHEET,
+        3, 2, 1, 1.0));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/script3.js",
+        ResourceType::SCRIPT,
+        4, 0, 1, 2.1));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/script4.js",
+        ResourceType::SCRIPT,
+        11, 0, 0, 2.1));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/image1.png",
+        ResourceType::IMAGE,
+        6, 3, 0, 2.2));
+    google.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/a.font",
+        ResourceType::LAST_TYPE,
+        2, 0, 0, 5.1));
 
     PrefetchData reddit(PREFETCH_KEY_TYPE_URL, "http://www.reddit.com/");
     reddit.last_visit = base::Time::FromInternalValue(2);
-    reddit.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://reddit-resource.com/script1.js",
-                               ResourceType::SCRIPT,
-                               4,
-                               0,
-                               1,
-                               1.0));
-    reddit.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://reddit-resource.com/script2.js",
-                               ResourceType::SCRIPT,
-                               2,
-                               0,
-                               0,
-                               2.1));
+    reddit.resources.push_back(ResourceRow(
+        "",
+        "http://reddit-resource.com/script1.js",
+        ResourceType::SCRIPT,
+        4, 0, 1, 1.0));
+    reddit.resources.push_back(ResourceRow(
+        "",
+        "http://reddit-resource.com/script2.js",
+        ResourceType::SCRIPT,
+        2, 0, 0, 2.1));
 
     PrefetchData yahoo(PREFETCH_KEY_TYPE_URL, "http://www.yahoo.com/");
     yahoo.last_visit = base::Time::FromInternalValue(3);
-    yahoo.resources.push_back(ResourceRow(std::string(),
-                                          "http://google.com/image.png",
-                                          ResourceType::IMAGE,
-                                          20,
-                                          1,
-                                          0,
-                                          10.0));
+    yahoo.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/image.png",
+        ResourceType::IMAGE,
+        20, 1, 0, 10.0));
 
     test_url_data_.clear();
     test_url_data_.insert(std::make_pair("http://www.google.com/", google));
@@ -287,55 +270,39 @@ void ResourcePrefetchPredictorTest::InitializeSampleData() {
   {  // Host data.
     PrefetchData facebook(PREFETCH_KEY_TYPE_HOST, "www.facebook.com");
     facebook.last_visit = base::Time::FromInternalValue(4);
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.facebook.com/style.css",
-                               ResourceType::STYLESHEET,
-                               5,
-                               2,
-                               1,
-                               1.1));
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.facebook.com/script.js",
-                               ResourceType::SCRIPT,
-                               4,
-                               0,
-                               1,
-                               2.1));
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.facebook.com/image.png",
-                               ResourceType::IMAGE,
-                               6,
-                               3,
-                               0,
-                               2.2));
-    facebook.resources.push_back(ResourceRow(std::string(),
-                                             "http://www.facebook.com/a.font",
-                                             ResourceType::LAST_TYPE,
-                                             2,
-                                             0,
-                                             0,
-                                             5.1));
-    facebook.resources
-        .push_back(ResourceRow(std::string(),
-                               "http://www.resources.facebook.com/script.js",
-                               ResourceType::SCRIPT,
-                               11,
-                               0,
-                               0,
-                               8.5));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/style.css",
+        ResourceType::STYLESHEET,
+        5, 2, 1, 1.1));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/script.js",
+        ResourceType::SCRIPT,
+        4, 0, 1, 2.1));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/image.png",
+        ResourceType::IMAGE,
+        6, 3, 0, 2.2));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.facebook.com/a.font",
+        ResourceType::LAST_TYPE,
+        2, 0, 0, 5.1));
+    facebook.resources.push_back(ResourceRow(
+        "",
+        "http://www.resources.facebook.com/script.js",
+        ResourceType::SCRIPT,
+        11, 0, 0, 8.5));
 
     PrefetchData yahoo(PREFETCH_KEY_TYPE_HOST, "www.yahoo.com");
     yahoo.last_visit = base::Time::FromInternalValue(5);
-    yahoo.resources.push_back(ResourceRow(std::string(),
-                                          "http://google.com/image.png",
-                                          ResourceType::IMAGE,
-                                          20,
-                                          1,
-                                          0,
-                                          10.0));
+    yahoo.resources.push_back(ResourceRow(
+        "",
+        "http://google.com/image.png",
+        ResourceType::IMAGE,
+        20, 1, 0, 10.0));
 
     test_host_data_.clear();
     test_host_data_.insert(std::make_pair("www.facebook.com", facebook));
@@ -376,14 +343,9 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationNotRecorded) {
   // Single navigation but history count is low, so should not record.
   AddUrlToHistory("http://www.google.com", 1);
 
-  URLRequestSummary main_frame =
-      CreateURLRequestSummary(1,
-                              1,
-                              "http://www.google.com",
-                              "http://www.google.com",
-                              ResourceType::MAIN_FRAME,
-                              std::string(),
-                              false);
+  URLRequestSummary main_frame = CreateURLRequestSummary(
+      1, 1, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1, static_cast<int>(predictor_->inflight_navigations_.size()));
 
@@ -402,27 +364,15 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationNotRecorded) {
   predictor_->RecordUrlResponse(resource3);
 
   PrefetchData host_data(PREFETCH_KEY_TYPE_HOST, "www.google.com");
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/style1.css",
-                                            ResourceType::STYLESHEET,
-                                            1,
-                                            0,
-                                            0,
-                                            1.0));
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/script1.js",
-                                            ResourceType::SCRIPT,
-                                            1,
-                                            0,
-                                            0,
-                                            2.0));
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/script2.js",
-                                            ResourceType::SCRIPT,
-                                            1,
-                                            0,
-                                            0,
-                                            3.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/style1.css",
+      ResourceType::STYLESHEET, 1, 0, 0, 1.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script1.js",
+      ResourceType::SCRIPT, 1, 0, 0, 2.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script2.js",
+      ResourceType::SCRIPT, 1, 0, 0, 3.0));
   EXPECT_CALL(*mock_tables_, UpdateData(empty_url_data_, host_data));
 
   predictor_->OnNavigationComplete(main_frame.navigation_id);
@@ -434,14 +384,9 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlNotInDB) {
   // resources and also for number of resources saved.
   AddUrlToHistory("http://www.google.com", 4);
 
-  URLRequestSummary main_frame =
-      CreateURLRequestSummary(1,
-                              1,
-                              "http://www.google.com",
-                              "http://www.google.com",
-                              ResourceType::MAIN_FRAME,
-                              std::string(),
-                              false);
+  URLRequestSummary main_frame = CreateURLRequestSummary(
+      1, 1, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1, static_cast<int>(predictor_->inflight_navigations_.size()));
 
@@ -479,34 +424,18 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlNotInDB) {
       resource7.resource_type);
 
   PrefetchData url_data(PREFETCH_KEY_TYPE_URL, "http://www.google.com/");
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/style1.css",
-                                           ResourceType::STYLESHEET,
-                                           1,
-                                           0,
-                                           0,
-                                           1.0));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script1.js",
-                                           ResourceType::SCRIPT,
-                                           1,
-                                           0,
-                                           0,
-                                           2.0));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script2.js",
-                                           ResourceType::SCRIPT,
-                                           1,
-                                           0,
-                                           0,
-                                           3.0));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/style2.css",
-                                           ResourceType::STYLESHEET,
-                                           1,
-                                           0,
-                                           0,
-                                           7.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/style1.css",
+      ResourceType::STYLESHEET, 1, 0, 0, 1.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script1.js",
+      ResourceType::SCRIPT, 1, 0, 0, 2.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script2.js",
+      ResourceType::SCRIPT, 1, 0, 0, 3.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/style2.css",
+      ResourceType::STYLESHEET, 1, 0, 0, 7.0));
   EXPECT_CALL(*mock_tables_, UpdateData(url_data, empty_host_data_));
 
   PrefetchData host_data(PREFETCH_KEY_TYPE_HOST, "www.google.com");
@@ -532,14 +461,9 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlInDB) {
   EXPECT_EQ(3, static_cast<int>(predictor_->url_table_cache_->size()));
   EXPECT_EQ(2, static_cast<int>(predictor_->host_table_cache_->size()));
 
-  URLRequestSummary main_frame =
-      CreateURLRequestSummary(1,
-                              1,
-                              "http://www.google.com",
-                              "http://www.google.com",
-                              ResourceType::MAIN_FRAME,
-                              std::string(),
-                              false);
+  URLRequestSummary main_frame = CreateURLRequestSummary(
+      1, 1, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1, static_cast<int>(predictor_->inflight_navigations_.size()));
 
@@ -577,34 +501,18 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlInDB) {
       resource7.resource_type);
 
   PrefetchData url_data(PREFETCH_KEY_TYPE_URL, "http://www.google.com/");
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/style1.css",
-                                           ResourceType::STYLESHEET,
-                                           4,
-                                           2,
-                                           0,
-                                           1.0));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script1.js",
-                                           ResourceType::SCRIPT,
-                                           1,
-                                           0,
-                                           0,
-                                           2.0));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script4.js",
-                                           ResourceType::SCRIPT,
-                                           11,
-                                           1,
-                                           1,
-                                           2.1));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://google.com/script2.js",
-                                           ResourceType::SCRIPT,
-                                           1,
-                                           0,
-                                           0,
-                                           3.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/style1.css",
+      ResourceType::STYLESHEET, 4, 2, 0, 1.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script1.js",
+      ResourceType::SCRIPT, 1, 0, 0, 2.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script4.js",
+      ResourceType::SCRIPT, 11, 1, 1, 2.1));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script2.js",
+      ResourceType::SCRIPT, 1, 0, 0, 3.0));
   EXPECT_CALL(*mock_tables_, UpdateData(url_data, empty_host_data_));
 
   EXPECT_CALL(*mock_tables_,
@@ -612,34 +520,18 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlInDB) {
                                     PREFETCH_KEY_TYPE_HOST));
 
   PrefetchData host_data(PREFETCH_KEY_TYPE_HOST, "www.google.com");
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/style1.css",
-                                            ResourceType::STYLESHEET,
-                                            1,
-                                            0,
-                                            0,
-                                            1.0));
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/script1.js",
-                                            ResourceType::SCRIPT,
-                                            1,
-                                            0,
-                                            0,
-                                            2.0));
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/script2.js",
-                                            ResourceType::SCRIPT,
-                                            1,
-                                            0,
-                                            0,
-                                            3.0));
-  host_data.resources.push_back(ResourceRow(std::string(),
-                                            "http://google.com/style2.css",
-                                            ResourceType::STYLESHEET,
-                                            1,
-                                            0,
-                                            0,
-                                            7.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/style1.css",
+      ResourceType::STYLESHEET, 1, 0, 0, 1.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script1.js",
+      ResourceType::SCRIPT, 1, 0, 0, 2.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/script2.js",
+      ResourceType::SCRIPT, 1, 0, 0, 3.0));
+  host_data.resources.push_back(ResourceRow(
+      "", "http://google.com/style2.css",
+      ResourceType::STYLESHEET, 1, 0, 0, 7.0));
   EXPECT_CALL(*mock_tables_, UpdateData(empty_url_data_, host_data));
 
   predictor_->OnNavigationComplete(main_frame.navigation_id);
@@ -660,14 +552,9 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlNotInDBAndDBFull) {
   EXPECT_EQ(3, static_cast<int>(predictor_->url_table_cache_->size()));
   EXPECT_EQ(2, static_cast<int>(predictor_->host_table_cache_->size()));
 
-  URLRequestSummary main_frame =
-      CreateURLRequestSummary(1,
-                              1,
-                              "http://www.nike.com",
-                              "http://www.nike.com",
-                              ResourceType::MAIN_FRAME,
-                              std::string(),
-                              false);
+  URLRequestSummary main_frame = CreateURLRequestSummary(
+      1, 1, "http://www.nike.com", "http://www.nike.com",
+      ResourceType::MAIN_FRAME, "", false);
   predictor_->RecordURLRequest(main_frame);
   EXPECT_EQ(1, static_cast<int>(predictor_->inflight_navigations_.size()));
 
@@ -688,20 +575,12 @@ TEST_F(ResourcePrefetchPredictorTest, NavigationUrlNotInDBAndDBFull) {
                                     PREFETCH_KEY_TYPE_HOST));
 
   PrefetchData url_data(PREFETCH_KEY_TYPE_URL, "http://www.nike.com/");
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://nike.com/style1.css",
-                                           ResourceType::STYLESHEET,
-                                           1,
-                                           0,
-                                           0,
-                                           1.0));
-  url_data.resources.push_back(ResourceRow(std::string(),
-                                           "http://nike.com/image2.png",
-                                           ResourceType::IMAGE,
-                                           1,
-                                           0,
-                                           0,
-                                           2.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://nike.com/style1.css",
+      ResourceType::STYLESHEET, 1, 0, 0, 1.0));
+  url_data.resources.push_back(ResourceRow(
+      "", "http://nike.com/image2.png",
+      ResourceType::IMAGE, 1, 0, 0, 2.0));
   EXPECT_CALL(*mock_tables_, UpdateData(url_data, empty_host_data_));
 
   PrefetchData host_data(PREFETCH_KEY_TYPE_HOST, "www.nike.com");
@@ -768,27 +647,15 @@ TEST_F(ResourcePrefetchPredictorTest, DeleteUrls) {
 }
 
 TEST_F(ResourcePrefetchPredictorTest, OnMainFrameRequest) {
-  URLRequestSummary summary1 = CreateURLRequestSummary(1,
-                                                       1,
-                                                       "http://www.google.com",
-                                                       "http://www.google.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
-  URLRequestSummary summary2 = CreateURLRequestSummary(1,
-                                                       2,
-                                                       "http://www.google.com",
-                                                       "http://www.google.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
-  URLRequestSummary summary3 = CreateURLRequestSummary(2,
-                                                       1,
-                                                       "http://www.yahoo.com",
-                                                       "http://www.yahoo.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
+  URLRequestSummary summary1 = CreateURLRequestSummary(
+      1, 1, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
+  URLRequestSummary summary2 = CreateURLRequestSummary(
+      1, 2, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
+  URLRequestSummary summary3 = CreateURLRequestSummary(
+      2, 1, "http://www.yahoo.com", "http://www.yahoo.com",
+      ResourceType::MAIN_FRAME, "", false);
 
   predictor_->OnMainFrameRequest(summary1);
   EXPECT_EQ(1, static_cast<int>(predictor_->inflight_navigations_.size()));
@@ -798,20 +665,12 @@ TEST_F(ResourcePrefetchPredictorTest, OnMainFrameRequest) {
   EXPECT_EQ(3, static_cast<int>(predictor_->inflight_navigations_.size()));
 
   // Insert anther with same navigation id. It should replace.
-  URLRequestSummary summary4 = CreateURLRequestSummary(1,
-                                                       1,
-                                                       "http://www.nike.com",
-                                                       "http://www.nike.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
-  URLRequestSummary summary5 = CreateURLRequestSummary(1,
-                                                       2,
-                                                       "http://www.google.com",
-                                                       "http://www.google.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
+  URLRequestSummary summary4 = CreateURLRequestSummary(
+      1, 1, "http://www.nike.com", "http://www.nike.com",
+      ResourceType::MAIN_FRAME, "", false);
+  URLRequestSummary summary5 = CreateURLRequestSummary(
+      1, 2, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
 
   predictor_->OnMainFrameRequest(summary4);
   EXPECT_EQ(3, static_cast<int>(predictor_->inflight_navigations_.size()));
@@ -822,13 +681,9 @@ TEST_F(ResourcePrefetchPredictorTest, OnMainFrameRequest) {
   predictor_->OnMainFrameRequest(summary5);
   EXPECT_EQ(3, static_cast<int>(predictor_->inflight_navigations_.size()));
 
-  URLRequestSummary summary6 = CreateURLRequestSummary(3,
-                                                       1,
-                                                       "http://www.shoes.com",
-                                                       "http://www.shoes.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
+  URLRequestSummary summary6 = CreateURLRequestSummary(
+      3, 1, "http://www.shoes.com", "http://www.shoes.com",
+      ResourceType::MAIN_FRAME, "", false);
   predictor_->OnMainFrameRequest(summary6);
   EXPECT_EQ(3, static_cast<int>(predictor_->inflight_navigations_.size()));
 
@@ -841,27 +696,15 @@ TEST_F(ResourcePrefetchPredictorTest, OnMainFrameRequest) {
 }
 
 TEST_F(ResourcePrefetchPredictorTest, OnMainFrameRedirect) {
-  URLRequestSummary summary1 = CreateURLRequestSummary(1,
-                                                       1,
-                                                       "http://www.google.com",
-                                                       "http://www.google.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
-  URLRequestSummary summary2 = CreateURLRequestSummary(1,
-                                                       2,
-                                                       "http://www.google.com",
-                                                       "http://www.google.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
-  URLRequestSummary summary3 = CreateURLRequestSummary(2,
-                                                       1,
-                                                       "http://www.yahoo.com",
-                                                       "http://www.yahoo.com",
-                                                       ResourceType::MAIN_FRAME,
-                                                       std::string(),
-                                                       false);
+  URLRequestSummary summary1 = CreateURLRequestSummary(
+      1, 1, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
+  URLRequestSummary summary2 = CreateURLRequestSummary(
+      1, 2, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
+  URLRequestSummary summary3 = CreateURLRequestSummary(
+      2, 1, "http://www.yahoo.com", "http://www.yahoo.com",
+      ResourceType::MAIN_FRAME, "", false);
 
   predictor_->OnMainFrameRedirect(summary1);
   EXPECT_TRUE(predictor_->inflight_navigations_.empty());
@@ -888,14 +731,9 @@ TEST_F(ResourcePrefetchPredictorTest, OnSubresourceResponse) {
   EXPECT_TRUE(predictor_->inflight_navigations_.empty());
 
   // Add an inflight navigation.
-  URLRequestSummary main_frame1 =
-      CreateURLRequestSummary(1,
-                              1,
-                              "http://www.google.com",
-                              "http://www.google.com",
-                              ResourceType::MAIN_FRAME,
-                              std::string(),
-                              false);
+  URLRequestSummary main_frame1 = CreateURLRequestSummary(
+      1, 1, "http://www.google.com", "http://www.google.com",
+      ResourceType::MAIN_FRAME, "", false);
   predictor_->OnMainFrameRequest(main_frame1);
   EXPECT_EQ(1, static_cast<int>(predictor_->inflight_navigations_.size()));
 
diff --git a/chrome/browser/predictors/resource_prefetcher_unittest.cc b/chrome/browser/predictors/resource_prefetcher_unittest.cc
index 865c8af..9d5ef5a 100644
--- a/chrome/browser/predictors/resource_prefetcher_unittest.cc
+++ b/chrome/browser/predictors/resource_prefetcher_unittest.cc
@@ -111,8 +111,7 @@ class ResourcePrefetcherTest : public testing::Test {
 
 
   void OnReceivedRedirect(const std::string& url) {
-    prefetcher_->OnReceivedRedirect(
-        GetInFlightRequest(url), GURL(std::string()), NULL);
+    prefetcher_->OnReceivedRedirect(GetInFlightRequest(url), GURL(""), NULL);
   }
   void OnAuthRequired(const std::string& url) {
     prefetcher_->OnAuthRequired(GetInFlightRequest(url), NULL);
diff --git a/chrome/browser/prefs/command_line_pref_store_unittest.cc b/chrome/browser/prefs/command_line_pref_store_unittest.cc
index 1e23383..5d2c939 100644
--- a/chrome/browser/prefs/command_line_pref_store_unittest.cc
+++ b/chrome/browser/prefs/command_line_pref_store_unittest.cc
@@ -116,7 +116,7 @@ TEST(CommandLinePrefStoreTest, MultipleSwitches) {
   ASSERT_EQ(Value::TYPE_DICTIONARY, value->GetType());
   ProxyConfigDictionary dict(static_cast<const DictionaryValue*>(value));
 
-  std::string string_result;
+  std::string string_result = "";
 
   ASSERT_TRUE(dict.GetProxyServer(&string_result));
   EXPECT_EQ("proxy", string_result);
@@ -172,9 +172,9 @@ TEST(CommandLinePrefStoreTest, ManualProxyModeInference) {
   store2->VerifyProxyMode(ProxyPrefs::MODE_PAC_SCRIPT);
 
   CommandLine cl3(CommandLine::NO_PROGRAM);
-  cl3.AppendSwitchASCII(switches::kProxyServer, std::string());
+  cl3.AppendSwitchASCII(switches::kProxyServer, "");
   scoped_refptr<TestCommandLinePrefStore> store3 =
-      new TestCommandLinePrefStore(&cl3);
+        new TestCommandLinePrefStore(&cl3);
   store3->VerifyProxyMode(ProxyPrefs::MODE_DIRECT);
 }
 
diff --git a/chrome/browser/prefs/proxy_config_dictionary.cc b/chrome/browser/prefs/proxy_config_dictionary.cc
index b6db822..a99fa7c 100644
--- a/chrome/browser/prefs/proxy_config_dictionary.cc
+++ b/chrome/browser/prefs/proxy_config_dictionary.cc
@@ -67,20 +67,12 @@ bool ProxyConfigDictionary::HasBypassList() const {
 
 // static
 DictionaryValue* ProxyConfigDictionary::CreateDirect() {
-  return CreateDictionary(ProxyPrefs::MODE_DIRECT,
-                          std::string(),
-                          false,
-                          std::string(),
-                          std::string());
+  return CreateDictionary(ProxyPrefs::MODE_DIRECT, "", false, "", "");
 }
 
 // static
 DictionaryValue* ProxyConfigDictionary::CreateAutoDetect() {
-  return CreateDictionary(ProxyPrefs::MODE_AUTO_DETECT,
-                          std::string(),
-                          false,
-                          std::string(),
-                          std::string());
+  return CreateDictionary(ProxyPrefs::MODE_AUTO_DETECT, "", false, "", "");
 }
 
 // static
@@ -88,10 +80,7 @@ DictionaryValue* ProxyConfigDictionary::CreatePacScript(
     const std::string& pac_url,
     bool pac_mandatory) {
   return CreateDictionary(ProxyPrefs::MODE_PAC_SCRIPT,
-                          pac_url,
-                          pac_mandatory,
-                          std::string(),
-                          std::string());
+                          pac_url, pac_mandatory, "", "");
 }
 
 // static
@@ -99,11 +88,8 @@ DictionaryValue* ProxyConfigDictionary::CreateFixedServers(
     const std::string& proxy_server,
     const std::string& bypass_list) {
   if (!proxy_server.empty()) {
-    return CreateDictionary(ProxyPrefs::MODE_FIXED_SERVERS,
-                            std::string(),
-                            false,
-                            proxy_server,
-                            bypass_list);
+    return CreateDictionary(
+        ProxyPrefs::MODE_FIXED_SERVERS, "", false, proxy_server, bypass_list);
   } else {
     return CreateDirect();
   }
@@ -111,11 +97,7 @@ DictionaryValue* ProxyConfigDictionary::CreateFixedServers(
 
 // static
 DictionaryValue* ProxyConfigDictionary::CreateSystem() {
-  return CreateDictionary(ProxyPrefs::MODE_SYSTEM,
-                          std::string(),
-                          false,
-                          std::string(),
-                          std::string());
+  return CreateDictionary(ProxyPrefs::MODE_SYSTEM, "", false, "", "");
 }
 
 // static
diff --git a/chrome/browser/prefs/proxy_policy_unittest.cc b/chrome/browser/prefs/proxy_policy_unittest.cc
index 512e514..ec51894 100644
--- a/chrome/browser/prefs/proxy_policy_unittest.cc
+++ b/chrome/browser/prefs/proxy_policy_unittest.cc
@@ -68,9 +68,9 @@ void assertBypassList(const ProxyConfigDictionary& dict,
 void assertProxyModeWithoutParams(const ProxyConfigDictionary& dict,
                                   ProxyPrefs::ProxyMode proxy_mode) {
   assertProxyMode(dict, proxy_mode);
-  assertProxyServer(dict, std::string());
-  assertPacUrl(dict, std::string());
-  assertBypassList(dict, std::string());
+  assertProxyServer(dict, "");
+  assertPacUrl(dict, "");
+  assertBypassList(dict, "");
 }
 
 }  // namespace
@@ -130,7 +130,7 @@ TEST_F(ProxyPolicyTest, OverridesCommandLineOptions) {
   ProxyConfigDictionary dict(prefs->GetDictionary(prefs::kProxy));
   assertProxyMode(dict, ProxyPrefs::MODE_FIXED_SERVERS);
   assertProxyServer(dict, "789");
-  assertPacUrl(dict, std::string());
+  assertPacUrl(dict, "");
   assertBypassList(dict, "123");
 
   // Try a second time time with the managed PrefStore in place, the
@@ -140,7 +140,7 @@ TEST_F(ProxyPolicyTest, OverridesCommandLineOptions) {
   ProxyConfigDictionary dict2(prefs->GetDictionary(prefs::kProxy));
   assertProxyMode(dict2, ProxyPrefs::MODE_FIXED_SERVERS);
   assertProxyServer(dict2, "ghi");
-  assertPacUrl(dict2, std::string());
+  assertPacUrl(dict2, "");
   assertBypassList(dict2, "abc");
 }
 
@@ -160,7 +160,7 @@ TEST_F(ProxyPolicyTest, OverridesUnrelatedCommandLineOptions) {
   ProxyConfigDictionary dict(prefs->GetDictionary(prefs::kProxy));
   assertProxyMode(dict, ProxyPrefs::MODE_FIXED_SERVERS);
   assertProxyServer(dict, "789");
-  assertPacUrl(dict, std::string());
+  assertPacUrl(dict, "");
   assertBypassList(dict, "123");
 
   // Try a second time time with the managed PrefStore in place, the
diff --git a/chrome/browser/prefs/session_startup_pref.cc b/chrome/browser/prefs/session_startup_pref.cc
index fbbf62f..d822cc0 100644
--- a/chrome/browser/prefs/session_startup_pref.cc
+++ b/chrome/browser/prefs/session_startup_pref.cc
@@ -45,7 +45,7 @@ void URLListToPref(const base::ListValue* url_list, SessionStartupPref* pref) {
   for (size_t i = 0; i < url_list->GetSize(); ++i) {
     std::string url_text;
     if (url_list->GetString(i, &url_text)) {
-      GURL fixed_url = URLFixerUpper::FixupURL(url_text, std::string());
+      GURL fixed_url = URLFixerUpper::FixupURL(url_text, "");
       pref->urls.push_back(fixed_url);
     }
   }
diff --git a/chrome/browser/prerender/prerender_contents.cc b/chrome/browser/prerender/prerender_contents.cc
index 508ec89..ff32646 100644
--- a/chrome/browser/prerender/prerender_contents.cc
+++ b/chrome/browser/prerender/prerender_contents.cc
@@ -465,8 +465,8 @@ WebContents* PrerenderContents::CreateWebContents(
   // TODO(ajwong): Remove the temporary map once prerendering is aware of
   // multiple session storage namespaces per tab.
   content::SessionStorageNamespaceMap session_storage_namespace_map;
-  session_storage_namespace_map[std::string()] = session_storage_namespace;
-  return WebContents::CreateWithSessionStorage(
+  session_storage_namespace_map[""] = session_storage_namespace;
+  return  WebContents::CreateWithSessionStorage(
       WebContents::CreateParams(profile_), session_storage_namespace_map);
 }
 
diff --git a/chrome/browser/prerender/prerender_histograms.cc b/chrome/browser/prerender/prerender_histograms.cc
index 325c00e..d836cf8 100644
--- a/chrome/browser/prerender/prerender_histograms.cc
+++ b/chrome/browser/prerender/prerender_histograms.cc
@@ -92,9 +92,9 @@ bool OriginIsOmnibox(Origin origin) {
 #define PREFIXED_HISTOGRAM_INTERNAL(origin, experiment, wash, HISTOGRAM, \
                                     histogram_name) { \
   { \
-    /* Do not rename.  HISTOGRAM expects a local variable "name". */           \
-    std::string name = ComposeHistogramName(std::string(), histogram_name);    \
-    HISTOGRAM;                                                                 \
+    /* Do not rename.  HISTOGRAM expects a local variable "name". */ \
+    std::string name = ComposeHistogramName("", histogram_name); \
+    HISTOGRAM; \
   } \
   /* Do not rename.  HISTOGRAM expects a local variable "name". */ \
   std::string name = GetHistogramName(origin, experiment, wash, \
diff --git a/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc b/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc
index 131b45a..299567a 100644
--- a/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc
+++ b/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc
@@ -66,7 +66,7 @@ CloudPrintSetupFlow* CloudPrintSetupFlow::OpenDialog(
       chrome::GetActiveDesktop());
   // Set the arguments for showing the gaia login page.
   DictionaryValue args;
-  args.SetString("user", std::string());
+  args.SetString("user", "");
   args.SetInteger("error", 0);
   args.SetBoolean("editable_user", true);
 
diff --git a/chrome/browser/printing/cloud_print/cloud_print_setup_source.cc b/chrome/browser/printing/cloud_print/cloud_print_setup_source.cc
index 8c18da8..7bb6d73 100644
--- a/chrome/browser/printing/cloud_print/cloud_print_setup_source.cc
+++ b/chrome/browser/printing/cloud_print/cloud_print_setup_source.cc
@@ -87,7 +87,7 @@ void CloudPrintSetupSource::StartDataRequest(
 
     // None of the strings used here currently have sync-specific wording in
     // them.  There is a unit test to catch if that happens.
-    dict->SetString("introduction", std::string());
+    dict->SetString("introduction", "");
     AddString(dict, "signinprefix", IDS_SYNC_LOGIN_SIGNIN_PREFIX);
     AddString(dict, "signinsuffix", IDS_SYNC_LOGIN_SIGNIN_SUFFIX);
     AddString(dict, "cannotbeblank", IDS_SYNC_CANNOT_BE_BLANK);
diff --git a/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc b/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc
index eb8eef4..2529a1d 100644
--- a/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc
+++ b/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc
@@ -251,7 +251,7 @@ net::URLRequestJob* PrintDialogCloudTest::Factory(
   return new net::URLRequestTestJob(request,
                                     network_delegate,
                                     net::URLRequestTestJob::test_headers(),
-                                    std::string(),
+                                    "",
                                     true);
 }
 
diff --git a/chrome/browser/printing/print_dialog_cloud_unittest.cc b/chrome/browser/printing/print_dialog_cloud_unittest.cc
index ce50f28..217fa53 100644
--- a/chrome/browser/printing/print_dialog_cloud_unittest.cc
+++ b/chrome/browser/printing/print_dialog_cloud_unittest.cc
@@ -270,7 +270,7 @@ TEST_F(CloudPrintDataSenderTest, NoData) {
 TEST_F(CloudPrintDataSenderTest, EmptyData) {
   EXPECT_CALL(*mock_helper_, CallJavascriptFunction(_, _, _)).Times(0);
 
-  std::string data;
+  std::string data("");
   scoped_refptr<CloudPrintDataSender> print_data_sender(
       CreateSender(base::RefCountedString::TakeString(&data)));
   base::FilePath test_data_file_name = GetTestDataFileName();
diff --git a/chrome/browser/profiles/gaia_info_update_service_factory.cc b/chrome/browser/profiles/gaia_info_update_service_factory.cc
index f8f46f7..88ef612 100644
--- a/chrome/browser/profiles/gaia_info_update_service_factory.cc
+++ b/chrome/browser/profiles/gaia_info_update_service_factory.cc
@@ -39,8 +39,7 @@ void GAIAInfoUpdateServiceFactory::RegisterUserPrefs(
     PrefRegistrySyncable* prefs) {
   prefs->RegisterInt64Pref(prefs::kProfileGAIAInfoUpdateTime, 0,
                            PrefRegistrySyncable::UNSYNCABLE_PREF);
-  prefs->RegisterStringPref(prefs::kProfileGAIAInfoPictureURL,
-                            std::string(),
+  prefs->RegisterStringPref(prefs::kProfileGAIAInfoPictureURL, "",
                             PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
 
diff --git a/chrome/browser/profiles/gaia_info_update_service_unittest.cc b/chrome/browser/profiles/gaia_info_update_service_unittest.cc
index 37dfdd7..dd85970 100644
--- a/chrome/browser/profiles/gaia_info_update_service_unittest.cc
+++ b/chrome/browser/profiles/gaia_info_update_service_unittest.cc
@@ -184,8 +184,7 @@ TEST_F(GAIAInfoUpdateServiceTest, LogOut) {
   GAIAInfoUpdateService service(profile());
   EXPECT_FALSE(service.GetCachedPictureURL().empty());
   // Log out.
-  profile()->GetPrefs()
-      ->SetString(prefs::kGoogleServicesUsername, std::string());
+  profile()->GetPrefs()->SetString(prefs::kGoogleServicesUsername, "");
 
   // Verify that the GAIA name and picture, and picture URL are unset.
   EXPECT_TRUE(GetCache()->GetGAIANameOfProfileAtIndex(0).empty());
@@ -194,8 +193,7 @@ TEST_F(GAIAInfoUpdateServiceTest, LogOut) {
 }
 
 TEST_F(GAIAInfoUpdateServiceTest, LogIn) {
-  profile()->GetPrefs()
-      ->SetString(prefs::kGoogleServicesUsername, std::string());
+  profile()->GetPrefs()->SetString(prefs::kGoogleServicesUsername, "");
   GAIAInfoUpdateServiceMock service(profile());
 
   // Log in.
diff --git a/chrome/browser/profiles/profile_downloader_unittest.cc b/chrome/browser/profiles/profile_downloader_unittest.cc
index 5346694..2e47968 100644
--- a/chrome/browser/profiles/profile_downloader_unittest.cc
+++ b/chrome/browser/profiles/profile_downloader_unittest.cc
@@ -68,25 +68,25 @@ TEST_F(ProfileDownloaderTest, ParseData) {
       true);
 
   // Data with only name.
-  VerifyWithNameAndURL("Pat Smith", std::string(), std::string(), true);
+  VerifyWithNameAndURL("Pat Smith", "", "", true);
 
   // Data with only URL.
   VerifyWithNameAndURL(
-      std::string(),
+      "",
       "https://example.com/--Abc/AAAAAAAAAAI/AAAAAAAAACQ/Efg/photo.jpg",
       "https://example.com/--Abc/AAAAAAAAAAI/AAAAAAAAACQ/Efg/s32-c/photo.jpg",
       true);
 
   // Data without name or URL.
-  VerifyWithNameAndURL(std::string(), std::string(), std::string(), false);
+  VerifyWithNameAndURL("", "", "", false);
 
   // Data with an invalid URL.
-  VerifyWithNameAndURL(std::string(), "invalid url", std::string(), false);
+  VerifyWithNameAndURL( "", "invalid url", "", false);
 }
 
 TEST_F(ProfileDownloaderTest, DefaultURL) {
   // Empty URL should be default photo
-  EXPECT_TRUE(ProfileDownloader::IsDefaultProfileImageURL(std::string()));
+  EXPECT_TRUE(ProfileDownloader::IsDefaultProfileImageURL(""));
   // Picasa default photo
   EXPECT_TRUE(ProfileDownloader::IsDefaultProfileImageURL(
       "https://example.com/-4/AAAAAAAAAAA/AAAAAAAAAAE/G/s64-c/photo.jpg"));
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index a068fb3..f99cbba 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -289,8 +289,9 @@ void ProfileImpl::RegisterUserPrefs(PrefRegistrySyncable* registry) {
   registry->RegisterIntegerPref(prefs::kProfileAvatarIndex,
                                 -1,
                                 PrefRegistrySyncable::SYNCABLE_PREF);
-  registry->RegisterStringPref(
-      prefs::kProfileName, std::string(), PrefRegistrySyncable::SYNCABLE_PREF);
+  registry->RegisterStringPref(prefs::kProfileName,
+                               "",
+                               PrefRegistrySyncable::SYNCABLE_PREF);
   registry->RegisterBooleanPref(prefs::kProfileIsManaged,
                                 false,
                                 PrefRegistrySyncable::SYNCABLE_PREF);
diff --git a/chrome/browser/profiles/profile_manager.cc b/chrome/browser/profiles/profile_manager.cc
index 69da963..59f2e69 100644
--- a/chrome/browser/profiles/profile_manager.cc
+++ b/chrome/browser/profiles/profile_manager.cc
@@ -890,7 +890,7 @@ void ProfileManager::CreateMultiProfileAsync(
 
 // static
 void ProfileManager::RegisterPrefs(PrefRegistrySimple* registry) {
-  registry->RegisterStringPref(prefs::kProfileLastUsed, std::string());
+  registry->RegisterStringPref(prefs::kProfileLastUsed, "");
   registry->RegisterIntegerPref(prefs::kProfilesNumCreated, 1);
   registry->RegisterListPref(prefs::kProfilesLastActive);
 }
diff --git a/chrome/browser/referrer_policy_browsertest.cc b/chrome/browser/referrer_policy_browsertest.cc
index 0b9f40f..83a32b4 100644
--- a/chrome/browser/referrer_policy_browsertest.cc
+++ b/chrome/browser/referrer_policy_browsertest.cc
@@ -376,7 +376,7 @@ IN_PROC_BROWSER_TEST_F(ReferrerPolicyTest, History) {
                                    EXPECT_ORIGIN_AS_REFERRER);
 
   // Navigate to C.
-  ui_test_utils::NavigateToURL(browser(), test_server_->GetURL(std::string()));
+  ui_test_utils::NavigateToURL(browser(), test_server_->GetURL(""));
 
   string16 expected_title =
       GetExpectedTitle(start_url, EXPECT_ORIGIN_AS_REFERRER);
diff --git a/chrome/browser/renderer_host/pepper/pepper_flash_clipboard_message_filter.cc b/chrome/browser/renderer_host/pepper/pepper_flash_clipboard_message_filter.cc
index be2ce33..f39e75a 100644
--- a/chrome/browser/renderer_host/pepper/pepper_flash_clipboard_message_filter.cc
+++ b/chrome/browser/renderer_host/pepper/pepper_flash_clipboard_message_filter.cc
@@ -316,7 +316,7 @@ int32_t PepperFlashClipboardMessageFilter::OnMsgWriteData(
         scw.WriteText(UTF8ToUTF16(data[i]));
         break;
       case PP_FLASH_CLIPBOARD_FORMAT_HTML:
-        scw.WriteHTML(UTF8ToUTF16(data[i]), std::string());
+        scw.WriteHTML(UTF8ToUTF16(data[i]), "");
         break;
       case PP_FLASH_CLIPBOARD_FORMAT_RTF:
         scw.WriteRTF(data[i]);
diff --git a/chrome/browser/safe_browsing/browser_feature_extractor.cc b/chrome/browser/safe_browsing/browser_feature_extractor.cc
index a40c66d..142f375 100644
--- a/chrome/browser/safe_browsing/browser_feature_extractor.cc
+++ b/chrome/browser/safe_browsing/browser_feature_extractor.cc
@@ -208,8 +208,8 @@ void BrowserFeatureExtractor::ExtractFeatures(const BrowseInfo* info,
   //   2) The first url on the same host as the candidate url (assuming that
   //      it's different from the candidate url).
   if (url_index != -1) {
-    AddNavigationFeatures(
-        std::string(), controller, url_index, info->url_redirects, request);
+    AddNavigationFeatures("", controller, url_index, info->url_redirects,
+                          request);
   }
   if (first_host_index != -1) {
     AddNavigationFeatures(features::kHostPrefix,
diff --git a/chrome/browser/safe_browsing/client_side_detection_host_unittest.cc b/chrome/browser/safe_browsing/client_side_detection_host_unittest.cc
index ec8b4e3..74ec857 100644
--- a/chrome/browser/safe_browsing/client_side_detection_host_unittest.cc
+++ b/chrome/browser/safe_browsing/client_side_detection_host_unittest.cc
@@ -635,11 +635,11 @@ TEST_F(ClientSideDetectionHostTest, UpdateIPHostMap) {
   BrowseInfo* browse_info = GetBrowseInfo();
 
   // Empty IP or host are skipped
-  UpdateIPHostMap("250.10.10.10", std::string());
+  UpdateIPHostMap("250.10.10.10", "");
   ASSERT_EQ(0U, browse_info->ips.size());
-  UpdateIPHostMap(std::string(), "google.com/");
+  UpdateIPHostMap("", "google.com/");
   ASSERT_EQ(0U, browse_info->ips.size());
-  UpdateIPHostMap(std::string(), std::string());
+  UpdateIPHostMap("", "");
   ASSERT_EQ(0U, browse_info->ips.size());
 
   std::set<std::string> expected_hosts;
diff --git a/chrome/browser/safe_browsing/client_side_detection_service_unittest.cc b/chrome/browser/safe_browsing/client_side_detection_service_unittest.cc
index ed533604..f5fd98b 100644
--- a/chrome/browser/safe_browsing/client_side_detection_service_unittest.cc
+++ b/chrome/browser/safe_browsing/client_side_detection_service_unittest.cc
@@ -252,8 +252,9 @@ TEST_F(ClientSideDetectionServiceTest, FetchModelTest) {
   Mock::VerifyAndClearExpectations(&service);
 
   // Empty model file.
-  SetModelFetchResponse(std::string(), true /* success */);
-  EXPECT_CALL(service, EndFetchModel(ClientSideDetectionService::MODEL_EMPTY))
+  SetModelFetchResponse("", true /* success */);
+  EXPECT_CALL(service, EndFetchModel(
+      ClientSideDetectionService::MODEL_EMPTY))
       .WillOnce(QuitCurrentMessageLoop());
   service.StartFetchModel();
   msg_loop_.Run();  // EndFetchModel will quit the message loop.
@@ -575,7 +576,7 @@ TEST_F(ClientSideDetectionServiceTest, IsBadIpAddress) {
   ClientSideDetectionService::SetBadSubnets(
       model, &(csd_service_->bad_subnets_));
   EXPECT_FALSE(csd_service_->IsBadIpAddress("blabla"));
-  EXPECT_FALSE(csd_service_->IsBadIpAddress(std::string()));
+  EXPECT_FALSE(csd_service_->IsBadIpAddress(""));
 
   EXPECT_TRUE(csd_service_->IsBadIpAddress(
       "2620:0:1000:3103:21a:a0ff:fe10:786e"));
diff --git a/chrome/browser/safe_browsing/download_protection_service_unittest.cc b/chrome/browser/safe_browsing/download_protection_service_unittest.cc
index af98856..e8da2ee 100644
--- a/chrome/browser/safe_browsing/download_protection_service_unittest.cc
+++ b/chrome/browser/safe_browsing/download_protection_service_unittest.cc
@@ -390,7 +390,7 @@ TEST_F(DownloadProtectionServiceTest, CheckClientDownloadFetchFailed) {
   net::FakeURLFetcherFactory factory(NULL);
   // HTTP request will fail.
   factory.SetFakeResponse(
-      DownloadProtectionService::GetDownloadRequestUrl(), std::string(), false);
+      DownloadProtectionService::GetDownloadRequestUrl(), "", false);
 
   base::FilePath a_tmp(FILE_PATH_LITERAL("a.tmp"));
   base::FilePath a_exe(FILE_PATH_LITERAL("a.exe"));
diff --git a/chrome/browser/safe_browsing/malware_details.cc b/chrome/browser/safe_browsing/malware_details.cc
index 7eb336d..41cf690 100644
--- a/chrome/browser/safe_browsing/malware_details.cc
+++ b/chrome/browser/safe_browsing/malware_details.cc
@@ -178,16 +178,16 @@ void MalwareDetails::StartCollection() {
   }
 
   // Add the nodes, starting from the page url.
-  AddUrl(page_url, GURL(), std::string(), NULL);
+  AddUrl(page_url, GURL(), "", NULL);
 
   // Add the resource_url and its original url, if non-empty and different.
   if (!resource_.original_url.is_empty() &&
       resource_.url != resource_.original_url) {
     // Add original_url, as the parent of resource_url.
-    AddUrl(resource_.original_url, GURL(), std::string(), NULL);
-    AddUrl(resource_.url, resource_.original_url, std::string(), NULL);
+    AddUrl(resource_.original_url, GURL(), "", NULL);
+    AddUrl(resource_.url, resource_.original_url, "", NULL);
   } else {
-    AddUrl(resource_.url, GURL(), std::string(), NULL);
+    AddUrl(resource_.url, GURL(), "", NULL);
   }
 
   // Add the redirect urls, if non-empty. The redirect urls do not include the
@@ -201,13 +201,13 @@ void MalwareDetails::StartCollection() {
   }
   // Set the previous redirect url as the parent of the next one
   for (unsigned int i = 0; i < resource_.redirect_urls.size(); ++i) {
-    AddUrl(resource_.redirect_urls[i], parent_url, std::string(), NULL);
+    AddUrl(resource_.redirect_urls[i], parent_url, "", NULL);
     parent_url = resource_.redirect_urls[i];
   }
 
   // Add the referrer url.
   if (nav_entry && !referrer_url.is_empty()) {
-    AddUrl(referrer_url, GURL(), std::string(), NULL);
+    AddUrl(referrer_url, GURL(), "", NULL);
   }
 
   // Get URLs of frames, scripts etc from the DOM.
@@ -287,7 +287,7 @@ void MalwareDetails::OnRedirectionCollectionReady() {
 void MalwareDetails::AddRedirectUrlList(const std::vector<GURL>& urls) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   for (size_t i = 0; i < urls.size()-1; ++i) {
-    AddUrl(urls[i], urls[i + 1], std::string(), NULL);
+    AddUrl(urls[i], urls[i+1], "", NULL);
   }
 }
 
diff --git a/chrome/browser/safe_browsing/ping_manager.cc b/chrome/browser/safe_browsing/ping_manager.cc
index 56580d00..6e73985 100644
--- a/chrome/browser/safe_browsing/ping_manager.cc
+++ b/chrome/browser/safe_browsing/ping_manager.cc
@@ -113,7 +113,7 @@ GURL SafeBrowsingPingManager::SafeBrowsingHitUrl(
          threat_type == SB_THREAT_TYPE_BINARY_MALWARE_HASH ||
          threat_type == SB_THREAT_TYPE_CLIENT_SIDE_PHISHING_URL);
   std::string url = SafeBrowsingProtocolManagerHelper::ComposeUrl(
-      url_prefix_, "report", client_name_, version_, std::string());
+      url_prefix_, "report", client_name_, version_, "");
   std::string threat_list = "none";
   switch (threat_type) {
     case SB_THREAT_TYPE_URL_MALWARE:
diff --git a/chrome/browser/safe_browsing/protocol_manager_unittest.cc b/chrome/browser/safe_browsing/protocol_manager_unittest.cc
index ca89ce5..0bd9c3a 100644
--- a/chrome/browser/safe_browsing/protocol_manager_unittest.cc
+++ b/chrome/browser/safe_browsing/protocol_manager_unittest.cc
@@ -378,7 +378,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, ExistingDatabase) {
 
   url_fetcher->set_status(net::URLRequestStatus());
   url_fetcher->set_response_code(200);
-  url_fetcher->SetResponseString(std::string());
+  url_fetcher->SetResponseString("");
   url_fetcher->delegate()->OnURLFetchComplete(url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -424,7 +424,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseBadBodyBackupSuccess) {
   // Respond to the backup successfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(200);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -460,7 +460,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseHttpErrorBackupError) {
   // Go ahead and respond to it.
   url_fetcher->set_status(net::URLRequestStatus());
   url_fetcher->set_response_code(404);
-  url_fetcher->SetResponseString(std::string());
+  url_fetcher->SetResponseString("");
   url_fetcher->delegate()->OnURLFetchComplete(url_fetcher);
 
   // There should now be a backup request.
@@ -471,7 +471,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseHttpErrorBackupError) {
   // Respond to the backup unsuccessfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(404);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -507,7 +507,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseHttpErrorBackupSuccess) {
   // Go ahead and respond to it.
   url_fetcher->set_status(net::URLRequestStatus());
   url_fetcher->set_response_code(404);
-  url_fetcher->SetResponseString(std::string());
+  url_fetcher->SetResponseString("");
   url_fetcher->delegate()->OnURLFetchComplete(url_fetcher);
 
   // There should now be a backup request.
@@ -519,7 +519,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseHttpErrorBackupSuccess) {
   // Respond to the backup successfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(200);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -555,7 +555,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseHttpErrorBackupTimeout) {
   // Go ahead and respond to it.
   url_fetcher->set_status(net::URLRequestStatus());
   url_fetcher->set_response_code(404);
-  url_fetcher->SetResponseString(std::string());
+  url_fetcher->SetResponseString("");
   url_fetcher->delegate()->OnURLFetchComplete(url_fetcher);
 
   // There should now be a backup request.
@@ -617,7 +617,7 @@ TEST_F(SafeBrowsingProtocolManagerTest,
   // Respond to the backup unsuccessfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(404);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -665,7 +665,7 @@ TEST_F(SafeBrowsingProtocolManagerTest,
   // Respond to the backup unsuccessfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(200);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -713,7 +713,7 @@ TEST_F(SafeBrowsingProtocolManagerTest,
   // Respond to the backup unsuccessfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(404);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -762,7 +762,7 @@ TEST_F(SafeBrowsingProtocolManagerTest,
   // Respond to the backup unsuccessfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(200);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -807,7 +807,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, UpdateResponseTimeoutBackupSuccess) {
   // Respond to the backup unsuccessfully.
   backup_url_fetcher->set_status(net::URLRequestStatus());
   backup_url_fetcher->set_response_code(200);
-  backup_url_fetcher->SetResponseString(std::string());
+  backup_url_fetcher->SetResponseString("");
   backup_url_fetcher->delegate()->OnURLFetchComplete(backup_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
@@ -888,7 +888,7 @@ TEST_F(SafeBrowsingProtocolManagerTest, EmptyRedirectResponse) {
       chunk_url_fetcher, "https://redirect-server.example.com/path");
   chunk_url_fetcher->set_status(net::URLRequestStatus());
   chunk_url_fetcher->set_response_code(200);
-  chunk_url_fetcher->SetResponseString(std::string());
+  chunk_url_fetcher->SetResponseString("");
   chunk_url_fetcher->delegate()->OnURLFetchComplete(chunk_url_fetcher);
 
   EXPECT_TRUE(pm->IsUpdateScheduled());
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
index 032d5ec..3d0f2d9 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
@@ -1004,8 +1004,8 @@ void SafeBrowsingBlockingPageV2::PopulateMalwareStringDictionary(
 
   if (!CanShowMalwareDetailsOption()) {
     strings->SetBoolean(kDisplayCheckBox, false);
-    strings->SetString("confirm_text", std::string());
-    strings->SetString(kBoxChecked, std::string());
+    strings->SetString("confirm_text", "");
+    strings->SetString(kBoxChecked, "");
   } else {
     // Show the checkbox for sending malware details.
     strings->SetBoolean(kDisplayCheckBox, true);
@@ -1022,7 +1022,7 @@ void SafeBrowsingBlockingPageV2::PopulateMalwareStringDictionary(
     if (IsPrefEnabled(prefs::kSafeBrowsingReportingEnabled))
       strings->SetString(kBoxChecked, "yes");
     else
-      strings->SetString(kBoxChecked, std::string());
+      strings->SetString(kBoxChecked, "");
   }
 
   strings->SetString("report_error", string16());
@@ -1042,11 +1042,10 @@ void SafeBrowsingBlockingPageV2::PopulatePhishingStringDictionary(
       string16(),
       l10n_util::GetStringUTF16(IDS_SAFE_BROWSING_PHISHING_V2_DESCRIPTION2));
 
-  strings->SetString("details", std::string());
-  strings->SetString("confirm_text", std::string());
-  strings->SetString(kBoxChecked, std::string());
-  strings->SetString(
-      "report_error",
+  strings->SetString("details", "");
+  strings->SetString("confirm_text", "");
+  strings->SetString(kBoxChecked, "");
+  strings->SetString("report_error",
       l10n_util::GetStringUTF16(IDS_SAFE_BROWSING_PHISHING_V2_REPORT_ERROR));
   strings->SetBoolean(kDisplayCheckBox, false);
   strings->SetString("learnMore",
diff --git a/chrome/browser/safe_browsing/safe_browsing_util.cc b/chrome/browser/safe_browsing/safe_browsing_util.cc
index 7e6710f..ef620a7 100644
--- a/chrome/browser/safe_browsing/safe_browsing_util.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_util.cc
@@ -298,10 +298,8 @@ void CanonicalizeUrl(const GURL& url,
       url_unescaped_str.length(), &parsed);
 
   // 3. In hostname, remove all leading and trailing dots.
-  const std::string host =
-      (parsed.host.len > 0)
-          ? url_unescaped_str.substr(parsed.host.begin, parsed.host.len)
-          : std::string();
+  const std::string host = (parsed.host.len > 0) ? url_unescaped_str.substr(
+      parsed.host.begin, parsed.host.len) : "";
   const char kCharsToTrim[] = ".";
   std::string host_without_end_dots;
   TrimString(host, kCharsToTrim, &host_without_end_dots);
@@ -311,11 +309,10 @@ void CanonicalizeUrl(const GURL& url,
       host_without_end_dots, '.'));
 
   // 5. In path, replace runs of consecutive slashes with a single slash.
-  std::string path =
-      (parsed.path.len > 0)
-          ? url_unescaped_str.substr(parsed.path.begin, parsed.path.len)
-          : std::string();
-  std::string path_without_consecutive_slash(RemoveConsecutiveChars(path, '/'));
+  std::string path = (parsed.path.len > 0) ? url_unescaped_str.substr(
+       parsed.path.begin, parsed.path.len): "";
+  std::string path_without_consecutive_slash(RemoveConsecutiveChars(
+      path, '/'));
 
   url_canon::Replacements<char> hp_replacements;
   hp_replacements.SetHost(host_without_consecutive_dots.data(),
diff --git a/chrome/browser/safe_browsing/two_phase_uploader.cc b/chrome/browser/safe_browsing/two_phase_uploader.cc
index df58625..9b6165e 100644
--- a/chrome/browser/safe_browsing/two_phase_uploader.cc
+++ b/chrome/browser/safe_browsing/two_phase_uploader.cc
@@ -63,7 +63,7 @@ void TwoPhaseUploader::OnURLFetchComplete(const net::URLFetcher* source) {
   if (!status.is_success()) {
     LOG(ERROR) << "URLFetcher failed, status=" << status.status()
                << " err=" << status.error();
-    Finish(status.error(), response_code, std::string());
+    Finish(status.error(), response_code, "");
     return;
   }
 
@@ -83,7 +83,7 @@ void TwoPhaseUploader::OnURLFetchComplete(const net::URLFetcher* source) {
         if (!source->GetResponseHeaders()->EnumerateHeader(
               NULL, kLocationHeader, &location)) {
           LOG(ERROR) << "no location header";
-          Finish(net::OK, response_code, std::string());
+          Finish(net::OK, response_code, "");
           return;
         }
         DVLOG(1) << "upload location: " << location;
diff --git a/chrome/browser/search/local_ntp_source.cc b/chrome/browser/search/local_ntp_source.cc
index 38cbd7a..d1fde35 100644
--- a/chrome/browser/search/local_ntp_source.cc
+++ b/chrome/browser/search/local_ntp_source.cc
@@ -74,7 +74,7 @@ std::string LocalNtpSource::GetMimeType(
       path == kCloseBarActiveFilename) {
     return "image/png";
   }
-  return std::string();
+  return "";
 }
 
 bool LocalNtpSource::ShouldServiceRequest(
diff --git a/chrome/browser/search/local_omnibox_popup_source.cc b/chrome/browser/search/local_omnibox_popup_source.cc
index fa2d940..1ae3c8a 100644
--- a/chrome/browser/search/local_omnibox_popup_source.cc
+++ b/chrome/browser/search/local_omnibox_popup_source.cc
@@ -76,7 +76,7 @@ std::string LocalOmniboxPopupSource::GetMimeType(
   if (path == kPageIconFilename || path == kPageIcon2xFilename ||
       path == kSearchIconFilename || path == kSearchIcon2xFilename)
     return "image/png";
-  return std::string();
+  return "";
 }
 
 bool LocalOmniboxPopupSource::ShouldServiceRequest(
diff --git a/chrome/browser/search/search.cc b/chrome/browser/search/search.cc
index 726bc89..83186b4 100644
--- a/chrome/browser/search/search.cc
+++ b/chrome/browser/search/search.cc
@@ -527,8 +527,7 @@ uint64 GetUInt64ValueForFlagWithDefault(const std::string& flag,
                                         uint64 default_value,
                                         const FieldTrialFlags& flags) {
   uint64 value;
-  std::string str_value =
-      GetStringValueForFlagWithDefault(flag, std::string(), flags);
+  std::string str_value = GetStringValueForFlagWithDefault(flag, "", flags);
   if (base::StringToUint64(str_value, &value))
     return value;
   return default_value;
diff --git a/chrome/browser/search/search_unittest.cc b/chrome/browser/search/search_unittest.cc
index 7c4bf4c..90ff642b 100644
--- a/chrome/browser/search/search_unittest.cc
+++ b/chrome/browser/search/search_unittest.cc
@@ -22,7 +22,7 @@ TEST(EmbeddedSearchFieldTrialTest, GetFieldTrialInfo) {
   uint64 group_number = 0;
   const uint64 ZERO = 0;
 
-  EXPECT_FALSE(GetFieldTrialInfo(std::string(), &flags, &group_number));
+  EXPECT_FALSE(GetFieldTrialInfo("", &flags, &group_number));
   EXPECT_EQ(ZERO, group_number);
   EXPECT_EQ(ZERO, flags.size());
 
@@ -62,10 +62,9 @@ TEST(EmbeddedSearchFieldTrialTest, GetFieldTrialInfo) {
   EXPECT_EQ(uint64(3), flags.size());
   EXPECT_EQ(true, GetBoolValueForFlagWithDefault("bar", false, flags));
   EXPECT_EQ(uint64(7), GetUInt64ValueForFlagWithDefault("baz", 0, flags));
-  EXPECT_EQ("dogs",
-            GetStringValueForFlagWithDefault("cat", std::string(), flags));
-  EXPECT_EQ("default",
-            GetStringValueForFlagWithDefault("moose", "default", flags));
+  EXPECT_EQ("dogs", GetStringValueForFlagWithDefault("cat", "", flags));
+  EXPECT_EQ("default", GetStringValueForFlagWithDefault(
+      "moose", "default", flags));
 
   group_number = 0;
   flags.clear();
diff --git a/chrome/browser/search_engines/template_url_prepopulate_data_unittest.cc b/chrome/browser/search_engines/template_url_prepopulate_data_unittest.cc
index aa47992..3237137 100644
--- a/chrome/browser/search_engines/template_url_prepopulate_data_unittest.cc
+++ b/chrome/browser/search_engines/template_url_prepopulate_data_unittest.cc
@@ -167,7 +167,7 @@ TEST(TemplateURLPrepopulateDataTest, ProvidersFromPrefs) {
   entry->SetInteger("id", 1002);
   entry->SetString("name", "bar");
   entry->SetString("keyword", "bark");
-  entry->SetString("encoding", std::string());
+  entry->SetString("encoding", "");
   overrides->Append(entry->DeepCopy());
   entry->SetInteger("id", 1003);
   entry->SetString("name", "baz");
diff --git a/chrome/browser/sessions/session_restore_browsertest.cc b/chrome/browser/sessions/session_restore_browsertest.cc
index e82391e..5e2953a 100644
--- a/chrome/browser/sessions/session_restore_browsertest.cc
+++ b/chrome/browser/sessions/session_restore_browsertest.cc
@@ -985,7 +985,7 @@ IN_PROC_BROWSER_TEST_F(SessionRestoreTest, SessionStorageAfterTabReplace) {
     ASSERT_TRUE(controller->GetDefaultSessionStorageNamespace());
 
     content::SessionStorageNamespaceMap session_storage_namespace_map;
-    session_storage_namespace_map[std::string()] =
+    session_storage_namespace_map[""] =
         controller->GetDefaultSessionStorageNamespace();
     scoped_ptr<content::WebContents> web_contents(
         content::WebContents::CreateWithSessionStorage(
diff --git a/chrome/browser/shell_integration_linux.cc b/chrome/browser/shell_integration_linux.cc
index c0be6de..2a656fe 100644
--- a/chrome/browser/shell_integration_linux.cc
+++ b/chrome/browser/shell_integration_linux.cc
@@ -435,7 +435,7 @@ ShellIntegration::DefaultWebClientSetPermission
 
 // static
 bool ShellIntegration::SetAsDefaultBrowser() {
-  return SetDefaultWebClient(std::string());
+  return SetDefaultWebClient("");
 }
 
 // static
@@ -445,7 +445,7 @@ bool ShellIntegration::SetAsDefaultProtocolClient(const std::string& protocol) {
 
 // static
 ShellIntegration::DefaultWebClientState ShellIntegration::GetDefaultBrowser() {
-  return GetIsDefaultWebClient(std::string());
+  return GetIsDefaultWebClient("");
 }
 
 // static
diff --git a/chrome/browser/shell_integration_unittest.cc b/chrome/browser/shell_integration_unittest.cc
index 8715114..0b81311 100644
--- a/chrome/browser/shell_integration_unittest.cc
+++ b/chrome/browser/shell_integration_unittest.cc
@@ -644,7 +644,7 @@ TEST(ShellIntegrationTest, GetDesktopFileContents) {
             test_cases[i].template_contents,
             web_app::GenerateApplicationNameFromURL(GURL(test_cases[i].url)),
             GURL(test_cases[i].url),
-            std::string(),
+            "",
             base::FilePath(),
             ASCIIToUTF16(test_cases[i].title),
             test_cases[i].icon_name,
diff --git a/chrome/browser/signin/about_signin_internals.cc b/chrome/browser/signin/about_signin_internals.cc
index e58a013..ad83b0d 100644
--- a/chrome/browser/signin/about_signin_internals.cc
+++ b/chrome/browser/signin/about_signin_internals.cc
@@ -25,8 +25,7 @@ AboutSigninInternals::AboutSigninInternals() : profile_(NULL) {
   for (size_t i = 0; i < kNumTokenPrefs; ++i) {
     signin_status_.token_info_map.insert(std::pair<std::string, TokenInfo>(
         kTokenPrefsArray[i],
-        TokenInfo(
-            std::string(), "Not Loaded", std::string(), kTokenPrefsArray[i])));
+        TokenInfo("", "Not Loaded", "", kTokenPrefsArray[i])));
   }
 }
 
@@ -171,7 +170,7 @@ void AboutSigninInternals::NotifyTokenReceivedFailure(
   const std::string value_pref = TokenPrefPath(token_name) + ".value";
   const std::string time_pref = TokenPrefPath(token_name) + ".time";
   const std::string status_pref = TokenPrefPath(token_name) + ".status";
-  profile_->GetPrefs()->SetString(value_pref.c_str(), std::string());
+  profile_->GetPrefs()->SetString(value_pref.c_str(), "");
   profile_->GetPrefs()->SetString(time_pref.c_str(), time_as_str);
   profile_->GetPrefs()->SetString(status_pref.c_str(), error);
 
@@ -187,7 +186,7 @@ void AboutSigninInternals::NotifyClearStoredToken(
   signin_status_.token_info_map[token_name].token.clear();
 
   const std::string value_pref = TokenPrefPath(token_name) + ".value";
-  profile_->GetPrefs()->SetString(value_pref.c_str(), std::string());
+  profile_->GetPrefs()->SetString(value_pref.c_str(), "");
 
   NotifyObservers();
 }
diff --git a/chrome/browser/signin/about_signin_internals_factory.cc b/chrome/browser/signin/about_signin_internals_factory.cc
index f5f197f..ccce353 100644
--- a/chrome/browser/signin/about_signin_internals_factory.cc
+++ b/chrome/browser/signin/about_signin_internals_factory.cc
@@ -42,8 +42,7 @@ void AboutSigninInternalsFactory::RegisterUserPrefs(
   for (int i = UNTIMED_FIELDS_BEGIN; i < UNTIMED_FIELDS_END; ++i) {
     const std::string pref_path = SigninStatusFieldToString(
         static_cast<UntimedSigninStatusField>(i));
-    user_prefs->RegisterStringPref(pref_path.c_str(),
-                                   std::string(),
+    user_prefs->RegisterStringPref(pref_path.c_str(), "",
                                    PrefRegistrySyncable::UNSYNCABLE_PREF);
   }
   for (int i = TIMED_FIELDS_BEGIN; i < TIMED_FIELDS_END; ++i) {
@@ -51,10 +50,10 @@ void AboutSigninInternalsFactory::RegisterUserPrefs(
         static_cast<TimedSigninStatusField>(i)) + ".value";
     const std::string time = SigninStatusFieldToString(
         static_cast<TimedSigninStatusField>(i)) + ".time";
-    user_prefs->RegisterStringPref(
-        value.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
-    user_prefs->RegisterStringPref(
-        time.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
+    user_prefs->RegisterStringPref(value.c_str(), "",
+                                   PrefRegistrySyncable::UNSYNCABLE_PREF);
+    user_prefs->RegisterStringPref(time.c_str(), "",
+                                   PrefRegistrySyncable::UNSYNCABLE_PREF);
   }
   // TokenService information for about:signin-internals.
   for (size_t i = 0; i < kNumTokenPrefs; i++) {
@@ -62,12 +61,12 @@ void AboutSigninInternalsFactory::RegisterUserPrefs(
     const std::string value = pref + ".value";
     const std::string status = pref + ".status";
     const std::string time = pref + ".time";
-    user_prefs->RegisterStringPref(
-        value.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
-    user_prefs->RegisterStringPref(
-        status.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
-    user_prefs->RegisterStringPref(
-        time.c_str(), std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
+    user_prefs->RegisterStringPref(value.c_str(), "",
+                                   PrefRegistrySyncable::UNSYNCABLE_PREF);
+    user_prefs->RegisterStringPref(status.c_str(), "",
+                                   PrefRegistrySyncable::UNSYNCABLE_PREF);
+    user_prefs->RegisterStringPref(time.c_str(), "",
+                                   PrefRegistrySyncable::UNSYNCABLE_PREF);
   }
 }
 
diff --git a/chrome/browser/signin/oauth2_token_service_unittest.cc b/chrome/browser/signin/oauth2_token_service_unittest.cc
index 7095b43..3649374 100644
--- a/chrome/browser/signin/oauth2_token_service_unittest.cc
+++ b/chrome/browser/signin/oauth2_token_service_unittest.cc
@@ -138,7 +138,7 @@ TEST_F(OAuth2TokenServiceTest, FailureShouldNotRetry) {
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
   EXPECT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
-  fetcher->SetResponseString(std::string());
+  fetcher->SetResponseString("");
   fetcher->delegate()->OnURLFetchComplete(fetcher);
   EXPECT_EQ(0, consumer_.number_of_correct_tokens_);
   EXPECT_EQ(1, consumer_.number_of_errors_);
@@ -251,7 +251,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndExpirationAndFailure) {
   fetcher = factory_.GetFetcherByID(0);
   EXPECT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
-  fetcher->SetResponseString(std::string());
+  fetcher->SetResponseString("");
   fetcher->delegate()->OnURLFetchComplete(fetcher);
   EXPECT_EQ(1, consumer_.number_of_correct_tokens_);
   EXPECT_EQ(1, consumer_.number_of_errors_);
@@ -374,7 +374,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndSignOutAndRequest) {
 
   // Signs out
   service_->IssueAuthTokenForTest(GaiaConstants::kGaiaOAuth2LoginRefreshToken,
-                                  std::string());
+                                  "");
   service_->EraseTokensFromDB();
 
   request = oauth2_service_->StartRequest(std::set<std::string>(), &consumer_);
@@ -404,7 +404,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndSignOutAndSignInAndSuccess) {
 
   // Signs out and signs in
   service_->IssueAuthTokenForTest(GaiaConstants::kGaiaOAuth2LoginRefreshToken,
-                                  std::string());
+                                  "");
   service_->EraseTokensFromDB();
   service_->IssueAuthTokenForTest(GaiaConstants::kGaiaOAuth2LoginRefreshToken,
                                   "refreshToken");
@@ -486,7 +486,7 @@ TEST_F(OAuth2TokenServiceTest, RetryingConsumer) {
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
   EXPECT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
-  fetcher->SetResponseString(std::string());
+  fetcher->SetResponseString("");
   fetcher->delegate()->OnURLFetchComplete(fetcher);
   EXPECT_EQ(0, consumer.number_of_correct_tokens_);
   EXPECT_EQ(1, consumer.number_of_errors_);
@@ -494,7 +494,7 @@ TEST_F(OAuth2TokenServiceTest, RetryingConsumer) {
   fetcher = factory_.GetFetcherByID(0);
   EXPECT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
-  fetcher->SetResponseString(std::string());
+  fetcher->SetResponseString("");
   fetcher->delegate()->OnURLFetchComplete(fetcher);
   EXPECT_EQ(0, consumer.number_of_correct_tokens_);
   EXPECT_EQ(2, consumer.number_of_errors_);
diff --git a/chrome/browser/signin/signin_internals_util.cc b/chrome/browser/signin/signin_internals_util.cc
index f187418..adae0a1 100644
--- a/chrome/browser/signin/signin_internals_util.cc
+++ b/chrome/browser/signin/signin_internals_util.cc
@@ -98,11 +98,11 @@ std::string SigninStatusFieldToString(UntimedSigninStatusField field) {
     ENUM_CASE(LSID);
     case UNTIMED_FIELDS_END:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 std::string SigninStatusFieldToString(TimedSigninStatusField field) {
@@ -113,11 +113,11 @@ std::string SigninStatusFieldToString(TimedSigninStatusField field) {
     ENUM_CASE(GET_USER_INFO_STATUS);
     case TIMED_FIELDS_END:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 SigninStatus::SigninStatus()
@@ -203,10 +203,10 @@ std::string SigninStatusFieldToLabel(UntimedSigninStatusField field) {
       return "Sid (Hash)";
     case UNTIMED_FIELDS_END:
       NOTREACHED();
-      return std::string();
+      return "";
   }
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 TimedSigninStatusValue SigninStatusFieldToLabel(
@@ -226,10 +226,10 @@ TimedSigninStatusValue SigninStatusFieldToLabel(
                                     "Last OnGetUserInfo Time");
     case TIMED_FIELDS_END:
       NOTREACHED();
-      return TimedSigninStatusValue("Error", std::string());
+      return TimedSigninStatusValue("Error", "");
   }
   NOTREACHED();
-  return TimedSigninStatusValue("Error", std::string());
+  return TimedSigninStatusValue("Error", "");
 }
 
 } //  namespace
diff --git a/chrome/browser/signin/signin_manager.cc b/chrome/browser/signin/signin_manager.cc
index ab5befc..a8bc081 100644
--- a/chrome/browser/signin/signin_manager.cc
+++ b/chrome/browser/signin/signin_manager.cc
@@ -305,9 +305,10 @@ std::string SigninManager::SigninTypeToString(
   }
 
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
+
 bool SigninManager::PrepareForSignin(SigninType type,
                                      const std::string& username,
                                      const std::string& password) {
@@ -467,8 +468,7 @@ void SigninManager::StartSignInWithOAuth(const std::string& username,
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
   const std::string& locale = g_browser_process->GetApplicationLocale();
 
-  client_login_->StartClientOAuth(
-      username, password, scopes, std::string(), locale);
+  client_login_->StartClientOAuth(username, password, scopes, "", locale);
 
   // Register for token availability.  The signin manager will pre-login the
   // user when the GAIA service token is ready for use.  Only do this if we
@@ -549,9 +549,10 @@ void SigninManager::SignOut() {
   profile_->GetPrefs()->ClearPref(prefs::kGoogleServicesUsername);
 
   // Erase (now) stale information from AboutSigninInternals.
-  NotifyDiagnosticsObservers(USERNAME, std::string());
-  NotifyDiagnosticsObservers(LSID, std::string());
-  NotifyDiagnosticsObservers(signin_internals_util::SID, std::string());
+  NotifyDiagnosticsObservers(USERNAME, "");
+  NotifyDiagnosticsObservers(LSID, "");
+  NotifyDiagnosticsObservers(
+      signin_internals_util::SID, "");
 
   TokenService* token_service = TokenServiceFactory::GetForProfile(profile_);
   content::NotificationService::current()->Notify(
diff --git a/chrome/browser/signin/signin_manager_factory.cc b/chrome/browser/signin/signin_manager_factory.cc
index 11dd5e6..67e33c0 100644
--- a/chrome/browser/signin/signin_manager_factory.cc
+++ b/chrome/browser/signin/signin_manager_factory.cc
@@ -39,11 +39,9 @@ SigninManagerFactory* SigninManagerFactory::GetInstance() {
 }
 
 void SigninManagerFactory::RegisterUserPrefs(PrefRegistrySyncable* registry) {
-  registry->RegisterStringPref(prefs::kGoogleServicesLastUsername,
-                               std::string(),
+  registry->RegisterStringPref(prefs::kGoogleServicesLastUsername, "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
-  registry->RegisterStringPref(prefs::kGoogleServicesUsername,
-                               std::string(),
+  registry->RegisterStringPref(prefs::kGoogleServicesUsername, "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterBooleanPref(prefs::kAutologinEnabled, true,
                                 PrefRegistrySyncable::UNSYNCABLE_PREF);
@@ -56,8 +54,7 @@ void SigninManagerFactory::RegisterUserPrefs(PrefRegistrySyncable* registry) {
 
 // static
 void SigninManagerFactory::RegisterPrefs(PrefRegistrySimple* registry) {
-  registry->RegisterStringPref(prefs::kGoogleServicesUsernamePattern,
-                               std::string());
+  registry->RegisterStringPref(prefs::kGoogleServicesUsernamePattern, "");
 }
 
 ProfileKeyedService* SigninManagerFactory::BuildServiceInstanceFor(
diff --git a/chrome/browser/signin/signin_manager_unittest.cc b/chrome/browser/signin/signin_manager_unittest.cc
index c49f7a1..79964d0 100644
--- a/chrome/browser/signin/signin_manager_unittest.cc
+++ b/chrome/browser/signin/signin_manager_unittest.cc
@@ -308,8 +308,7 @@ TEST_F(SigninManagerTest, SignInClientLogin) {
   manager_->Initialize(profile_.get());
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
-  manager_->StartSignIn(
-      "user@gmail.com", "password", std::string(), std::string());
+  manager_->StartSignIn("user@gmail.com", "password", "", "");
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
   SimulateValidResponseClientLogin(true);
@@ -341,7 +340,7 @@ TEST_F(SigninManagerTest, Prohibited) {
   EXPECT_TRUE(manager_->IsAllowedUsername("happy@google.com"));
   EXPECT_FALSE(manager_->IsAllowedUsername("test@invalid.com"));
   EXPECT_FALSE(manager_->IsAllowedUsername("test@notgoogle.com"));
-  EXPECT_FALSE(manager_->IsAllowedUsername(std::string()));
+  EXPECT_FALSE(manager_->IsAllowedUsername(""));
 }
 
 TEST_F(SigninManagerTest, TestAlternateWildcard) {
@@ -354,7 +353,7 @@ TEST_F(SigninManagerTest, TestAlternateWildcard) {
   EXPECT_TRUE(manager_->IsAllowedUsername("happy@google.com"));
   EXPECT_FALSE(manager_->IsAllowedUsername("test@invalid.com"));
   EXPECT_FALSE(manager_->IsAllowedUsername("test@notgoogle.com"));
-  EXPECT_FALSE(manager_->IsAllowedUsername(std::string()));
+  EXPECT_FALSE(manager_->IsAllowedUsername(""));
 }
 
 TEST_F(SigninManagerTest, ProhibitedAtStartup) {
@@ -422,7 +421,7 @@ TEST_F(SigninManagerTest, SignInWithCredentialsEmptyPasswordValidCookie) {
         net::CookieMonster::SetCookiesCallback());
 
   // Since the password is empty, will verify the gaia cookies first.
-  manager_->StartSignInWithCredentials("0", "user@gmail.com", std::string());
+  manager_->StartSignInWithCredentials("0", "user@gmail.com", "");
 
   WaitUntilUIDone();
 
@@ -435,7 +434,7 @@ TEST_F(SigninManagerTest, SignInWithCredentialsEmptyPasswordNoValidCookie) {
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
   // Since the password is empty, will verify the gaia cookies first.
-  manager_->StartSignInWithCredentials("0", "user@gmail.com", std::string());
+  manager_->StartSignInWithCredentials("0", "user@gmail.com", "");
 
   WaitUntilUIDone();
 
@@ -459,7 +458,7 @@ TEST_F(SigninManagerTest, SignInWithCredentialsEmptyPasswordInValidCookie) {
         net::CookieMonster::SetCookiesCallback());
 
   // Since the password is empty, must verify the gaia cookies first.
-  manager_->StartSignInWithCredentials("0", "user@gmail.com", std::string());
+  manager_->StartSignInWithCredentials("0", "user@gmail.com", "");
 
   WaitUntilUIDone();
 
@@ -472,7 +471,7 @@ TEST_F(SigninManagerTest, SignInClientLoginNoGPlus) {
   manager_->Initialize(profile_.get());
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
   SimulateValidResponseClientLogin(false);
@@ -483,7 +482,7 @@ TEST_F(SigninManagerTest, ClearTransientSigninData) {
   manager_->Initialize(profile_.get());
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   EXPECT_TRUE(manager_->GetAuthenticatedUsername().empty());
 
   SimulateValidResponseClientLogin(false);
@@ -514,7 +513,7 @@ TEST_F(SigninManagerTest, ClearTransientSigninData) {
 
 TEST_F(SigninManagerTest, SignOutClientLogin) {
   manager_->Initialize(profile_.get());
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   SimulateValidResponseClientLogin(false);
   manager_->OnClientLoginSuccess(credentials_);
 
@@ -530,7 +529,7 @@ TEST_F(SigninManagerTest, SignOutClientLogin) {
 
 TEST_F(SigninManagerTest, SignInFailureClientLogin) {
   manager_->Initialize(profile_.get());
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   GoogleServiceAuthError error(GoogleServiceAuthError::REQUEST_CANCELED);
   manager_->OnClientLoginFailure(error);
 
@@ -548,7 +547,7 @@ TEST_F(SigninManagerTest, SignInFailureClientLogin) {
 
 TEST_F(SigninManagerTest, ProvideSecondFactorSuccess) {
   manager_->Initialize(profile_.get());
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   GoogleServiceAuthError error(GoogleServiceAuthError::TWO_FACTOR);
   manager_->OnClientLoginFailure(error);
 
@@ -567,7 +566,7 @@ TEST_F(SigninManagerTest, ProvideSecondFactorSuccess) {
 
 TEST_F(SigninManagerTest, ProvideSecondFactorFailure) {
   manager_->Initialize(profile_.get());
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   GoogleServiceAuthError error1(GoogleServiceAuthError::TWO_FACTOR);
   manager_->OnClientLoginFailure(error1);
 
@@ -597,7 +596,7 @@ TEST_F(SigninManagerTest, ProvideSecondFactorFailure) {
 
 TEST_F(SigninManagerTest, SignOutMidConnect) {
   manager_->Initialize(profile_.get());
-  manager_->StartSignIn("username", "password", std::string(), std::string());
+  manager_->StartSignIn("username", "password", "", "");
   manager_->SignOut();
   EXPECT_EQ(0U, google_login_success_.size());
   EXPECT_EQ(0U, google_login_failure_.size());
diff --git a/chrome/browser/signin/token_service_unittest.cc b/chrome/browser/signin/token_service_unittest.cc
index fbe83df..617a394 100644
--- a/chrome/browser/signin/token_service_unittest.cc
+++ b/chrome/browser/signin/token_service_unittest.cc
@@ -225,7 +225,7 @@ TEST_F(TokenServiceTest, OnTokenSuccessUpdate) {
   EXPECT_EQ(service_->GetTokenForService(GaiaConstants::kSyncService),
             "token2");
 
-  service_->OnIssueAuthTokenSuccess(GaiaConstants::kSyncService, std::string());
+  service_->OnIssueAuthTokenSuccess(GaiaConstants::kSyncService, "");
   EXPECT_TRUE(service_->HasTokenForService(GaiaConstants::kSyncService));
   EXPECT_EQ(service_->GetTokenForService(GaiaConstants::kSyncService), "");
 }
diff --git a/chrome/browser/spellchecker/spelling_service_client_unittest.cc b/chrome/browser/spellchecker/spelling_service_client_unittest.cc
index 5833fce..d3243e8 100644
--- a/chrome/browser/spellchecker/spelling_service_client_unittest.cc
+++ b/chrome/browser/spellchecker/spelling_service_client_unittest.cc
@@ -343,7 +343,7 @@ TEST_F(SpellingServiceClientTest, AvailableServices) {
   // SpellingServiceClient::IsAvailable() describes why this function returns
   // false for suggestions.) If there is no language set, then we
   // do not allow any remote.
-  pref->SetString(prefs::kSpellCheckDictionary, std::string());
+  pref->SetString(prefs::kSpellCheckDictionary, "");
   EXPECT_FALSE(client_.IsAvailable(&profile_, kSuggest));
   EXPECT_FALSE(client_.IsAvailable(&profile_, kSpellcheck));
 
diff --git a/chrome/browser/ssl/ssl_blocking_page.cc b/chrome/browser/ssl/ssl_blocking_page.cc
index 615c4c6..6942d1e 100644
--- a/chrome/browser/ssl/ssl_blocking_page.cc
+++ b/chrome/browser/ssl/ssl_blocking_page.cc
@@ -218,9 +218,9 @@ std::string SSLBlockingPage::GetHTMLContents() {
                         l10n_util::GetStringUTF16(
                             IDS_SSL_ERROR_PAGE_CANNOT_PROCEED));
     } else {
-      strings.SetString("reasonForNotProceeding", std::string());
+      strings.SetString("reasonForNotProceeding", "");
     }
-    strings.SetString("errorType", std::string());
+    strings.SetString("errorType", "");
   }
 
   strings.SetString("textdirection", base::i18n::IsRTL() ? "rtl" : "ltr");
@@ -318,6 +318,6 @@ void SSLBlockingPage::SetExtraInfo(
     strings->SetString(keys[i], extra_info[i]);
   }
   for (; i < 5; i++) {
-    strings->SetString(keys[i], std::string());
+    strings->SetString(keys[i], "");
   }
 }
diff --git a/chrome/browser/ssl/ssl_browser_tests.cc b/chrome/browser/ssl/ssl_browser_tests.cc
index d4afe0f..42cfbf6 100644
--- a/chrome/browser/ssl/ssl_browser_tests.cc
+++ b/chrome/browser/ssl/ssl_browser_tests.cc
@@ -738,9 +738,9 @@ IN_PROC_BROWSER_TEST_F(SSLUITest, MAYBE_TestHTTPSErrorWithNoNavEntry) {
 IN_PROC_BROWSER_TEST_F(SSLUITest, TestBadHTTPSDownload) {
   ASSERT_TRUE(test_server()->Start());
   ASSERT_TRUE(https_server_expired_.Start());
-  GURL url_non_dangerous = test_server()->GetURL(std::string());
-  GURL url_dangerous =
-      https_server_expired_.GetURL("files/downloads/dangerous/dangerous.exe");
+  GURL url_non_dangerous = test_server()->GetURL("");
+  GURL url_dangerous = https_server_expired_.GetURL(
+      "files/downloads/dangerous/dangerous.exe");
   base::ScopedTempDir downloads_directory_;
 
   // Need empty temp dir to avoid having Chrome ask us for a new filename
diff --git a/chrome/browser/storage_monitor/media_storage_util.cc b/chrome/browser/storage_monitor/media_storage_util.cc
index dc9c61b..72602fa 100644
--- a/chrome/browser/storage_monitor/media_storage_util.cc
+++ b/chrome/browser/storage_monitor/media_storage_util.cc
@@ -187,9 +187,8 @@ std::string MediaStorageUtil::MakeDeviceId(Type type,
 bool MediaStorageUtil::CrackDeviceId(const std::string& device_id,
                                      Type* type, std::string* unique_id) {
   size_t prefix_length = device_id.find_first_of(':');
-  std::string prefix = prefix_length != std::string::npos
-                           ? device_id.substr(0, prefix_length + 1)
-                           : std::string();
+  std::string prefix = prefix_length != std::string::npos ?
+                       device_id.substr(0, prefix_length + 1) : "";
 
   Type found_type;
   if (prefix == kRemovableMassStorageWithDCIMPrefix) {
diff --git a/chrome/browser/sync/glue/session_model_associator_unittest.cc b/chrome/browser/sync/glue/session_model_associator_unittest.cc
index e5ceab1e..d1f63bb 100644
--- a/chrome/browser/sync/glue/session_model_associator_unittest.cc
+++ b/chrome/browser/sync/glue/session_model_associator_unittest.cc
@@ -375,7 +375,7 @@ TEST_F(SyncSessionModelAssociatorTest, SetSessionTabFromDelegate) {
 // Create tab specifics with an empty favicon. Ensure it gets ignored and not
 // stored into the synced favicon lookups.
 TEST_F(SyncSessionModelAssociatorTest, LoadEmptyFavicon) {
-  std::string favicon;
+  std::string favicon = "";
   std::string favicon_url = "http://www.faviconurl.com/favicon.ico";
   std::string page_url = "http://www.faviconurl.com/page.html";
   sync_pb::SessionTab tab;
diff --git a/chrome/browser/sync/glue/sync_backend_host_unittest.cc b/chrome/browser/sync/glue/sync_backend_host_unittest.cc
index d05dd46..96d1acb 100644
--- a/chrome/browser/sync/glue/sync_backend_host_unittest.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_unittest.cc
@@ -194,7 +194,7 @@ class SyncBackendHostTest : public testing::Test {
         WillOnce(InvokeWithoutArgs(QuitMessageLoop));
     backend_->Initialize(&mock_frontend_,
                          syncer::WeakHandle<syncer::JsEventHandler>(),
-                         GURL(std::string()),
+                         GURL(""),
                          credentials_,
                          true,
                          &fake_manager_factory_,
diff --git a/chrome/browser/sync/glue/synced_session.h b/chrome/browser/sync/glue/synced_session.h
index 80ff9be..a1d0d68 100644
--- a/chrome/browser/sync/glue/synced_session.h
+++ b/chrome/browser/sync/glue/synced_session.h
@@ -74,7 +74,7 @@ struct SyncedSession {
       case SyncedSession::TYPE_TABLET:
         return "tablet";
       default:
-        return std::string();
+        return "";
     }
   }
 
diff --git a/chrome/browser/sync/invalidations/invalidator_storage.cc b/chrome/browser/sync/invalidations/invalidator_storage.cc
index e88d0e2..acbbd47 100644
--- a/chrome/browser/sync/invalidations/invalidator_storage.cc
+++ b/chrome/browser/sync/invalidations/invalidator_storage.cc
@@ -282,10 +282,8 @@ void InvalidatorStorage::SetBootstrapData(const std::string& data) {
 }
 
 std::string InvalidatorStorage::GetBootstrapData() const {
-  std::string base64_data(
-      pref_service_
-          ? pref_service_->GetString(prefs::kInvalidatorInvalidationState)
-          : std::string());
+  std::string base64_data(pref_service_ ?
+      pref_service_->GetString(prefs::kInvalidatorInvalidationState) : "");
   std::string data;
   base::Base64Decode(base64_data, &data);
   return data;
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index a58fff4..2d8bbd3 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -726,7 +726,7 @@ void ProfileSyncService::ClearUnrecoverableError() {
 std::string ProfileSyncService::GetExperimentNameForDataType(
     syncer::ModelType data_type) {
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 void ProfileSyncService::RegisterNewDataType(syncer::ModelType data_type) {
diff --git a/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc b/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
index 1ad62a1..bc62c97 100644
--- a/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
@@ -706,9 +706,9 @@ TEST_F(ProfileSyncServiceBookmarkTest, ServerChangeProcessing) {
       "'about:blank','gnotesWin','location=0,menubar=0," \
       "scrollbars=0,status=0,toolbar=0,width=300," \
       "height=300,resizable');});");
-  adds.AddURL(std::wstring(), javascript_url, other_bookmarks_id(), 0);
-  int64 u6 = adds.AddURL(
-      L"Sync1", "http://www.syncable.edu/", mobile_bookmarks_id(), 0);
+  adds.AddURL(L"", javascript_url, other_bookmarks_id(), 0);
+  int64 u6 = adds.AddURL(L"Sync1", "http://www.syncable.edu/",
+                         mobile_bookmarks_id(), 0);
 
   syncer::ChangeRecordList::const_iterator it;
   // The bookmark model shouldn't yet have seen any of the nodes of |adds|.
diff --git a/chrome/browser/sync/profile_sync_service_harness.cc b/chrome/browser/sync/profile_sync_service_harness.cc
index eb0b074..c290374 100644
--- a/chrome/browser/sync/profile_sync_service_harness.cc
+++ b/chrome/browser/sync/profile_sync_service_harness.cc
@@ -134,7 +134,7 @@ ProfileSyncServiceHarness* ProfileSyncServiceHarness::CreateAndAttach(
     NOTREACHED() << "Profile has never signed into sync.";
     return NULL;
   }
-  return new ProfileSyncServiceHarness(profile, std::string(), std::string());
+  return new ProfileSyncServiceHarness(profile, "", "");
 }
 
 void ProfileSyncServiceHarness::SetCredentials(const std::string& username,
@@ -179,8 +179,7 @@ bool ProfileSyncServiceHarness::SetupSync(
   service_->SetSetupInProgress(true);
 
   // Authenticate sync client using GAIA credentials.
-  service_->signin()
-      ->StartSignIn(username_, password_, std::string(), std::string());
+  service_->signin()->StartSignIn(username_, password_, "", "");
 
   // Wait for the OnBackendInitialized() callback.
   if (!AwaitBackendInitialized()) {
@@ -1015,7 +1014,7 @@ std::string ProfileSyncServiceHarness::GetSerializedProgressMarker(
 
   syncer::ProgressMarkerMap::const_iterator it =
       markers_map.find(model_type);
-  return (it != markers_map.end()) ? it->second : std::string();
+  return (it != markers_map.end()) ? it->second : "";
 }
 
 std::string ProfileSyncServiceHarness::GetClientInfoString(
diff --git a/chrome/browser/sync/profile_sync_service_session_unittest.cc b/chrome/browser/sync/profile_sync_service_session_unittest.cc
index 4ed28ab..1ee92a6 100644
--- a/chrome/browser/sync/profile_sync_service_session_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_session_unittest.cc
@@ -85,10 +85,8 @@ class FakeProfileSyncService : public TestProfileSyncService {
   virtual ~FakeProfileSyncService() {}
 
   virtual scoped_ptr<DeviceInfo> GetLocalDeviceInfo() const OVERRIDE {
-    return scoped_ptr<DeviceInfo>(new DeviceInfo("client_name",
-                                                 std::string(),
-                                                 std::string(),
-                                                 sync_pb::SyncEnums::TYPE_WIN));
+    return scoped_ptr<DeviceInfo>(
+        new DeviceInfo("client_name", "", "", sync_pb::SyncEnums::TYPE_WIN));
   }
 };
 
diff --git a/chrome/browser/sync/profile_sync_service_startup_unittest.cc b/chrome/browser/sync/profile_sync_service_startup_unittest.cc
index d85946e..1a00308 100644
--- a/chrome/browser/sync/profile_sync_service_startup_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_startup_unittest.cc
@@ -189,10 +189,9 @@ TEST_F(ProfileSyncServiceStartupTest, StartFirstTime) {
   // Create some tokens in the token service; the service will startup when
   // it is notified that tokens are available.
   sync_->SetSetupInProgress(true);
-  sync_->signin()
-      ->StartSignIn("test_user", std::string(), std::string(), std::string());
-  TokenServiceFactory::GetForProfile(profile_.get())
-      ->IssueAuthTokenForTest(GaiaConstants::kSyncService, "sync_token");
+  sync_->signin()->StartSignIn("test_user", "", "", "");
+  TokenServiceFactory::GetForProfile(profile_.get())->IssueAuthTokenForTest(
+      GaiaConstants::kSyncService, "sync_token");
   TokenServiceFactory::GetForProfile(profile_.get())->IssueAuthTokenForTest(
       GaiaConstants::kGaiaOAuth2LoginRefreshToken, "oauth2_login_token");
   sync_->SetSetupInProgress(false);
@@ -236,8 +235,7 @@ TEST_F(ProfileSyncServiceStartupTest, StartNoCredentials) {
   EXPECT_CALL(observer_, OnStateChanged()).Times(AnyNumber());
 
   sync_->SetSetupInProgress(true);
-  sync_->signin()
-      ->StartSignIn("test_user", std::string(), std::string(), std::string());
+  sync_->signin()->StartSignIn("test_user", "", "", "");
   // NOTE: Unlike StartFirstTime, this test does not issue any auth tokens.
   token_service->LoadTokensFromDB();
   sync_->SetSetupInProgress(false);
@@ -271,10 +269,9 @@ TEST_F(ProfileSyncServiceStartupTest, StartInvalidCredentials) {
   EXPECT_CALL(*data_type_manager, Stop()).Times(1);
   EXPECT_CALL(observer_, OnStateChanged()).Times(AnyNumber());
   sync_->SetSetupInProgress(true);
-  sync_->signin()
-      ->StartSignIn("test_user", std::string(), std::string(), std::string());
-  token_service->IssueAuthTokenForTest(GaiaConstants::kSyncService,
-                                       "sync_token");
+  sync_->signin()->StartSignIn("test_user", "", "", "");
+  token_service->IssueAuthTokenForTest(
+      GaiaConstants::kSyncService, "sync_token");
   sync_->SetSetupInProgress(false);
   MessageLoop::current()->Run();
 
diff --git a/chrome/browser/sync/sync_prefs.cc b/chrome/browser/sync/sync_prefs.cc
index a5c58e8..0c7a4bd 100644
--- a/chrome/browser/sync/sync_prefs.cc
+++ b/chrome/browser/sync/sync_prefs.cc
@@ -87,10 +87,10 @@ void SyncPrefs::RegisterUserPrefs(PrefRegistrySyncable* registry) {
                                 false,
                                 PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kSyncEncryptionBootstrapToken,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kSyncKeystoreEncryptionBootstrapToken,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 #if defined(OS_CHROMEOS)
   registry->RegisterStringPref(prefs::kSyncSpareBootstrapToken,
@@ -99,7 +99,7 @@ void SyncPrefs::RegisterUserPrefs(PrefRegistrySyncable* registry) {
 #endif
 
   registry->RegisterStringPref(prefs::kSyncSessionsGUID,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 
   // We will start prompting people about new data types after the launch of
@@ -181,9 +181,9 @@ void SyncPrefs::SetStartSuppressed(bool is_suppressed) {
 
 std::string SyncPrefs::GetGoogleServicesUsername() const {
   DCHECK(CalledOnValidThread());
-  return pref_service_
-             ? pref_service_->GetString(prefs::kGoogleServicesUsername)
-             : std::string();
+  return
+      pref_service_ ?
+      pref_service_->GetString(prefs::kGoogleServicesUsername) : "";
 }
 
 base::Time SyncPrefs::GetLastSyncedTime() const {
@@ -266,9 +266,9 @@ bool SyncPrefs::IsManaged() const {
 
 std::string SyncPrefs::GetEncryptionBootstrapToken() const {
   DCHECK(CalledOnValidThread());
-  return pref_service_
-             ? pref_service_->GetString(prefs::kSyncEncryptionBootstrapToken)
-             : std::string();
+  return
+      pref_service_ ?
+      pref_service_->GetString(prefs::kSyncEncryptionBootstrapToken) : "";
 }
 
 void SyncPrefs::SetEncryptionBootstrapToken(const std::string& token) {
@@ -278,9 +278,10 @@ void SyncPrefs::SetEncryptionBootstrapToken(const std::string& token) {
 
 std::string SyncPrefs::GetKeystoreEncryptionBootstrapToken() const {
   DCHECK(CalledOnValidThread());
-  return pref_service_ ? pref_service_->GetString(
-                             prefs::kSyncKeystoreEncryptionBootstrapToken)
-                       : std::string();
+  return
+      pref_service_ ?
+      pref_service_->GetString(prefs::kSyncKeystoreEncryptionBootstrapToken) :
+      "";
 }
 
 void SyncPrefs::SetKeystoreEncryptionBootstrapToken(const std::string& token) {
@@ -290,8 +291,9 @@ void SyncPrefs::SetKeystoreEncryptionBootstrapToken(const std::string& token) {
 
 std::string SyncPrefs::GetSyncSessionsGUID() const {
   DCHECK(CalledOnValidThread());
-  return pref_service_ ? pref_service_->GetString(prefs::kSyncSessionsGUID)
-                       : std::string();
+  return
+      pref_service_ ?
+      pref_service_->GetString(prefs::kSyncSessionsGUID) : "";
 }
 
 void SyncPrefs::SetSyncSessionsGUID(const std::string& guid) {
diff --git a/chrome/browser/sync/test/integration/sync_extension_helper.cc b/chrome/browser/sync/test/integration/sync_extension_helper.cc
index fc007af9..84cf7547 100644
--- a/chrome/browser/sync/test/integration/sync_extension_helper.cc
+++ b/chrome/browser/sync/test/integration/sync_extension_helper.cc
@@ -63,7 +63,7 @@ std::string SyncExtensionHelper::InstallExtension(
   scoped_refptr<Extension> extension = GetExtension(profile, name, type);
   if (!extension.get()) {
     NOTREACHED() << "Could not install extension " << name;
-    return std::string();
+    return "";
   }
   profile->GetExtensionService()->OnExtensionInstalled(
       extension, syncer::StringOrdinal(), false /* no requirement errors */,
diff --git a/chrome/browser/sync_file_system/drive_file_sync_client.cc b/chrome/browser/sync_file_system/drive_file_sync_client.cc
index 7f8903a..b6c8095 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_client.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_client.cc
@@ -129,7 +129,7 @@ DriveFileSyncClient::DriveFileSyncClient(Profile* profile)
   drive_service_.reset(new google_apis::GDataWapiService(
       profile->GetRequestContext(),
       GURL(google_apis::GDataWapiUrlGenerator::kBaseUrlForProduction),
-      std::string() /* custom_user_agent */));
+      "" /* custom_user_agent */));
   drive_service_->Initialize(profile);
   drive_service_->AddObserver(this);
   net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service.cc b/chrome/browser/sync_file_system/drive_file_sync_service.cc
index 15691f49..c7a12a7 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service.cc
@@ -411,8 +411,7 @@ void DriveFileSyncService::RegisterOriginForTrackingChanges(
 void DriveFileSyncService::UnregisterOriginForTrackingChanges(
     const GURL& origin,
     const SyncStatusCallback& callback) {
-  scoped_ptr<TaskToken> token(
-      GetToken(FROM_HERE, TASK_TYPE_DATABASE, std::string()));
+  scoped_ptr<TaskToken> token(GetToken(FROM_HERE, TASK_TYPE_DATABASE, ""));
   if (!token) {
     pending_tasks_.push_back(base::Bind(
         &DriveFileSyncService::UnregisterOriginForTrackingChanges,
@@ -443,8 +442,7 @@ void DriveFileSyncService::EnableOriginForTrackingChanges(
   if (!metadata_store_->IsOriginDisabled(origin))
     return;
 
-  scoped_ptr<TaskToken> token(
-      GetToken(FROM_HERE, TASK_TYPE_DATABASE, std::string()));
+  scoped_ptr<TaskToken> token(GetToken(FROM_HERE, TASK_TYPE_DATABASE, ""));
   if (!token) {
     pending_tasks_.push_back(base::Bind(
         &DriveFileSyncService::EnableOriginForTrackingChanges,
@@ -465,8 +463,7 @@ void DriveFileSyncService::DisableOriginForTrackingChanges(
       !metadata_store_->IsIncrementalSyncOrigin(origin))
     return;
 
-  scoped_ptr<TaskToken> token(
-      GetToken(FROM_HERE, TASK_TYPE_DATABASE, std::string()));
+  scoped_ptr<TaskToken> token(GetToken(FROM_HERE, TASK_TYPE_DATABASE, ""));
   if (!token) {
     pending_tasks_.push_back(base::Bind(
         &DriveFileSyncService::DisableOriginForTrackingChanges,
diff --git a/chrome/browser/tab_contents/spelling_menu_observer_browsertest.cc b/chrome/browser/tab_contents/spelling_menu_observer_browsertest.cc
index 47d6bdb..fd5ca6f 100644
--- a/chrome/browser/tab_contents/spelling_menu_observer_browsertest.cc
+++ b/chrome/browser/tab_contents/spelling_menu_observer_browsertest.cc
@@ -301,7 +301,7 @@ IN_PROC_BROWSER_TEST_F(SpellingMenuObserverTest, EnableSpellingService) {
       new SpellingMenuObserver(menu.get()));
   menu->SetObserver(observer.get());
   menu->GetPrefs()->SetBoolean(prefs::kSpellCheckUseSpellingService, true);
-  menu->GetPrefs()->SetString(prefs::kSpellCheckDictionary, std::string());
+  menu->GetPrefs()->SetString(prefs::kSpellCheckDictionary, "");
 
   content::ContextMenuParams params;
   params.is_editable = true;
diff --git a/chrome/browser/themes/theme_syncable_service_unittest.cc b/chrome/browser/themes/theme_syncable_service_unittest.cc
index 8fa7d25..8a1829f 100644
--- a/chrome/browser/themes/theme_syncable_service_unittest.cc
+++ b/chrome/browser/themes/theme_syncable_service_unittest.cc
@@ -104,7 +104,7 @@ class FakeThemeService : public ThemeService {
     if (theme_extension_)
       return theme_extension_->id();
     else
-      return std::string();
+      return "";
   }
 
   const extensions::Extension* theme_extension() const {
diff --git a/chrome/browser/translate/translate_manager_browsertest.cc b/chrome/browser/translate/translate_manager_browsertest.cc
index 8f2b12d..1078295 100644
--- a/chrome/browser/translate/translate_manager_browsertest.cc
+++ b/chrome/browser/translate/translate_manager_browsertest.cc
@@ -538,7 +538,7 @@ TEST_F(TranslateManagerBrowserTest, TranslateUnknownLanguage) {
   RenderViewHostTester::TestOnMessageReceived(
       rvh(),
       ChromeViewHostMsg_PageTranslated(
-          2, 0, std::string(), "en", TranslateErrors::UNKNOWN_LANGUAGE));
+          2, 0, "", "en", TranslateErrors::UNKNOWN_LANGUAGE));
   infobar = GetTranslateInfoBar();
   ASSERT_TRUE(infobar != NULL);
   EXPECT_EQ(TranslateInfoBarDelegate::TRANSLATION_ERROR,
diff --git a/chrome/browser/translate/translate_manager_unittest.cc b/chrome/browser/translate/translate_manager_unittest.cc
index 6b176a1..9b25c95 100644
--- a/chrome/browser/translate/translate_manager_unittest.cc
+++ b/chrome/browser/translate/translate_manager_unittest.cc
@@ -16,7 +16,7 @@
 typedef testing::Test TranslateManagerTest;
 
 TEST_F(TranslateManagerTest, CheckTranslatableURL) {
-  GURL empty_url = GURL(std::string());
+  GURL empty_url = GURL("");
   EXPECT_FALSE(TranslateManager::IsTranslatableURL(empty_url));
 
   std::string chrome = std::string(chrome::kChromeUIScheme) + "://flags";
diff --git a/chrome/browser/ui/app_list/app_list_service.cc b/chrome/browser/ui/app_list/app_list_service.cc
index a0bf010..f02da1e 100644
--- a/chrome/browser/ui/app_list/app_list_service.cc
+++ b/chrome/browser/ui/app_list/app_list_service.cc
@@ -66,7 +66,7 @@ void AppListService::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterIntegerPref(prefs::kAppListLaunchCount, 0);
   registry->RegisterInt64Pref(prefs::kLastAppListAppLaunchPing, 0);
   registry->RegisterIntegerPref(prefs::kAppListAppLaunchCount, 0);
-  registry->RegisterStringPref(prefs::kAppListProfile, std::string());
+  registry->RegisterStringPref(prefs::kAppListProfile, "");
 #if defined(OS_WIN)
   registry->RegisterBooleanPref(prefs::kRestartWithAppList, false);
 #endif
diff --git a/chrome/browser/ui/blocked_content/blocked_content_tab_helper.cc b/chrome/browser/ui/blocked_content/blocked_content_tab_helper.cc
index 844f210..2ee22c3 100644
--- a/chrome/browser/ui/blocked_content/blocked_content_tab_helper.cc
+++ b/chrome/browser/ui/blocked_content/blocked_content_tab_helper.cc
@@ -110,8 +110,10 @@ void BlockedContentTabHelper::AddPopup(content::WebContents* new_contents,
 
   if (creator.is_valid() &&
       profile->GetHostContentSettingsMap()->GetContentSetting(
-          creator, creator, CONTENT_SETTINGS_TYPE_POPUPS, std::string()) ==
-          CONTENT_SETTING_ALLOW) {
+          creator,
+          creator,
+          CONTENT_SETTINGS_TYPE_POPUPS,
+          "") == CONTENT_SETTING_ALLOW) {
     content::WebContentsDelegate* delegate = web_contents()->GetDelegate();
     if (delegate) {
       delegate->AddNewContents(web_contents(),
diff --git a/chrome/browser/ui/browser.cc b/chrome/browser/ui/browser.cc
index a31b4b0..47f07ca 100644
--- a/chrome/browser/ui/browser.cc
+++ b/chrome/browser/ui/browser.cc
@@ -813,13 +813,9 @@ void Browser::OpenFile() {
   ui::SelectFileDialog::FileTypeInfo file_types;
   file_types.support_drive = true;
   select_file_dialog_->SelectFile(ui::SelectFileDialog::SELECT_OPEN_FILE,
-                                  string16(),
-                                  directory,
-                                  &file_types,
-                                  0,
-                                  base::FilePath::StringType(),
-                                  parent_window,
-                                  NULL);
+                                  string16(), directory,
+                                  &file_types, 0, FILE_PATH_LITERAL(""),
+                                  parent_window, NULL);
 }
 
 void Browser::UpdateDownloadShelfVisibility(bool visible) {
diff --git a/chrome/browser/ui/browser_browsertest.cc b/chrome/browser/ui/browser_browsertest.cc
index e253102..5e6b769 100644
--- a/chrome/browser/ui/browser_browsertest.cc
+++ b/chrome/browser/ui/browser_browsertest.cc
@@ -558,7 +558,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, NullOpenerRedirectForksProcess) {
                                     base::FilePath(kDocRoot));
   ASSERT_TRUE(https_test_server.Start());
   GURL http_url(test_server()->GetURL("files/title1.html"));
-  GURL https_url(https_test_server.GetURL(std::string()));
+  GURL https_url(https_test_server.GetURL(""));
 
   // Start with an http URL.
   ui_test_utils::NavigateToURL(browser(), http_url);
@@ -647,7 +647,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, OtherRedirectsDontForkProcess) {
                                     base::FilePath(kDocRoot));
   ASSERT_TRUE(https_test_server.Start());
   GURL http_url(test_server()->GetURL("files/title1.html"));
-  GURL https_url(https_test_server.GetURL(std::string()));
+  GURL https_url(https_test_server.GetURL(""));
 
   // Start with an http URL.
   ui_test_utils::NavigateToURL(browser(), http_url);
@@ -747,7 +747,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, CommandCreateAppShortcutHttp) {
       browser()->command_controller()->command_updater();
 
   ASSERT_TRUE(test_server()->Start());
-  GURL http_url(test_server()->GetURL(std::string()));
+  GURL http_url(test_server()->GetURL(""));
   ASSERT_TRUE(http_url.SchemeIs(chrome::kHttpScheme));
   ui_test_utils::NavigateToURL(browser(), http_url);
   EXPECT_TRUE(command_updater->IsCommandEnabled(IDC_CREATE_SHORTCUTS));
@@ -775,7 +775,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, CommandCreateAppShortcutFtp) {
                               net::TestServer::kLocalhost,
                               base::FilePath(kDocRoot));
   ASSERT_TRUE(test_server.Start());
-  GURL ftp_url(test_server.GetURL(std::string()));
+  GURL ftp_url(test_server.GetURL(""));
   ASSERT_TRUE(ftp_url.SchemeIs(chrome::kFtpScheme));
   ui_test_utils::NavigateToURL(browser(), ftp_url);
   EXPECT_TRUE(command_updater->IsCommandEnabled(IDC_CREATE_SHORTCUTS));
@@ -807,7 +807,7 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, CommandCreateAppShortcutInvalid) {
 // DISABLED: http://crbug.com/72310
 IN_PROC_BROWSER_TEST_F(BrowserTest, DISABLED_ConvertTabToAppShortcut) {
   ASSERT_TRUE(test_server()->Start());
-  GURL http_url(test_server()->GetURL(std::string()));
+  GURL http_url(test_server()->GetURL(""));
   ASSERT_TRUE(http_url.SchemeIs(chrome::kHttpScheme));
 
   ASSERT_EQ(1, browser()->tab_strip_model()->count());
diff --git a/chrome/browser/ui/browser_tab_contents.cc b/chrome/browser/ui/browser_tab_contents.cc
index fdcaa16..c4fe56c 100644
--- a/chrome/browser/ui/browser_tab_contents.cc
+++ b/chrome/browser/ui/browser_tab_contents.cc
@@ -172,10 +172,8 @@ void BrowserTabContents::AttachTabHelpers(WebContents* web_contents) {
   // because the connected state may change while this tab is open.  Having a
   // one-click signin helper attached does not cause problems if the profile
   // happens to be already connected.
-  if (OneClickSigninHelper::CanOffer(web_contents,
-                                     OneClickSigninHelper::CAN_OFFER_FOR_ALL,
-                                     std::string(),
-                                     NULL)) {
+  if (OneClickSigninHelper::CanOffer(
+          web_contents, OneClickSigninHelper::CAN_OFFER_FOR_ALL, "", NULL)) {
     OneClickSigninHelper::CreateForWebContents(web_contents);
   }
 #endif
diff --git a/chrome/browser/ui/browser_tabrestore.cc b/chrome/browser/ui/browser_tabrestore.cc
index 373de5c..0e96e0d 100644
--- a/chrome/browser/ui/browser_tabrestore.cc
+++ b/chrome/browser/ui/browser_tabrestore.cc
@@ -50,7 +50,7 @@ WebContents* CreateRestoredTab(
   // session_storage_namespace.h include since we only need that to assign
   // into the map.
   content::SessionStorageNamespaceMap session_storage_namespace_map;
-  session_storage_namespace_map[std::string()] = session_storage_namespace;
+  session_storage_namespace_map[""] = session_storage_namespace;
   WebContents::CreateParams create_params(
       browser->profile(),
       tab_util::GetSiteInstanceForNewTab(browser->profile(), restore_url));
diff --git a/chrome/browser/ui/certificate_dialogs.cc b/chrome/browser/ui/certificate_dialogs.cc
index 939c3a13..8e69b5d 100644
--- a/chrome/browser/ui/certificate_dialogs.cc
+++ b/chrome/browser/ui/certificate_dialogs.cc
@@ -52,7 +52,7 @@ std::string GetBase64String(net::X509Certificate::OSCertHandle cert) {
   if (!base::Base64Encode(
       x509_certificate_model::GetDerString(cert), &base64)) {
     LOG(ERROR) << "base64 encoding error";
-    return std::string();
+    return "";
   }
   return "-----BEGIN CERTIFICATE-----\r\n" +
       WrapAt64(base64) +
diff --git a/chrome/browser/ui/chrome_pages.cc b/chrome/browser/ui/chrome_pages.cc
index 7fed38a..fe9300c 100644
--- a/chrome/browser/ui/chrome_pages.cc
+++ b/chrome/browser/ui/chrome_pages.cc
@@ -65,7 +65,7 @@ void ShowBookmarkManager(Browser* browser) {
 }
 
 void ShowBookmarkManagerForNode(Browser* browser, int64 node_id) {
-  OpenBookmarkManagerWithHash(browser, std::string(), node_id);
+  OpenBookmarkManagerWithHash(browser, "", node_id);
 }
 
 void ShowHistory(Browser* browser) {
diff --git a/chrome/browser/ui/chrome_select_file_policy_unittest.cc b/chrome/browser/ui/chrome_select_file_policy_unittest.cc
index ad735f8..d5a6c10 100644
--- a/chrome/browser/ui/chrome_select_file_policy_unittest.cc
+++ b/chrome/browser/ui/chrome_select_file_policy_unittest.cc
@@ -56,7 +56,7 @@ class FileSelectionUser : public ui::SelectFileDialog::Listener {
                                     file_path,
                                     NULL,
                                     0,
-                                    base::FilePath::StringType()),
+                                    FILE_PATH_LITERAL(""),
                                     NULL,
                                     NULL);
     file_selection_initialisation_in_progress = false;
diff --git a/chrome/browser/ui/fullscreen/fullscreen_controller_state_test.cc b/chrome/browser/ui/fullscreen/fullscreen_controller_state_test.cc
index 3c851f4..34bb7f0 100644
--- a/chrome/browser/ui/fullscreen/fullscreen_controller_state_test.cc
+++ b/chrome/browser/ui/fullscreen/fullscreen_controller_state_test.cc
@@ -658,7 +658,7 @@ FullscreenControllerStateTest::StateTransitionInfo
 std::string FullscreenControllerStateTest::GetAndClearDebugLog() {
   debugging_log_ << "(End of Debugging Log)\n";
   std::string output_log = "\nDebugging Log:\n" + debugging_log_.str();
-  debugging_log_.str(std::string());
+  debugging_log_.str("");
   return output_log;
 }
 
diff --git a/chrome/browser/ui/gtk/bookmarks/bookmark_utils_gtk.cc b/chrome/browser/ui/gtk/bookmarks/bookmark_utils_gtk.cc
index a4d0a2b..3796706 100644
--- a/chrome/browser/ui/gtk/bookmarks/bookmark_utils_gtk.cc
+++ b/chrome/browser/ui/gtk/bookmarks/bookmark_utils_gtk.cc
@@ -462,12 +462,7 @@ bool CreateNewBookmarkFromNetscapeURL(GtkSelectionData* selection_data,
 
 string16 GetNameForURL(const GURL& url) {
   if (url.is_valid()) {
-    return net::GetSuggestedFilename(url,
-                                     std::string(),
-                                     std::string(),
-                                     std::string(),
-                                     std::string(),
-                                     std::string());
+    return net::GetSuggestedFilename(url, "", "", "", "", std::string());
   } else {
     return l10n_util::GetStringUTF16(IDS_APP_UNTITLED_SHORTCUT_FILE_NAME);
   }
diff --git a/chrome/browser/ui/gtk/constrained_web_dialog_delegate_gtk.cc b/chrome/browser/ui/gtk/constrained_web_dialog_delegate_gtk.cc
index fdb10b5..fe42588 100644
--- a/chrome/browser/ui/gtk/constrained_web_dialog_delegate_gtk.cc
+++ b/chrome/browser/ui/gtk/constrained_web_dialog_delegate_gtk.cc
@@ -127,7 +127,7 @@ ConstrainedWebDialogDelegateViewGtk::ConstrainedWebDialogDelegateViewGtk(
 
 void ConstrainedWebDialogDelegateViewGtk::OnDestroy(GtkWidget* widget) {
   if (!impl_->closed_via_webui())
-    GetWebDialogDelegate()->OnDialogClosed(std::string());
+    GetWebDialogDelegate()->OnDialogClosed("");
   delete this;
 }
 
diff --git a/chrome/browser/ui/gtk/first_run_bubble.cc b/chrome/browser/ui/gtk/first_run_bubble.cc
index 70bf245..7207758 100644
--- a/chrome/browser/ui/gtk/first_run_bubble.cc
+++ b/chrome/browser/ui/gtk/first_run_bubble.cc
@@ -44,12 +44,10 @@ FirstRunBubble::FirstRunBubble(Browser* browser,
     : browser_(browser),
       bubble_(NULL) {
   GtkThemeService* theme_service = GtkThemeService::GetFrom(browser->profile());
-  GtkWidget* title = theme_service->BuildLabel(std::string(), ui::kGdkBlack);
-  char* markup = g_markup_printf_escaped(
-      kSearchLabelMarkup,
+  GtkWidget* title = theme_service->BuildLabel("", ui::kGdkBlack);
+  char* markup = g_markup_printf_escaped(kSearchLabelMarkup,
       l10n_util::GetStringFUTF8(IDS_FR_BUBBLE_TITLE,
-                                GetDefaultSearchEngineName(browser->profile()))
-          .c_str());
+          GetDefaultSearchEngineName(browser->profile())).c_str());
   gtk_label_set_markup(GTK_LABEL(title), markup);
   g_free(markup);
 
diff --git a/chrome/browser/ui/gtk/location_bar_view_gtk.cc b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
index 9bd0ebb..befcd30 100644
--- a/chrome/browser/ui/gtk/location_bar_view_gtk.cc
+++ b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
@@ -410,9 +410,9 @@ void LocationBarViewGtk::Init(bool popup_window_mode) {
 
   // Tab to search (the keyword box on the left hand side).
   tab_to_search_full_label_ =
-      theme_service_->BuildLabel(std::string(), ui::kGdkBlack);
+      theme_service_->BuildLabel("", ui::kGdkBlack);
   tab_to_search_partial_label_ =
-      theme_service_->BuildLabel(std::string(), ui::kGdkBlack);
+      theme_service_->BuildLabel("", ui::kGdkBlack);
   GtkWidget* tab_to_search_label_hbox = gtk_hbox_new(FALSE, 0);
   gtk_box_pack_start(GTK_BOX(tab_to_search_label_hbox),
                      tab_to_search_full_label_, FALSE, FALSE, 0);
@@ -458,12 +458,12 @@ void LocationBarViewGtk::Init(bool popup_window_mode) {
   tab_to_search_hint_ = gtk_hbox_new(FALSE, 0);
   gtk_widget_set_name(tab_to_search_hint_, "chrome-tab-to-search-hint");
   tab_to_search_hint_leading_label_ =
-      theme_service_->BuildLabel(std::string(), kHintTextColor);
+      theme_service_->BuildLabel("", kHintTextColor);
   gtk_widget_set_sensitive(tab_to_search_hint_leading_label_, FALSE);
   tab_to_search_hint_icon_ = gtk_image_new_from_pixbuf(
       rb.GetNativeImageNamed(IDR_LOCATION_BAR_KEYWORD_HINT_TAB).ToGdkPixbuf());
   tab_to_search_hint_trailing_label_ =
-      theme_service_->BuildLabel(std::string(), kHintTextColor);
+      theme_service_->BuildLabel("", kHintTextColor);
   gtk_widget_set_sensitive(tab_to_search_hint_trailing_label_, FALSE);
   gtk_box_pack_start(GTK_BOX(tab_to_search_hint_),
                      tab_to_search_hint_leading_label_,
diff --git a/chrome/browser/ui/gtk/ssl_client_certificate_selector.cc b/chrome/browser/ui/gtk/ssl_client_certificate_selector.cc
index d96e1d2..ebf2e78 100644
--- a/chrome/browser/ui/gtk/ssl_client_certificate_selector.cc
+++ b/chrome/browser/ui/gtk/ssl_client_certificate_selector.cc
@@ -249,7 +249,7 @@ std::string SSLClientCertificateSelector::FormatComboBoxText(
     net::X509Certificate::OSCertHandle cert, const std::string& nickname) {
   std::string rv(nickname);
   rv += " [";
-  rv += x509_certificate_model::GetSerialNumberHexified(cert, std::string());
+  rv += x509_certificate_model::GetSerialNumberHexified(cert, "");
   rv += ']';
   return rv;
 }
@@ -266,8 +266,8 @@ std::string SSLClientCertificateSelector::FormatDetailsText(
   rv += "\n  ";
   rv += l10n_util::GetStringFUTF8(
       IDS_CERT_SERIAL_NUMBER_FORMAT,
-      UTF8ToUTF16(x509_certificate_model::GetSerialNumberHexified(
-          cert, std::string())));
+      UTF8ToUTF16(
+          x509_certificate_model::GetSerialNumberHexified(cert, "")));
 
   base::Time issued, expires;
   if (x509_certificate_model::GetTimes(cert, &issued, &expires)) {
diff --git a/chrome/browser/ui/prefs/prefs_tab_helper.cc b/chrome/browser/ui/prefs/prefs_tab_helper.cc
index 7056161..b629064 100644
--- a/chrome/browser/ui/prefs/prefs_tab_helper.cc
+++ b/chrome/browser/ui/prefs/prefs_tab_helper.cc
@@ -152,7 +152,7 @@ ALL_FONT_SCRIPTS(WEBKIT_WEBPREFS_FONTS_STANDARD)
       // We haven't already set a default value for this font preference, so set
       // an empty string as the default.
       registry->RegisterStringPref(
-          pref_name, std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
+          pref_name, "", PrefRegistrySyncable::UNSYNCABLE_PREF);
     }
   }
 }
@@ -587,7 +587,7 @@ void PrefsTabHelper::RegisterUserPrefs(PrefRegistrySyncable* registry) {
                                         IDS_STATIC_ENCODING_LIST,
                                         PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kRecentlySelectedEncoding,
-                               std::string(),
+                               "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 
   RegisterPrefsToMigrate(registry);
@@ -666,7 +666,7 @@ void PrefsTabHelper::OnWebPrefChanged(const std::string& pref_name) {
     if (pref_value.empty()) {
       WebPreferences web_prefs =
           web_contents_->GetRenderViewHost()->GetWebkitPreferences();
-      OverrideFontFamily(&web_prefs, generic_family, script, std::string());
+      OverrideFontFamily(&web_prefs, generic_family, script, "");
       web_contents_->GetRenderViewHost()->UpdateWebkitPreferences(web_prefs);
       return;
     }
diff --git a/chrome/browser/ui/search/instant_browsertest.cc b/chrome/browser/ui/search/instant_browsertest.cc
index 2e4beb2..6afe15b 100644
--- a/chrome/browser/ui/search/instant_browsertest.cc
+++ b/chrome/browser/ui/search/instant_browsertest.cc
@@ -607,7 +607,7 @@ IN_PROC_BROWSER_TEST_F(InstantTest, PageVisibility) {
   EXPECT_TRUE(CheckVisibilityIs(overlay, true));
 
   // Deleting the omnibox text should hide the overlay.
-  SetOmniboxText(std::string());
+  SetOmniboxText("");
   EXPECT_TRUE(CheckVisibilityIs(active_tab, true));
   EXPECT_TRUE(CheckVisibilityIs(overlay, false));
 
diff --git a/chrome/browser/ui/startup/startup_browser_creator_impl.cc b/chrome/browser/ui/startup/startup_browser_creator_impl.cc
index 1d0cff3..7600026 100644
--- a/chrome/browser/ui/startup/startup_browser_creator_impl.cc
+++ b/chrome/browser/ui/startup/startup_browser_creator_impl.cc
@@ -933,8 +933,8 @@ void StartupBrowserCreatorImpl::AddStartupURLs(
                          GURL(std::string(chrome::kChromeUISettingsURL) +
                               chrome::kManagedUserSettingsSubPage));
     if (has_reset_local_passphrase_switch) {
-      prefs->SetString(prefs::kManagedModeLocalPassphrase, std::string());
-      prefs->SetString(prefs::kManagedModeLocalSalt, std::string());
+      prefs->SetString(prefs::kManagedModeLocalPassphrase, "");
+      prefs->SetString(prefs::kManagedModeLocalSalt, "");
     }
   }
 
diff --git a/chrome/browser/ui/sync/one_click_signin_helper_unittest.cc b/chrome/browser/ui/sync/one_click_signin_helper_unittest.cc
index 4892ab6..e879b6e 100644
--- a/chrome/browser/ui/sync/one_click_signin_helper_unittest.cc
+++ b/chrome/browser/ui/sync/one_click_signin_helper_unittest.cc
@@ -389,15 +389,13 @@ TEST_F(OneClickSigninHelperTest, CanOfferNoContents) {
       "user@gmail.com", &error_message));
   EXPECT_EQ("", error_message);
   EXPECT_FALSE(OneClickSigninHelper::CanOffer(
-      NULL,
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      &error_message));
+      NULL, OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+      "", &error_message));
   EXPECT_EQ("", error_message);
 }
 
 TEST_F(OneClickSigninHelperTest, CanOffer) {
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
         WillRepeatedly(Return(true));
@@ -410,10 +408,9 @@ TEST_F(OneClickSigninHelperTest, CanOffer) {
       web_contents(), OneClickSigninHelper::CAN_OFFER_FOR_ALL,
       "user@gmail.com", NULL));
   EXPECT_TRUE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      NULL));
+                  web_contents(),
+                  OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+                  "", NULL));
 
   EnableOneClick(false);
 
@@ -427,15 +424,14 @@ TEST_F(OneClickSigninHelperTest, CanOffer) {
       web_contents(), OneClickSigninHelper::CAN_OFFER_FOR_ALL,
       "user@gmail.com", &error_message));
   EXPECT_FALSE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      &error_message));
+                  web_contents(),
+                  OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+                  "", &error_message));
   EXPECT_EQ("", error_message);
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferFirstSetup) {
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
         WillRepeatedly(Return(true));
@@ -458,10 +454,8 @@ TEST_F(OneClickSigninHelperTest, CanOfferFirstSetup) {
       OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
       "foo@gmail.com", NULL));
   EXPECT_TRUE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      NULL));
+      web_contents(), OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+      "", NULL));
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferProfileConnected) {
@@ -498,14 +492,12 @@ TEST_F(OneClickSigninHelperTest, CanOfferProfileConnected) {
                                       UTF8ToUTF16("foo@gmail.com")),
             error_message);
   EXPECT_TRUE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      &error_message));
+      web_contents(), OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+      "", &error_message));
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferUsernameNotAllowed) {
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
       WillRepeatedly(Return(false));
@@ -521,15 +513,16 @@ TEST_F(OneClickSigninHelperTest, CanOfferUsernameNotAllowed) {
       "foo@gmail.com", &error_message));
   EXPECT_EQ(l10n_util::GetStringUTF8(IDS_SYNC_LOGIN_NAME_PROHIBITED),
             error_message);
-  EXPECT_TRUE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      &error_message));
+  EXPECT_TRUE(
+      OneClickSigninHelper::CanOffer(
+          web_contents(),
+          OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+          "",
+          &error_message));
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferWithRejectedEmail) {
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
         WillRepeatedly(Return(true));
@@ -558,7 +551,7 @@ TEST_F(OneClickSigninHelperTest, CanOfferWithRejectedEmail) {
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferIncognito) {
-  CreateSigninManager(true, std::string());
+  CreateSigninManager(true, "");
 
   std::string error_message;
   EXPECT_FALSE(OneClickSigninHelper::CanOffer(
@@ -570,15 +563,13 @@ TEST_F(OneClickSigninHelperTest, CanOfferIncognito) {
       "user@gmail.com", &error_message));
   EXPECT_EQ("", error_message);
   EXPECT_FALSE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      &error_message));
+      web_contents(), OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+      "", &error_message));
   EXPECT_EQ("", error_message);
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferNoSigninCookies) {
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
   AllowSigninCookies(false);
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
@@ -594,10 +585,8 @@ TEST_F(OneClickSigninHelperTest, CanOfferNoSigninCookies) {
       "user@gmail.com", &error_message));
   EXPECT_EQ("", error_message);
   EXPECT_FALSE(OneClickSigninHelper::CanOffer(
-      web_contents(),
-      OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
-      std::string(),
-      &error_message));
+      web_contents(), OneClickSigninHelper::CAN_OFFER_FOR_INTERSTITAL_ONLY,
+      "", &error_message));
   EXPECT_EQ("", error_message);
 }
 
@@ -606,7 +595,7 @@ TEST_F(OneClickSigninHelperTest, CanOfferUntrustedProcess) {
   ASSERT_NE(trusted.GetID(), process()->GetID());
   // Make sure the RenderProcessHost used by the test is untrusted.
   SetTrustedSigninProcessID(trusted.GetID());
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
         WillRepeatedly(Return(true));
@@ -618,7 +607,7 @@ TEST_F(OneClickSigninHelperTest, CanOfferUntrustedProcess) {
 }
 
 TEST_F(OneClickSigninHelperTest, CanOfferDisabledByPolicy) {
-  CreateSigninManager(false, std::string());
+  CreateSigninManager(false, "");
 
   EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
         WillRepeatedly(Return(true));
@@ -653,7 +642,7 @@ TEST_F(OneClickSigninHelperTest, CanOfferDisabledByPolicy) {
 // Should not crash if a helper instance is not associated with an incognito
 // web contents.
 TEST_F(OneClickSigninHelperTest, ShowInfoBarUIThreadIncognito) {
-  CreateSigninManager(true, std::string());
+  CreateSigninManager(true, "");
   OneClickSigninHelper* helper =
       OneClickSigninHelper::FromWebContents(web_contents());
   EXPECT_EQ(NULL, helper);
@@ -668,9 +657,9 @@ TEST_F(OneClickSigninHelperTest, ShowInfoBarUIThreadIncognito) {
 // config sync, then Chrome should redirect immidiately to sync settings page,
 // and upon successful setup, redirect back to webstore.
 TEST_F(OneClickSigninHelperTest, SigninFromWebstoreWithConfigSyncfirst) {
-  CreateSigninManager(false, std::string());
-  EXPECT_CALL(*signin_manager_, IsAllowedUsername(_))
-      .WillRepeatedly(Return(true));
+  CreateSigninManager(false, "");
+  EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
+        WillRepeatedly(Return(true));
 
   CreateProfileSyncServiceMock();
 
@@ -698,9 +687,9 @@ TEST_F(OneClickSigninHelperTest, SigninFromWebstoreWithConfigSyncfirst) {
 }
 
 TEST_F(OneClickSigninHelperTest, ShowSigninBubbleAfterSigninComplete) {
-  CreateSigninManager(false, std::string());
-  EXPECT_CALL(*signin_manager_, IsAllowedUsername(_))
-      .WillRepeatedly(Return(true));
+  CreateSigninManager(false, "");
+  EXPECT_CALL(*signin_manager_, IsAllowedUsername(_)).
+        WillRepeatedly(Return(true));
 
   CreateProfileSyncServiceMock();
 
@@ -736,34 +725,31 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThread) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::CAN_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadIncognito) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(true));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadNoIOData) {
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, NULL));
+                valid_gaia_url_, "", &request_, NULL));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadBadURL) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
-  EXPECT_EQ(
-      OneClickSigninHelper::IGNORE_REQUEST,
-      OneClickSigninHelper::CanOfferOnIOThreadImpl(
-          GURL("https://foo.com/"), std::string(), &request_, io_data.get()));
   EXPECT_EQ(OneClickSigninHelper::IGNORE_REQUEST,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                GURL("http://accounts.google.com/"),
-                std::string(),
-                &request_,
-                io_data.get()));
+                GURL("https://foo.com/"), "", &request_, io_data.get()));
+  EXPECT_EQ(OneClickSigninHelper::IGNORE_REQUEST,
+            OneClickSigninHelper::CanOfferOnIOThreadImpl(
+                GURL("http://accounts.google.com/"), "",
+                &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadReferrer) {
@@ -810,7 +796,7 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadDisabled) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadSignedIn) {
@@ -820,7 +806,7 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadSignedIn) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadEmailNotAllowed) {
@@ -828,7 +814,7 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadEmailNotAllowed) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadEmailAlreadyUsed) {
@@ -841,7 +827,7 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadEmailAlreadyUsed) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadWithRejectedEmail) {
@@ -849,7 +835,7 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadWithRejectedEmail) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadNoSigninCookies) {
@@ -857,14 +843,14 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadNoSigninCookies) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
 
 TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadDisabledByPolicy) {
   scoped_ptr<TestProfileIOData> io_data(CreateTestProfileIOData(false));
   EXPECT_EQ(OneClickSigninHelper::CAN_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 
   // Simulate a policy disabling signin by writing kSigninAllowed directly.
   // We should not offer to sign in the browser.
@@ -872,7 +858,7 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadDisabledByPolicy) {
       prefs::kSigninAllowed, base::Value::CreateBooleanValue(false));
   EXPECT_EQ(OneClickSigninHelper::DONT_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 
   // Reset the preference.
   profile_->GetTestingPrefService()->SetManagedPref(
@@ -884,5 +870,5 @@ TEST_F(OneClickSigninHelperIOTest, CanOfferOnIOThreadDisabledByPolicy) {
       prefs::kSyncManaged, base::Value::CreateBooleanValue(true));
   EXPECT_EQ(OneClickSigninHelper::CAN_OFFER,
             OneClickSigninHelper::CanOfferOnIOThreadImpl(
-                valid_gaia_url_, std::string(), &request_, io_data.get()));
+                valid_gaia_url_, "", &request_, io_data.get()));
 }
diff --git a/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc b/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc
index 4115f18..4b003cf 100644
--- a/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc
+++ b/chrome/browser/ui/sync/tab_contents_synced_tab_delegate.cc
@@ -43,7 +43,7 @@ Profile* TabContentsSyncedTabDelegate::profile() const {
 std::string TabContentsSyncedTabDelegate::GetExtensionAppId() const {
   const scoped_refptr<const extensions::Extension> extension_app(
       extensions::TabHelper::FromWebContents(web_contents_)->extension_app());
-  return (extension_app.get() ? extension_app->id() : std::string());
+  return (extension_app.get() ? extension_app->id() : "");
 }
 
 int TabContentsSyncedTabDelegate::GetCurrentEntryIndex() const {
diff --git a/chrome/browser/ui/website_settings/website_settings.cc b/chrome/browser/ui/website_settings/website_settings.cc
index 8a37c39..daf7257 100644
--- a/chrome/browser/ui/website_settings/website_settings.cc
+++ b/chrome/browser/ui/website_settings/website_settings.cc
@@ -143,18 +143,12 @@ void WebsiteSettings::OnSitePermissionChanged(ContentSettingsType type,
       secondary_pattern = ContentSettingsPattern::Wildcard();
       // Set permission for both microphone and camera.
       content_settings_->SetContentSetting(
-          primary_pattern,
-          secondary_pattern,
-          CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC,
-          std::string(),
-          setting);
+          primary_pattern, secondary_pattern,
+          CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC, "", setting);
 
       content_settings_->SetContentSetting(
-          primary_pattern,
-          secondary_pattern,
-          CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA,
-          std::string(),
-          setting);
+          primary_pattern, secondary_pattern,
+          CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA, "", setting);
       break;
     }
     default:
@@ -173,7 +167,7 @@ void WebsiteSettings::OnSitePermissionChanged(ContentSettingsType type,
     // can not create media settings exceptions by hand.
     content_settings::SettingInfo info;
     scoped_ptr<Value> v(content_settings_->GetWebsiteSetting(
-        site_url_, site_url_, type, std::string(), &info));
+        site_url_, site_url_, type, "", &info));
     DCHECK(info.source == content_settings::SETTING_SOURCE_USER);
     ContentSettingsPattern::Relation r1 =
         info.primary_pattern.Compare(primary_pattern);
@@ -194,7 +188,7 @@ void WebsiteSettings::OnSitePermissionChanged(ContentSettingsType type,
     if (setting != CONTENT_SETTING_DEFAULT)
       value = Value::CreateIntegerValue(setting);
     content_settings_->SetWebsiteSetting(
-        primary_pattern, secondary_pattern, type, std::string(), value);
+        primary_pattern, secondary_pattern, type, "", value);
   }
 
   show_info_bar_ = true;
@@ -458,20 +452,14 @@ void WebsiteSettings::PresentSitePermissions() {
     content_settings::SettingInfo info;
     if (permission_info.type == CONTENT_SETTINGS_TYPE_MEDIASTREAM) {
       scoped_ptr<base::Value> mic_value(content_settings_->GetWebsiteSetting(
-          site_url_,
-          site_url_,
-          CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC,
-          std::string(),
-          &info));
+          site_url_, site_url_, CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC,
+          "", &info));
       ContentSetting mic_setting =
           content_settings::ValueToContentSetting(mic_value.get());
 
       scoped_ptr<base::Value> camera_value(content_settings_->GetWebsiteSetting(
-          site_url_,
-          site_url_,
-          CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA,
-          std::string(),
-          &info));
+          site_url_, site_url_, CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA,
+          "", &info));
       ContentSetting camera_setting =
           content_settings::ValueToContentSetting(camera_value.get());
 
@@ -481,7 +469,7 @@ void WebsiteSettings::PresentSitePermissions() {
         permission_info.setting = mic_setting;
     } else {
       scoped_ptr<Value> value(content_settings_->GetWebsiteSetting(
-          site_url_, site_url_, permission_info.type, std::string(), &info));
+          site_url_, site_url_, permission_info.type, "", &info));
       DCHECK(value.get());
       if (value->GetType() == Value::TYPE_INTEGER) {
         permission_info.setting =
diff --git a/chrome/browser/ui/website_settings/website_settings_unittest.cc b/chrome/browser/ui/website_settings/website_settings_unittest.cc
index 8f486af..4fe881a 100644
--- a/chrome/browser/ui/website_settings/website_settings_unittest.cc
+++ b/chrome/browser/ui/website_settings/website_settings_unittest.cc
@@ -165,22 +165,22 @@ TEST_F(WebsiteSettingsTest, OnPermissionsChanged) {
   HostContentSettingsMap* content_settings =
       profile()->GetHostContentSettingsMap();
   ContentSetting setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_POPUPS, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_POPUPS, "");
   EXPECT_EQ(setting, CONTENT_SETTING_BLOCK);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_PLUGINS, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_PLUGINS, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ALLOW);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_GEOLOCATION, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_GEOLOCATION, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ASK);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_NOTIFICATIONS, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_NOTIFICATIONS, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ASK);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ASK);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ASK);
 
   EXPECT_CALL(*mock_ui(), SetIdentityInfo(_));
@@ -212,22 +212,22 @@ TEST_F(WebsiteSettingsTest, OnPermissionsChanged) {
 
   // Verify that the site permissions were changed correctly.
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_POPUPS, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_POPUPS, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ALLOW);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_PLUGINS, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_PLUGINS, "");
   EXPECT_EQ(setting, CONTENT_SETTING_BLOCK);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_GEOLOCATION, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_GEOLOCATION, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ALLOW);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_NOTIFICATIONS, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_NOTIFICATIONS, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ALLOW);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ALLOW);
   setting = content_settings->GetContentSetting(
-      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA, std::string());
+      url(), url(), CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA, "");
   EXPECT_EQ(setting, CONTENT_SETTING_ALLOW);
 }
 
diff --git a/chrome/browser/ui/webui/about_ui.cc b/chrome/browser/ui/webui/about_ui.cc
index b2dc2ae..861d2be 100644
--- a/chrome/browser/ui/webui/about_ui.cc
+++ b/chrome/browser/ui/webui/about_ui.cc
@@ -785,21 +785,15 @@ std::string AboutSandbox() {
 
   data.append("<table>");
 
-  AboutSandboxRow(&data,
-                  std::string(),
-                  IDS_ABOUT_SANDBOX_SUID_SANDBOX,
+  AboutSandboxRow(&data, "", IDS_ABOUT_SANDBOX_SUID_SANDBOX,
                   status & content::kSandboxLinuxSUID);
   AboutSandboxRow(&data, "&nbsp;&nbsp;", IDS_ABOUT_SANDBOX_PID_NAMESPACES,
                   status & content::kSandboxLinuxPIDNS);
   AboutSandboxRow(&data, "&nbsp;&nbsp;", IDS_ABOUT_SANDBOX_NET_NAMESPACES,
                   status & content::kSandboxLinuxNetNS);
-  AboutSandboxRow(&data,
-                  std::string(),
-                  IDS_ABOUT_SANDBOX_SECCOMP_LEGACY_SANDBOX,
+  AboutSandboxRow(&data, "", IDS_ABOUT_SANDBOX_SECCOMP_LEGACY_SANDBOX,
                   status & content::kSandboxLinuxSeccompLegacy);
-  AboutSandboxRow(&data,
-                  std::string(),
-                  IDS_ABOUT_SANDBOX_SECCOMP_BPF_SANDBOX,
+  AboutSandboxRow(&data, "", IDS_ABOUT_SANDBOX_SECCOMP_BPF_SANDBOX,
                   status & content::kSandboxLinuxSeccompBpf);
 
   data.append("</table>");
diff --git a/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc b/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc
index 19e6404..0bfa286 100644
--- a/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc
+++ b/chrome/browser/ui/webui/downloads_dom_handler_browsertest.cc
@@ -147,7 +147,7 @@ IN_PROC_BROWSER_TEST_F(DownloadsDOMHandlerTest,
       base::FilePath(FILE_PATH_LITERAL("/path/to/file")),
       base::FilePath(FILE_PATH_LITERAL("/path/to/file")),
       url_chain,
-      GURL(std::string()),
+      GURL(""),
       current,
       current,
       128,
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
index 11ea684..bd3bc6f 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -930,14 +930,9 @@ void ExtensionSettingsHandler::HandleLoadUnpackedExtensionMessage(
   load_extension_dialog_ = ui::SelectFileDialog::Create(
       this, new ChromeSelectFilePolicy(web_ui()->GetWebContents()));
   load_extension_dialog_->SelectFile(
-      kSelectType,
-      select_title,
-      last_unpacked_directory_,
-      NULL,
-      kFileTypeIndex,
-      base::FilePath::StringType(),
-      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
-      NULL);
+      kSelectType, select_title, last_unpacked_directory_, NULL,
+      kFileTypeIndex, FILE_PATH_LITERAL(""),
+      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(), NULL);
 }
 
 void ExtensionSettingsHandler::ShowAlert(const std::string& message) {
diff --git a/chrome/browser/ui/webui/extensions/pack_extension_handler.cc b/chrome/browser/ui/webui/extensions/pack_extension_handler.cc
index d201c91..a69cd4d 100644
--- a/chrome/browser/ui/webui/extensions/pack_extension_handler.cc
+++ b/chrome/browser/ui/webui/extensions/pack_extension_handler.cc
@@ -184,12 +184,8 @@ void PackExtensionHandler::HandleSelectFilePathMessage(
   load_extension_dialog_ = ui::SelectFileDialog::Create(
       this, new ChromeSelectFilePolicy(web_ui()->GetWebContents()));
   load_extension_dialog_->SelectFile(
-      type,
-      select_title,
-      base::FilePath(),
-      &info,
-      file_type_index,
-      base::FilePath::StringType(),
+      type, select_title, base::FilePath(), &info, file_type_index,
+      FILE_PATH_LITERAL(""),
       web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
       NULL);
 }
diff --git a/chrome/browser/ui/webui/favicon_source.cc b/chrome/browser/ui/webui/favicon_source.cc
index 232b6eb..6864120 100644
--- a/chrome/browser/ui/webui/favicon_source.cc
+++ b/chrome/browser/ui/webui/favicon_source.cc
@@ -253,8 +253,10 @@ void FaviconSource::OnFaviconDataAvailable(
 
 void FaviconSource::SendDefaultResponse(
     const content::URLDataSource::GotDataCallback& callback) {
-  SendDefaultResponse(
-      IconRequest(callback, std::string(), 16, ui::SCALE_FACTOR_100P));
+  SendDefaultResponse(IconRequest(callback,
+                                  "",
+                                  16,
+                                  ui::SCALE_FACTOR_100P));
 }
 
 void FaviconSource::SendDefaultResponse(const IconRequest& icon_request) {
diff --git a/chrome/browser/ui/webui/feedback_ui.cc b/chrome/browser/ui/webui/feedback_ui.cc
index b28e065..3cb20bf 100644
--- a/chrome/browser/ui/webui/feedback_ui.cc
+++ b/chrome/browser/ui/webui/feedback_ui.cc
@@ -409,23 +409,23 @@ bool FeedbackHandler::Init() {
       std::string query_str = *it;
       if (StartsWithASCII(query_str, std::string(kSessionIDParameter), true)) {
         ReplaceFirstSubstringAfterOffset(
-            &query_str, 0, kSessionIDParameter, std::string());
+            &query_str, 0, kSessionIDParameter, "");
         if (!base::StringToInt(query_str, &session_id))
           return false;
       } else if (StartsWithASCII(*it, std::string(kTabIndexParameter), true)) {
         ReplaceFirstSubstringAfterOffset(
-            &query_str, 0, kTabIndexParameter, std::string());
+            &query_str, 0, kTabIndexParameter, "");
         if (!base::StringToInt(query_str, &index))
           return false;
       } else if (StartsWithASCII(*it, std::string(kCustomPageUrlParameter),
                                  true)) {
         ReplaceFirstSubstringAfterOffset(
-            &query_str, 0, kCustomPageUrlParameter, std::string());
+            &query_str, 0, kCustomPageUrlParameter, "");
         custom_page_url = query_str;
       } else if (StartsWithASCII(*it, std::string(kCategoryTagParameter),
                                  true)) {
         ReplaceFirstSubstringAfterOffset(
-            &query_str, 0, kCategoryTagParameter, std::string());
+            &query_str, 0, kCategoryTagParameter, "");
         category_tag_ = query_str;
 #if defined(OS_CHROMEOS)
       } else if (StartsWithASCII(*it, std::string(kTimestampParameter), true)) {
diff --git a/chrome/browser/ui/webui/inspect_ui.cc b/chrome/browser/ui/webui/inspect_ui.cc
index b98ea9e..b0b67c3 100644
--- a/chrome/browser/ui/webui/inspect_ui.cc
+++ b/chrome/browser/ui/webui/inspect_ui.cc
@@ -462,7 +462,7 @@ void InspectUI::OnAdbPages(
     targets.Append(target_data);
   }
 
-  std::string json_string;
+  std::string json_string = "";
   base::JSONWriter::Write(&targets, &json_string);
   callback.Run(base::RefCountedString::TakeString(&json_string));
 }
diff --git a/chrome/browser/ui/webui/instant_ui.cc b/chrome/browser/ui/webui/instant_ui.cc
index 23a255c..f84bf9a 100644
--- a/chrome/browser/ui/webui/instant_ui.cc
+++ b/chrome/browser/ui/webui/instant_ui.cc
@@ -169,7 +169,6 @@ InstantUI::InstantUI(content::WebUI* web_ui) : WebUIController(web_ui) {
 
 // static
 void InstantUI::RegisterUserPrefs(PrefRegistrySyncable* registry) {
-  registry->RegisterStringPref(prefs::kInstantUIZeroSuggestUrlPrefix,
-                               std::string(),
+  registry->RegisterStringPref(prefs::kInstantUIZeroSuggestUrlPrefix, "",
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
diff --git a/chrome/browser/ui/webui/net_internals/net_internals_ui.cc b/chrome/browser/ui/webui/net_internals/net_internals_ui.cc
index 0ac1324..cea9824 100644
--- a/chrome/browser/ui/webui/net_internals/net_internals_ui.cc
+++ b/chrome/browser/ui/webui/net_internals/net_internals_ui.cc
@@ -1409,7 +1409,7 @@ void NetInternalsMessageHandler::IOThreadImpl::OnGetSpdyStatus(
     next_protos_value = Value::CreateStringValue(
         JoinString(net::HttpStreamFactory::next_protos(), ','));
   } else {
-    next_protos_value = Value::CreateStringValue(std::string());
+    next_protos_value = Value::CreateStringValue("");
   }
   status_dict->Set("next_protos", next_protos_value);
 
diff --git a/chrome/browser/ui/webui/options/browser_options_handler.cc b/chrome/browser/ui/webui/options/browser_options_handler.cc
index 54c5c31..48f4f60 100644
--- a/chrome/browser/ui/webui/options/browser_options_handler.cc
+++ b/chrome/browser/ui/webui/options/browser_options_handler.cc
@@ -1194,11 +1194,8 @@ void BrowserOptionsHandler::HandleSelectDownloadLocation(
       ui::SelectFileDialog::SELECT_FOLDER,
       l10n_util::GetStringUTF16(IDS_OPTIONS_DOWNLOADLOCATION_BROWSE_TITLE),
       pref_service->GetFilePath(prefs::kDownloadDefaultDirectory),
-      &info,
-      0,
-      base::FilePath::StringType(),
-      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
-      NULL);
+      &info, 0, FILE_PATH_LITERAL(""),
+      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(), NULL);
 }
 
 void BrowserOptionsHandler::FileSelected(const base::FilePath& path, int index,
diff --git a/chrome/browser/ui/webui/options/certificate_manager_handler.cc b/chrome/browser/ui/webui/options/certificate_manager_handler.cc
index f30eaec..c1e18da 100644
--- a/chrome/browser/ui/webui/options/certificate_manager_handler.cc
+++ b/chrome/browser/ui/webui/options/certificate_manager_handler.cc
@@ -326,7 +326,7 @@ void CertificateManagerHandler::GetLocalizedValues(
       l10n_util::GetStringUTF16(IDS_CERT_MANAGER_DELETE_CA_DESCRIPTION));
   localized_strings->SetString("unknownCertsTabDeleteConfirm",
       l10n_util::GetStringUTF16(IDS_CERT_MANAGER_DELETE_UNKNOWN_FORMAT));
-  localized_strings->SetString("unknownCertsTabDeleteImpact", std::string());
+  localized_strings->SetString("unknownCertsTabDeleteImpact", "");
 
   // Certificate Restore overlay strings.
   localized_strings->SetString("certificateRestorePasswordDescription",
@@ -614,7 +614,7 @@ void CertificateManagerHandler::ExportPersonalPasswordSelected(
   chrome::UnlockCertSlotIfNecessary(
       selected_cert_list_[0].get(),
       chrome::kCryptoModulePasswordCertExport,
-      std::string(),  // unused.
+      "",  // unused.
       base::Bind(&CertificateManagerHandler::ExportPersonalSlotsUnlocked,
                  base::Unretained(this)));
 }
@@ -723,7 +723,7 @@ void CertificateManagerHandler::ImportPersonalFileRead(
   chrome::UnlockSlotsIfNecessary(
       modules,
       chrome::kCryptoModulePasswordCertImport,
-      std::string(),  // unused.
+      "",  // unused.
       base::Bind(&CertificateManagerHandler::ImportPersonalSlotUnlocked,
                  base::Unretained(this)));
 }
diff --git a/chrome/browser/ui/webui/options/content_settings_handler.cc b/chrome/browser/ui/webui/options/content_settings_handler.cc
index 549856b..85249bc 100644
--- a/chrome/browser/ui/webui/options/content_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/content_settings_handler.cc
@@ -123,7 +123,7 @@ std::string ContentSettingToString(ContentSetting setting) {
       NOTREACHED();
   }
 
-  return std::string();
+  return "";
 }
 
 ContentSetting ContentSettingFromString(const std::string& name) {
@@ -151,9 +151,8 @@ DictionaryValue* GetExceptionForPage(
   DictionaryValue* exception = new DictionaryValue();
   exception->SetString(kOrigin, pattern.ToString());
   exception->SetString(kEmbeddingOrigin,
-                       secondary_pattern == ContentSettingsPattern::Wildcard()
-                           ? std::string()
-                           : secondary_pattern.ToString());
+      secondary_pattern == ContentSettingsPattern::Wildcard() ? "" :
+          secondary_pattern.ToString());
   exception->SetString(kSetting, ContentSettingToString(setting));
   exception->SetString(kSource, provider_name);
   return exception;
@@ -605,7 +604,7 @@ void ContentSettingsHandler::UpdateMediaSettingsView() {
   media_ui_settings.SetString("askText", "mediaStreamAsk");
   media_ui_settings.SetString("blockText", "mediaStreamBlock");
   media_ui_settings.SetBoolean("showBubble", false);
-  media_ui_settings.SetString("bubbleText", std::string());
+  media_ui_settings.SetString("bubbleText", "");
 
   web_ui()->CallJavascriptFunction("ContentSettings.updateMediaUI",
                                    media_ui_settings);
@@ -1053,16 +1052,18 @@ void ContentSettingsHandler::RemoveMediaException(
       mode == "normal" ? GetContentSettingsMap() :
                          GetOTRContentSettingsMap();
   if (settings_map) {
-    settings_map->SetWebsiteSetting(ContentSettingsPattern::FromString(pattern),
-                                    ContentSettingsPattern::Wildcard(),
-                                    CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC,
-                                    std::string(),
-                                    NULL);
-    settings_map->SetWebsiteSetting(ContentSettingsPattern::FromString(pattern),
-                                    ContentSettingsPattern::Wildcard(),
-                                    CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA,
-                                    std::string(),
-                                    NULL);
+    settings_map->SetWebsiteSetting(
+        ContentSettingsPattern::FromString(pattern),
+        ContentSettingsPattern::Wildcard(),
+        CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC,
+        "",
+        NULL);
+    settings_map->SetWebsiteSetting(
+        ContentSettingsPattern::FromString(pattern),
+        ContentSettingsPattern::Wildcard(),
+        CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA,
+        "",
+        NULL);
   }
 }
 
@@ -1087,11 +1088,10 @@ void ContentSettingsHandler::RemoveExceptionFromHostContentSettingsMap(
   if (settings_map) {
     settings_map->SetWebsiteSetting(
         ContentSettingsPattern::FromString(pattern),
-        secondary_pattern.empty()
-            ? ContentSettingsPattern::Wildcard()
-            : ContentSettingsPattern::FromString(secondary_pattern),
+        secondary_pattern.empty() ? ContentSettingsPattern::Wildcard() :
+            ContentSettingsPattern::FromString(secondary_pattern),
         type,
-        std::string(),
+        "",
         NULL);
   }
 }
@@ -1259,7 +1259,7 @@ void ContentSettingsHandler::SetException(const ListValue* args) {
     settings_map->SetContentSetting(ContentSettingsPattern::FromString(pattern),
                                     ContentSettingsPattern::Wildcard(),
                                     type,
-                                    std::string(),
+                                    "",
                                     ContentSettingFromString(setting));
   }
 }
diff --git a/chrome/browser/ui/webui/options/font_settings_handler.cc b/chrome/browser/ui/webui/options/font_settings_handler.cc
index 558effc..61f1524 100644
--- a/chrome/browser/ui/webui/options/font_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/font_settings_handler.cc
@@ -188,8 +188,8 @@ void FontSettingsHandler::FontsListHasLoaded(
       option->Append(new base::StringValue(has_rtl_chars ? "rtl" : "ltr"));
     } else {
       // Add empty name/value to indicate a separator item.
-      option->Append(new base::StringValue(std::string()));
-      option->Append(new base::StringValue(std::string()));
+      option->Append(new base::StringValue(""));
+      option->Append(new base::StringValue(""));
     }
     encoding_list.Append(option);
   }
diff --git a/chrome/browser/ui/webui/options/managed_user_passphrase_handler.cc b/chrome/browser/ui/webui/options/managed_user_passphrase_handler.cc
index f3aac91..2090137 100644
--- a/chrome/browser/ui/webui/options/managed_user_passphrase_handler.cc
+++ b/chrome/browser/ui/webui/options/managed_user_passphrase_handler.cc
@@ -110,8 +110,8 @@ void ManagedUserPassphraseHandler::IsPassphraseSet(
 void ManagedUserPassphraseHandler::ResetPassphrase(
     const base::ListValue* args) {
   PrefService* pref_service = Profile::FromWebUI(web_ui())->GetPrefs();
-  pref_service->SetString(prefs::kManagedModeLocalPassphrase, std::string());
-  pref_service->SetString(prefs::kManagedModeLocalSalt, std::string());
+  pref_service->SetString(prefs::kManagedModeLocalPassphrase, "");
+  pref_service->SetString(prefs::kManagedModeLocalSalt, "");
 }
 
 void ManagedUserPassphraseHandler::SetLocalPassphrase(
diff --git a/chrome/browser/ui/webui/options/preferences_browsertest.cc b/chrome/browser/ui/webui/options/preferences_browsertest.cc
index 8dbc971..5839538 100644
--- a/chrome/browser/ui/webui/options/preferences_browsertest.cc
+++ b/chrome/browser/ui/webui/options/preferences_browsertest.cc
@@ -343,7 +343,7 @@ void PreferencesBrowserTest::VerifySetPref(const std::string& name,
   std::string observed_json;
   ASSERT_TRUE(content::ExecuteScriptAndExtractString(
       render_view_host_, javascript.str(), &observed_json));
-  VerifyObservedPref(observed_json, name, value, std::string(), false, !commit);
+  VerifyObservedPref(observed_json, name, value, "", false, !commit);
   VerifyAndClearExpectations();
 }
 
@@ -385,7 +385,7 @@ void PreferencesBrowserTest::VerifyCommit(const std::string& name,
 void PreferencesBrowserTest::VerifySetCommit(const std::string& name,
                                              const base::Value* value) {
   ExpectSetCommit(name, value);
-  VerifyCommit(name, value, std::string());
+  VerifyCommit(name, value, "");
   VerifyAndClearExpectations();
 }
 
@@ -476,8 +476,8 @@ IN_PROC_BROWSER_TEST_F(PreferencesBrowserTest, FetchPrefs) {
 
   // Verify notifications when default values are in effect.
   SetupJavaScriptTestEnvironment(pref_names_, &observed_json);
-  VerifyObservedPrefs(
-      observed_json, pref_names_, default_values_, std::string(), false, false);
+  VerifyObservedPrefs(observed_json, pref_names_, default_values_,
+                      "", false, false);
 
   // Verify notifications when recommended values are in effect.
   SetUserPolicies(policy_names_, non_default_values_,
@@ -497,12 +497,8 @@ IN_PROC_BROWSER_TEST_F(PreferencesBrowserTest, FetchPrefs) {
   ClearUserPolicies();
   SetUserValues(pref_names_, non_default_values_);
   SetupJavaScriptTestEnvironment(pref_names_, &observed_json);
-  VerifyObservedPrefs(observed_json,
-                      pref_names_,
-                      non_default_values_,
-                      std::string(),
-                      false,
-                      false);
+  VerifyObservedPrefs(observed_json, pref_names_, non_default_values_,
+                      "", false, false);
 }
 
 // Verifies that setting a user-modified pref value through the JavaScript
@@ -554,7 +550,7 @@ IN_PROC_BROWSER_TEST_F(PreferencesBrowserTest, DialogPrefsSetRollback) {
   ASSERT_NO_FATAL_FAILURE(SetupJavaScriptTestEnvironment(pref_names_, NULL));
   for (size_t i = 0; i < pref_names_.size(); ++i) {
     VerifySetPref(pref_names_[i], types_[i], non_default_values_[i], false);
-    VerifyRollback(pref_names_[i], default_values_[i], std::string());
+    VerifyRollback(pref_names_[i], default_values_[i], "");
   }
 
   // Verify behavior when recommended values are in effect.
@@ -596,7 +592,7 @@ IN_PROC_BROWSER_TEST_F(PreferencesBrowserTest, DialogPrefsClearRollback) {
   ASSERT_NO_FATAL_FAILURE(SetupJavaScriptTestEnvironment(pref_names_, NULL));
   for (size_t i = 0; i < pref_names_.size(); ++i) {
     VerifyClearPref(pref_names_[i], default_values_[i], false);
-    VerifyRollback(pref_names_[i], non_default_values_[i], std::string());
+    VerifyRollback(pref_names_[i], non_default_values_[i], "");
   }
 }
 
@@ -628,19 +624,15 @@ IN_PROC_BROWSER_TEST_F(PreferencesBrowserTest, NotificationsOnBackendChanges) {
   StartObserving();
   ClearUserPolicies();
   FinishObserving(&observed_json);
-  VerifyObservedPrefs(
-      observed_json, pref_names_, default_values_, std::string(), false, false);
+  VerifyObservedPrefs(observed_json, pref_names_, default_values_,
+                      "", false, false);
 
   // Verify notifications when user-modified values come into effect.
   StartObserving();
   SetUserValues(pref_names_, non_default_values_);
   FinishObserving(&observed_json);
-  VerifyObservedPrefs(observed_json,
-                      pref_names_,
-                      non_default_values_,
-                      std::string(),
-                      false,
-                      false);
+  VerifyObservedPrefs(observed_json, pref_names_, non_default_values_,
+                      "", false, false);
 }
 
 #if defined(OS_CHROMEOS)
diff --git a/chrome/browser/ui/webui/policy_ui_browsertest.cc b/chrome/browser/ui/webui/policy_ui_browsertest.cc
index 6293fef..6af1613 100644
--- a/chrome/browser/ui/webui/policy_ui_browsertest.cc
+++ b/chrome/browser/ui/webui/policy_ui_browsertest.cc
@@ -43,7 +43,7 @@ std::vector<std::string> PopulateExpectedPolicy(
         metadata->scope == policy::POLICY_SCOPE_MACHINE ?
             IDS_POLICY_SCOPE_DEVICE : IDS_POLICY_SCOPE_USER));
   } else {
-    expected_policy.push_back(std::string());
+    expected_policy.push_back("");
   }
 
   // Populate expected level.
@@ -52,7 +52,7 @@ std::vector<std::string> PopulateExpectedPolicy(
         metadata->level == policy::POLICY_LEVEL_RECOMMENDED ?
             IDS_POLICY_LEVEL_RECOMMENDED : IDS_POLICY_LEVEL_MANDATORY));
   } else {
-    expected_policy.push_back(std::string());
+    expected_policy.push_back("");
   }
 
   // Populate expected policy name.
@@ -178,7 +178,7 @@ IN_PROC_BROWSER_TEST_F(PolicyUITest, SendPolicyNames) {
   for (const policy::PolicyDefinitionList::Entry* policy = policies->begin;
       policy != policies->end; ++policy) {
     expected_policies.push_back(
-        PopulateExpectedPolicy(policy->name, std::string(), NULL, false));
+        PopulateExpectedPolicy(policy->name, "", NULL, false));
   }
 
   // Retrieve the contents of the policy table from the UI and verify that it
@@ -240,8 +240,7 @@ IN_PROC_BROWSER_TEST_F(PolicyUITest, SendPolicyValues) {
        policy != policies->end; ++policy) {
     std::map<std::string, std::string>::const_iterator it =
         expected_values.find(policy->name);
-    const std::string value =
-        it == expected_values.end() ? std::string() : it->second;
+    const std::string value = it == expected_values.end() ? "" : it->second;
     const policy::PolicyMap::Entry* metadata = values.Get(policy->name);
     expected_policies.insert(
         metadata ? expected_policies.begin() + first_unset_position++ :
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
index 7899260..0525da3 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -866,7 +866,7 @@ void PrintPreviewHandler::SelectFile(const base::FilePath& default_filename) {
       sticky_settings->save_path()->Append(default_filename),
       &file_type_info,
       0,
-      base::FilePath::StringType(),
+      FILE_PATH_LITERAL(""),
       platform_util::GetTopLevel(
           preview_web_contents()->GetView()->GetNativeView()),
       NULL);
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_ui.cc b/chrome/browser/ui/webui/print_preview/print_preview_ui.cc
index 4e10802..52cbe91 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_ui.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_ui.cc
@@ -571,7 +571,7 @@ void PrintPreviewUI::OnClosePrintPreviewDialog() {
   ConstrainedWebDialogDelegate* delegate = GetConstrainedDelegate();
   if (!delegate)
     return;
-  delegate->GetWebDialogDelegate()->OnDialogClosed(std::string());
+  delegate->GetWebDialogDelegate()->OnDialogClosed("");
   delegate->OnDialogCloseFromWebUI();
 }
 
diff --git a/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog_unittest.cc b/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog_unittest.cc
index cd6f5fe..e24b730 100644
--- a/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog_unittest.cc
+++ b/chrome/browser/ui/webui/signin/profile_signin_confirmation_dialog_unittest.cc
@@ -142,11 +142,11 @@ class ProfileSigninConfirmationDialogTest : public testing::Test {
                                    false);
 
     // Create a dialog, but don't display it.
-    dialog_ = new ProfileSigninConfirmationDialog(profile_.get(),
-                                                  std::string(),
-                                                  base::Bind(&base::DoNothing),
-                                                  base::Bind(&base::DoNothing),
-                                                  base::Bind(&base::DoNothing));
+    dialog_ = new ProfileSigninConfirmationDialog(
+        profile_.get(), "",
+        base::Bind(&base::DoNothing),
+        base::Bind(&base::DoNothing),
+        base::Bind(&base::DoNothing));
   }
 
   virtual void TearDown() OVERRIDE {
@@ -204,10 +204,10 @@ TEST_F(ProfileSigninConfirmationDialogTest, PromptForNewProfile_Extensions) {
               &ProfileSigninConfirmationDialog::CheckShouldPromptForNewProfile,
               base::Unretained(dialog_))));
 
-  scoped_refptr<extensions::Extension> extension =
-      CreateExtension("foo", std::string());
+  scoped_refptr<extensions::Extension> extension = CreateExtension("foo", "");
   extensions->extension_prefs()->AddGrantedPermissions(
-      extension->id(), make_scoped_refptr(new extensions::PermissionSet));
+      extension->id(),
+      make_scoped_refptr(new extensions::PermissionSet));
   extensions->AddExtension(extension);
   EXPECT_TRUE(
       GetCallbackResult(
diff --git a/chrome/browser/ui/webui/sync_setup_handler_unittest.cc b/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
index 19f2d0e..f958519 100644
--- a/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler_unittest.cc
@@ -457,13 +457,8 @@ TEST_P(SyncSetupHandlerTest, DisplayBasicLogin) {
     // Now make sure that the appropriate params are being passed.
     DictionaryValue* dictionary;
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
-    CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
-                           false,
-                           GoogleServiceAuthError::NONE,
-                           std::string(),
-                           true,
-                           std::string());
+    CheckShowSyncSetupArgs(
+        dictionary, "", false, GoogleServiceAuthError::NONE, "", true, "");
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -499,13 +494,8 @@ TEST_P(SyncSetupHandlerTest, DisplayForceLogin) {
     // Now make sure that the appropriate params are being passed.
     DictionaryValue* dictionary;
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
-    CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
-                           false,
-                           GoogleServiceAuthError::NONE,
-                           std::string(),
-                           true,
-                           std::string());
+    CheckShowSyncSetupArgs(
+        dictionary, "", false, GoogleServiceAuthError::NONE, "", true, "");
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -689,7 +679,7 @@ TEST_P(SyncSetupHandlerTest, HandleGaiaAuthFailure) {
 
   if (!SyncPromoUI::UseWebBasedSigninFlow()) {
     // Fake a failed signin attempt.
-    handler_->TryLogin(kTestUser, kTestPassword, std::string(), std::string());
+    handler_->TryLogin(kTestUser, kTestPassword, "", "");
     GoogleServiceAuthError error(
         GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS);
     handler_->SigninFailed(error);
@@ -705,13 +695,9 @@ TEST_P(SyncSetupHandlerTest, HandleGaiaAuthFailure) {
     // Now make sure that the appropriate params are being passed.
     DictionaryValue* dictionary;
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
-    CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
-                           false,
-                           GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS,
-                           kTestUser,
-                           true,
-                           std::string());
+    CheckShowSyncSetupArgs(
+        dictionary, "", false, GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS,
+        kTestUser, true, "");
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -732,7 +718,7 @@ TEST_P(SyncSetupHandlerTest, HandleCaptcha) {
 
   if (!SyncPromoUI::UseWebBasedSigninFlow()) {
     // Fake a failed signin attempt that requires a captcha.
-    handler_->TryLogin(kTestUser, kTestPassword, std::string(), std::string());
+    handler_->TryLogin(kTestUser, kTestPassword, "", "");
     GoogleServiceAuthError error =
         GoogleServiceAuthError::FromClientLoginCaptchaChallenge(
             "token", GURL(kTestCaptchaImageUrl), GURL(kTestCaptchaUnlockUrl));
@@ -748,13 +734,9 @@ TEST_P(SyncSetupHandlerTest, HandleCaptcha) {
     // Now make sure that the appropriate params are being passed.
     DictionaryValue* dictionary;
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
-    CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
-                           false,
-                           GoogleServiceAuthError::CAPTCHA_REQUIRED,
-                           kTestUser,
-                           true,
-                           kTestCaptchaImageUrl);
+    CheckShowSyncSetupArgs(
+        dictionary, "", false, GoogleServiceAuthError::CAPTCHA_REQUIRED,
+        kTestUser, true, kTestCaptchaImageUrl);
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -776,7 +758,7 @@ TEST_P(SyncSetupHandlerTest, UnrecoverableErrorInitializingSync) {
     ASSERT_EQ(1U, web_ui_.call_data().size());
     // Fake a successful GAIA request (gaia credentials valid, but signin not
     // complete yet).
-    handler_->TryLogin(kTestUser, kTestPassword, std::string(), std::string());
+    handler_->TryLogin(kTestUser, kTestPassword, "", "");
     handler_->GaiaCredentialsValid();
     ASSERT_EQ(2U, web_ui_.call_data().size());
     EXPECT_EQ("SyncSetupOverlay.showSuccessAndSettingUp",
@@ -798,13 +780,9 @@ TEST_P(SyncSetupHandlerTest, UnrecoverableErrorInitializingSync) {
     // Now make sure that the appropriate params are being passed.
     DictionaryValue* dictionary;
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
-    CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
-                           true,
-                           GoogleServiceAuthError::NONE,
-                           kTestUser,
-                           true,
-                           std::string());
+    CheckShowSyncSetupArgs(
+        dictionary, "", true, GoogleServiceAuthError::NONE,
+        kTestUser, true, "");
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -825,7 +803,7 @@ TEST_P(SyncSetupHandlerTest, GaiaErrorInitializingSync) {
     ASSERT_EQ(1U, web_ui_.call_data().size());
     // Fake a successful GAIA request (gaia credentials valid, but signin not
     // complete yet).
-    handler_->TryLogin(kTestUser, kTestPassword, std::string(), std::string());
+    handler_->TryLogin(kTestUser, kTestPassword, "", "");
     handler_->GaiaCredentialsValid();
     ASSERT_EQ(2U, web_ui_.call_data().size());
     EXPECT_EQ("SyncSetupOverlay.showSuccessAndSettingUp",
@@ -848,13 +826,9 @@ TEST_P(SyncSetupHandlerTest, GaiaErrorInitializingSync) {
     // Now make sure that the appropriate params are being passed.
     DictionaryValue* dictionary;
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
-    CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
-                           false,
-                           GoogleServiceAuthError::SERVICE_UNAVAILABLE,
-                           kTestUser,
-                           true,
-                           std::string());
+    CheckShowSyncSetupArgs(
+        dictionary, "", false, GoogleServiceAuthError::SERVICE_UNAVAILABLE,
+        kTestUser, true, "");
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -863,7 +837,7 @@ TEST_P(SyncSetupHandlerTest, GaiaErrorInitializingSync) {
 
 TEST_P(SyncSetupHandlerTest, TestSyncEverything) {
   std::string args = GetConfiguration(
-      NULL, SYNC_ALL_DATA, GetAllTypes(), std::string(), ENCRYPT_PASSWORDS);
+      NULL, SYNC_ALL_DATA, GetAllTypes(), "", ENCRYPT_PASSWORDS);
   ListValue list_args;
   list_args.Append(new StringValue(args));
   EXPECT_CALL(*mock_pss_, IsPassphraseRequiredForDecryption())
@@ -881,7 +855,7 @@ TEST_P(SyncSetupHandlerTest, TestSyncEverything) {
 
 TEST_P(SyncSetupHandlerTest, TurnOnEncryptAll) {
   std::string args = GetConfiguration(
-      NULL, SYNC_ALL_DATA, GetAllTypes(), std::string(), ENCRYPT_ALL_DATA);
+      NULL, SYNC_ALL_DATA, GetAllTypes(), "", ENCRYPT_ALL_DATA);
   ListValue list_args;
   list_args.Append(new StringValue(args));
   EXPECT_CALL(*mock_pss_, IsPassphraseRequiredForDecryption())
@@ -900,7 +874,7 @@ TEST_P(SyncSetupHandlerTest, TurnOnEncryptAll) {
 
 TEST_P(SyncSetupHandlerTest, TestPassphraseStillRequired) {
   std::string args = GetConfiguration(
-      NULL, SYNC_ALL_DATA, GetAllTypes(), std::string(), ENCRYPT_PASSWORDS);
+      NULL, SYNC_ALL_DATA, GetAllTypes(), "", ENCRYPT_PASSWORDS);
   ListValue list_args;
   list_args.Append(new StringValue(args));
   EXPECT_CALL(*mock_pss_, IsPassphraseRequiredForDecryption())
@@ -1016,11 +990,8 @@ TEST_P(SyncSetupHandlerTest, TestSyncIndividualTypes) {
   for (it = user_selectable_types.First(); it.Good(); it.Inc()) {
     syncer::ModelTypeSet type_to_set;
     type_to_set.Put(it.Get());
-    std::string args = GetConfiguration(NULL,
-                                        CHOOSE_WHAT_TO_SYNC,
-                                        type_to_set,
-                                        std::string(),
-                                        ENCRYPT_PASSWORDS);
+    std::string args = GetConfiguration(
+        NULL, CHOOSE_WHAT_TO_SYNC, type_to_set, "", ENCRYPT_PASSWORDS);
     ListValue list_args;
     list_args.Append(new StringValue(args));
     EXPECT_CALL(*mock_pss_, IsPassphraseRequiredForDecryption())
@@ -1039,11 +1010,8 @@ TEST_P(SyncSetupHandlerTest, TestSyncIndividualTypes) {
 }
 
 TEST_P(SyncSetupHandlerTest, TestSyncAllManually) {
-  std::string args = GetConfiguration(NULL,
-                                      CHOOSE_WHAT_TO_SYNC,
-                                      GetAllTypes(),
-                                      std::string(),
-                                      ENCRYPT_PASSWORDS);
+  std::string args = GetConfiguration(
+      NULL, CHOOSE_WHAT_TO_SYNC, GetAllTypes(), "", ENCRYPT_PASSWORDS);
   ListValue list_args;
   list_args.Append(new StringValue(args));
   EXPECT_CALL(*mock_pss_, IsPassphraseRequiredForDecryption())
@@ -1106,12 +1074,12 @@ TEST_P(SyncSetupHandlerTest, ShowSyncSetupWithAuthError) {
     ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
     // We should display a login screen with a non-editable username filled in.
     CheckShowSyncSetupArgs(dictionary,
-                           std::string(),
+                           "",
                            false,
                            GoogleServiceAuthError::NONE,
                            kTestUser,
                            false,
-                           std::string());
+                           "");
   } else {
     ASSERT_FALSE(handler_->is_configuring_sync());
     ASSERT_TRUE(handler_->have_signin_tracker());
@@ -1276,9 +1244,9 @@ TEST_P(SyncSetupHandlerTest, SubmitAuthWithInvalidUsername) {
   DictionaryValue args;
   args.SetString("user", "user@not_allowed.com");
   args.SetString("pass", "password");
-  args.SetString("captcha", std::string());
-  args.SetString("otp", std::string());
-  args.SetString("accessCode", std::string());
+  args.SetString("captcha", "");
+  args.SetString("otp", "");
+  args.SetString("accessCode", "");
   std::string json;
   base::JSONWriter::Write(&args, &json);
   ListValue list_args;
@@ -1299,13 +1267,8 @@ TEST_P(SyncSetupHandlerTest, SubmitAuthWithInvalidUsername) {
   DictionaryValue* dictionary;
   ASSERT_TRUE(data.arg2->GetAsDictionary(&dictionary));
   std::string err = l10n_util::GetStringUTF8(IDS_SYNC_LOGIN_NAME_PROHIBITED);
-  CheckShowSyncSetupArgs(dictionary,
-                         err,
-                         false,
-                         GoogleServiceAuthError::NONE,
-                         std::string(),
-                         true,
-                         std::string());
+  CheckShowSyncSetupArgs(
+      dictionary, err, false, GoogleServiceAuthError::NONE, "", true, "");
   handler_->CloseSyncSetup();
   EXPECT_EQ(NULL,
             LoginUIServiceFactory::GetForProfile(
diff --git a/chrome/browser/ui/webui/version_ui.cc b/chrome/browser/ui/webui/version_ui.cc
index 6497ae0..678492a 100644
--- a/chrome/browser/ui/webui/version_ui.cc
+++ b/chrome/browser/ui/webui/version_ui.cc
@@ -92,7 +92,7 @@ content::WebUIDataSource* CreateVersionUIDataSource(Profile* profile) {
   html_source->AddString("command_line",
       WideToUTF16(CommandLine::ForCurrentProcess()->GetCommandLineString()));
 #elif defined(OS_POSIX)
-  std::string command_line;
+  std::string command_line = "";
   typedef std::vector<std::string> ArgvList;
   const ArgvList& argv = CommandLine::ForCurrentProcess()->argv();
   for (ArgvList::const_iterator iter = argv.begin(); iter != argv.end(); iter++)
diff --git a/chrome/browser/value_store/leveldb_value_store.cc b/chrome/browser/value_store/leveldb_value_store.cc
index bad05dd..47ad0c0 100644
--- a/chrome/browser/value_store/leveldb_value_store.cc
+++ b/chrome/browser/value_store/leveldb_value_store.cc
@@ -334,7 +334,7 @@ std::string LeveldbValueStore::EnsureDbIsOpen() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
   if (db_.get())
-    return std::string();
+    return "";
 
 #if defined(OS_POSIX)
   std::string os_path(db_path_.value());
@@ -356,7 +356,7 @@ std::string LeveldbValueStore::EnsureDbIsOpen() {
   }
 
   db_.reset(db);
-  return std::string();
+  return "";
 }
 
 std::string LeveldbValueStore::ReadFromDb(
@@ -371,7 +371,7 @@ std::string LeveldbValueStore::ReadFromDb(
   if (s.IsNotFound()) {
     // Despite there being no value, it was still a success.
     // Check this first because ok() is false on IsNotFound.
-    return std::string();
+    return "";
   }
 
   if (!s.ok())
@@ -384,7 +384,7 @@ std::string LeveldbValueStore::ReadFromDb(
   }
 
   setting->reset(value);
-  return std::string();
+  return "";
 }
 
 std::string LeveldbValueStore::AddToBatch(
@@ -410,16 +410,16 @@ std::string LeveldbValueStore::AddToBatch(
     batch->Put(key, value_as_json);
   }
 
-  return std::string();
+  return "";
 }
 
 std::string LeveldbValueStore::WriteToDb(leveldb::WriteBatch* batch) {
   leveldb::Status status = db_->Write(leveldb::WriteOptions(), batch);
   if (status.IsNotFound()) {
     NOTREACHED() << "IsNotFound() but writing?!";
-    return std::string();
+    return "";
   }
-  return status.ok() ? std::string() : status.ToString();
+  return status.ok() ? "" : status.ToString();
 }
 
 bool LeveldbValueStore::IsEmpty() {
diff --git a/chrome/browser/web_applications/web_app_unittest.cc b/chrome/browser/web_applications/web_app_unittest.cc
index 149f62b..0bd1c01 100644
--- a/chrome/browser/web_applications/web_app_unittest.cc
+++ b/chrome/browser/web_applications/web_app_unittest.cc
@@ -71,8 +71,9 @@ TEST_F(WebApplicationTest, AppDirWithId) {
 TEST_F(WebApplicationTest, AppDirWithUrl) {
   base::FilePath profile_path(FILE_PATH_LITERAL("profile"));
   base::FilePath result(web_app::GetWebAppDataDirectory(
-      profile_path, std::string(), GURL("http://example.com")));
+      profile_path, "", GURL("http://example.com")));
   base::FilePath expected = profile_path.AppendASCII("Web Applications")
-      .AppendASCII("example.com").AppendASCII("http_80");
+                                  .AppendASCII("example.com")
+                                  .AppendASCII("http_80");
   EXPECT_EQ(expected, result);
 }
diff --git a/chrome/browser/webdata/keyword_table.cc b/chrome/browser/webdata/keyword_table.cc
index 10d224e..956d60b 100644
--- a/chrome/browser/webdata/keyword_table.cc
+++ b/chrome/browser/webdata/keyword_table.cc
@@ -388,7 +388,7 @@ bool KeywordTable::MigrateToVersion45RemoveLogoIDAndAutogenerateColumns() {
   // Migrate the keywords backup table as well.
   if (!MigrateKeywordsTableForVersion45("keywords_backup") ||
       !meta_table_->SetValue("Default Search Provider ID Backup Signature",
-                             std::string()))
+                             ""))
     return false;
 
   return transaction.Commit();
@@ -409,7 +409,7 @@ bool KeywordTable::MigrateToVersion47AddAlternateURLsColumn() {
   if (!db_->Execute("ALTER TABLE keywords_backup ADD COLUMN "
                     "alternate_urls VARCHAR DEFAULT ''") ||
       !meta_table_->SetValue("Default Search Provider ID Backup Signature",
-                             std::string()))
+                             ""))
     return false;
 
   return transaction.Commit();
diff --git a/chrome/browser/webdata/token_service_table_unittest.cc b/chrome/browser/webdata/token_service_table_unittest.cc
index 3c60ccf..db409f8 100644
--- a/chrome/browser/webdata/token_service_table_unittest.cc
+++ b/chrome/browser/webdata/token_service_table_unittest.cc
@@ -89,7 +89,7 @@ TEST_F(TokenServiceTableTest, MAYBE_TokenServiceGetSet) {
   out_map.clear();
 
   // try blanking it - won't remove it from the db though!
-  EXPECT_TRUE(table_->SetTokenForService(service, std::string()));
+  EXPECT_TRUE(table_->SetTokenForService(service, ""));
   EXPECT_TRUE(table_->GetAllTokens(&out_map));
   EXPECT_EQ(out_map.find(service)->second, "");
   out_map.clear();
diff --git a/chrome/common/child_process_logging_posix.cc b/chrome/common/child_process_logging_posix.cc
index 496103e..1690cd5 100644
--- a/chrome/common/child_process_logging_posix.cc
+++ b/chrome/common/child_process_logging_posix.cc
@@ -66,7 +66,7 @@ void SetActiveURL(const GURL& url) {
 
 void SetClientId(const std::string& client_id) {
   std::string str(client_id);
-  ReplaceSubstringsAfterOffset(&str, 0, "-", std::string());
+  ReplaceSubstringsAfterOffset(&str, 0, "-", "");
 
   if (str.empty())
     return;
diff --git a/chrome/common/content_settings_helper.cc b/chrome/common/content_settings_helper.cc
index 68e8d40..306cbe7 100644
--- a/chrome/common/content_settings_helper.cc
+++ b/chrome/common/content_settings_helper.cc
@@ -12,14 +12,11 @@
 namespace content_settings_helper {
 
 std::string OriginToString(const GURL& origin) {
-  std::string port_component(origin.IntPort() != url_parse::PORT_UNSPECIFIED
-                                 ? ":" + origin.port()
-                                 : std::string());
-  std::string scheme_component(!origin.SchemeIs(chrome::kHttpScheme)
-                                   ? origin.scheme() +
-                                     content::kStandardSchemeSeparator
-                                   : std::string());
-   return scheme_component + origin.host() + port_component;
+   std::string port_component(origin.IntPort() != url_parse::PORT_UNSPECIFIED ?
+      ":" + origin.port() : "");
+  std::string scheme_component(!origin.SchemeIs(chrome::kHttpScheme) ?
+      origin.scheme() + content::kStandardSchemeSeparator : "");
+  return scheme_component + origin.host() + port_component;
 }
 
 string16 OriginToString16(const GURL& origin) {
diff --git a/chrome/common/content_settings_pattern.cc b/chrome/common/content_settings_pattern.cc
index ee02312..9153de6 100644
--- a/chrome/common/content_settings_pattern.cc
+++ b/chrome/common/content_settings_pattern.cc
@@ -26,7 +26,7 @@ std::string GetDefaultPort(const std::string& scheme) {
     return "80";
   if (scheme == chrome::kHttpsScheme)
     return "443";
-  return std::string();
+  return "";
 }
 
 // Returns true if |sub_domain| is a sub domain or equls |domain|.  E.g.
@@ -501,7 +501,7 @@ const std::string ContentSettingsPattern::ToString() const {
   if (IsValid())
     return content_settings::PatternParser::ToString(parts_);
   else
-    return std::string();
+    return "";
 }
 
 ContentSettingsPattern::Relation ContentSettingsPattern::Compare(
diff --git a/chrome/common/content_settings_pattern_parser.cc b/chrome/common/content_settings_pattern_parser.cc
index 73da479..2f823cc 100644
--- a/chrome/common/content_settings_pattern_parser.cc
+++ b/chrome/common/content_settings_pattern_parser.cc
@@ -198,7 +198,7 @@ std::string PatternParser::ToString(
       parts.is_port_wildcard)
     return "*";
 
-  std::string str;
+  std::string str = "";
   if (!parts.is_scheme_wildcard)
     str += parts.scheme + content::kStandardSchemeSeparator;
 
diff --git a/chrome/common/content_settings_pattern_unittest.cc b/chrome/common/content_settings_pattern_unittest.cc
index c1c1e37..921f97b 100644
--- a/chrome/common/content_settings_pattern_unittest.cc
+++ b/chrome/common/content_settings_pattern_unittest.cc
@@ -420,8 +420,8 @@ TEST(ContentSettingsPatternTest, InvalidPatterns) {
   EXPECT_STREQ("", ContentSettingsPattern().ToString().c_str());
 
   // Empty pattern string
-  EXPECT_FALSE(Pattern(std::string()).IsValid());
-  EXPECT_STREQ("", Pattern(std::string()).ToString().c_str());
+  EXPECT_FALSE(Pattern("").IsValid());
+  EXPECT_STREQ("", Pattern("").ToString().c_str());
 
   // Pattern strings with invalid scheme part.
   EXPECT_FALSE(Pattern("ftp://myhost.org").IsValid());
@@ -630,7 +630,8 @@ TEST(ContentSettingsPatternTest, PatternSupport_Legacy) {
   EXPECT_TRUE(
       Pattern("file:///tmp/test.html").Matches(
               GURL("file:///tmp/test.html")));
-  EXPECT_FALSE(Pattern(std::string()).Matches(GURL("http://www.example.com/")));
+  EXPECT_FALSE(Pattern("").Matches(
+               GURL("http://www.example.com/")));
   EXPECT_FALSE(Pattern("[*.]example.com").Matches(
                GURL("http://example.org/")));
   EXPECT_FALSE(Pattern("example.com").Matches(
diff --git a/chrome/common/extensions/api/commands/commands_handler.cc b/chrome/common/extensions/api/commands/commands_handler.cc
index b5ed3c4..309a204 100644
--- a/chrome/common/extensions/api/commands/commands_handler.cc
+++ b/chrome/common/extensions/api/commands/commands_handler.cc
@@ -137,10 +137,8 @@ void CommandsHandler::MaybeSetBrowserActionDefault(const Extension* extension,
                                                    CommandsInfo* info) {
   if (extension->manifest()->HasKey(keys::kBrowserAction) &&
       !info->browser_action_command.get()) {
-    info->browser_action_command.reset(
-        new Command(extension_manifest_values::kBrowserActionCommandEvent,
-                    string16(),
-                    std::string()));
+    info->browser_action_command.reset(new Command(
+        extension_manifest_values::kBrowserActionCommandEvent, string16(), ""));
   }
 }
 
diff --git a/chrome/common/extensions/api/extension_action/browser_action_manifest_unittest.cc b/chrome/common/extensions/api/extension_action/browser_action_manifest_unittest.cc
index ac5040c..84277176 100644
--- a/chrome/common/extensions/api/extension_action/browser_action_manifest_unittest.cc
+++ b/chrome/common/extensions/api/extension_action/browser_action_manifest_unittest.cc
@@ -100,13 +100,15 @@ TEST_F(BrowserActionManifestTest,
 TEST_F(BrowserActionManifestTest,
        BrowserActionManifestIcons_InvalidDefaultIcon) {
   scoped_ptr<DictionaryValue> manifest_value = DictionaryBuilder()
-      .Set("name", "Invalid default icon").Set("version", "1.0.0")
+      .Set("name", "Invalid default icon")
+      .Set("version", "1.0.0")
       .Set("manifest_version", 2)
-      .Set("browser_action",
-           DictionaryBuilder().Set(
-               "default_icon",
-               DictionaryBuilder().Set("19", std::string())  // Invalid value.
-                   .Set("24", "icon24.png").Set("38", "icon38.png"))).Build();
+      .Set("browser_action", DictionaryBuilder()
+          .Set("default_icon", DictionaryBuilder()
+              .Set("19", "")  // Invalid value.
+              .Set("24", "icon24.png")
+              .Set("38", "icon38.png")))
+     .Build();
 
   string16 error = ErrorUtils::FormatErrorMessageUTF16(
       errors::kInvalidIconPath, "19");
diff --git a/chrome/common/extensions/api/extension_api.cc b/chrome/common/extensions/api/extension_api.cc
index 97a2fdd..b1095a4 100644
--- a/chrome/common/extensions/api/extension_api.cc
+++ b/chrome/common/extensions/api/extension_api.cc
@@ -426,11 +426,10 @@ Feature::Availability ExtensionAPI::IsAvailable(const std::string& full_name,
 
   // Check APIs not using the feature system first.
   if (!feature) {
-    return IsNonFeatureAPIAvailable(api_name, context, extension, url)
-               ? Feature::CreateAvailability(Feature::IS_AVAILABLE,
-                                             std::string())
-               : Feature::CreateAvailability(Feature::INVALID_CONTEXT,
-                                             kUnavailableMessage);
+    return IsNonFeatureAPIAvailable(api_name, context, extension, url) ?
+        Feature::CreateAvailability(Feature::IS_AVAILABLE, "") :
+        Feature::CreateAvailability(Feature::INVALID_CONTEXT,
+                                    kUnavailableMessage);
   }
 
   Feature::Availability availability =
@@ -446,7 +445,7 @@ Feature::Availability ExtensionAPI::IsAvailable(const std::string& full_name,
       return dependency_availability;
   }
 
-  return Feature::CreateAvailability(Feature::IS_AVAILABLE, std::string());
+  return Feature::CreateAvailability(Feature::IS_AVAILABLE, "");
 }
 
 bool ExtensionAPI::IsPrivileged(const std::string& full_name) {
@@ -635,7 +634,7 @@ std::string ExtensionAPI::GetAPINameFromFullName(const std::string& full_name,
   }
 
   *child_name = "";
-  return std::string();
+  return "";
 }
 
 bool ExtensionAPI::IsAPIAllowed(const std::string& name,
diff --git a/chrome/common/extensions/api/extension_api_unittest.cc b/chrome/common/extensions/api/extension_api_unittest.cc
index f980b57..98830ea 100644
--- a/chrome/common/extensions/api/extension_api_unittest.cc
+++ b/chrome/common/extensions/api/extension_api_unittest.cc
@@ -97,7 +97,7 @@ TEST_F(ExtensionAPITest, IsPrivileged) {
   EXPECT_TRUE(extension_api->IsPrivileged("runtime.lastError"));
 
   // Default unknown names to privileged for paranoia's sake.
-  EXPECT_TRUE(extension_api->IsPrivileged(std::string()));
+  EXPECT_TRUE(extension_api->IsPrivileged(""));
   EXPECT_TRUE(extension_api->IsPrivileged("<unknown-namespace>"));
   EXPECT_TRUE(extension_api->IsPrivileged("extension.<unknown-member>"));
 
@@ -224,8 +224,8 @@ TEST(ExtensionAPI, APIFeatures) {
 TEST_F(ExtensionAPITest, LazyGetSchema) {
   scoped_ptr<ExtensionAPI> apis(ExtensionAPI::CreateWithDefaultConfiguration());
 
-  EXPECT_EQ(NULL, apis->GetSchema(std::string()));
-  EXPECT_EQ(NULL, apis->GetSchema(std::string()));
+  EXPECT_EQ(NULL, apis->GetSchema(""));
+  EXPECT_EQ(NULL, apis->GetSchema(""));
   EXPECT_EQ(NULL, apis->GetSchema("experimental"));
   EXPECT_EQ(NULL, apis->GetSchema("experimental"));
   EXPECT_EQ(NULL, apis->GetSchema("foo"));
diff --git a/chrome/common/extensions/csp_validator_unittest.cc b/chrome/common/extensions/csp_validator_unittest.cc
index 13cbfe8..e96c42d 100644
--- a/chrome/common/extensions/csp_validator_unittest.cc
+++ b/chrome/common/extensions/csp_validator_unittest.cc
@@ -23,10 +23,10 @@ TEST(ExtensionCSPValidator, IsLegal) {
 }
 
 TEST(ExtensionCSPValidator, IsSecure) {
-  EXPECT_FALSE(
-      ContentSecurityPolicyIsSecure(std::string(), Manifest::TYPE_EXTENSION));
-  EXPECT_FALSE(ContentSecurityPolicyIsSecure("img-src https://google.com",
-                                             Manifest::TYPE_EXTENSION));
+  EXPECT_FALSE(ContentSecurityPolicyIsSecure(
+      "", Manifest::TYPE_EXTENSION));
+  EXPECT_FALSE(ContentSecurityPolicyIsSecure(
+      "img-src https://google.com", Manifest::TYPE_EXTENSION));
 
   EXPECT_FALSE(ContentSecurityPolicyIsSecure(
       "default-src *", Manifest::TYPE_EXTENSION));
@@ -146,10 +146,9 @@ TEST(ExtensionCSPValidator, IsSecure) {
 }
 
 TEST(ExtensionCSPValidator, IsSandboxed) {
-  EXPECT_FALSE(ContentSecurityPolicyIsSandboxed(std::string(),
-                                                Manifest::TYPE_EXTENSION));
-  EXPECT_FALSE(ContentSecurityPolicyIsSandboxed("img-src https://google.com",
-                                                Manifest::TYPE_EXTENSION));
+  EXPECT_FALSE(ContentSecurityPolicyIsSandboxed("", Manifest::TYPE_EXTENSION));
+  EXPECT_FALSE(ContentSecurityPolicyIsSandboxed(
+      "img-src https://google.com", Manifest::TYPE_EXTENSION));
 
   // Sandbox directive is required.
   EXPECT_TRUE(ContentSecurityPolicyIsSandboxed(
diff --git a/chrome/common/extensions/extension.cc b/chrome/common/extensions/extension.cc
index 42407b8..a941208 100644
--- a/chrome/common/extensions/extension.cc
+++ b/chrome/common/extensions/extension.cc
@@ -437,8 +437,8 @@ bool Extension::ParsePermissions(const char* key,
   if (manifest_->HasKey(key)) {
     const ListValue* permissions = NULL;
     if (!manifest_->GetList(key, &permissions)) {
-      *error = ErrorUtils::FormatErrorMessageUTF16(errors::kInvalidPermissions,
-                                                   std::string());
+      *error = ErrorUtils::FormatErrorMessageUTF16(
+          errors::kInvalidPermissions, "");
       return false;
     }
 
diff --git a/chrome/common/extensions/extension_file_util_unittest.cc b/chrome/common/extensions/extension_file_util_unittest.cc
index 6d68bc1..cb9260f 100644
--- a/chrome/common/extensions/extension_file_util_unittest.cc
+++ b/chrome/common/extensions/extension_file_util_unittest.cc
@@ -304,7 +304,7 @@ TEST_F(ExtensionFileUtilTest, ExtensionResourceURLToFilePath) {
   // Setup filesystem for testing.
   base::FilePath root_path;
   ASSERT_TRUE(file_util::CreateNewTempDirectory(
-      base::FilePath::StringType(), &root_path));
+        FILE_PATH_LITERAL(""), &root_path));
   ASSERT_TRUE(file_util::AbsolutePath(&root_path));
 
   base::FilePath api_path = root_path.Append(FILE_PATH_LITERAL("apiname"));
diff --git a/chrome/common/extensions/extension_icon_set_unittest.cc b/chrome/common/extensions/extension_icon_set_unittest.cc
index c7300a7..1202cda 100644
--- a/chrome/common/extensions/extension_icon_set_unittest.cc
+++ b/chrome/common/extensions/extension_icon_set_unittest.cc
@@ -62,7 +62,7 @@ TEST(ExtensionIconSet, Values) {
   EXPECT_TRUE(icons.ContainsPath("foo"));
   EXPECT_TRUE(icons.ContainsPath("bar"));
   EXPECT_FALSE(icons.ContainsPath("baz"));
-  EXPECT_FALSE(icons.ContainsPath(std::string()));
+  EXPECT_FALSE(icons.ContainsPath(""));
 
   icons.Clear();
   EXPECT_FALSE(icons.ContainsPath("foo"));
@@ -83,7 +83,7 @@ TEST(ExtensionIconSet, FindSize) {
   EXPECT_EQ(extension_misc::EXTENSION_ICON_INVALID,
             icons.GetIconSizeFromPath("baz"));
   EXPECT_EQ(extension_misc::EXTENSION_ICON_INVALID,
-            icons.GetIconSizeFromPath(std::string()));
+            icons.GetIconSizeFromPath(""));
 
   icons.Clear();
   EXPECT_EQ(extension_misc::EXTENSION_ICON_INVALID,
diff --git a/chrome/common/extensions/extension_l10n_util.cc b/chrome/common/extensions/extension_l10n_util.cc
index d2dada0..b86ab49 100644
--- a/chrome/common/extensions/extension_l10n_util.cc
+++ b/chrome/common/extensions/extension_l10n_util.cc
@@ -44,7 +44,7 @@ std::string GetDefaultLocaleFromManifest(const DictionaryValue& manifest,
     return default_locale;
 
   *error = errors::kInvalidDefaultLocale;
-  return std::string();
+  return "";
 
 }
 
diff --git a/chrome/common/extensions/extension_localization_peer_unittest.cc b/chrome/common/extensions/extension_localization_peer_unittest.cc
index df74791..92085ed 100644
--- a/chrome/common/extensions/extension_localization_peer_unittest.cc
+++ b/chrome/common/extensions/extension_localization_peer_unittest.cc
@@ -144,8 +144,8 @@ TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestBadURLRequestStatus) {
   EXPECT_CALL(*original_peer_, OnCompletedRequest(
     net::ERR_ABORTED, false, "", base::TimeTicks()));
 
-  filter_peer->OnCompletedRequest(
-      net::ERR_FAILED, false, std::string(), base::TimeTicks());
+  filter_peer->OnCompletedRequest(net::ERR_FAILED, false, "",
+                                  base::TimeTicks());
 }
 
 TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestEmptyData) {
@@ -159,8 +159,7 @@ TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestEmptyData) {
   EXPECT_CALL(*original_peer_, OnCompletedRequest(
       net::OK, false, "", base::TimeTicks()));
 
-  filter_peer->OnCompletedRequest(
-      net::OK, false, std::string(), base::TimeTicks());
+  filter_peer->OnCompletedRequest(net::OK, false, "", base::TimeTicks());
 }
 
 TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestNoCatalogs) {
@@ -179,16 +178,14 @@ TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestNoCatalogs) {
   EXPECT_CALL(*original_peer_, OnCompletedRequest(
           net::OK, false, "", base::TimeTicks())).Times(2);
 
-  filter_peer->OnCompletedRequest(
-      net::OK, false, std::string(), base::TimeTicks());
+  filter_peer->OnCompletedRequest(net::OK, false, "", base::TimeTicks());
 
   // Test if Send gets called again (it shouldn't be) when first call returned
   // an empty dictionary.
   filter_peer =
       CreateExtensionLocalizationPeer("text/css", GURL(kExtensionUrl_1));
   SetData(filter_peer, "some text");
-  filter_peer->OnCompletedRequest(
-      net::OK, false, std::string(), base::TimeTicks());
+  filter_peer->OnCompletedRequest(net::OK, false, "", base::TimeTicks());
 }
 
 TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestWithCatalogs) {
@@ -216,8 +213,7 @@ TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestWithCatalogs) {
   EXPECT_CALL(*original_peer_, OnCompletedRequest(
       net::OK, false, "", base::TimeTicks()));
 
-  filter_peer->OnCompletedRequest(
-      net::OK, false, std::string(), base::TimeTicks());
+  filter_peer->OnCompletedRequest(net::OK, false, "", base::TimeTicks());
 }
 
 TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestReplaceMessagesFails) {
@@ -245,6 +241,5 @@ TEST_F(ExtensionLocalizationPeerTest, OnCompletedRequestReplaceMessagesFails) {
   EXPECT_CALL(*original_peer_, OnCompletedRequest(
       net::OK, false, "", base::TimeTicks()));
 
-  filter_peer->OnCompletedRequest(
-      net::OK, false, std::string(), base::TimeTicks());
+  filter_peer->OnCompletedRequest(net::OK, false, "", base::TimeTicks());
 }
diff --git a/chrome/common/extensions/extension_set.cc b/chrome/common/extensions/extension_set.cc
index 8b68fb6..84872b8 100644
--- a/chrome/common/extensions/extension_set.cc
+++ b/chrome/common/extensions/extension_set.cc
@@ -77,11 +77,11 @@ std::string ExtensionSet::GetExtensionOrAppIDByURL(
   DCHECK(!info.origin().isNull());
 
   if (info.url().SchemeIs(extensions::kExtensionScheme))
-    return info.origin().isUnique() ? std::string() : info.url().host();
+    return info.origin().isUnique() ? "" : info.url().host();
 
   const Extension* extension = GetExtensionOrAppByURL(info);
   if (!extension)
-    return std::string();
+    return "";
 
   return extension->id();
 }
diff --git a/chrome/common/extensions/extension_set_unittest.cc b/chrome/common/extensions/extension_set_unittest.cc
index c27b0a9..1703966 100644
--- a/chrome/common/extensions/extension_set_unittest.cc
+++ b/chrome/common/extensions/extension_set_unittest.cc
@@ -59,8 +59,7 @@ TEST(ExtensionSetTest, ExtensionSet) {
   scoped_refptr<Extension> ext3(CreateTestExtension(
       "b", "http://dev.chromium.org/", "http://dev.chromium.org/"));
 
-  scoped_refptr<Extension> ext4(
-      CreateTestExtension("c", std::string(), std::string()));
+  scoped_refptr<Extension> ext4(CreateTestExtension("c", "", ""));
 
   ASSERT_TRUE(ext1 && ext2 && ext3 && ext4);
 
@@ -119,10 +118,8 @@ TEST(ExtensionSetTest, ExtensionSet) {
   EXPECT_FALSE(extensions.GetByID(ext2->id()));
 
   // Make a union of a set with 3 more extensions (only 2 are new).
-  scoped_refptr<Extension> ext5(
-      CreateTestExtension("d", std::string(), std::string()));
-  scoped_refptr<Extension> ext6(
-      CreateTestExtension("e", std::string(), std::string()));
+  scoped_refptr<Extension> ext5(CreateTestExtension("d", "", ""));
+  scoped_refptr<Extension> ext6(CreateTestExtension("e", "", ""));
   ASSERT_TRUE(ext5 && ext6);
 
   scoped_ptr<ExtensionSet> to_add(new ExtensionSet());
diff --git a/chrome/common/extensions/extension_sync_type_unittest.cc b/chrome/common/extensions/extension_sync_type_unittest.cc
index b25e197..3256c8d 100644
--- a/chrome/common/extensions/extension_sync_type_unittest.cc
+++ b/chrome/common/extensions/extension_sync_type_unittest.cc
@@ -56,7 +56,7 @@ class ExtensionSyncTypeTest : public ExtensionTest {
       ListValue* plugins = new ListValue();
       for (int i = 0; i < num_plugins; ++i) {
         DictionaryValue* plugin = new DictionaryValue();
-        plugin->SetString(keys::kPluginsPath, std::string());
+        plugin->SetString(keys::kPluginsPath, "");
         plugins->Set(i, plugin);
       }
       source.Set(keys::kPlugins, plugins);
@@ -158,7 +158,7 @@ TEST_F(ExtensionSyncTypeTest, DisplayInXManifestProperties) {
   manifest.SetString(keys::kName, "TestComponentApp");
   manifest.SetString(keys::kVersion, "0.0.0.0");
   manifest.SetString(keys::kApp, "true");
-  manifest.SetString(keys::kPlatformAppBackgroundPage, std::string());
+  manifest.SetString(keys::kPlatformAppBackgroundPage, "");
 
   std::string error;
   scoped_refptr<Extension> app;
diff --git a/chrome/common/extensions/extension_unittest.cc b/chrome/common/extensions/extension_unittest.cc
index edf24c4..6a3c80d 100644
--- a/chrome/common/extensions/extension_unittest.cc
+++ b/chrome/common/extensions/extension_unittest.cc
@@ -233,22 +233,16 @@ TEST_F(ExtensionTest, MimeTypeSniffing) {
   ASSERT_TRUE(file_util::ReadFileToString(path, &data));
 
   std::string result;
-  EXPECT_TRUE(net::SniffMimeType(data.c_str(),
-                                 data.size(),
-                                 GURL("http://www.example.com/foo.crx"),
-                                 std::string(),
-                                 &result));
+  EXPECT_TRUE(net::SniffMimeType(data.c_str(), data.size(),
+              GURL("http://www.example.com/foo.crx"), "", &result));
   EXPECT_EQ(std::string(Extension::kMimeType), result);
 
   data.clear();
   result.clear();
   path = path.DirName().AppendASCII("bad_magic.crx");
   ASSERT_TRUE(file_util::ReadFileToString(path, &data));
-  EXPECT_TRUE(net::SniffMimeType(data.c_str(),
-                                 data.size(),
-                                 GURL("http://www.example.com/foo.crx"),
-                                 std::string(),
-                                 &result));
+  EXPECT_TRUE(net::SniffMimeType(data.c_str(), data.size(),
+              GURL("http://www.example.com/foo.crx"), "", &result));
   EXPECT_EQ("application/octet-stream", result);
 }
 
diff --git a/chrome/common/extensions/features/api_feature.cc b/chrome/common/extensions/features/api_feature.cc
index f6d826e..0020632 100644
--- a/chrome/common/extensions/features/api_feature.cc
+++ b/chrome/common/extensions/features/api_feature.cc
@@ -26,7 +26,7 @@ std::string APIFeature::Parse(const DictionaryValue* value) {
   if (GetContexts()->empty())
     return name() + ": API features must specify at least one context.";
 
-  return std::string();
+  return "";
 }
 
 }  // namespace
diff --git a/chrome/common/extensions/features/complex_feature.cc b/chrome/common/extensions/features/complex_feature.cc
index a4515d0e4..f6f1c11 100644
--- a/chrome/common/extensions/features/complex_feature.cc
+++ b/chrome/common/extensions/features/complex_feature.cc
@@ -76,7 +76,7 @@ std::string ComplexFeature::GetAvailabilityMessage(AvailabilityResult result,
                                                    Manifest::Type type,
                                                    const GURL& url) const {
   if (result == IS_AVAILABLE)
-    return std::string();
+    return "";
 
   // TODO(justinlin): Form some kind of combined availabilities/messages from
   // SimpleFeatures.
diff --git a/chrome/common/extensions/features/manifest_feature.cc b/chrome/common/extensions/features/manifest_feature.cc
index 5196b52..cd4a53f 100644
--- a/chrome/common/extensions/features/manifest_feature.cc
+++ b/chrome/common/extensions/features/manifest_feature.cc
@@ -47,7 +47,7 @@ std::string ManifestFeature::Parse(const DictionaryValue* value) {
   if (!GetContexts()->empty())
     return name() + ": Manifest features do not support contexts.";
 
-  return std::string();
+  return "";
 }
 
 }  // namespace
diff --git a/chrome/common/extensions/features/permission_feature.cc b/chrome/common/extensions/features/permission_feature.cc
index 4681aa2..72b261f 100644
--- a/chrome/common/extensions/features/permission_feature.cc
+++ b/chrome/common/extensions/features/permission_feature.cc
@@ -49,7 +49,7 @@ std::string PermissionFeature::Parse(const DictionaryValue* value) {
   if (!GetContexts()->empty())
     return name() + ": Permission features do not support contexts.";
 
-  return std::string();
+  return "";
 }
 
 }  // namespace
diff --git a/chrome/common/extensions/features/simple_feature.cc b/chrome/common/extensions/features/simple_feature.cc
index 4b08c60..13c8573 100644
--- a/chrome/common/extensions/features/simple_feature.cc
+++ b/chrome/common/extensions/features/simple_feature.cc
@@ -168,7 +168,7 @@ std::string GetDisplayTypeName(Manifest::Type type) {
   }
 
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 }  // namespace
@@ -229,7 +229,7 @@ std::string SimpleFeature::Parse(const DictionaryValue* value) {
     return name() + ": Allowing web_page contexts requires supplying a value " +
         "for matches.";
   }
-  return std::string();
+  return "";
 }
 
 Feature::Availability SimpleFeature::IsAvailableToManifest(
@@ -313,7 +313,7 @@ std::string SimpleFeature::GetAvailabilityMessage(
     AvailabilityResult result, Manifest::Type type, const GURL& url) const {
   switch (result) {
     case IS_AVAILABLE:
-      return std::string();
+      return "";
     case NOT_FOUND_IN_WHITELIST:
       return base::StringPrintf(
           "'%s' is not allowed for specified extension ID.",
@@ -381,7 +381,7 @@ std::string SimpleFeature::GetAvailabilityMessage(
   }
 
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 Feature::Availability SimpleFeature::CreateAvailability(
diff --git a/chrome/common/extensions/features/simple_feature_unittest.cc b/chrome/common/extensions/features/simple_feature_unittest.cc
index 4f92a34..443b152 100644
--- a/chrome/common/extensions/features/simple_feature_unittest.cc
+++ b/chrome/common/extensions/features/simple_feature_unittest.cc
@@ -91,13 +91,9 @@ TEST_F(ExtensionSimpleFeatureTest, Whitelist) {
   EXPECT_EQ(Feature::NOT_FOUND_IN_WHITELIST, feature.IsAvailableToManifest(
       kIdBaz, Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION, -1,
       Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::NOT_FOUND_IN_WHITELIST,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::NOT_FOUND_IN_WHITELIST, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
 
   feature.extension_types()->insert(Manifest::TYPE_LEGACY_PACKAGED_APP);
   EXPECT_EQ(Feature::NOT_FOUND_IN_WHITELIST, feature.IsAvailableToManifest(
@@ -137,35 +133,19 @@ TEST_F(ExtensionSimpleFeatureTest, PackageType) {
   feature.extension_types()->insert(Manifest::TYPE_EXTENSION);
   feature.extension_types()->insert(Manifest::TYPE_LEGACY_PACKAGED_APP);
 
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_EXTENSION,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_LEGACY_PACKAGED_APP,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-
-  EXPECT_EQ(
-      Feature::INVALID_TYPE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::INVALID_TYPE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_THEME,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_EXTENSION, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_LEGACY_PACKAGED_APP, Feature::UNSPECIFIED_LOCATION,
+      -1, Feature::UNSPECIFIED_PLATFORM).result());
+
+  EXPECT_EQ(Feature::INVALID_TYPE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::INVALID_TYPE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_THEME, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
 }
 
 TEST_F(ExtensionSimpleFeatureTest, Context) {
@@ -240,107 +220,64 @@ TEST_F(ExtensionSimpleFeatureTest, Location) {
   // If the feature specifies "component" as its location, then only component
   // extensions can access it.
   feature.set_location(Feature::COMPONENT_LOCATION);
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::COMPONENT_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::INVALID_LOCATION,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::COMPONENT_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::INVALID_LOCATION, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
 
   // But component extensions can access anything else, whatever their location.
   feature.set_location(Feature::UNSPECIFIED_LOCATION);
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::COMPONENT_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::COMPONENT_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
 }
 
 TEST_F(ExtensionSimpleFeatureTest, Platform) {
   SimpleFeature feature;
   feature.set_platform(Feature::CHROMEOS_PLATFORM);
-  EXPECT_EQ(Feature::IS_AVAILABLE,
-            feature.IsAvailableToManifest(std::string(),
-                                          Manifest::TYPE_UNKNOWN,
-                                          Feature::UNSPECIFIED_LOCATION,
-                                          -1,
-                                          Feature::CHROMEOS_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::INVALID_PLATFORM,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    -1,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::CHROMEOS_PLATFORM).result());
+  EXPECT_EQ(Feature::INVALID_PLATFORM, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION, -1,
+      Feature::UNSPECIFIED_PLATFORM).result());
 }
 
 TEST_F(ExtensionSimpleFeatureTest, Version) {
   SimpleFeature feature;
   feature.set_min_manifest_version(5);
 
-  EXPECT_EQ(
-      Feature::INVALID_MIN_MANIFEST_VERSION,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    0,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::INVALID_MIN_MANIFEST_VERSION,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    4,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    5,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    10,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::INVALID_MIN_MANIFEST_VERSION,
+            feature.IsAvailableToManifest(
+                "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+                0, Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::INVALID_MIN_MANIFEST_VERSION,
+            feature.IsAvailableToManifest(
+                "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+                4, Feature::UNSPECIFIED_PLATFORM).result());
+
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+      5, Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+      10, Feature::UNSPECIFIED_PLATFORM).result());
 
   feature.set_max_manifest_version(8);
 
-  EXPECT_EQ(
-      Feature::INVALID_MAX_MANIFEST_VERSION,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    10,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    8,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
-  EXPECT_EQ(
-      Feature::IS_AVAILABLE,
-      feature.IsAvailableToManifest(std::string(),
-                                    Manifest::TYPE_UNKNOWN,
-                                    Feature::UNSPECIFIED_LOCATION,
-                                    7,
-                                    Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::INVALID_MAX_MANIFEST_VERSION,
+            feature.IsAvailableToManifest(
+                "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+                10, Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE,
+            feature.IsAvailableToManifest(
+                "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+                8, Feature::UNSPECIFIED_PLATFORM).result());
+  EXPECT_EQ(Feature::IS_AVAILABLE, feature.IsAvailableToManifest(
+      "", Manifest::TYPE_UNKNOWN, Feature::UNSPECIFIED_LOCATION,
+      7, Feature::UNSPECIFIED_PLATFORM).result());
 }
 
 TEST_F(ExtensionSimpleFeatureTest, ParseNull) {
@@ -612,15 +549,15 @@ TEST_F(ExtensionSimpleFeatureTest, SupportedChannel) {
 
   // Default supported channel (trunk).
   EXPECT_EQ(Feature::IS_AVAILABLE,
-            IsAvailableInChannel(std::string(), VersionInfo::CHANNEL_UNKNOWN));
+      IsAvailableInChannel("", VersionInfo::CHANNEL_UNKNOWN));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
-            IsAvailableInChannel(std::string(), VersionInfo::CHANNEL_CANARY));
+      IsAvailableInChannel("", VersionInfo::CHANNEL_CANARY));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
-            IsAvailableInChannel(std::string(), VersionInfo::CHANNEL_DEV));
+      IsAvailableInChannel("", VersionInfo::CHANNEL_DEV));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
-            IsAvailableInChannel(std::string(), VersionInfo::CHANNEL_BETA));
+      IsAvailableInChannel("", VersionInfo::CHANNEL_BETA));
   EXPECT_EQ(Feature::UNSUPPORTED_CHANNEL,
-            IsAvailableInChannel(std::string(), VersionInfo::CHANNEL_STABLE));
+      IsAvailableInChannel("", VersionInfo::CHANNEL_STABLE));
 }
 
 }  // namespace
diff --git a/chrome/common/extensions/manifest_tests/extension_manifest_test.cc b/chrome/common/extensions/manifest_tests/extension_manifest_test.cc
index 4e72588..b61d5f7 100644
--- a/chrome/common/extensions/manifest_tests/extension_manifest_test.cc
+++ b/chrome/common/extensions/manifest_tests/extension_manifest_test.cc
@@ -217,16 +217,20 @@ ExtensionManifestTest::Testcase::Testcase(std::string manifest_filename,
 
 ExtensionManifestTest::Testcase::Testcase(std::string manifest_filename)
     : manifest_filename_(manifest_filename),
+      expected_error_(""),
       location_(extensions::Manifest::INTERNAL),
-      flags_(Extension::NO_FLAGS) {}
+      flags_(Extension::NO_FLAGS) {
+}
 
 ExtensionManifestTest::Testcase::Testcase(
     std::string manifest_filename,
     extensions::Manifest::Location location,
     int flags)
     : manifest_filename_(manifest_filename),
+      expected_error_(""),
       location_(location),
-      flags_(flags) {}
+      flags_(flags) {
+}
 
 void ExtensionManifestTest::RunTestcases(const Testcase* testcases,
                                          size_t num_testcases,
diff --git a/chrome/common/extensions/manifest_tests/extension_manifests_platformapp_unittest.cc b/chrome/common/extensions/manifest_tests/extension_manifests_platformapp_unittest.cc
index bb93903..1fdab49 100644
--- a/chrome/common/extensions/manifest_tests/extension_manifests_platformapp_unittest.cc
+++ b/chrome/common/extensions/manifest_tests/extension_manifests_platformapp_unittest.cc
@@ -98,7 +98,7 @@ TEST_F(PlatformAppsManifestTest, PlatformAppContentSecurityPolicy) {
   EXPECT_TRUE(extension->is_platform_app());
   EXPECT_EQ(
       "default-src 'self' https://www.google.com",
-      CSPInfo::GetResourceContentSecurityPolicy(extension, std::string()));
+      CSPInfo::GetResourceContentSecurityPolicy(extension, ""));
 
   // But even whitelisted ones must specify a secure policy.
   LoadAndExpectError(
diff --git a/chrome/common/extensions/manifest_url_handler.cc b/chrome/common/extensions/manifest_url_handler.cc
index 690cc03..2e18eb1 100644
--- a/chrome/common/extensions/manifest_url_handler.cc
+++ b/chrome/common/extensions/manifest_url_handler.cc
@@ -125,8 +125,8 @@ bool HomepageURLHandler::Parse(Extension* extension, string16* error) {
   std::string homepage_url_str;
   if (!extension->manifest()->GetString(keys::kHomepageURL,
                                         &homepage_url_str)) {
-    *error = ErrorUtils::FormatErrorMessageUTF16(errors::kInvalidHomepageURL,
-                                                 std::string());
+    *error = ErrorUtils::FormatErrorMessageUTF16(
+        errors::kInvalidHomepageURL, "");
     return false;
   }
   manifest_url->url_ = GURL(homepage_url_str);
@@ -156,8 +156,8 @@ bool UpdateURLHandler::Parse(Extension* extension, string16* error) {
   std::string tmp_update_url;
 
   if (!extension->manifest()->GetString(keys::kUpdateURL, &tmp_update_url)) {
-    *error = ErrorUtils::FormatErrorMessageUTF16(errors::kInvalidUpdateURL,
-                                                 std::string());
+    *error = ErrorUtils::FormatErrorMessageUTF16(
+        errors::kInvalidUpdateURL, "");
     return false;
   }
 
diff --git a/chrome/common/extensions/message_bundle.cc b/chrome/common/extensions/message_bundle.cc
index bb7d547..708e2e4 100644
--- a/chrome/common/extensions/message_bundle.cc
+++ b/chrome/common/extensions/message_bundle.cc
@@ -303,7 +303,7 @@ std::string MessageBundle::GetL10nMessage(const std::string& name,
     return it->second;
   }
 
-  return std::string();
+  return "";
 }
 
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/chrome/common/extensions/permissions/bluetooth_device_permission_data.cc b/chrome/common/extensions/permissions/bluetooth_device_permission_data.cc
index 82c5acd..3698ebf 100644
--- a/chrome/common/extensions/permissions/bluetooth_device_permission_data.cc
+++ b/chrome/common/extensions/permissions/bluetooth_device_permission_data.cc
@@ -18,7 +18,9 @@ const char* kDeviceAddressKey = "deviceAddress";
 
 namespace extensions {
 
-BluetoothDevicePermissionData::BluetoothDevicePermissionData() {}
+BluetoothDevicePermissionData::BluetoothDevicePermissionData()
+  : device_address_("") {
+}
 
 BluetoothDevicePermissionData::BluetoothDevicePermissionData(
     const std::string& device_address) : device_address_(device_address) {
diff --git a/chrome/common/extensions/permissions/socket_permission_unittest.cc b/chrome/common/extensions/permissions/socket_permission_unittest.cc
index 05e7d3d..6bb07be 100644
--- a/chrome/common/extensions/permissions/socket_permission_unittest.cc
+++ b/chrome/common/extensions/permissions/socket_permission_unittest.cc
@@ -48,7 +48,7 @@ TEST_F(SocketPermissionTest, General) {
 TEST_F(SocketPermissionTest, Parse) {
   SocketPermissionData data;
 
-  EXPECT_FALSE(data.ParseForTest(std::string()));
+  EXPECT_FALSE(data.ParseForTest(""));
   EXPECT_FALSE(data.ParseForTest("*"));
   EXPECT_FALSE(data.ParseForTest("\00\00*"));
   EXPECT_FALSE(data.ParseForTest("\01*"));
diff --git a/chrome/common/extensions/update_manifest_unittest.cc b/chrome/common/extensions/update_manifest_unittest.cc
index 2a16b9c..9af11df 100644
--- a/chrome/common/extensions/update_manifest_unittest.cc
+++ b/chrome/common/extensions/update_manifest_unittest.cc
@@ -120,7 +120,7 @@ TEST(ExtensionUpdateManifestTest, TestUpdateManifest) {
   UpdateManifest parser;
 
   // Test parsing of a number of invalid xml cases
-  EXPECT_FALSE(parser.Parse(std::string()));
+  EXPECT_FALSE(parser.Parse(""));
   EXPECT_FALSE(parser.errors().empty());
 
   EXPECT_TRUE(parser.Parse(kMissingAppId));
diff --git a/chrome/common/json_schema/json_schema_validator.cc b/chrome/common/json_schema/json_schema_validator.cc
index 6e5e070..a303442 100644
--- a/chrome/common/json_schema/json_schema_validator.cc
+++ b/chrome/common/json_schema/json_schema_validator.cc
@@ -99,7 +99,7 @@ std::string JSONSchemaValidator::GetJSONSchemaType(const Value* value) {
       return schema::kArray;
     default:
       NOTREACHED() << "Unexpected value type: " << value->GetType();
-      return std::string();
+      return "";
   }
 }
 
@@ -147,7 +147,7 @@ JSONSchemaValidator::~JSONSchemaValidator() {}
 
 bool JSONSchemaValidator::Validate(const Value* instance) {
   errors_.clear();
-  Validate(instance, schema_root_, std::string());
+  Validate(instance, schema_root_, "");
   return errors_.empty();
 }
 
diff --git a/chrome/common/json_schema/json_schema_validator_unittest_base.cc b/chrome/common/json_schema/json_schema_validator_unittest_base.cc
index 8ce82b7..ecd9846 100644
--- a/chrome/common/json_schema/json_schema_validator_unittest_base.cc
+++ b/chrome/common/json_schema/json_schema_validator_unittest_base.cc
@@ -130,9 +130,7 @@ void JSONSchemaValidatorTestBase::TestStringPattern() {
               schema.get(), NULL);
   ExpectNotValid(TEST_SOURCE,
                  scoped_ptr<base::Value>(new base::StringValue("bar")).get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
+                 schema.get(), NULL, "",
                  JSONSchemaValidator::FormatErrorMessage(
                      JSONSchemaValidator::kStringPattern, "foo+"));
 }
@@ -152,16 +150,10 @@ void JSONSchemaValidatorTestBase::TestEnum() {
 
   ExpectNotValid(TEST_SOURCE,
                  scoped_ptr<base::Value>(new base::StringValue("42")).get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
-                 JSONSchemaValidator::kInvalidEnum);
+                 schema.get(), NULL, "", JSONSchemaValidator::kInvalidEnum);
   ExpectNotValid(TEST_SOURCE,
                  scoped_ptr<base::Value>(base::Value::CreateNullValue()).get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
-                 JSONSchemaValidator::kInvalidEnum);
+                 schema.get(), NULL, "", JSONSchemaValidator::kInvalidEnum);
 }
 
 void JSONSchemaValidatorTestBase::TestChoices() {
@@ -181,24 +173,14 @@ void JSONSchemaValidatorTestBase::TestChoices() {
 
   ExpectNotValid(TEST_SOURCE,
                  scoped_ptr<base::Value>(new base::StringValue("foo")).get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
-                 JSONSchemaValidator::kInvalidChoice);
+                 schema.get(), NULL, "", JSONSchemaValidator::kInvalidChoice);
   ExpectNotValid(TEST_SOURCE,
                  scoped_ptr<base::Value>(new base::ListValue()).get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
-                 JSONSchemaValidator::kInvalidChoice);
+                 schema.get(), NULL, "", JSONSchemaValidator::kInvalidChoice);
 
   instance->SetInteger("foo", 42);
-  ExpectNotValid(TEST_SOURCE,
-                 instance.get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
-                 JSONSchemaValidator::kInvalidChoice);
+  ExpectNotValid(TEST_SOURCE, instance.get(),
+                 schema.get(), NULL, "", JSONSchemaValidator::kInvalidChoice);
 }
 
 void JSONSchemaValidatorTestBase::TestExtends() {
@@ -351,11 +333,7 @@ void JSONSchemaValidatorTestBase::TestArrayTuple() {
   ExpectValid(TEST_SOURCE, instance.get(), schema.get(), NULL);
 
   instance->Append(new base::StringValue("anything"));
-  ExpectNotValid(TEST_SOURCE,
-                 instance.get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
+  ExpectNotValid(TEST_SOURCE, instance.get(), schema.get(), NULL, "",
                  JSONSchemaValidator::FormatErrorMessage(
                      JSONSchemaValidator::kArrayMaxItems, "2"));
 
@@ -425,21 +403,13 @@ void JSONSchemaValidatorTestBase::TestArrayNonTuple() {
   ExpectValid(TEST_SOURCE, instance.get(), schema.get(), NULL);
 
   instance->Append(new base::StringValue("x"));
-  ExpectNotValid(TEST_SOURCE,
-                 instance.get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
+  ExpectNotValid(TEST_SOURCE, instance.get(), schema.get(), NULL, "",
                  JSONSchemaValidator::FormatErrorMessage(
                      JSONSchemaValidator::kArrayMaxItems, "3"));
   instance->Remove(1, NULL);
   instance->Remove(1, NULL);
   instance->Remove(1, NULL);
-  ExpectNotValid(TEST_SOURCE,
-                 instance.get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
+  ExpectNotValid(TEST_SOURCE, instance.get(), schema.get(), NULL, "",
                  JSONSchemaValidator::FormatErrorMessage(
                      JSONSchemaValidator::kArrayMinItems, "2"));
 
@@ -466,20 +436,15 @@ void JSONSchemaValidatorTestBase::TestString() {
                   new base::StringValue("xxxxxxxxxx")).get(),
               schema.get(), NULL);
 
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::StringValue(std::string())).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(
-          JSONSchemaValidator::kStringMinLength, "1"));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(new base::StringValue("")).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kStringMinLength, "1"));
   ExpectNotValid(
       TEST_SOURCE,
       scoped_ptr<base::Value>(new base::StringValue("xxxxxxxxxxx")).get(),
-      schema.get(),
-      NULL,
-      std::string(),
+      schema.get(), NULL, "",
       JSONSchemaValidator::FormatErrorMessage(
           JSONSchemaValidator::kStringMaxLength, "10"));
 }
@@ -504,19 +469,16 @@ void JSONSchemaValidatorTestBase::TestNumber() {
               scoped_ptr<base::Value>(new base::FundamentalValue(88.88)).get(),
               schema.get(), NULL);
 
-  ExpectNotValid(TEST_SOURCE,
-                 scoped_ptr<base::Value>(new base::FundamentalValue(0.5)).get(),
-                 schema.get(),
-                 NULL,
-                 std::string(),
-                 JSONSchemaValidator::FormatErrorMessage(
-                     JSONSchemaValidator::kNumberMinimum, "1"));
+  ExpectNotValid(
+      TEST_SOURCE,
+      scoped_ptr<base::Value>(new base::FundamentalValue(0.5)).get(),
+      schema.get(), NULL, "",
+      JSONSchemaValidator::FormatErrorMessage(
+          JSONSchemaValidator::kNumberMinimum, "1"));
   ExpectNotValid(
       TEST_SOURCE,
       scoped_ptr<base::Value>(new base::FundamentalValue(100.1)).get(),
-      schema.get(),
-      NULL,
-      std::string(),
+      schema.get(), NULL, "",
       JSONSchemaValidator::FormatErrorMessage(
           JSONSchemaValidator::kNumberMaximum, "100"));
 }
@@ -644,83 +606,73 @@ void JSONSchemaValidatorTestBase::TestTypes() {
 
   // not valid
   schema->SetString(schema::kType, schema::kObject);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::ListValue()).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(
-          JSONSchemaValidator::kInvalidType, schema::kObject, schema::kArray));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(new base::ListValue()).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kObject,
+                     schema::kArray));
 
   schema->SetString(schema::kType, schema::kObject);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(base::Value::CreateNullValue()).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(
-          JSONSchemaValidator::kInvalidType, schema::kObject, schema::kNull));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(base::Value::CreateNullValue()).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kObject,
+                     schema::kNull));
 
   schema->SetString(schema::kType, schema::kArray);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::FundamentalValue(42)).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(
-          JSONSchemaValidator::kInvalidType, schema::kArray, schema::kInteger));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(new base::FundamentalValue(42)).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kArray,
+                     schema::kInteger));
 
   schema->SetString(schema::kType, schema::kString);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::FundamentalValue(42)).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(JSONSchemaValidator::kInvalidType,
-                                              schema::kString,
-                                              schema::kInteger));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(new base::FundamentalValue(42)).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kString,
+                     schema::kInteger));
 
   schema->SetString(schema::kType, schema::kNumber);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::StringValue("42")).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(
-          JSONSchemaValidator::kInvalidType, schema::kNumber, schema::kString));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(new base::StringValue("42")).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kNumber,
+                     schema::kString));
 
   schema->SetString(schema::kType, schema::kInteger);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::FundamentalValue(88.8)).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::kInvalidTypeIntegerNumber);
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(
+                     new base::FundamentalValue(88.8)).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::kInvalidTypeIntegerNumber);
 
   schema->SetString(schema::kType, schema::kBoolean);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::FundamentalValue(1)).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(JSONSchemaValidator::kInvalidType,
-                                              schema::kBoolean,
-                                              schema::kInteger));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(new base::FundamentalValue(1)).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kBoolean,
+                     schema::kInteger));
 
   schema->SetString(schema::kType, schema::kNull);
-  ExpectNotValid(
-      TEST_SOURCE,
-      scoped_ptr<base::Value>(new base::FundamentalValue(false)).get(),
-      schema.get(),
-      NULL,
-      std::string(),
-      JSONSchemaValidator::FormatErrorMessage(
-          JSONSchemaValidator::kInvalidType, schema::kNull, schema::kBoolean));
+  ExpectNotValid(TEST_SOURCE,
+                 scoped_ptr<base::Value>(
+                     new base::FundamentalValue(false)).get(),
+                 schema.get(), NULL, "",
+                 JSONSchemaValidator::FormatErrorMessage(
+                     JSONSchemaValidator::kInvalidType,
+                     schema::kNull,
+                     schema::kBoolean));
 }
diff --git a/chrome/common/metrics/entropy_provider_unittest.cc b/chrome/common/metrics/entropy_provider_unittest.cc
index c3547ab..9881d7e 100644
--- a/chrome/common/metrics/entropy_provider_unittest.cc
+++ b/chrome/common/metrics/entropy_provider_unittest.cc
@@ -200,7 +200,7 @@ TEST_F(EntropyProviderTest, UseOneTimeRandomizationSHA1) {
     trials[i]->UseOneTimeRandomization();
 
     for (int j = 0; j < 100; ++j)
-      trials[i]->AppendGroup(std::string(), 1);
+      trials[i]->AppendGroup("", 1);
   }
 
   // The trials are most likely to give different results since they have
@@ -228,7 +228,7 @@ TEST_F(EntropyProviderTest, UseOneTimeRandomizationPermuted) {
     trials[i]->UseOneTimeRandomization();
 
     for (int j = 0; j < 100; ++j)
-      trials[i]->AppendGroup(std::string(), 1);
+      trials[i]->AppendGroup("", 1);
   }
 
   // The trials are most likely to give different results since they have
diff --git a/chrome/common/net/x509_certificate_model.cc b/chrome/common/net/x509_certificate_model.cc
index e1f0847..950b4f2 100644
--- a/chrome/common/net/x509_certificate_model.cc
+++ b/chrome/common/net/x509_certificate_model.cc
@@ -61,7 +61,7 @@ std::string ProcessRawBytesWithSeparators(const unsigned char* data,
   size_t kMin = 0U;
 
   if (!data_length)
-    return std::string();
+    return "";
 
   ret.reserve(std::max(kMin, data_length * 3 - 1));
 
diff --git a/chrome/common/net/x509_certificate_model_nss.cc b/chrome/common/net/x509_certificate_model_nss.cc
index 51e2642..5f40ce3 100644
--- a/chrome/common/net/x509_certificate_model_nss.cc
+++ b/chrome/common/net/x509_certificate_model_nss.cc
@@ -100,8 +100,8 @@ using net::X509Certificate;
 using std::string;
 
 string GetCertNameOrNickname(X509Certificate::OSCertHandle cert_handle) {
-  string name = ProcessIDN(
-      Stringize(CERT_GetCommonName(&cert_handle->subject), std::string()));
+  string name = ProcessIDN(Stringize(CERT_GetCommonName(&cert_handle->subject),
+                                     ""));
   if (!name.empty())
     return name;
   return GetNickname(cert_handle);
@@ -132,7 +132,7 @@ string GetVersion(X509Certificate::OSCertHandle cert_handle) {
       SEC_ASN1DecodeInteger(&cert_handle->version, &version) == SECSuccess) {
     return base::UintToString(version + 1);
   }
-  return std::string();
+  return "";
 }
 
 net::CertType GetType(X509Certificate::OSCertHandle cert_handle) {
@@ -142,7 +142,7 @@ net::CertType GetType(X509Certificate::OSCertHandle cert_handle) {
 string GetEmailAddress(X509Certificate::OSCertHandle cert_handle) {
   if (cert_handle->emailAddr)
     return cert_handle->emailAddr;
-  return std::string();
+  return "";
 }
 
 void GetUsageStrings(X509Certificate::OSCertHandle cert_handle,
@@ -346,14 +346,14 @@ string GetCMSString(const X509Certificate::OSCertHandles& cert_chain,
       message.get(), cert_chain[start], PR_FALSE));
   if (!signed_data.get()) {
     DLOG(ERROR) << "NSS_CMSSignedData_Create failed";
-    return std::string();
+    return "";
   }
   // Add the rest of the chain (if any).
   for (size_t i = start + 1; i < end; ++i) {
     if (NSS_CMSSignedData_AddCertificate(signed_data.get(), cert_chain[i]) !=
         SECSuccess) {
       DLOG(ERROR) << "NSS_CMSSignedData_AddCertificate failed on " << i;
-      return std::string();
+      return "";
     }
   }
 
@@ -363,7 +363,7 @@ string GetCMSString(const X509Certificate::OSCertHandles& cert_chain,
     ignore_result(signed_data.release());
   } else {
     DLOG(ERROR) << "NSS_CMSMessage_GetContentInfo failed";
-    return std::string();
+    return "";
   }
 
   SECItem cert_p7 = { siBuffer, NULL, 0 };
@@ -373,12 +373,12 @@ string GetCMSString(const X509Certificate::OSCertHandles& cert_chain,
                                                    NULL);
   if (!ecx) {
     DLOG(ERROR) << "NSS_CMSEncoder_Start failed";
-    return std::string();
+    return "";
   }
 
   if (NSS_CMSEncoder_Finish(ecx) != SECSuccess) {
     DLOG(ERROR) << "NSS_CMSEncoder_Finish failed";
-    return std::string();
+    return "";
   }
 
   return string(reinterpret_cast<const char*>(cert_p7.data), cert_p7.len);
diff --git a/chrome/common/pref_names_util_unittest.cc b/chrome/common/pref_names_util_unittest.cc
index 9f215ea..2d1356a 100644
--- a/chrome/common/pref_names_util_unittest.cc
+++ b/chrome/common/pref_names_util_unittest.cc
@@ -28,7 +28,7 @@ void ExpectParse(const std::string& path,
 }  // namespace
 
 TEST(PrefNamesUtilTest, Basic) {
-  ExpectNoParse(std::string());
+  ExpectNoParse("");
   ExpectNoParse(".");
   ExpectNoParse(".....");
   ExpectNoParse("webkit.webprefs.fonts.");
@@ -43,8 +43,8 @@ TEST(PrefNamesUtilTest, Basic) {
   // We don't particularly care about the parsed family and script for these
   // inputs, but just want to make sure it does something reasonable. Returning
   // false may also be an option.
-  ExpectParse("webkit.webprefs.fonts...", std::string(), ".");
-  ExpectParse("webkit.webprefs.fonts....", std::string(), "..");
+  ExpectParse("webkit.webprefs.fonts...", "", ".");
+  ExpectParse("webkit.webprefs.fonts....", "", "..");
 
   // Check that passing NULL output params is okay.
   EXPECT_TRUE(pref_names_util::ParseFontNamePrefPath(
diff --git a/chrome/renderer/autofill/password_autofill_agent_browsertest.cc b/chrome/renderer/autofill/password_autofill_agent_browsertest.cc
index 567c305..4a619f5 100644
--- a/chrome/renderer/autofill/password_autofill_agent_browsertest.cc
+++ b/chrome/renderer/autofill/password_autofill_agent_browsertest.cc
@@ -251,7 +251,7 @@ TEST_F(PasswordAutofillAgentTest, NoInitialAutocompleteForReadOnly) {
 
   // Only the username should have been autocompleted.
   // TODO(jcivelli): may be we should not event fill the username?
-  CheckTextFieldsState(kAliceUsername, true, std::string(), false);
+  CheckTextFieldsState(kAliceUsername, true, "", false);
 }
 
 // Tests that having a non-matching username precludes the autocomplete.
@@ -263,7 +263,7 @@ TEST_F(PasswordAutofillAgentTest, NoInitialAutocompleteForFilledField) {
   SimulateOnFillPasswordForm(fill_data_);
 
   // Neither field should be autocompleted.
-  CheckTextFieldsState("bogus", false, std::string(), false);
+  CheckTextFieldsState("bogus", false, "", false);
 }
 
 // Tests that having a matching username does not preclude the autocomplete.
@@ -288,7 +288,7 @@ TEST_F(PasswordAutofillAgentTest, PasswordClearOnEdit) {
   SimulateUsernameChange("alicia", true);
 
   // The password should have been cleared.
-  CheckTextFieldsState("alicia", false, std::string(), false);
+  CheckTextFieldsState("alicia", false, "", false);
 }
 
 // Tests that we only autocomplete on focus lost and with a full username match
@@ -299,27 +299,27 @@ TEST_F(PasswordAutofillAgentTest, WaitUsername) {
   SimulateOnFillPasswordForm(fill_data_);
 
   // No auto-fill should have taken place.
-  CheckTextFieldsState(std::string(), false, std::string(), false);
+  CheckTextFieldsState("", false, "", false);
 
   // No autocomplete should happen when text is entered in the username.
   SimulateUsernameChange("a", true);
-  CheckTextFieldsState("a", false, std::string(), false);
+  CheckTextFieldsState("a", false, "", false);
   SimulateUsernameChange("al", true);
-  CheckTextFieldsState("al", false, std::string(), false);
+  CheckTextFieldsState("al", false, "", false);
   SimulateUsernameChange(kAliceUsername, true);
-  CheckTextFieldsState(kAliceUsername, false, std::string(), false);
+  CheckTextFieldsState(kAliceUsername, false, "", false);
 
   // Autocomplete should happen only when the username textfield is blurred with
   // a full match.
   username_element_.setValue("a");
   autofill_agent_->textFieldDidEndEditing(username_element_);
-  CheckTextFieldsState("a", false, std::string(), false);
+  CheckTextFieldsState("a", false, "", false);
   username_element_.setValue("al");
   autofill_agent_->textFieldDidEndEditing(username_element_);
-  CheckTextFieldsState("al", false, std::string(), false);
+  CheckTextFieldsState("al", false, "", false);
   username_element_.setValue("alices");
   autofill_agent_->textFieldDidEndEditing(username_element_);
-  CheckTextFieldsState("alices", false, std::string(), false);
+  CheckTextFieldsState("alices", false, "", false);
   username_element_.setValue(ASCIIToUTF16(kAliceUsername));
   autofill_agent_->textFieldDidEndEditing(username_element_);
   CheckTextFieldsState(kAliceUsername, true, kAlicePassword, true);
@@ -351,7 +351,7 @@ TEST_F(PasswordAutofillAgentTest, InlineAutocomplete) {
   // Test that deleting does not trigger autocomplete.
   SimulateKeyDownEvent(username_element_, ui::VKEY_BACK);
   SimulateUsernameChange("alic", true);
-  CheckTextFieldsState("alic", false, std::string(), false);
+  CheckTextFieldsState("alic", false, "", false);
   CheckUsernameSelection(4, 4);  // No selection.
   // Reset the last pressed key to something other than backspace.
   SimulateKeyDownEvent(username_element_, ui::VKEY_A);
@@ -361,7 +361,7 @@ TEST_F(PasswordAutofillAgentTest, InlineAutocomplete) {
   // practice the username should no longer be 'alice' and the selected range
   // should be empty.
   SimulateUsernameChange("alf", true);
-  CheckTextFieldsState("alf", false, std::string(), false);
+  CheckTextFieldsState("alf", false, "", false);
   CheckUsernameSelection(3, 3);  // No selection.
 
   // Ok, so now the user removes all the text and enters the letter 'b'.
@@ -379,7 +379,7 @@ TEST_F(PasswordAutofillAgentTest, InlineAutocomplete) {
   // want case-sensitive autocompletion, so the username and the selected range
   // should be empty.
   SimulateUsernameChange("c", true);
-  CheckTextFieldsState("c", false, std::string(), false);
+  CheckTextFieldsState("c", false, "", false);
   CheckUsernameSelection(1, 1);
 }
 
@@ -419,7 +419,7 @@ TEST_F(PasswordAutofillAgentTest, SuggestionSelect) {
                                                WebKit::WebString(),
                                                0);
   // Autocomplete should not have kicked in.
-  CheckTextFieldsState(std::string(), false, std::string(), false);
+  CheckTextFieldsState("", false, "", false);
 }
 
 }  // namespace autofill
diff --git a/chrome/renderer/automation/automation_renderer_helper_browsertest.cc b/chrome/renderer/automation/automation_renderer_helper_browsertest.cc
index 65bd018..659d312 100644
--- a/chrome/renderer/automation/automation_renderer_helper_browsertest.cc
+++ b/chrome/renderer/automation/automation_renderer_helper_browsertest.cc
@@ -84,9 +84,9 @@ TEST_F(AutomationRendererHelperTest, RTLSnapshot) {
 }
 
 TEST_F(AutomationRendererHelperTest, ScriptChain) {
-  ScriptEvaluationRequest request("({'result': 10})", std::string());
-  ScriptEvaluationRequest request_plus1("({'result': arguments[0].result + 1})",
-                                        std::string());
+  ScriptEvaluationRequest request("({'result': 10})", "");
+  ScriptEvaluationRequest request_plus1(
+      "({'result': arguments[0].result + 1})", "");
   std::vector<ScriptEvaluationRequest> script_chain;
   script_chain.push_back(request);
   script_chain.push_back(request_plus1);
@@ -102,10 +102,10 @@ TEST_F(AutomationRendererHelperTest, ScriptChain) {
 }
 
 TEST_F(AutomationRendererHelperTest, ScriptChainError) {
-  ScriptEvaluationRequest request("({'result': 10})", std::string());
+  ScriptEvaluationRequest request("({'result': 10})", "");
   ScriptEvaluationRequest error_request(
       "({'result': arguments[0].result + 1, 'error': {'msg': 'some msg'}})",
-      std::string());
+      "");
   std::vector<ScriptEvaluationRequest> script_chain;
   script_chain.push_back(request);
   script_chain.push_back(error_request);
diff --git a/chrome/renderer/chrome_content_renderer_client_unittest.cc b/chrome/renderer/chrome_content_renderer_client_unittest.cc
index 1387ff0..b099eea 100644
--- a/chrome/renderer/chrome_content_renderer_client_unittest.cc
+++ b/chrome/renderer/chrome_content_renderer_client_unittest.cc
@@ -96,8 +96,8 @@ scoped_refptr<const extensions::Extension> CreateTestExtension(
 
 scoped_refptr<const extensions::Extension> CreateExtension(
     bool is_unrestricted, bool is_from_webstore) {
-  return CreateTestExtension(
-      is_unrestricted, is_from_webstore, kNotHostedApp, std::string());
+  return CreateTestExtension(is_unrestricted, is_from_webstore, kNotHostedApp,
+                             "");
 }
 
 scoped_refptr<const extensions::Extension> CreateHostedApp(
diff --git a/chrome/renderer/content_settings_observer_browsertest.cc b/chrome/renderer/content_settings_observer_browsertest.cc
index 8397c94..f4777d2 100644
--- a/chrome/renderer/content_settings_observer_browsertest.cc
+++ b/chrome/renderer/content_settings_observer_browsertest.cc
@@ -110,11 +110,12 @@ TEST_F(ChromeRenderViewTest, JSBlockSentAfterPageLoad) {
   ContentSettingsForOneType& script_setting_rules =
       content_setting_rules.script_rules;
   script_setting_rules.push_back(
-      ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
-                                  ContentSettingsPattern::Wildcard(),
-                                  CONTENT_SETTING_BLOCK,
-                                  std::string(),
-                                  false));
+      ContentSettingPatternSource(
+          ContentSettingsPattern::Wildcard(),
+          ContentSettingsPattern::Wildcard(),
+          CONTENT_SETTING_BLOCK,
+          "",
+          false));
   ContentSettingsObserver* observer = ContentSettingsObserver::Get(view_);
   observer->SetContentSettingRules(&content_setting_rules);
 
@@ -192,7 +193,7 @@ TEST_F(ChromeRenderViewTest, ImagesBlockedByDefault) {
       ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
                                   ContentSettingsPattern::Wildcard(),
                                   CONTENT_SETTING_BLOCK,
-                                  std::string(),
+                                  "",
                                   false));
 
   ContentSettingsObserver* observer = ContentSettingsObserver::Get(view_);
@@ -210,7 +211,7 @@ TEST_F(ChromeRenderViewTest, ImagesBlockedByDefault) {
           ContentSettingsPattern::Wildcard(),
           ContentSettingsPattern::FromString(mock_observer.image_origin_),
           CONTENT_SETTING_ALLOW,
-          std::string(),
+          "",
           false));
 
   EXPECT_CALL(
@@ -235,7 +236,7 @@ TEST_F(ChromeRenderViewTest, ImagesAllowedByDefault) {
       ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
                                   ContentSettingsPattern::Wildcard(),
                                   CONTENT_SETTING_ALLOW,
-                                  std::string(),
+                                  "",
                                   false));
 
   ContentSettingsObserver* observer = ContentSettingsObserver::Get(view_);
@@ -254,7 +255,7 @@ TEST_F(ChromeRenderViewTest, ImagesAllowedByDefault) {
           ContentSettingsPattern::Wildcard(),
           ContentSettingsPattern::FromString(mock_observer.image_origin_),
           CONTENT_SETTING_BLOCK,
-          std::string(),
+          "",
           false));
   EXPECT_CALL(mock_observer,
               OnContentBlocked(CONTENT_SETTINGS_TYPE_IMAGES, std::string()));
@@ -269,11 +270,12 @@ TEST_F(ChromeRenderViewTest, ContentSettingsBlockScripts) {
   ContentSettingsForOneType& script_setting_rules =
       content_setting_rules.script_rules;
   script_setting_rules.push_back(
-      ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
-                                  ContentSettingsPattern::Wildcard(),
-                                  CONTENT_SETTING_BLOCK,
-                                  std::string(),
-                                  false));
+      ContentSettingPatternSource(
+          ContentSettingsPattern::Wildcard(),
+          ContentSettingsPattern::Wildcard(),
+          CONTENT_SETTING_BLOCK,
+          "",
+          false));
 
   ContentSettingsObserver* observer = ContentSettingsObserver::Get(view_);
   observer->SetContentSettingRules(&content_setting_rules);
@@ -304,11 +306,12 @@ TEST_F(ChromeRenderViewTest, ContentSettingsAllowScripts) {
   ContentSettingsForOneType& script_setting_rules =
       content_setting_rules.script_rules;
   script_setting_rules.push_back(
-      ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
-                                  ContentSettingsPattern::Wildcard(),
-                                  CONTENT_SETTING_ALLOW,
-                                  std::string(),
-                                  false));
+      ContentSettingPatternSource(
+          ContentSettingsPattern::Wildcard(),
+          ContentSettingsPattern::Wildcard(),
+          CONTENT_SETTING_ALLOW,
+          "",
+          false));
 
   ContentSettingsObserver* observer = ContentSettingsObserver::Get(view_);
   observer->SetContentSettingRules(&content_setting_rules);
@@ -340,20 +343,18 @@ TEST_F(ChromeRenderViewTest, ContentSettingsInterstitialPages) {
   ContentSettingsForOneType& script_setting_rules =
       content_setting_rules.script_rules;
   script_setting_rules.push_back(
-      ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
-                                  ContentSettingsPattern::Wildcard(),
-                                  CONTENT_SETTING_BLOCK,
-                                  std::string(),
-                                  false));
+      ContentSettingPatternSource(
+          ContentSettingsPattern::Wildcard(),
+          ContentSettingsPattern::Wildcard(),
+          CONTENT_SETTING_BLOCK, "", false));
   // Block images.
   ContentSettingsForOneType& image_setting_rules =
       content_setting_rules.image_rules;
   image_setting_rules.push_back(
-      ContentSettingPatternSource(ContentSettingsPattern::Wildcard(),
-                                  ContentSettingsPattern::Wildcard(),
-                                  CONTENT_SETTING_BLOCK,
-                                  std::string(),
-                                  false));
+      ContentSettingPatternSource(
+          ContentSettingsPattern::Wildcard(),
+          ContentSettingsPattern::Wildcard(),
+          CONTENT_SETTING_BLOCK, "", false));
 
   ContentSettingsObserver* observer = ContentSettingsObserver::Get(view_);
   observer->SetContentSettingRules(&content_setting_rules);
diff --git a/chrome/renderer/extensions/chrome_v8_context.cc b/chrome/renderer/extensions/chrome_v8_context.cc
index 5feff00..b4ae80e 100644
--- a/chrome/renderer/extensions/chrome_v8_context.cc
+++ b/chrome/renderer/extensions/chrome_v8_context.cc
@@ -63,7 +63,7 @@ void ChromeV8Context::Invalidate() {
 }
 
 std::string ChromeV8Context::GetExtensionID() {
-  return extension_ ? extension_->id() : std::string();
+  return extension_ ? extension_->id() : "";
 }
 
 // static
@@ -187,7 +187,7 @@ std::string ChromeV8Context::GetContextTypeDescription() {
     case Feature::WEB_PAGE_CONTEXT:            return "WEB_PAGE";
   }
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 ChromeV8Context* ChromeV8Context::GetContext() {
diff --git a/chrome/renderer/extensions/extension_helper.cc b/chrome/renderer/extensions/extension_helper.cc
index ac456a8..a488cb7 100644
--- a/chrome/renderer/extensions/extension_helper.cc
+++ b/chrome/renderer/extensions/extension_helper.cc
@@ -313,12 +313,8 @@ void ExtensionHelper::OnExecuteCode(
   WebFrame* main_frame = webview->mainFrame();
   if (!main_frame) {
     ListValue val;
-    Send(new ExtensionHostMsg_ExecuteCodeFinished(routing_id(),
-                                                  params.request_id,
-                                                  "No main frame",
-                                                  -1,
-                                                  GURL(std::string()),
-                                                  val));
+    Send(new ExtensionHostMsg_ExecuteCodeFinished(
+        routing_id(), params.request_id, "No main frame", -1, GURL(""), val));
     return;
   }
 
diff --git a/chrome/renderer/extensions/resource_request_policy.cc b/chrome/renderer/extensions/resource_request_policy.cc
index 83ccb3f..116b218 100644
--- a/chrome/renderer/extensions/resource_request_policy.cc
+++ b/chrome/renderer/extensions/resource_request_policy.cc
@@ -51,8 +51,7 @@ bool ResourceRequestPolicy::CanRequestResource(
   // some extensions want to be able to do things like create their own
   // launchers.
   std::string resource_root_relative_path =
-      resource_url.path().empty() ? std::string()
-                                  : resource_url.path().substr(1);
+      resource_url.path().empty() ? "" : resource_url.path().substr(1);
   if (extension->is_hosted_app() &&
       !IconsInfo::GetIcons(extension)
           .ContainsPath(resource_root_relative_path)) {
diff --git a/chrome/renderer/extensions/user_script_scheduler.cc b/chrome/renderer/extensions/user_script_scheduler.cc
index f194a23..3cb01ba 100644
--- a/chrome/renderer/extensions/user_script_scheduler.cc
+++ b/chrome/renderer/extensions/user_script_scheduler.cc
@@ -147,13 +147,13 @@ void UserScriptScheduler::ExecuteCodeImpl(
   // Since extension info is sent separately from user script info, they can
   // be out of sync. We just ignore this situation.
   if (!extension) {
-    render_view->Send(
-        new ExtensionHostMsg_ExecuteCodeFinished(render_view->GetRoutingID(),
-                                                 params.request_id,
-                                                 std::string(),  // no error
-                                                 -1,
-                                                 GURL(std::string()),
-                                                 execution_results));
+    render_view->Send(new ExtensionHostMsg_ExecuteCodeFinished(
+        render_view->GetRoutingID(),
+        params.request_id,
+        "",  // no error
+        -1,
+        GURL(""),
+        execution_results));
     return;
   }
 
diff --git a/chrome/renderer/extensions/user_script_slave.cc b/chrome/renderer/extensions/user_script_slave.cc
index 3e64b7d..f715207 100644
--- a/chrome/renderer/extensions/user_script_slave.cc
+++ b/chrome/renderer/extensions/user_script_slave.cc
@@ -92,7 +92,7 @@ std::string UserScriptSlave::GetExtensionIdForIsolatedWorld(
     if (iter->second == isolated_world_id)
       return iter->first;
   }
-  return std::string();
+  return "";
 }
 
 // static
diff --git a/chrome/renderer/plugins/plugin_uma_unittest.cc b/chrome/renderer/plugins/plugin_uma_unittest.cc
index 3b1950c..99e6271 100644
--- a/chrome/renderer/plugins/plugin_uma_unittest.cc
+++ b/chrome/renderer/plugins/plugin_uma_unittest.cc
@@ -118,8 +118,9 @@ TEST_F(PluginUMATest, WidevineCdm) {
 }
 
 TEST_F(PluginUMATest, BySrcExtension) {
-  ExpectPluginType(
-      PluginUMAReporter::QUICKTIME, std::string(), GURL("file://file.mov"));
+  ExpectPluginType(PluginUMAReporter::QUICKTIME,
+                   "",
+                   GURL("file://file.mov"));
 
   // When plugin's mime type is given, we don't check extension.
   ExpectPluginType(PluginUMAReporter::UNSUPPORTED_MIMETYPE,
@@ -127,36 +128,40 @@ TEST_F(PluginUMATest, BySrcExtension) {
                    GURL("http://file.mov"));
 
   ExpectPluginType(PluginUMAReporter::WINDOWS_MEDIA_PLAYER,
-                   std::string(),
+                   "",
                    GURL("file://file.asx"));
-  ExpectPluginType(
-      PluginUMAReporter::REALPLAYER, std::string(), GURL("file://file.rm"));
+  ExpectPluginType(PluginUMAReporter::REALPLAYER,
+                   "",
+                   GURL("file://file.rm"));
   ExpectPluginType(PluginUMAReporter::QUICKTIME,
-                   std::string(),
+                   "",
                    GURL("http://aaa/file.mov?x=aaaa&y=b#c"));
   ExpectPluginType(PluginUMAReporter::QUICKTIME,
-                   std::string(),
+                   "",
                    GURL("http://file.mov?x=aaaa&y=b#c"));
   ExpectPluginType(PluginUMAReporter::SHOCKWAVE_FLASH,
-                   std::string(),
+                   "",
                    GURL("http://file.swf?x=aaaa&y=b#c"));
   ExpectPluginType(PluginUMAReporter::SHOCKWAVE_FLASH,
-                   std::string(),
+                   "",
                    GURL("http://file.spl?x=aaaa&y=b#c"));
 
   ExpectPluginType(PluginUMAReporter::UNSUPPORTED_EXTENSION,
-                   std::string(),
+                   "",
                    GURL("http://file.unknown_extension"));
-  ExpectPluginType(
-      PluginUMAReporter::UNSUPPORTED_EXTENSION, std::string(), GURL("http://"));
-  ExpectPluginType(
-      PluginUMAReporter::UNSUPPORTED_EXTENSION, std::string(), GURL("mov"));
+  ExpectPluginType(PluginUMAReporter::UNSUPPORTED_EXTENSION,
+                   "",
+                   GURL("http://"));
+  ExpectPluginType(PluginUMAReporter::UNSUPPORTED_EXTENSION,
+                   "",
+                   GURL("mov"));
 }
 
 TEST_F(PluginUMATest, CaseSensitivity) {
   ExpectPluginType(PluginUMAReporter::QUICKTIME,
                    "video/QUICKTIME",
                    GURL("http://file.aaa"));
-  ExpectPluginType(
-      PluginUMAReporter::QUICKTIME, std::string(), GURL("http://file.MoV"));
+  ExpectPluginType(PluginUMAReporter::QUICKTIME,
+                   "",
+                   GURL("http://file.MoV"));
 }
diff --git a/chrome/renderer/safe_browsing/malware_dom_details_browsertest.cc b/chrome/renderer/safe_browsing/malware_dom_details_browsertest.cc
index 8a120cb..034655f 100644
--- a/chrome/renderer/safe_browsing/malware_dom_details_browsertest.cc
+++ b/chrome/renderer/safe_browsing/malware_dom_details_browsertest.cc
@@ -97,7 +97,7 @@ TEST_F(MalwareDOMDetailsTest, Everything) {
   }
 
   { // >50 subframes, to verify kMaxNodes.
-    std::string html;
+    std::string html = "";
     for (int i = 0; i < 55; ++i) {
       // The iframe contents is just a number.
       GURL iframe_url(base::StringPrintf("%s%d", urlprefix, i));
@@ -113,7 +113,7 @@ TEST_F(MalwareDOMDetailsTest, Everything) {
   }
 
   { // A page with >50 scripts, to verify kMaxNodes.
-    std::string html;
+    std::string html = "";
     for (int i = 0; i < 55; ++i) {
       // The iframe contents is just a number.
       GURL script_url(base::StringPrintf("%s%d", urlprefix, i));
diff --git a/chrome/service/cloud_print/cloud_print_proxy.cc b/chrome/service/cloud_print/cloud_print_proxy.cc
index 12eee70..a65da81 100644
--- a/chrome/service/cloud_print/cloud_print_proxy.cc
+++ b/chrome/service/cloud_print/cloud_print_proxy.cc
@@ -85,10 +85,10 @@ void CloudPrintProxy::EnableForUser(const std::string& lsid) {
   DCHECK(backend_.get());
   // Read persisted robot credentials because we may decide to reuse it if the
   // passed in LSID belongs the same user.
-  std::string robot_refresh_token = service_prefs_->GetString(
-      prefs::kCloudPrintRobotRefreshToken, std::string());
+  std::string robot_refresh_token =
+      service_prefs_->GetString(prefs::kCloudPrintRobotRefreshToken, "");
   std::string robot_email =
-      service_prefs_->GetString(prefs::kCloudPrintRobotEmail, std::string());
+      service_prefs_->GetString(prefs::kCloudPrintRobotEmail, "");
   user_email_ = service_prefs_->GetString(prefs::kCloudPrintEmail, user_email_);
 
   // If we have been passed in an LSID, we want to use this to authenticate.
@@ -104,7 +104,7 @@ void CloudPrintProxy::EnableForUser(const std::string& lsid) {
     } else {
       // Finally see if we have persisted user credentials (legacy case).
       std::string cloud_print_token =
-          service_prefs_->GetString(prefs::kCloudPrintAuthToken, std::string());
+          service_prefs_->GetString(prefs::kCloudPrintAuthToken, "");
       DCHECK(!cloud_print_token.empty());
       backend_->InitializeWithToken(cloud_print_token);
     }
@@ -124,7 +124,7 @@ void CloudPrintProxy::EnableForUserWithRobot(
 
   ShutdownBackend();
   std::string proxy_id(
-      service_prefs_->GetString(prefs::kCloudPrintProxyId, std::string()));
+      service_prefs_->GetString(prefs::kCloudPrintProxyId, ""));
   service_prefs_->RemovePref(prefs::kCloudPrintRoot);
   if (!proxy_id.empty()) {
     // Keep only proxy id;
@@ -204,8 +204,7 @@ void CloudPrintProxy::GetProxyInfo(CloudPrintProxyInfo* info) {
   // If the Cloud Print service is not enabled, we may need to read the old
   // value of proxy_id from prefs.
   if (info->proxy_id.empty())
-    info->proxy_id =
-        service_prefs_->GetString(prefs::kCloudPrintProxyId, std::string());
+    info->proxy_id = service_prefs_->GetString(prefs::kCloudPrintProxyId, "");
 }
 
 void CloudPrintProxy::CheckCloudPrintProxyPolicy() {
diff --git a/chrome/service/cloud_print/cloud_print_url_fetcher_unittest.cc b/chrome/service/cloud_print/cloud_print_url_fetcher_unittest.cc
index a86d24c..343eaa8 100644
--- a/chrome/service/cloud_print/cloud_print_url_fetcher_unittest.cc
+++ b/chrome/service/cloud_print/cloud_print_url_fetcher_unittest.cc
@@ -217,9 +217,9 @@ void CloudPrintURLFetcherTest::CreateFetcher(const GURL& url, int max_retries) {
 
   // Registers an entry for test url. It only allows 3 requests to be sent
   // in 200 milliseconds.
-  scoped_refptr<net::URLRequestThrottlerEntry>
-  entry(new net::URLRequestThrottlerEntry(
-      fetcher_->throttler_manager(), std::string(), 200, 3, 1, 2.0, 0.0, 256));
+  scoped_refptr<net::URLRequestThrottlerEntry> entry(
+      new net::URLRequestThrottlerEntry(
+          fetcher_->throttler_manager(), "", 200, 3, 1, 2.0, 0.0, 256));
   fetcher_->throttler_manager()->OverrideEntryForTests(url, entry);
 
   max_retries_ = max_retries;
diff --git a/chrome/service/cloud_print/connector_settings.cc b/chrome/service/cloud_print/connector_settings.cc
index 1e9b761..2b43b15 100644
--- a/chrome/service/cloud_print/connector_settings.cc
+++ b/chrome/service/cloud_print/connector_settings.cc
@@ -32,7 +32,7 @@ ConnectorSettings::~ConnectorSettings() {
 void ConnectorSettings::InitFrom(ServiceProcessPrefs* prefs) {
   CopyFrom(ConnectorSettings());
 
-  proxy_id_ = prefs->GetString(prefs::kCloudPrintProxyId, std::string());
+  proxy_id_ = prefs->GetString(prefs::kCloudPrintProxyId, "");
   if (proxy_id_.empty()) {
     proxy_id_ = PrintSystem::GenerateProxyId();
     prefs->SetString(prefs::kCloudPrintProxyId, proxy_id_);
@@ -51,8 +51,7 @@ void ConnectorSettings::InitFrom(ServiceProcessPrefs* prefs) {
   }
 
   // Check if there is an override for the cloud print server URL.
-  server_url_ =
-      GURL(prefs->GetString(prefs::kCloudPrintServiceURL, std::string()));
+  server_url_ = GURL(prefs->GetString(prefs::kCloudPrintServiceURL, ""));
   DCHECK(server_url_.is_empty() || server_url_.is_valid());
   if (server_url_.is_empty() || !server_url_.is_valid()) {
     server_url_ = GURL(kDefaultCloudPrintServerUrl);
diff --git a/chrome/service/cloud_print/printer_job_handler_unittest.cc b/chrome/service/cloud_print/printer_job_handler_unittest.cc
index 0576bb0..9e19519 100644
--- a/chrome/service/cloud_print/printer_job_handler_unittest.cc
+++ b/chrome/service/cloud_print/printer_job_handler_unittest.cc
@@ -194,7 +194,7 @@ const char kExamplePrinterDescription[] = "Example Description";
 
 // These are functions used to construct the various sample strings.
 std::string JobListResponse(int num_jobs) {
-  std::string job_objects;
+  std::string job_objects = "";
   for (int i = 0; i < num_jobs; i++) {
     job_objects = job_objects + StringPrintf(kExampleJobObject, i+1, i+1, i+1,
                                              i+1);
@@ -683,7 +683,7 @@ TEST_F(PrinterJobHandlerTest, TicketDownloadFailureTest) {
                            JobListResponse(2), true);
   factory_.SetFakeResponse(JobListURI(kJobFetchReasonQueryMore),
                            JobListResponse(0), true);
-  factory_.SetFakeResponse(TicketURI(1), std::string(), false);
+  factory_.SetFakeResponse(TicketURI(1), "", false);
 
   EXPECT_CALL(url_callback_, OnRequestCreate(GURL(TicketURI(1)), _))
       .Times(AtLeast(1));
@@ -734,7 +734,7 @@ TEST_F(PrinterJobHandlerTest, DISABLED_ManyFailureTest) {
 
   SetUpJobSuccessTest(1);
 
-  factory_.SetFakeResponse(TicketURI(1), std::string(), false);
+  factory_.SetFakeResponse(TicketURI(1), "", false);
 
   loop_.PostDelayedTask(FROM_HERE,
                         base::Bind(&net::FakeURLFetcherFactory::SetFakeResponse,
@@ -759,7 +759,7 @@ TEST_F(PrinterJobHandlerTest, DISABLED_CompleteFailureTest) {
   factory_.SetFakeResponse(JobListURI(kJobFetchReasonRetry),
                            JobListResponse(1), true);
   factory_.SetFakeResponse(ErrorURI(1), StatusResponse(1, "ERROR"), true);
-  factory_.SetFakeResponse(TicketURI(1), std::string(), false);
+  factory_.SetFakeResponse(TicketURI(1), "", false);
 
   EXPECT_CALL(url_callback_,
               OnRequestCreate(GURL(JobListURI(kJobFetchReasonStartup)), _))
diff --git a/chrome/service/cloud_print/printer_job_queue_handler_unittest.cc b/chrome/service/cloud_print/printer_job_queue_handler_unittest.cc
index b29f5a4..05532b9 100644
--- a/chrome/service/cloud_print/printer_job_queue_handler_unittest.cc
+++ b/chrome/service/cloud_print/printer_job_queue_handler_unittest.cc
@@ -81,7 +81,7 @@ TEST_F(PrinterJobQueueHandlerTest, BasicJobReadTest) {
 
   std::set<std::string> expected_tags;
   expected_tags.insert("^own");
-  expected_tags.insert(std::string());
+  expected_tags.insert("");
   std::set<std::string> actual_tags;
   actual_tags.insert(jobs[0].tags_.begin(), jobs[0].tags_.end());
 
diff --git a/chrome/service/service_process.cc b/chrome/service/service_process.cc
index 32d5cc2..2cae376 100644
--- a/chrome/service/service_process.cc
+++ b/chrome/service/service_process.cc
@@ -175,8 +175,7 @@ bool ServiceProcess::Initialize(MessageLoopForUI* message_loop,
   } else {
     // If no command-line value was specified, read the last used locale from
     // the prefs.
-    locale =
-        service_prefs_->GetString(prefs::kApplicationLocale, std::string());
+    locale = service_prefs_->GetString(prefs::kApplicationLocale, "");
     // If no locale was specified anywhere, use the default one.
     if (locale.empty())
       locale = kDefaultServiceProcessLocale;
diff --git a/chrome/service/service_process_prefs_unittest.cc b/chrome/service/service_process_prefs_unittest.cc
index 3d7ae1f..5d68ab3 100644
--- a/chrome/service/service_process_prefs_unittest.cc
+++ b/chrome/service/service_process_prefs_unittest.cc
@@ -39,8 +39,9 @@ TEST_F(ServiceProcessPrefsTest, RetrievePrefs) {
   prefs_->WritePrefs();
   message_loop_.RunUntilIdle();
   prefs_->SetBoolean("testb", false);   // overwrite
-  prefs_->SetString("tests", std::string());  // overwrite
+  prefs_->SetString("tests", "");   // overwrite
   prefs_->ReadPrefs();
   EXPECT_EQ(prefs_->GetBoolean("testb", false), true);
-  EXPECT_EQ(prefs_->GetString("tests", std::string()), "testvalue");
+  EXPECT_EQ(prefs_->GetString("tests", ""), "testvalue");
 }
+
diff --git a/chrome/test/base/ui_test_utils.cc b/chrome/test/base/ui_test_utils.cc
index fbf366d..f3b91f6 100644
--- a/chrome/test/base/ui_test_utils.cc
+++ b/chrome/test/base/ui_test_utils.cc
@@ -187,7 +187,7 @@ bool GetCurrentTabTitle(const Browser* browser, string16* title) {
   NavigationEntry* last_entry = web_contents->GetController().GetActiveEntry();
   if (!last_entry)
     return false;
-  title->assign(last_entry->GetTitleForDisplay(std::string()));
+  title->assign(last_entry->GetTitleForDisplay(""));
   return true;
 }
 
diff --git a/chrome/test/chromedriver/capabilities_unittest.cc b/chrome/test/chromedriver/capabilities_unittest.cc
index 9bf6c32..f6ac5ec 100644
--- a/chrome/test/chromedriver/capabilities_unittest.cc
+++ b/chrome/test/chromedriver/capabilities_unittest.cc
@@ -21,7 +21,7 @@ TEST(ParseCapabilities, WithAndroidPackage) {
 TEST(ParseCapabilities, EmptyAndroidPackage) {
   Capabilities capabilities;
   base::DictionaryValue caps;
-  caps.SetString("chromeOptions.android_package", std::string());
+  caps.SetString("chromeOptions.android_package", "");
   Status status = capabilities.Parse(caps);
   ASSERT_FALSE(status.IsOk());
 }
diff --git a/chrome/test/chromedriver/chrome/automation_extension.cc b/chrome/test/chromedriver/chrome/automation_extension.cc
index 63ad223..0a91cf5 100644
--- a/chrome/test/chromedriver/chrome/automation_extension.cc
+++ b/chrome/test/chromedriver/chrome/automation_extension.cc
@@ -52,11 +52,8 @@ Status AutomationExtension::GetWindowInfo(int* x,
                                           int* height) {
   base::ListValue args;
   scoped_ptr<base::Value> result;
-  Status status = web_view_->CallAsyncFunction(std::string(),
-                                               "getWindowInfo",
-                                               args,
-                                               base::TimeDelta::FromSeconds(10),
-                                               &result);
+  Status status = web_view_->CallAsyncFunction(
+      "", "getWindowInfo", args, base::TimeDelta::FromSeconds(10), &result);
   if (status.IsError())
     return status;
 
@@ -81,9 +78,6 @@ Status AutomationExtension::UpdateWindow(
   base::ListValue args;
   args.Append(update_info.DeepCopy());
   scoped_ptr<base::Value> result;
-  return web_view_->CallAsyncFunction(std::string(),
-                                      "updateWindow",
-                                      args,
-                                      base::TimeDelta::FromSeconds(10),
-                                      &result);
+  return web_view_->CallAsyncFunction(
+      "", "updateWindow", args, base::TimeDelta::FromSeconds(10), &result);
 }
diff --git a/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc b/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
index 49dfad2..bee5bd2 100644
--- a/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
+++ b/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
@@ -67,7 +67,7 @@ Status ChromeDesktopImpl::GetAutomationExtension(
       return status;
 
     // Wait for the extension background page to load.
-    status = web_view->WaitForPendingNavigations(std::string());
+    status = web_view->WaitForPendingNavigations("");
     if (status.IsError())
       return status;
 
diff --git a/chrome/test/chromedriver/chrome/devtools_http_client.cc b/chrome/test/chromedriver/chrome/devtools_http_client.cc
index 3cfcdae..c0fc841 100644
--- a/chrome/test/chromedriver/chrome/devtools_http_client.cc
+++ b/chrome/test/chromedriver/chrome/devtools_http_client.cc
@@ -169,8 +169,7 @@ Status DevToolsHttpClient::CloseFrontends(const std::string& for_client_id) {
 
     scoped_ptr<base::Value> result;
     status = web_view->EvaluateScript(
-        std::string(),
-        "document.querySelector('*[id^=\"close-button-\"').click();",
+        "", "document.querySelector('*[id^=\"close-button-\"').click();",
         &result);
     // Ignore disconnected error, because it may be closed already.
     if (status.IsError() && status.code() != kDisconnected)
diff --git a/chrome/test/chromedriver/chrome/devtools_http_client_unittest.cc b/chrome/test/chromedriver/chrome/devtools_http_client_unittest.cc
index c92abb8..eff9b3f 100644
--- a/chrome/test/chromedriver/chrome/devtools_http_client_unittest.cc
+++ b/chrome/test/chromedriver/chrome/devtools_http_client_unittest.cc
@@ -64,7 +64,8 @@ TEST(ParseWebViewsInfo, WithoutDebuggerUrl) {
   ASSERT_TRUE(status.IsOk());
   ASSERT_EQ(1u, views_info.GetSize());
   ExpectEqual(
-      WebViewInfo("1", std::string(), "http://page1", WebViewInfo::kPage),
+      WebViewInfo(
+          "1", "", "http://page1", WebViewInfo::kPage),
       views_info.Get(0));
 }
 
diff --git a/chrome/test/chromedriver/chrome/javascript_dialog_manager_unittest.cc b/chrome/test/chromedriver/chrome/javascript_dialog_manager_unittest.cc
index 1333090..fcc3dce 100644
--- a/chrome/test/chromedriver/chrome/javascript_dialog_manager_unittest.cc
+++ b/chrome/test/chromedriver/chrome/javascript_dialog_manager_unittest.cc
@@ -19,7 +19,7 @@ TEST(JavaScriptDialogManager, NoDialog) {
   ASSERT_EQ(kNoAlertOpen, manager.GetDialogMessage(&message).code());
   ASSERT_FALSE(manager.IsDialogOpen());
   ASSERT_STREQ("HI", message.c_str());
-  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, "").code());
 }
 
 namespace {
@@ -73,7 +73,7 @@ TEST(JavaScriptDialogManager, ReconnectClearsStateAndSendsEnable) {
   ASSERT_EQ("Page.enable", client.method_);
   ASSERT_FALSE(manager.IsDialogOpen());
   ASSERT_EQ(kNoAlertOpen, manager.GetDialogMessage(&message).code());
-  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, "").code());
 }
 
 namespace {
@@ -125,10 +125,10 @@ TEST(JavaScriptDialogManager, OneDialog) {
   ASSERT_EQ("hi", message);
 
   client.set_closing_count(1);
-  ASSERT_EQ(kOk, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kOk, manager.HandleDialog(false, "").code());
   ASSERT_FALSE(manager.IsDialogOpen());
   ASSERT_EQ(kNoAlertOpen, manager.GetDialogMessage(&message).code());
-  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, "").code());
 }
 
 TEST(JavaScriptDialogManager, TwoDialogs) {
@@ -145,16 +145,16 @@ TEST(JavaScriptDialogManager, TwoDialogs) {
   ASSERT_TRUE(manager.IsDialogOpen());
   ASSERT_EQ("1", message);
 
-  ASSERT_EQ(kOk, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kOk, manager.HandleDialog(false, "").code());
   ASSERT_TRUE(manager.IsDialogOpen());
   ASSERT_EQ(kOk, manager.GetDialogMessage(&message).code());
   ASSERT_EQ("2", message);
 
   client.set_closing_count(2);
-  ASSERT_EQ(kOk, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kOk, manager.HandleDialog(false, "").code());
   ASSERT_FALSE(manager.IsDialogOpen());
   ASSERT_EQ(kNoAlertOpen, manager.GetDialogMessage(&message).code());
-  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, "").code());
 }
 
 TEST(JavaScriptDialogManager, OneDialogManualClose) {
@@ -174,5 +174,5 @@ TEST(JavaScriptDialogManager, OneDialogManualClose) {
   manager.OnEvent("Page.javascriptDialogClosing", params);
   ASSERT_FALSE(manager.IsDialogOpen());
   ASSERT_EQ(kNoAlertOpen, manager.GetDialogMessage(&message).code());
-  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, std::string()).code());
+  ASSERT_EQ(kNoAlertOpen, manager.HandleDialog(false, "").code());
 }
diff --git a/chrome/test/chromedriver/chrome/navigation_tracker_unittest.cc b/chrome/test/chromedriver/chrome/navigation_tracker_unittest.cc
index 19a78ef3..79cc0f6 100644
--- a/chrome/test/chromedriver/chrome/navigation_tracker_unittest.cc
+++ b/chrome/test/chromedriver/chrome/navigation_tracker_unittest.cc
@@ -173,7 +173,7 @@ class DeterminingLoadStateDevToolsClient : public StubDevToolsClient {
 
 TEST(NavigationTracker, UnknownStateForcesStart) {
   base::DictionaryValue params;
-  DeterminingLoadStateDevToolsClient client(true, std::string(), &params);
+  DeterminingLoadStateDevToolsClient client(true, "", &params);
   NavigationTracker tracker(&client);
   ASSERT_NO_FATAL_FAILURE(AssertPendingState(&tracker, "f", true));
 }
diff --git a/chrome/test/chromedriver/chrome/stub_chrome.cc b/chrome/test/chromedriver/chrome/stub_chrome.cc
index d990d4e..39888a8 100644
--- a/chrome/test/chromedriver/chrome/stub_chrome.cc
+++ b/chrome/test/chromedriver/chrome/stub_chrome.cc
@@ -11,7 +11,7 @@ StubChrome::StubChrome() {}
 StubChrome::~StubChrome() {}
 
 std::string StubChrome::GetVersion() {
-  return std::string();
+  return "";
 }
 
 int StubChrome::GetBuildNo() {
@@ -49,7 +49,7 @@ Status StubChrome::GetAutomationExtension(AutomationExtension** extension) {
 }
 
 std::string StubChrome::GetOperatingSystemName() {
-  return std::string();
+  return "";
 }
 
 Status StubChrome::Quit() {
diff --git a/chrome/test/chromedriver/chrome/web_view_impl_unittest.cc b/chrome/test/chromedriver/chrome/web_view_impl_unittest.cc
index ecdc85b..37e3284 100644
--- a/chrome/test/chromedriver/chrome/web_view_impl_unittest.cc
+++ b/chrome/test/chromedriver/chrome/web_view_impl_unittest.cc
@@ -60,8 +60,8 @@ void AssertEvalFails(const base::DictionaryValue& command_result) {
   scoped_ptr<base::DictionaryValue> result;
   FakeDevToolsClient client;
   client.set_result(command_result);
-  Status status = internal::EvaluateScript(
-      &client, 0, std::string(), internal::ReturnByValue, &result);
+  Status status = internal::EvaluateScript(&client, 0, "",
+                                           internal::ReturnByValue, &result);
   ASSERT_EQ(kUnknownError, status.code());
   ASSERT_FALSE(result);
 }
@@ -72,8 +72,8 @@ TEST(EvaluateScript, CommandError) {
   scoped_ptr<base::DictionaryValue> result;
   FakeDevToolsClient client;
   client.set_status(Status(kUnknownError));
-  Status status = internal::EvaluateScript(
-      &client, 0, std::string(), internal::ReturnByValue, &result);
+  Status status = internal::EvaluateScript(&client, 0, "",
+                                           internal::ReturnByValue, &result);
   ASSERT_EQ(kUnknownError, status.code());
   ASSERT_FALSE(result);
 }
@@ -104,7 +104,7 @@ TEST(EvaluateScript, Ok) {
   FakeDevToolsClient client;
   client.set_result(dict);
   ASSERT_TRUE(internal::EvaluateScript(
-      &client, 0, std::string(), internal::ReturnByValue, &result).IsOk());
+      &client, 0, "", internal::ReturnByValue, &result).IsOk());
   ASSERT_TRUE(result);
   ASSERT_TRUE(result->HasKey("key"));
 }
@@ -117,7 +117,7 @@ TEST(EvaluateScriptAndGetValue, MissingType) {
   dict.SetInteger("result.value", 1);
   client.set_result(dict);
   ASSERT_TRUE(internal::EvaluateScriptAndGetValue(
-      &client, 0, std::string(), &result).IsError());
+      &client, 0, "", &result).IsError());
 }
 
 TEST(EvaluateScriptAndGetValue, Undefined) {
@@ -127,8 +127,8 @@ TEST(EvaluateScriptAndGetValue, Undefined) {
   dict.SetBoolean("wasThrown", false);
   dict.SetString("result.type", "undefined");
   client.set_result(dict);
-  Status status =
-      internal::EvaluateScriptAndGetValue(&client, 0, std::string(), &result);
+  Status status = internal::EvaluateScriptAndGetValue(
+      &client, 0, "", &result);
   ASSERT_EQ(kOk, status.code());
   ASSERT_TRUE(result && result->IsType(base::Value::TYPE_NULL));
 }
@@ -141,8 +141,8 @@ TEST(EvaluateScriptAndGetValue, Ok) {
   dict.SetString("result.type", "integer");
   dict.SetInteger("result.value", 1);
   client.set_result(dict);
-  Status status =
-      internal::EvaluateScriptAndGetValue(&client, 0, std::string(), &result);
+  Status status = internal::EvaluateScriptAndGetValue(
+      &client, 0, "", &result);
   ASSERT_EQ(kOk, status.code());
   int value;
   ASSERT_TRUE(result && result->GetAsInteger(&value));
@@ -158,7 +158,7 @@ TEST(EvaluateScriptAndGetObject, NoObject) {
   bool got_object;
   std::string object_id;
   ASSERT_TRUE(internal::EvaluateScriptAndGetObject(
-      &client, 0, std::string(), &got_object, &object_id).IsOk());
+      &client, 0, "", &got_object, &object_id).IsOk());
   ASSERT_FALSE(got_object);
   ASSERT_TRUE(object_id.empty());
 }
@@ -172,7 +172,7 @@ TEST(EvaluateScriptAndGetObject, Ok) {
   bool got_object;
   std::string object_id;
   ASSERT_TRUE(internal::EvaluateScriptAndGetObject(
-      &client, 0, std::string(), &got_object, &object_id).IsOk());
+      &client, 0, "", &got_object, &object_id).IsOk());
   ASSERT_TRUE(got_object);
   ASSERT_STREQ("id", object_id.c_str());
 }
diff --git a/chrome/test/chromedriver/chromedriver.cc b/chrome/test/chromedriver/chromedriver.cc
index 8f7ddce0..40e48fc 100644
--- a/chrome/test/chromedriver/chromedriver.cc
+++ b/chrome/test/chromedriver/chromedriver.cc
@@ -36,7 +36,7 @@ void SetError(const std::string& error_msg,
               std::string* response) {
   base::DictionaryValue value;
   value.SetString("message", error_msg);
-  SetResponse(kUnknownError, &value, std::string(), response);
+  SetResponse(kUnknownError, &value, "", response);
 }
 
 }  // namespace
@@ -120,6 +120,6 @@ void Shutdown() {
   scoped_ptr<base::Value> value;
   std::string session_id;
   g_command_executor->ExecuteCommand(
-      "quitAll", params, std::string(), &status_code, &value, &session_id);
+      "quitAll", params, "", &status_code, &value, &session_id);
   delete g_command_executor;
 }
diff --git a/chrome/test/chromedriver/chromedriver_unittest.cc b/chrome/test/chromedriver/chromedriver_unittest.cc
index 9e585e3..91e1e06 100644
--- a/chrome/test/chromedriver/chromedriver_unittest.cc
+++ b/chrome/test/chromedriver/chromedriver_unittest.cc
@@ -164,7 +164,7 @@ TEST(ChromeDriver, ExecuteCommand) {
     base::DictionaryValue params;
     scoped_ptr<base::Value> value(base::Value::CreateNullValue());
     mock->Expect(scoped_ptr<ExpectedCommand>(new ExpectedCommand(
-        "quitAll", params, std::string(), kOk, value.Pass(), std::string())));
+        "quitAll", params, "", kOk, value.Pass(), "")));
   }
   Shutdown();
 }
diff --git a/chrome/test/chromedriver/command_executor_impl_unittest.cc b/chrome/test/chromedriver/command_executor_impl_unittest.cc
index dafa6e4..f538d06 100644
--- a/chrome/test/chromedriver/command_executor_impl_unittest.cc
+++ b/chrome/test/chromedriver/command_executor_impl_unittest.cc
@@ -118,11 +118,8 @@ TEST(CommandExecutorImplTest, CommandThatReturnsError) {
   StatusCode status_code;
   scoped_ptr<base::Value> value;
   std::string out_session_id;
-  executor.ExecuteCommand("simpleCommand",
-                          params,
-                          std::string(),
-                          &status_code,
-                          &value,
+  executor.ExecuteCommand("simpleCommand", params, "",
+                          &status_code, &value,
                           &out_session_id);
   ASSERT_EQ(kUnknownError, status_code);
   ASSERT_TRUE(value);
diff --git a/chrome/test/chromedriver/commands_unittest.cc b/chrome/test/chromedriver/commands_unittest.cc
index dcfc06f..dabe0e2 100644
--- a/chrome/test/chromedriver/commands_unittest.cc
+++ b/chrome/test/chromedriver/commands_unittest.cc
@@ -28,8 +28,7 @@ TEST(CommandsTest, GetStatus) {
   base::DictionaryValue params;
   scoped_ptr<base::Value> value;
   std::string session_id;
-  ASSERT_EQ(
-      kOk, ExecuteGetStatus(params, std::string(), &value, &session_id).code());
+  ASSERT_EQ(kOk, ExecuteGetStatus(params, "", &value, &session_id).code());
   base::DictionaryValue* dict;
   ASSERT_TRUE(value->GetAsDictionary(&dict));
   base::Value* unused;
@@ -73,7 +72,7 @@ TEST(CommandsTest, QuitAll) {
   scoped_ptr<base::Value> value;
   std::string session_id;
   Status status =
-      ExecuteQuitAll(cmd, &map, params, std::string(), &value, &session_id);
+      ExecuteQuitAll(cmd, &map, params, "", &value, &session_id);
   ASSERT_EQ(kOk, status.code());
   ASSERT_FALSE(value.get());
   ASSERT_EQ(2, count);
@@ -244,7 +243,7 @@ TEST(CommandsTest, SuccessfulFindElement) {
   FindElementWebView web_view(true, kElementExistsQueryTwice);
   Session session("id");
   session.implicit_wait = 1000;
-  session.SwitchToSubFrame("frame_id1", std::string());
+  session.SwitchToSubFrame("frame_id1", "");
   base::DictionaryValue params;
   params.SetString("using", "id");
   params.SetString("value", "a");
@@ -273,7 +272,7 @@ TEST(CommandsTest, SuccessfulFindElements) {
   FindElementWebView web_view(false, kElementExistsQueryTwice);
   Session session("id");
   session.implicit_wait = 1000;
-  session.SwitchToSubFrame("frame_id2", std::string());
+  session.SwitchToSubFrame("frame_id2", "");
   base::DictionaryValue params;
   params.SetString("using", "name");
   params.SetString("value", "b");
@@ -307,7 +306,7 @@ TEST(CommandsTest, SuccessfulFindChildElement) {
   FindElementWebView web_view(true, kElementExistsQueryTwice);
   Session session("id");
   session.implicit_wait = 1000;
-  session.SwitchToSubFrame("frame_id3", std::string());
+  session.SwitchToSubFrame("frame_id3", "");
   base::DictionaryValue params;
   params.SetString("using", "tag name");
   params.SetString("value", "div");
@@ -345,7 +344,7 @@ TEST(CommandsTest, SuccessfulFindChildElements) {
   FindElementWebView web_view(false, kElementExistsQueryTwice);
   Session session("id");
   session.implicit_wait = 1000;
-  session.SwitchToSubFrame("frame_id4", std::string());
+  session.SwitchToSubFrame("frame_id4", "");
   base::DictionaryValue params;
   params.SetString("using", "class name");
   params.SetString("value", "c");
diff --git a/chrome/test/chromedriver/key_converter.cc b/chrome/test/chromedriver/key_converter.cc
index 49b95f3..64c6099 100644
--- a/chrome/test/chromedriver/key_converter.cc
+++ b/chrome/test/chromedriver/key_converter.cc
@@ -158,13 +158,11 @@ bool KeyCodeFromShorthandKey(char16 key_utf16,
 }  // namespace
 
 KeyEvent CreateKeyDownEvent(ui::KeyboardCode key_code, int modifiers) {
-  return KeyEvent(
-      kRawKeyDownEventType, modifiers, std::string(), std::string(), key_code);
+  return KeyEvent(kRawKeyDownEventType, modifiers, "", "", key_code);
 }
 
 KeyEvent CreateKeyUpEvent(ui::KeyboardCode key_code, int modifiers) {
-  return KeyEvent(
-      kKeyUpEventType, modifiers, std::string(), std::string(), key_code);
+  return KeyEvent(kKeyUpEventType, modifiers, "", "", key_code);
 }
 
 KeyEvent CreateCharEvent(const std::string& unmodified_text,
diff --git a/chrome/test/chromedriver/keycode_text_conversion_x.cc b/chrome/test/chromedriver/keycode_text_conversion_x.cc
index 7cf3b32..5b89935 100644
--- a/chrome/test/chromedriver/keycode_text_conversion_x.cc
+++ b/chrome/test/chromedriver/keycode_text_conversion_x.cc
@@ -180,7 +180,7 @@ bool GetXModifierMask(Display* display, int modifier, int* x_modifier) {
 std::string ConvertKeyCodeToText(ui::KeyboardCode key_code, int modifiers) {
   int x_key_code = KeyboardCodeToXKeyCode(key_code);
   if (x_key_code == -1)
-    return std::string();
+    return "";
 
   XEvent event;
   memset(&event, 0, sizeof(XEvent));
@@ -211,7 +211,7 @@ std::string ConvertKeyCodeToText(ui::KeyboardCode key_code, int modifiers) {
   uint16 character = ui::GetCharacterFromXEvent(&event);
 
   if (!character)
-    return std::string();
+    return "";
   return UTF16ToUTF8(string16(1, character));
 }
 
diff --git a/chrome/test/chromedriver/server/http_handler_unittest.cc b/chrome/test/chromedriver/server/http_handler_unittest.cc
index a4d81a4..d516902 100644
--- a/chrome/test/chromedriver/server/http_handler_unittest.cc
+++ b/chrome/test/chromedriver/server/http_handler_unittest.cc
@@ -56,7 +56,7 @@ TEST(HttpHandlerTest, HandleUnknownCommand) {
       scoped_ptr<CommandExecutor>(new DummyExecutor()),
       scoped_ptr<HttpHandler::CommandMap>(new HttpHandler::CommandMap()),
       "/");
-  HttpRequest request(kGet, "/path", std::string());
+  HttpRequest request(kGet, "/path", "");
   HttpResponse response;
   handler.Handle(request, &response);
   ASSERT_EQ(HttpResponse::kNotFound, response.status());
@@ -68,7 +68,7 @@ TEST(HttpHandlerTest, HandleNewSession) {
   HttpHandler handler(
       scoped_ptr<CommandExecutor>(new DummyExecutor()),
       map.Pass(), "/base/");
-  HttpRequest request(kPost, "/base/session", std::string());
+  HttpRequest request(kPost, "/base/session", "");
   HttpResponse response;
   handler.Handle(request, &response);
   ASSERT_EQ(HttpResponse::kSeeOther, response.status());
@@ -96,7 +96,7 @@ TEST(HttpHandlerTest, HandleUnimplementedCommand) {
   HttpHandler handler(
       scoped_ptr<CommandExecutor>(new DummyExecutor(kUnknownCommand)),
       map.Pass(), "/");
-  HttpRequest request(kPost, "/path", std::string());
+  HttpRequest request(kPost, "/path", "");
   HttpResponse response;
   handler.Handle(request, &response);
   ASSERT_EQ(HttpResponse::kNotImplemented, response.status());
@@ -108,7 +108,7 @@ TEST(HttpHandlerTest, HandleCommand) {
   HttpHandler handler(
       scoped_ptr<CommandExecutor>(new DummyExecutor()),
       map.Pass(), "/");
-  HttpRequest request(kPost, "/path", std::string());
+  HttpRequest request(kPost, "/path", "");
   HttpResponse response;
   handler.Handle(request, &response);
   ASSERT_EQ(HttpResponse::kOk, response.status());
@@ -140,9 +140,9 @@ TEST(MatchesCommandTest, DiffPathLength) {
   ASSERT_FALSE(internal::MatchesCommand(
       kPost, "path", command, &session_id, &params));
   ASSERT_FALSE(internal::MatchesCommand(
-      kPost, std::string(), command, &session_id, &params));
-  ASSERT_FALSE(
-      internal::MatchesCommand(kPost, "/", command, &session_id, &params));
+      kPost, "", command, &session_id, &params));
+  ASSERT_FALSE(internal::MatchesCommand(
+      kPost, "/", command, &session_id, &params));
   ASSERT_FALSE(internal::MatchesCommand(
       kPost, "path/path/path", command, &session_id, &params));
 }
diff --git a/chrome/test/chromedriver/session.cc b/chrome/test/chromedriver/session.cc
index ae10238..d6f6673 100644
--- a/chrome/test/chromedriver/session.cc
+++ b/chrome/test/chromedriver/session.cc
@@ -67,7 +67,7 @@ void Session::SwitchToSubFrame(const std::string& frame_id,
 
 std::string Session::GetCurrentFrameId() const {
   if (frames.empty())
-    return std::string();
+    return "";
   return frames.back().frame_id;
 }
 
diff --git a/chrome/test/chromedriver/session_commands.cc b/chrome/test/chromedriver/session_commands.cc
index 4be22c4..8fdea23 100644
--- a/chrome/test/chromedriver/session_commands.cc
+++ b/chrome/test/chromedriver/session_commands.cc
@@ -201,8 +201,7 @@ Status ExecuteSwitchToWindow(
       status = web_view->ConnectIfNecessary();
       if (status.IsError())
         return status;
-      status = web_view->CallFunction(
-          std::string(), kGetWindowNameScript, args, &result);
+      status = web_view->CallFunction("", kGetWindowNameScript, args, &result);
       if (status.IsError())
         return status;
       std::string window_name;
diff --git a/chrome/test/chromedriver/window_commands.cc b/chrome/test/chromedriver/window_commands.cc
index e7b7cd1..557d572 100644
--- a/chrome/test/chromedriver/window_commands.cc
+++ b/chrome/test/chromedriver/window_commands.cc
@@ -347,8 +347,7 @@ Status ExecuteGoBack(
     WebView* web_view,
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value) {
-  return web_view->EvaluateScript(
-      std::string(), "window.history.back();", value);
+  return web_view->EvaluateScript("", "window.history.back();", value);
 }
 
 Status ExecuteGoForward(
@@ -356,8 +355,7 @@ Status ExecuteGoForward(
     WebView* web_view,
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value) {
-  return web_view->EvaluateScript(
-      std::string(), "window.history.forward();", value);
+  return web_view->EvaluateScript("", "window.history.forward();", value);
 }
 
 Status ExecuteRefresh(
diff --git a/chrome/test/gpu/gpu_pixel_browsertest.cc b/chrome/test/gpu/gpu_pixel_browsertest.cc
index 82972a0..71d9478 100644
--- a/chrome/test/gpu/gpu_pixel_browsertest.cc
+++ b/chrome/test/gpu/gpu_pixel_browsertest.cc
@@ -145,7 +145,7 @@ class GpuPixelBrowserTest : public InProcessBrowserTest {
     const char* test_status_prefixes[] = {"DISABLED_", "FLAKY_", "FAILS_"};
     for (size_t i = 0; i < arraysize(test_status_prefixes); ++i) {
       ReplaceFirstSubstringAfterOffset(
-          &test_name_, 0, test_status_prefixes[i], std::string());
+          &test_name_, 0, test_status_prefixes[i], "");
     }
 
     ui::DisableTestCompositor();
diff --git a/chrome/test/perf/dom_checker_uitest.cc b/chrome/test/perf/dom_checker_uitest.cc
index f22cce4..f966250 100644
--- a/chrome/test/perf/dom_checker_uitest.cc
+++ b/chrome/test/perf/dom_checker_uitest.cc
@@ -143,24 +143,20 @@ class DomCheckerTest : public UITest {
   }
 
   bool WaitUntilTestCompletes(TabProxy* tab) {
-    return WaitUntilJavaScriptCondition(
-        tab,
-        std::wstring(),
+    return WaitUntilJavaScriptCondition(tab, L"",
         L"window.domAutomationController.send(automation.IsDone());",
         TestTimeouts::large_test_timeout());
   }
 
   bool GetTestCount(TabProxy* tab, int* test_count) {
-    return tab->ExecuteAndExtractInt(
-        std::wstring(),
+    return tab->ExecuteAndExtractInt(L"",
         L"window.domAutomationController.send(automation.GetTestCount());",
         test_count);
   }
 
   bool GetTestsFailed(TabProxy* tab, ResultsSet* tests_failed) {
     std::wstring json_wide;
-    bool succeeded = tab->ExecuteAndExtractString(
-        std::wstring(),
+    bool succeeded = tab->ExecuteAndExtractString(L"",
         L"window.domAutomationController.send("
         L"    JSON.stringify(automation.GetFailures()));",
         &json_wide);
diff --git a/chrome/test/perf/feature_startup_test.cc b/chrome/test/perf/feature_startup_test.cc
index 0caaa44..c11a386 100644
--- a/chrome/test/perf/feature_startup_test.cc
+++ b/chrome/test/perf/feature_startup_test.cc
@@ -38,8 +38,7 @@ class NewTabUIStartupTest : public UIPerfTest {
     std::string times;
     for (int i = 0; i < kNumCycles; ++i)
       base::StringAppendF(&times, "%.2f,", timings[i].InMillisecondsF());
-    perf_test::PrintResultList(
-        "new_tab", std::string(), label, times, "ms", important);
+    perf_test::PrintResultList("new_tab", "", label, times, "ms", important);
   }
 
   void InitProfile(UITestBase::ProfileType profile_type) {
diff --git a/chrome/test/perf/frame_rate/frame_rate_tests.cc b/chrome/test/perf/frame_rate/frame_rate_tests.cc
index 7b36b27..7be2b36 100644
--- a/chrome/test/perf/frame_rate/frame_rate_tests.cc
+++ b/chrome/test/perf/frame_rate/frame_rate_tests.cc
@@ -196,10 +196,8 @@ class FrameRateTest
     // race condition caused by an html redirect. If that is the case, verify
     // that flag kHasRedirect is enabled for the current test.
     ASSERT_TRUE(WaitUntilJavaScriptCondition(
-        tab,
-        std::wstring(),
-        L"window.domAutomationController.send(__initialized);",
-        TestTimeouts::large_test_timeout()));
+      tab, L"", L"window.domAutomationController.send(__initialized);",
+      TestTimeouts::large_test_timeout()));
 
     if (HasFlag(kForceGpuComposited)) {
       ASSERT_TRUE(tab->NavigateToURLAsync(
@@ -211,9 +209,7 @@ class FrameRateTest
 
     // Block until the tests completes.
     ASSERT_TRUE(WaitUntilJavaScriptCondition(
-        tab,
-        std::wstring(),
-        L"window.domAutomationController.send(!__running_all);",
+        tab, L"", L"window.domAutomationController.send(!__running_all);",
         TestTimeouts::large_test_timeout()));
 
     // TODO(jbates): remove this check when ref builds are updated.
@@ -229,7 +225,7 @@ class FrameRateTest
     // Read out the results.
     std::wstring json;
     ASSERT_TRUE(tab->ExecuteAndExtractString(
-        std::wstring(),
+        L"",
         L"window.domAutomationController.send("
         L"JSON.stringify(__calc_results_total()));",
         &json));
@@ -251,12 +247,8 @@ class FrameRateTest
                                                 results["sigmas"].c_str());
 
     std::string mean_and_error = results["mean"] + "," + results["sigma"];
-    perf_test::PrintResultMeanAndError(name,
-                                       std::string(),
-                                       trace_name,
-                                       mean_and_error,
-                                       "milliseconds-per-frame",
-                                       true);
+    perf_test::PrintResultMeanAndError(name, "", trace_name, mean_and_error,
+                                       "milliseconds-per-frame", true);
 
     // Navigate back to NTP so that we can quit without timing out during the
     // wait-for-idle stage in test framework.
diff --git a/chrome/test/perf/indexeddb_uitest.cc b/chrome/test/perf/indexeddb_uitest.cc
index 48db062..787f2bf1 100644
--- a/chrome/test/perf/indexeddb_uitest.cc
+++ b/chrome/test/perf/indexeddb_uitest.cc
@@ -63,8 +63,7 @@ class IndexedDBTest : public UIPerfTest {
 
   bool GetResults(TabProxy* tab, ResultsMap* results) {
     std::wstring json_wide;
-    bool succeeded = tab->ExecuteAndExtractString(
-        std::wstring(),
+    bool succeeded = tab->ExecuteAndExtractString(L"",
         L"window.domAutomationController.send("
         L"    JSON.stringify(automation.getResults()));",
         &json_wide);
@@ -85,8 +84,8 @@ class IndexedDBTest : public UIPerfTest {
 
     ResultsMap::const_iterator it = results.begin();
     for (; it != results.end(); ++it)
-      perf_test::PrintResultList(
-          it->first, std::string(), trace_name, it->second, "ms", false);
+      perf_test::PrintResultList(it->first, "", trace_name, it->second, "ms",
+                                 false);
   }
 
   DISALLOW_COPY_AND_ASSIGN(IndexedDBTest);
diff --git a/chrome/test/perf/page_cycler_test.cc b/chrome/test/perf/page_cycler_test.cc
index 9d13000..4354faf 100644
--- a/chrome/test/perf/page_cycler_test.cc
+++ b/chrome/test/perf/page_cycler_test.cc
@@ -215,11 +215,10 @@ class PageCyclerTest : public UIPerfTest {
 
     // Get the timing cookie value from the DOM automation.
     std::wstring wcookie;
-    ASSERT_TRUE(tab->ExecuteAndExtractString(
-        std::wstring(),
-        L"window.domAutomationController.send("
-        L"JSON.stringify(__get_timings()));",
-        &wcookie));
+    ASSERT_TRUE(tab->ExecuteAndExtractString(L"",
+          L"window.domAutomationController.send("
+          L"JSON.stringify(__get_timings()));",
+          &wcookie));
     cookie = base::SysWideToNativeMB(wcookie);
 
     // JSON.stringify() encapsulates the returned string in quotes, strip them.
@@ -261,8 +260,8 @@ class PageCyclerTest : public UIPerfTest {
 
     printf("Pages: [%s]\n", base::SysWideToNativeMB(pages).c_str());
 
-    perf_test::PrintResultList(
-        graph, std::string(), trace_name, timings, "ms", true /* important */);
+    perf_test::PrintResultList(graph, "", trace_name, timings, "ms",
+                               true /* important */);
   }
 
   void RunTest(const char* graph, const char* name, bool use_http) {
@@ -276,7 +275,7 @@ class PageCyclerTest : public UIPerfTest {
     ASSERT_TRUE(tab.get());
     std::wstring whistogram;
     ASSERT_TRUE(tab->ExecuteAndExtractString(
-        std::wstring(),
+        L"",
         L"window.domAutomationController.send("
         L"window.domAutomationController.getHistogram ? "
         L"window.domAutomationController.getHistogram(\"" +
diff --git a/chrome/test/perf/perf_test.cc b/chrome/test/perf/perf_test.cc
index ec1d214..68c92e1 100644
--- a/chrome/test/perf/perf_test.cc
+++ b/chrome/test/perf/perf_test.cc
@@ -54,14 +54,8 @@ void PrintResult(const std::string& measurement,
                  size_t value,
                  const std::string& units,
                  bool important) {
-  PrintResultsImpl(measurement,
-                   modifier,
-                   trace,
-                   base::UintToString(value),
-                   std::string(),
-                   std::string(),
-                   units,
-                   important);
+  PrintResultsImpl(measurement, modifier, trace, base::UintToString(value),
+                   "", "", units, important);
 }
 
 void AppendResult(std::string& output,
@@ -71,14 +65,9 @@ void AppendResult(std::string& output,
                   size_t value,
                   const std::string& units,
                   bool important) {
-  output += ResultsToString(measurement,
-                            modifier,
-                            trace,
+  output += ResultsToString(measurement, modifier, trace,
                             base::UintToString(value),
-                            std::string(),
-                            std::string(),
-                            units,
-                            important);
+                            "", "", units, important);
 }
 
 void PrintResult(const std::string& measurement,
@@ -87,13 +76,7 @@ void PrintResult(const std::string& measurement,
                  const std::string& value,
                  const std::string& units,
                  bool important) {
-  PrintResultsImpl(measurement,
-                   modifier,
-                   trace,
-                   value,
-                   std::string(),
-                   std::string(),
-                   units,
+  PrintResultsImpl(measurement, modifier, trace, value, "", "", units,
                    important);
 }
 
@@ -104,13 +87,7 @@ void AppendResult(std::string& output,
                   const std::string& value,
                   const std::string& units,
                   bool important) {
-  output += ResultsToString(measurement,
-                            modifier,
-                            trace,
-                            value,
-                            std::string(),
-                            std::string(),
-                            units,
+  output += ResultsToString(measurement, modifier, trace, value, "", "", units,
                             important);
 }
 
@@ -256,120 +233,40 @@ std::string IOPerfInfoToString(const std::string& test_name,
   }
 
   std::string t_name(test_name);
-  AppendResult(output,
-               "read_op_b",
-               std::string(),
-               "r_op_b" + t_name,
-               read_op_b,
-               "ops",
+  AppendResult(output, "read_op_b", "", "r_op_b" + t_name, read_op_b, "ops",
                false);
-  AppendResult(output,
-               "write_op_b",
-               std::string(),
-               "w_op_b" + t_name,
-               write_op_b,
-               "ops",
+  AppendResult(output, "write_op_b", "", "w_op_b" + t_name, write_op_b, "ops",
                false);
-  AppendResult(output,
-               "other_op_b",
-               std::string(),
-               "o_op_b" + t_name,
-               other_op_b,
-               "ops",
+  AppendResult(output, "other_op_b", "", "o_op_b" + t_name, other_op_b, "ops",
                false);
-  AppendResult(output,
-               "total_op_b",
-               std::string(),
-               "IO_op_b" + t_name,
-               total_op_b,
-               "ops",
+  AppendResult(output, "total_op_b", "", "IO_op_b" + t_name, total_op_b, "ops",
                false);
 
-  AppendResult(output,
-               "read_byte_b",
-               std::string(),
-               "r_b" + t_name,
-               read_byte_b,
-               "kb",
+  AppendResult(output, "read_byte_b", "", "r_b" + t_name, read_byte_b, "kb",
                false);
-  AppendResult(output,
-               "write_byte_b",
-               std::string(),
-               "w_b" + t_name,
-               write_byte_b,
-               "kb",
+  AppendResult(output, "write_byte_b", "", "w_b" + t_name, write_byte_b, "kb",
                false);
-  AppendResult(output,
-               "other_byte_b",
-               std::string(),
-               "o_b" + t_name,
-               other_byte_b,
-               "kb",
+  AppendResult(output, "other_byte_b", "", "o_b" + t_name, other_byte_b, "kb",
                false);
-  AppendResult(output,
-               "total_byte_b",
-               std::string(),
-               "IO_b" + t_name,
-               total_byte_b,
-               "kb",
+  AppendResult(output, "total_byte_b", "", "IO_b" + t_name, total_byte_b, "kb",
                false);
 
-  AppendResult(output,
-               "read_op_r",
-               std::string(),
-               "r_op_r" + t_name,
-               read_op_r,
-               "ops",
+  AppendResult(output, "read_op_r", "", "r_op_r" + t_name, read_op_r, "ops",
                false);
-  AppendResult(output,
-               "write_op_r",
-               std::string(),
-               "w_op_r" + t_name,
-               write_op_r,
-               "ops",
+  AppendResult(output, "write_op_r", "", "w_op_r" + t_name, write_op_r, "ops",
                false);
-  AppendResult(output,
-               "other_op_r",
-               std::string(),
-               "o_op_r" + t_name,
-               other_op_r,
-               "ops",
+  AppendResult(output, "other_op_r", "", "o_op_r" + t_name, other_op_r, "ops",
                false);
-  AppendResult(output,
-               "total_op_r",
-               std::string(),
-               "IO_op_r" + t_name,
-               total_op_r,
-               "ops",
+  AppendResult(output, "total_op_r", "", "IO_op_r" + t_name, total_op_r, "ops",
                false);
 
-  AppendResult(output,
-               "read_byte_r",
-               std::string(),
-               "r_r" + t_name,
-               read_byte_r,
-               "kb",
+  AppendResult(output, "read_byte_r", "", "r_r" + t_name, read_byte_r, "kb",
                false);
-  AppendResult(output,
-               "write_byte_r",
-               std::string(),
-               "w_r" + t_name,
-               write_byte_r,
-               "kb",
+  AppendResult(output, "write_byte_r", "", "w_r" + t_name, write_byte_r, "kb",
                false);
-  AppendResult(output,
-               "other_byte_r",
-               std::string(),
-               "o_r" + t_name,
-               other_byte_r,
-               "kb",
+  AppendResult(output, "other_byte_r", "", "o_r" + t_name, other_byte_r, "kb",
                false);
-  AppendResult(output,
-               "total_byte_r",
-               std::string(),
-               "IO_r" + t_name,
-               total_byte_r,
-               "kb",
+  AppendResult(output, "total_byte_r", "", "IO_r" + t_name, total_byte_r, "kb",
                false);
 
   return output;
@@ -495,57 +392,29 @@ std::string MemoryUsageInfoToString(const std::string& test_name,
                total_working_set_size, "bytes",
                false /* not important */);
 #elif defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_ANDROID)
-  AppendResult(output,
-               "vm_size_final_b",
-               std::string(),
-               "vm_size_f_b" + trace_name,
-               browser_virtual_size,
-               "bytes",
+  AppendResult(output, "vm_size_final_b", "", "vm_size_f_b" + trace_name,
+               browser_virtual_size, "bytes",
                false /* not important */);
-  AppendResult(output,
-               "vm_rss_final_b",
-               std::string(),
-               "vm_rss_f_b" + trace_name,
-               browser_working_set_size,
-               "bytes",
+  AppendResult(output, "vm_rss_final_b", "", "vm_rss_f_b" + trace_name,
+               browser_working_set_size, "bytes",
                false /* not important */);
-  AppendResult(output,
-               "vm_size_final_r",
-               std::string(),
-               "vm_size_f_r" + trace_name,
-               renderer_virtual_size,
-               "bytes",
+  AppendResult(output, "vm_size_final_r", "", "vm_size_f_r" + trace_name,
+               renderer_virtual_size, "bytes",
                false /* not important */);
-  AppendResult(output,
-               "vm_rss_final_r",
-               std::string(),
-               "vm_rss_f_r" + trace_name,
-               renderer_working_set_size,
-               "bytes",
+  AppendResult(output, "vm_rss_final_r", "", "vm_rss_f_r" + trace_name,
+               renderer_working_set_size, "bytes",
                false /* not important */);
-  AppendResult(output,
-               "vm_size_final_t",
-               std::string(),
-               "vm_size_f_t" + trace_name,
-               total_virtual_size,
-               "bytes",
+  AppendResult(output, "vm_size_final_t", "", "vm_size_f_t" + trace_name,
+               total_virtual_size, "bytes",
                false /* not important */);
-  AppendResult(output,
-               "vm_rss_final_t",
-               std::string(),
-               "vm_rss_f_t" + trace_name,
-               total_working_set_size,
-               "bytes",
+  AppendResult(output, "vm_rss_final_t", "", "vm_rss_f_t" + trace_name,
+               total_working_set_size, "bytes",
                false /* not important */);
 #else
   NOTIMPLEMENTED();
 #endif
-  AppendResult(output,
-               "processes",
-               std::string(),
-               "proc_" + trace_name,
-               chrome_processes.size(),
-               "count",
+  AppendResult(output, "processes", "", "proc_" + trace_name,
+               chrome_processes.size(), "count",
                false /* not important */);
 
   return output;
@@ -570,12 +439,7 @@ std::string SystemCommitChargeToString(const std::string& test_name,
                                        bool important) {
   std::string trace_name(test_name);
   std::string output;
-  AppendResult(output,
-               "commit_charge",
-               std::string(),
-               "cc" + trace_name,
-               charge,
-               "kb",
+  AppendResult(output, "commit_charge", "", "cc" + trace_name, charge, "kb",
                important);
   return output;
 }
diff --git a/chrome/test/perf/rendering/latency_tests.cc b/chrome/test/perf/rendering/latency_tests.cc
index fdd00d7..70939fd 100644
--- a/chrome/test/perf/rendering/latency_tests.cc
+++ b/chrome/test/perf/rendering/latency_tests.cc
@@ -153,7 +153,7 @@ class LatencyTest
         return "software";
       default:
         NOTREACHED() << "invalid mode";
-        return std::string();
+        return "";
     }
   }
 
@@ -586,12 +586,8 @@ double LatencyTest::CalculateLatency() {
   std::string trace_name = GetTraceName(test_flags_);
   std::string mean_and_error = base::StringPrintf("%f,%f", mean_latency,
                                                   mean_error);
-  perf_test::PrintResultMeanAndError(GetModeString(),
-                                     std::string(),
-                                     trace_name,
-                                     mean_and_error,
-                                     "frames",
-                                     true);
+  perf_test::PrintResultMeanAndError(GetModeString(), "", trace_name,
+                                     mean_and_error, "frames", true);
   return mean_latency;
 }
 
diff --git a/chrome/test/perf/rendering/throughput_tests.cc b/chrome/test/perf/rendering/throughput_tests.cc
index 08a1483..79d6bbb 100644
--- a/chrome/test/perf/rendering/throughput_tests.cc
+++ b/chrome/test/perf/rendering/throughput_tests.cc
@@ -383,12 +383,8 @@ class ThroughputTest : public BrowserPerfTest {
                              ran_on_gpu ? "gpu" : "software";
     std::string mean_and_error = base::StringPrintf("%f,%f", mean_ms,
                                                     std_dev_ms);
-    perf_test::PrintResultMeanAndError(test_name,
-                                       std::string(),
-                                       trace_name,
-                                       mean_and_error,
-                                       "frame_time",
-                                       true);
+    perf_test::PrintResultMeanAndError(test_name, "", trace_name,
+                                       mean_and_error, "frame_time", true);
 
     if (flags & kAllowExternalDNS)
       ResetAllowExternalDNS();
diff --git a/chrome/test/perf/shutdown_test.cc b/chrome/test/perf/shutdown_test.cc
index d97c58b..7cbc7b6 100644
--- a/chrome/test/perf/shutdown_test.cc
+++ b/chrome/test/perf/shutdown_test.cc
@@ -114,8 +114,7 @@ class ShutdownTest : public UIPerfTest {
     std::string times;
     for (int i = 0; i < numCycles; ++i)
       base::StringAppendF(&times, "%.2f,", timings[i].InMillisecondsF());
-    perf_test::PrintResultList(
-        graph, std::string(), trace, times, "ms", important);
+    perf_test::PrintResultList(graph, "", trace, times, "ms", important);
   }
 };
 
diff --git a/chrome/test/perf/startup_test.cc b/chrome/test/perf/startup_test.cc
index 0a07ce8..1d8243f 100644
--- a/chrome/test/perf/startup_test.cc
+++ b/chrome/test/perf/startup_test.cc
@@ -295,8 +295,7 @@ class StartupTest : public UIPerfTest {
                           "%.2f,",
                           timings[i].end_to_end.InMillisecondsF());
     }
-    perf_test::PrintResultList(
-        graph, std::string(), trace, times, "ms", important);
+    perf_test::PrintResultList(graph, "", trace, times, "ms", important);
 
     if (num_tabs > 0) {
       std::string name_base = trace;
@@ -306,15 +305,15 @@ class StartupTest : public UIPerfTest {
       name = name_base + "-start";
       for (int i = 0; i < numCycles; ++i)
         base::StringAppendF(&times, "%.2f,", timings[i].first_start_ms);
-      perf_test::PrintResultList(
-          graph, std::string(), name.c_str(), times, "ms", important);
+      perf_test::PrintResultList(graph, "", name.c_str(), times, "ms",
+                                 important);
 
       times.clear();
       name = name_base + "-first";
       for (int i = 0; i < numCycles; ++i)
         base::StringAppendF(&times, "%.2f,", timings[i].first_stop_ms);
-      perf_test::PrintResultList(
-          graph, std::string(), name.c_str(), times, "ms", important);
+      perf_test::PrintResultList(graph, "", name.c_str(), times, "ms",
+                                 important);
 
       if (nth_timed_tab > 0) {
         // Display only the time necessary to load the first n tabs.
@@ -322,8 +321,8 @@ class StartupTest : public UIPerfTest {
         name = name_base + "-" + base::IntToString(nth_timed_tab);
         for (int i = 0; i < numCycles; ++i)
           base::StringAppendF(&times, "%.2f,", timings[i].nth_tab_stop_ms);
-        perf_test::PrintResultList(
-            graph, std::string(), name.c_str(), times, "ms", important);
+        perf_test::PrintResultList(graph, "", name.c_str(), times, "ms",
+                                   important);
       }
 
       if (num_tabs > 1) {
@@ -332,8 +331,8 @@ class StartupTest : public UIPerfTest {
         name = name_base + "-all";
         for (int i = 0; i < numCycles; ++i)
           base::StringAppendF(&times, "%.2f,", timings[i].last_stop_ms);
-        perf_test::PrintResultList(
-            graph, std::string(), name.c_str(), times, "ms", important);
+        perf_test::PrintResultList(graph, "", name.c_str(), times, "ms",
+                                   important);
       }
     }
   }
diff --git a/chrome/test/perf/tab_switching_test.cc b/chrome/test/perf/tab_switching_test.cc
index a56c792..45a0891 100644
--- a/chrome/test/perf/tab_switching_test.cc
+++ b/chrome/test/perf/tab_switching_test.cc
@@ -69,8 +69,7 @@ class TabSwitchingUITest : public UIPerfTest {
       std::string times;
       for (int i = 0; i < kNumCycles; ++i)
         base::StringAppendF(&times, "%.2f,", timings[i].InMillisecondsF());
-      perf_test::PrintResultList(
-          "times", std::string(), label, times, "ms", important);
+      perf_test::PrintResultList("times", "", label, times, "ms", important);
   }
 
   void RunTabSwitchingUITest(const char* label, bool important) {
diff --git a/chrome/test/perf/url_fetch_test.cc b/chrome/test/perf/url_fetch_test.cc
index 2cffb68..6c8712f 100644
--- a/chrome/test/perf/url_fetch_test.cc
+++ b/chrome/test/perf/url_fetch_test.cc
@@ -77,8 +77,8 @@ class UrlFetchTest : public UIPerfTest {
           "window.domAutomationController.send(%s);", var_to_fetch);
 
       std::wstring value;
-      bool success = tab->ExecuteAndExtractString(
-          std::wstring(), ASCIIToWide(script), &value);
+      bool success = tab->ExecuteAndExtractString(L"", ASCIIToWide(script),
+                                                  &value);
       ASSERT_TRUE(success);
       result->javascript_variable = WideToUTF8(value);
     }
diff --git a/chrome/test/ppapi/ppapi_test.cc b/chrome/test/ppapi/ppapi_test.cc
index 4cc99f4..bec32a6 100644
--- a/chrome/test/ppapi/ppapi_test.cc
+++ b/chrome/test/ppapi/ppapi_test.cc
@@ -156,7 +156,7 @@ GURL PPAPITestBase::GetTestFileUrl(const std::string& test_case) {
   GURL test_url = net::FilePathToFileURL(test_path);
 
   GURL::Replacements replacements;
-  std::string query = BuildQuery(std::string(), test_case);
+  std::string query = BuildQuery("", test_case);
   replacements.SetQuery(query.c_str(), url_parse::Component(0, query.size()));
   return test_url.ReplaceComponents(replacements);
 }
@@ -182,7 +182,7 @@ void PPAPITestBase::RunTestViaHTTP(const std::string& test_case) {
                               net::TestServer::kLocalhost,
                               document_root);
   ASSERT_TRUE(http_server.Start());
-  RunTestURL(GetTestURL(http_server, test_case, std::string()));
+  RunTestURL(GetTestURL(http_server, test_case, ""));
 }
 
 void PPAPITestBase::RunTestWithSSLServer(const std::string& test_case) {
diff --git a/chrome/test/reliability/automated_ui_tests.cc b/chrome/test/reliability/automated_ui_tests.cc
index 4654082..fd50b23 100644
--- a/chrome/test/reliability/automated_ui_tests.cc
+++ b/chrome/test/reliability/automated_ui_tests.cc
@@ -505,7 +505,7 @@ bool AutomatedUITest::ChangeEncoding() {
   std::string cur_locale = g_browser_process->GetApplicationLocale();
   const std::vector<CharacterEncoding::EncodingInfo>* encodings =
       CharacterEncoding::GetCurrentDisplayEncodings(
-          cur_locale, "ISO-8859-1,windows-1252", std::string());
+          cur_locale, "ISO-8859-1,windows-1252", "");
   DCHECK(encodings);
   DCHECK(!encodings->empty());
   unsigned len = static_cast<unsigned>(encodings->size());
diff --git a/chrome/test/ui/ui_test.cc b/chrome/test/ui/ui_test.cc
index 40bdf16..cf839fb 100644
--- a/chrome/test/ui/ui_test.cc
+++ b/chrome/test/ui/ui_test.cc
@@ -516,7 +516,7 @@ bool UITestBase::BeginTracing(const std::string& categories) {
 std::string UITestBase::EndTracing() {
   std::string json_trace_output;
   if (!automation()->EndTracing(&json_trace_output))
-    return std::string();
+    return "";
   return json_trace_output;
 }
 
diff --git a/chrome/test/webdriver/commands/command.cc b/chrome/test/webdriver/commands/command.cc
index dfde908..1471e0a 100644
--- a/chrome/test/webdriver/commands/command.cc
+++ b/chrome/test/webdriver/commands/command.cc
@@ -32,7 +32,7 @@ bool Command::Init(Response* const response) {
 void Command::Finish(Response* const response) {}
 
 std::string Command::GetPathVariable(const size_t i) const {
-  return i < path_segments_.size() ? path_segments_.at(i) : std::string();
+  return i < path_segments_.size() ? path_segments_.at(i) : "";
 }
 
 bool Command::HasParameter(const std::string& key) const {
diff --git a/chrome/test/webdriver/commands/set_timeout_commands_unittest.cc b/chrome/test/webdriver/commands/set_timeout_commands_unittest.cc
index 767fbb1..2db4f4c 100644
--- a/chrome/test/webdriver/commands/set_timeout_commands_unittest.cc
+++ b/chrome/test/webdriver/commands/set_timeout_commands_unittest.cc
@@ -55,7 +55,7 @@ TEST(ImplicitWaitCommandTest, SettingImplicitWaits) {
   ASSERT_EQ(0, test_session.implicit_wait()) << "Sanity check failed";
 
   std::vector<std::string> path_segments;
-  path_segments.push_back(std::string());
+  path_segments.push_back("");
   path_segments.push_back("session");
   path_segments.push_back(test_session.id());
   path_segments.push_back("timeouts");
diff --git a/chrome/test/webdriver/frame_path.cc b/chrome/test/webdriver/frame_path.cc
index fd45a8d..bce634d9 100644
--- a/chrome/test/webdriver/frame_path.cc
+++ b/chrome/test/webdriver/frame_path.cc
@@ -8,7 +8,7 @@
 
 namespace webdriver {
 
-FramePath::FramePath() {}
+FramePath::FramePath() : path_("") {}
 
 FramePath::FramePath(const FramePath& other) : path_(other.path_) {}
 
diff --git a/chrome/test/webdriver/keycode_text_conversion_gtk.cc b/chrome/test/webdriver/keycode_text_conversion_gtk.cc
index 302d708..05b17db 100644
--- a/chrome/test/webdriver/keycode_text_conversion_gtk.cc
+++ b/chrome/test/webdriver/keycode_text_conversion_gtk.cc
@@ -23,7 +23,7 @@ std::string ConvertKeyCodeToText(ui::KeyboardCode key_code, int modifiers) {
     gdk_key_code = gdk_keyval_to_upper(gdk_key_code);
   guint32 unicode_char = gdk_keyval_to_unicode(gdk_key_code);
   if (!unicode_char)
-    return std::string();
+    return "";
   gchar buffer[6];
   gint length = g_unichar_to_utf8(unicode_char, buffer);
   return std::string(buffer, length);
diff --git a/chrome/test/webdriver/webdriver_dispatch_unittest.cc b/chrome/test/webdriver/webdriver_dispatch_unittest.cc
index 8e75edb..855711d 100644
--- a/chrome/test/webdriver/webdriver_dispatch_unittest.cc
+++ b/chrome/test/webdriver/webdriver_dispatch_unittest.cc
@@ -158,7 +158,7 @@ class ParseRequestInfoTest : public testing::Test {
   virtual ~ParseRequestInfoTest() {}
 
   virtual void TearDown() {
-    SessionManager::GetInstance()->set_url_base(std::string());
+    SessionManager::GetInstance()->set_url_base("");
   }
 
  private:
@@ -178,7 +178,7 @@ TEST_F(ParseRequestInfoTest, ParseRequestWithEmptyUrlBase) {
   base::DictionaryValue* parameters;
   Response response;
 
-  SessionManager::GetInstance()->set_url_base(std::string());
+  SessionManager::GetInstance()->set_url_base("");
   EXPECT_TRUE(internal::ParseRequestInfo(
       &request_info,
       NULL,  // NULL is ok because GET not POST is used
diff --git a/chrome/test/webdriver/webdriver_key_converter.cc b/chrome/test/webdriver/webdriver_key_converter.cc
index b83d3cb..e19e9dc 100644
--- a/chrome/test/webdriver/webdriver_key_converter.cc
+++ b/chrome/test/webdriver/webdriver_key_converter.cc
@@ -162,19 +162,11 @@ bool KeyCodeFromShorthandKey(char16 key_utf16,
 namespace webdriver {
 
 WebKeyEvent CreateKeyDownEvent(ui::KeyboardCode key_code, int modifiers) {
-  return WebKeyEvent(automation::kRawKeyDownType,
-                     key_code,
-                     std::string(),
-                     std::string(),
-                     modifiers);
+  return WebKeyEvent(automation::kRawKeyDownType, key_code, "", "", modifiers);
 }
 
 WebKeyEvent CreateKeyUpEvent(ui::KeyboardCode key_code, int modifiers) {
-  return WebKeyEvent(automation::kKeyUpType,
-                     key_code,
-                     std::string(),
-                     std::string(),
-                     modifiers);
+  return WebKeyEvent(automation::kKeyUpType, key_code, "", "", modifiers);
 }
 
 WebKeyEvent CreateCharEvent(const std::string& unmodified_text,
diff --git a/chrome/test/webdriver/webdriver_session.cc b/chrome/test/webdriver/webdriver_session.cc
index 6ed89d9..953120a 100644
--- a/chrome/test/webdriver/webdriver_session.cc
+++ b/chrome/test/webdriver/webdriver_session.cc
@@ -942,11 +942,9 @@ Error* Session::GetElementRegionInView(
     // Find the frame element for the current frame path.
     FrameId frame_id(current_target_.view_id, frame_path.Parent());
     ElementId frame_element;
-    error = FindElement(frame_id,
-                        ElementId(std::string()),
-                        LocatorType::kXpath,
-                        frame_path.BaseName().value(),
-                        &frame_element);
+    error = FindElement(
+        frame_id, ElementId(""),
+        LocatorType::kXpath, frame_path.BaseName().value(), &frame_element);
     if (error) {
       std::string context = base::StringPrintf(
           "Could not find frame element (%s) in frame (%s)",
diff --git a/chrome/test/webdriver/webdriver_session_manager.cc b/chrome/test/webdriver/webdriver_session_manager.cc
index aa5aeca..8dc42e2 100644
--- a/chrome/test/webdriver/webdriver_session_manager.cc
+++ b/chrome/test/webdriver/webdriver_session_manager.cc
@@ -49,7 +49,7 @@ std::string SessionManager::url_base() const {
   return url_base_;
 }
 
-SessionManager::SessionManager() {}
+SessionManager::SessionManager() : port_(""), url_base_("") {}
 
 SessionManager::~SessionManager() {}
 
diff --git a/chrome/tools/ipclist/ipcfuzz.cc b/chrome/tools/ipclist/ipcfuzz.cc
index 1d288c5..0eafb14 100644
--- a/chrome/tools/ipclist/ipcfuzz.cc
+++ b/chrome/tools/ipclist/ipcfuzz.cc
@@ -180,17 +180,17 @@ class DefaultFuzzer : public IPC::Fuzzer {
   }
 
   virtual void FuzzString(std::string* value) OVERRIDE {
-    FuzzStringType<std::string>(value, frequency_, "BORKED", std::string());
+    FuzzStringType<std::string>(value, frequency_, "BORKED", "");
   }
 
   virtual void FuzzWString(std::wstring* value) OVERRIDE {
-    FuzzStringType<std::wstring>(value, frequency_, L"BORKED", std::wstring());
+    FuzzStringType<std::wstring>(value, frequency_, L"BORKED", L"");
   }
 
   virtual void FuzzString16(string16* value) OVERRIDE {
     FuzzStringType<string16>(value, frequency_,
                              WideToUTF16(L"BORKED"),
-                             WideToUTF16(std::wstring()));
+                             WideToUTF16(L""));
   }
 
   virtual void FuzzData(char* data, int length) OVERRIDE {
diff --git a/chrome/utility/profile_import_handler.cc b/chrome/utility/profile_import_handler.cc
index 413feea..473581c 100644
--- a/chrome/utility/profile_import_handler.cc
+++ b/chrome/utility/profile_import_handler.cc
@@ -68,7 +68,7 @@ void ProfileImportHandler::OnImportItemFinished(uint16 item) {
   items_to_import_ ^= item;  // Remove finished item from mask.
   // If we've finished with all items, notify the browser process.
   if (items_to_import_ == 0) {
-    Send(new ProfileImportProcessHostMsg_Import_Finished(true, std::string()));
+    Send(new ProfileImportProcessHostMsg_Import_Finished(true, ""));
     ImporterCleanup();
   }
 }
diff --git a/components/autofill/browser/phone_number_i18n_unittest.cc b/components/autofill/browser/phone_number_i18n_unittest.cc
index 0547520..7744272 100644
--- a/components/autofill/browser/phone_number_i18n_unittest.cc
+++ b/components/autofill/browser/phone_number_i18n_unittest.cc
@@ -337,7 +337,7 @@ TEST(PhoneNumberI18NTest, PhoneNumbersMatch) {
   // Same numbers, undefined country code.
   EXPECT_TRUE(PhoneNumbersMatch(ASCIIToUTF16("4158889999"),
                                 ASCIIToUTF16("4158889999"),
-                                std::string(),
+                                "",
                                 "en-US"));
 
   // Numbers differ by country code only.
diff --git a/components/autofill/browser/wallet/full_wallet_unittest.cc b/components/autofill/browser/wallet/full_wallet_unittest.cc
index 5a65940..9eead30 100644
--- a/components/autofill/browser/wallet/full_wallet_unittest.cc
+++ b/components/autofill/browser/wallet/full_wallet_unittest.cc
@@ -402,8 +402,8 @@ TEST_F(FullWalletTest, CreateFullWalletWithRequiredActions) {
 
   FullWallet full_wallet(-1,
                          -1,
-                         std::string(),
-                         std::string(),
+                         "",
+                         "",
                          scoped_ptr<Address>(),
                          scoped_ptr<Address>(),
                          required_actions);
@@ -411,13 +411,14 @@ TEST_F(FullWalletTest, CreateFullWalletWithRequiredActions) {
 
   ASSERT_FALSE(required_actions.empty());
   required_actions.pop_back();
-  FullWallet different_required_actions(-1,
-                                        -1,
-                                        std::string(),
-                                        std::string(),
-                                        scoped_ptr<Address>(),
-                                        scoped_ptr<Address>(),
-                                        required_actions);
+  FullWallet different_required_actions(
+      -1,
+      -1,
+      "",
+      "",
+      scoped_ptr<Address>(),
+      scoped_ptr<Address>(),
+      required_actions);
   EXPECT_NE(full_wallet, different_required_actions);
 }
 
diff --git a/components/autofill/browser/wallet/wallet_address_unittest.cc b/components/autofill/browser/wallet/wallet_address_unittest.cc
index 7ac92f7..0949c6a 100644
--- a/components/autofill/browser/wallet/wallet_address_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_address_unittest.cc
@@ -176,7 +176,7 @@ TEST_F(WalletAddressTest, CreateAddressMissingObjectId) {
                   ASCIIToUTF16("administrative_area_name"),
                   ASCIIToUTF16("postal_code_number"),
                   ASCIIToUTF16("phone_number"),
-                  std::string());
+                  "");
   ASSERT_EQ(address, *Address::CreateAddress(*dict_));
 }
 
@@ -243,7 +243,7 @@ TEST_F(WalletAddressTest, CreateDisplayAddress) {
                   ASCIIToUTF16("state"),
                   ASCIIToUTF16("postal_code"),
                   ASCIIToUTF16("phone_number"),
-                  std::string());
+                  "");
   ASSERT_EQ(address, *Address::CreateDisplayAddress(*dict_));
 }
 
@@ -272,7 +272,7 @@ TEST_F(WalletAddressTest, ToDictionaryWithoutID) {
                   ASCIIToUTF16("administrative_area_name"),
                   ASCIIToUTF16("postal_code_number"),
                   ASCIIToUTF16("phone_number"),
-                  std::string());
+                  "");
 
   EXPECT_TRUE(expected.Equals(address.ToDictionaryWithoutID().get()));
 }
diff --git a/components/autofill/browser/wallet/wallet_client_unittest.cc b/components/autofill/browser/wallet/wallet_client_unittest.cc
index 6229847..27d1a2d 100644
--- a/components/autofill/browser/wallet/wallet_client_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_client_unittest.cc
@@ -810,8 +810,9 @@ TEST_F(WalletClientTest, NetworkFailureOnExpectedVoidResponse) {
   delegate_.ExpectBaselineMetrics(NO_ESCROW_REQUEST, HAS_WALLET_REQUEST);
   delegate_.ExpectWalletErrorMetric(AutofillMetrics::WALLET_NETWORK_ERROR);
 
-  wallet_client_->SendAutocheckoutStatus(
-      autofill::SUCCESS, GURL(kMerchantUrl), std::string());
+  wallet_client_->SendAutocheckoutStatus(autofill::SUCCESS,
+                                         GURL(kMerchantUrl),
+                                         "");
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
   ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
@@ -839,8 +840,9 @@ TEST_F(WalletClientTest, RequestError) {
   delegate_.ExpectBaselineMetrics(NO_ESCROW_REQUEST, HAS_WALLET_REQUEST);
   delegate_.ExpectWalletErrorMetric(AutofillMetrics::WALLET_BAD_REQUEST);
 
-  wallet_client_->SendAutocheckoutStatus(
-      autofill::SUCCESS, GURL(kMerchantUrl), std::string());
+  wallet_client_->SendAutocheckoutStatus(autofill::SUCCESS,
+                                         GURL(kMerchantUrl),
+                                         "");
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
   ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_BAD_REQUEST);
diff --git a/components/autofill/browser/wallet/wallet_items_unittest.cc b/components/autofill/browser/wallet/wallet_items_unittest.cc
index 9495d8b..552a31b 100644
--- a/components/autofill/browser/wallet/wallet_items_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_items_unittest.cc
@@ -418,7 +418,7 @@ TEST_F(WalletItemsTest, CreateMaskedInstrument) {
                                           ASCIIToUTF16("state"),
                                           ASCIIToUTF16("postal_code"),
                                           ASCIIToUTF16("phone_number"),
-                                          std::string()));
+                                          ""));
   std::vector<string16> supported_currencies;
   supported_currencies.push_back(ASCIIToUTF16("currency"));
   WalletItems::MaskedInstrument masked_instrument(
@@ -520,7 +520,7 @@ TEST_F(WalletItemsTest, CreateWalletItems) {
                                                   ASCIIToUTF16("state"),
                                                   ASCIIToUTF16("postal_code"),
                                                   ASCIIToUTF16("phone_number"),
-                                                  std::string()));
+                                                  ""));
   std::vector<string16> supported_currencies;
   supported_currencies.push_back(ASCIIToUTF16("currency"));
   scoped_ptr<WalletItems::MaskedInstrument> masked_instrument(
diff --git a/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc b/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc
index 20175b1..e574d55 100644
--- a/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc
@@ -120,10 +120,9 @@ class WalletSigninHelperTest : public testing::Test {
 
   void MockFailedOAuthLoginResponse404() {
     SetUpFetcherResponseAndCompleteRequest(
-        GaiaUrls::GetInstance()->client_login_url(),
-        404,
+        GaiaUrls::GetInstance()->client_login_url(), 404,
         net::ResponseCookies(),
-        std::string());
+        "");
   }
 
   void MockSuccessfulGaiaUserInfoResponse(const std::string& username) {
@@ -135,10 +134,9 @@ class WalletSigninHelperTest : public testing::Test {
 
   void MockFailedGaiaUserInfoResponse404() {
     SetUpFetcherResponseAndCompleteRequest(
-        GaiaUrls::GetInstance()->get_user_info_url(),
-        404,
+        GaiaUrls::GetInstance()->get_user_info_url(), 404,
         net::ResponseCookies(),
-        std::string());
+        "");
   }
 
   void MockSuccessfulGetAccountInfoResponse(const std::string& username) {
@@ -152,24 +150,23 @@ class WalletSigninHelperTest : public testing::Test {
 
   void MockFailedGetAccountInfoResponse404() {
     SetUpFetcherResponseAndCompleteRequest(
-        signin_helper_->GetGetAccountInfoUrlForTesting(),
-        404,
+        signin_helper_->GetGetAccountInfoUrlForTesting(), 404,
         net::ResponseCookies(),
-        std::string());
+        "");
   }
 
   void MockSuccessfulPassiveAuthUrlMergeAndRedirectResponse() {
-    SetUpFetcherResponseAndCompleteRequest(wallet::GetPassiveAuthUrl().spec(),
-                                           200,
-                                           net::ResponseCookies(),
-                                           std::string());
+    SetUpFetcherResponseAndCompleteRequest(
+        wallet::GetPassiveAuthUrl().spec(), 200,
+        net::ResponseCookies(),
+        "");
   }
 
   void MockFailedPassiveAuthUrlMergeAndRedirectResponse404() {
-    SetUpFetcherResponseAndCompleteRequest(wallet::GetPassiveAuthUrl().spec(),
-                                           404,
-                                           net::ResponseCookies(),
-                                           std::string());
+    SetUpFetcherResponseAndCompleteRequest(
+        wallet::GetPassiveAuthUrl().spec(), 404,
+        net::ResponseCookies(),
+        "");
   }
 
   WalletSigninHelperForTesting::State state() const {
diff --git a/content/browser/accessibility/accessibility_tree_formatter.cc b/content/browser/accessibility/accessibility_tree_formatter.cc
index 3904bc0..cbe0629 100644
--- a/content/browser/accessibility/accessibility_tree_formatter.cc
+++ b/content/browser/accessibility/accessibility_tree_formatter.cc
@@ -80,28 +80,28 @@ void AccessibilityTreeFormatter::Initialize() {}
 // static
 const base::FilePath::StringType
 AccessibilityTreeFormatter::GetActualFileSuffix() {
-  return base::FilePath::StringType();
+  return FILE_PATH_LITERAL("");
 }
 
 // static
 const base::FilePath::StringType
 AccessibilityTreeFormatter::GetExpectedFileSuffix() {
-  return base::FilePath::StringType();
+  return FILE_PATH_LITERAL("");
 }
 
 // static
 const std::string AccessibilityTreeFormatter::GetAllowEmptyString() {
-  return std::string();
+  return "";
 }
 
 // static
 const std::string AccessibilityTreeFormatter::GetAllowString() {
-  return std::string();
+  return "";
 }
 
 // static
 const std::string AccessibilityTreeFormatter::GetDenyString() {
-  return std::string();
+  return "";
 }
 #endif
 
diff --git a/content/browser/accessibility/cross_platform_accessibility_browsertest.cc b/content/browser/accessibility/cross_platform_accessibility_browsertest.cc
index ff5789a..9fe99c4 100644
--- a/content/browser/accessibility/cross_platform_accessibility_browsertest.cc
+++ b/content/browser/accessibility/cross_platform_accessibility_browsertest.cc
@@ -107,7 +107,7 @@ std::string CrossPlatformAccessibilityBrowserTest::GetAttr(
   if (iter != node.string_attributes.end())
     return UTF16ToUTF8(iter->second);
   else
-    return std::string();
+    return "";
 }
 
 // Convenience method to get the value of a particular AccessibilityNodeData
diff --git a/content/browser/browser_plugin/browser_plugin_guest.cc b/content/browser/browser_plugin/browser_plugin_guest.cc
index 3248afd..14dbc9a 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest.cc
@@ -92,7 +92,7 @@ static std::string RetrieveDownloadURLFromRequestId(
       ResourceDispatcherHostImpl::Get()->GetURLRequest(global_id);
   if (url_request)
     return url_request->url().possibly_invalid_spec();
-  return std::string();
+  return "";
 }
 
 }
diff --git a/content/browser/browser_plugin/browser_plugin_host_browsertest.cc b/content/browser/browser_plugin/browser_plugin_host_browsertest.cc
index 94568493..23977a5 100644
--- a/content/browser/browser_plugin/browser_plugin_host_browsertest.cc
+++ b/content/browser/browser_plugin/browser_plugin_host_browsertest.cc
@@ -388,8 +388,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest,
       TestShortHangTimeoutGuestFactory::GetInstance());
   const char kEmbedderURL[] =
       "files/browser_plugin_embedder_guest_unresponsive.html";
-  StartBrowserPluginTest(
-      kEmbedderURL, kHTMLForGuestBusyLoop, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuestBusyLoop, true, "");
   // Wait until the busy loop starts.
   {
     const string16 expected_title = ASCIIToUTF16("start");
@@ -454,7 +453,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, NavigateAfterResize) {
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, AdvanceFocus) {
   const char kEmbedderURL[] = "files/browser_plugin_focus.html";
   const char* kGuestURL = "files/browser_plugin_focus_child.html";
-  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, "");
 
   SimulateMouseClick(test_embedder()->web_contents(), 0,
       WebKit::WebMouseEvent::ButtonLeft);
@@ -485,7 +484,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, EmbedderChangedAfterSwap) {
 
   // 1. Load an embedder page with one guest in it.
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
 
   // 2. Navigate to a URL in https, so we trigger a RenderViewHost swap.
   GURL test_https_url(https_server.GetURL(
@@ -511,7 +510,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, EmbedderChangedAfterSwap) {
 // web_contents.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, EmbedderSameAfterNav) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
   WebContentsImpl* embedder_web_contents = test_embedder()->web_contents();
 
   // Navigate to another page in same host and port, so RenderViewHost swap
@@ -536,7 +535,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, EmbedderSameAfterNav) {
 // This test verifies that hiding the embedder also hides the guest.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, BrowserPluginVisibilityChanged) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
 
   // Hide the Browser Plugin.
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
@@ -550,7 +549,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, BrowserPluginVisibilityChanged) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, EmbedderVisibilityChanged) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
 
   // Hide the embedder.
   test_embedder()->web_contents()->WasHidden();
@@ -562,7 +561,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, EmbedderVisibilityChanged) {
 // This test verifies that calling the reload method reloads the guest.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, ReloadGuest) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
 
   test_guest()->ResetUpdateRectCount();
 
@@ -576,7 +575,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, ReloadGuest) {
 // to the guest's WebContents.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, StopGuest) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
 
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
@@ -588,8 +587,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, StopGuest) {
 // plugin correctly updates the touch-event handling state in the embedder.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, AcceptTouchEvents) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(
-      kEmbedderURL, kHTMLForGuestTouchHandler, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuestTouchHandler, true, "");
 
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
@@ -617,7 +615,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, AcceptTouchEvents) {
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, Renavigate) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
   StartBrowserPluginTest(
-      kEmbedderURL, GetHTMLForGuestWithTitle("P1"), true, std::string());
+      kEmbedderURL, GetHTMLForGuestWithTitle("P1"), true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
 
@@ -712,7 +710,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, Renavigate) {
 // and that the guest is reset.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, ReloadEmbedder) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
 
@@ -763,7 +761,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, ReloadEmbedder) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, TerminateGuest) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
 
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
@@ -778,7 +776,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, TerminateGuest) {
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, BackAfterTerminateGuest) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
   StartBrowserPluginTest(
-      kEmbedderURL, GetHTMLForGuestWithTitle("P1"), true, std::string());
+      kEmbedderURL, GetHTMLForGuestWithTitle("P1"), true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
 
@@ -820,7 +818,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, BackAfterTerminateGuest) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadStart) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, "");
 
   const string16 expected_title = ASCIIToUTF16(kHTMLForGuest);
   content::TitleWatcher title_watcher(test_embedder()->web_contents(),
@@ -837,7 +835,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadStart) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadAbort) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, "");
 
   {
     // Navigate the guest to "close-socket".
@@ -884,7 +882,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadAbort) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadRedirect) {
   const char kEmbedderURL[] = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, "");
 
   const string16 expected_title = ASCIIToUTF16("redirected");
   content::TitleWatcher title_watcher(test_embedder()->web_contents(),
@@ -924,8 +922,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadRedirect) {
 // correctly.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, MAYBE_AcceptDragEvents) {
   const char kEmbedderURL[] = "files/browser_plugin_dragging.html";
-  StartBrowserPluginTest(
-      kEmbedderURL, kHTMLForGuestAcceptDrag, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuestAcceptDrag, true, "");
 
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
@@ -981,7 +978,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, PostMessage) {
   const char* kTesting = "testing123";
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
   const char* kGuestURL = "files/browser_plugin_post_message_guest.html";
-  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
   {
@@ -1009,7 +1006,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, DISABLED_PostMessageToIFrame) {
   const char* kTesting = "testing123";
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
   const char* kGuestURL = "files/browser_plugin_post_message_guest.html";
-  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
   {
@@ -1055,7 +1052,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, DISABLED_PostMessageToIFrame) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadStop) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, "");
 
   const string16 expected_title = ASCIIToUTF16("loadStop");
   content::TitleWatcher title_watcher(
@@ -1072,7 +1069,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadStop) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, LoadCommit) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, "about:blank", true, "");
 
   const string16 expected_title = ASCIIToUTF16(
       base::StringPrintf("loadCommit:%s", kHTMLForGuest));
@@ -1108,7 +1105,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, HiddenBeforeNavigation) {
 // the new guest will inherit the visibility state of the old guest.
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, VisibilityPreservation) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
   // Hide the BrowserPlugin.
@@ -1148,7 +1145,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, FocusBeforeNavigation) {
 // crbug.com/170249
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, DISABLED_FocusPreservation) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
   RenderViewHostImpl* guest_rvh = static_cast<RenderViewHostImpl*>(
@@ -1187,7 +1184,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, DISABLED_FocusPreservation) {
 
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, FocusTracksEmbedder) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
-  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kHTMLForGuest, true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
   RenderViewHostImpl* guest_rvh = static_cast<RenderViewHostImpl*>(
@@ -1232,7 +1229,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, AutoSizeBeforeNavigation) {
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, AutoSizeAfterNavigation) {
   const char* kEmbedderURL = "files/browser_plugin_embedder.html";
   StartBrowserPluginTest(
-      kEmbedderURL, kHTMLForGuestWithSize, true, std::string());
+      kEmbedderURL, kHTMLForGuestWithSize, true, "");
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
 
@@ -1286,7 +1283,7 @@ IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, GetRenderViewHostAtPositionTest) {
 IN_PROC_BROWSER_TEST_F(BrowserPluginHostTest, ChangeWindowName) {
   const char kEmbedderURL[] = "files/browser_plugin_naming_embedder.html";
   const char* kGuestURL = "files/browser_plugin_naming_guest.html";
-  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, std::string());
+  StartBrowserPluginTest(kEmbedderURL, kGuestURL, false, "");
 
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       test_embedder()->web_contents()->GetRenderViewHost());
diff --git a/content/browser/database_browsertest.cc b/content/browser/database_browsertest.cc
index 29030ad..48f7304 100644
--- a/content/browser/database_browsertest.cc
+++ b/content/browser/database_browsertest.cc
@@ -102,7 +102,7 @@ IN_PROC_BROWSER_TEST_F(DatabaseTest, DeleteRecord) {
   CreateTable(shell());
   InsertRecord(shell(), "text");
   DeleteRecord(shell(), 0);
-  CompareRecords(shell(), std::string());
+  CompareRecords(shell(), "");
 
   InsertRecord(shell(), "0");
   InsertRecord(shell(), "1");
@@ -151,12 +151,12 @@ IN_PROC_BROWSER_TEST_F(DatabaseTest, DatabaseOperations) {
   for (int i = 0; i < 10; ++i)
     DeleteRecord(shell(), 0);
 
-  CompareRecords(shell(), std::string());
+  CompareRecords(shell(), "");
 
   RunScriptAndCheckResult(
       shell(), "deleteRecord(1)", "could not find row with index: 1");
 
-  CompareRecords(shell(), std::string());
+  CompareRecords(shell(), "");
 }
 
 // Create records in the database and verify they persist after reload.
@@ -186,7 +186,7 @@ IN_PROC_BROWSER_TEST_F(DatabaseTest, OffTheRecordCannotReadRegularDatabase) {
   ASSERT_FALSE(HasTable(otr));
 
   CreateTable(otr);
-  CompareRecords(otr, std::string());
+  CompareRecords(otr, "");
 }
 
 // Attempt to read a database created in an off the record browser from a
@@ -200,7 +200,7 @@ IN_PROC_BROWSER_TEST_F(DatabaseTest, RegularCannotReadOffTheRecordDatabase) {
   Navigate(shell());
   ASSERT_FALSE(HasTable(shell()));
   CreateTable(shell());
-  CompareRecords(shell(), std::string());
+  CompareRecords(shell(), "");
 }
 
 // Verify DB changes within first window are present in the second window.
diff --git a/content/browser/devtools/devtools_http_handler_impl.cc b/content/browser/devtools/devtools_http_handler_impl.cc
index 4869c2b..414785e 100644
--- a/content/browser/devtools/devtools_http_handler_impl.cc
+++ b/content/browser/devtools/devtools_http_handler_impl.cc
@@ -459,7 +459,7 @@ void DevToolsHttpHandlerImpl::OnJsonRequestUI(
                       content::GetContentClient()->GetProduct());
     version.SetString("User-Agent",
                       webkit_glue::GetUserAgent(GURL(chrome::kAboutBlankURL)));
-    SendJson(connection_id, net::HTTP_OK, &version, std::string());
+    SendJson(connection_id, net::HTTP_OK, &version, "");
     return;
   }
 
@@ -506,7 +506,7 @@ void DevToolsHttpHandlerImpl::OnJsonRequestUI(
     }
     std::string host = info.headers["Host"];
     scoped_ptr<base::DictionaryValue> dictionary(SerializePageInfo(rvh, host));
-    SendJson(connection_id, net::HTTP_OK, dictionary.get(), std::string());
+    SendJson(connection_id, net::HTTP_OK, dictionary.get(), "");
     return;
   }
 
@@ -552,7 +552,7 @@ void DevToolsHttpHandlerImpl::CollectWorkerInfo(ListValue* target_list,
 
 void DevToolsHttpHandlerImpl::SendTargetList(int connection_id,
                                              ListValue* target_list) {
-  SendJson(connection_id, net::HTTP_OK, target_list, std::string());
+  SendJson(connection_id, net::HTTP_OK, target_list, "");
   delete target_list;
   Release();  // Balanced OnJsonRequestUI.
 }
diff --git a/content/browser/devtools/devtools_http_handler_unittest.cc b/content/browser/devtools/devtools_http_handler_unittest.cc
index c926015..839ef60 100644
--- a/content/browser/devtools/devtools_http_handler_unittest.cc
+++ b/content/browser/devtools/devtools_http_handler_unittest.cc
@@ -56,20 +56,20 @@ class DummyListenSocketFactory : public net::StreamListenSocketFactory {
 
 class DummyDelegate : public DevToolsHttpHandlerDelegate {
  public:
-  virtual std::string GetDiscoveryPageHTML() OVERRIDE { return std::string(); }
+  virtual std::string GetDiscoveryPageHTML() OVERRIDE { return ""; }
   virtual bool BundlesFrontendResources() OVERRIDE { return true; }
   virtual base::FilePath GetDebugFrontendDir() OVERRIDE {
     return base::FilePath();
   }
   virtual std::string GetPageThumbnailData(const GURL& url) OVERRIDE {
-    return std::string();
+    return "";
   }
   virtual RenderViewHost* CreateNewTarget() OVERRIDE { return NULL; }
   virtual TargetType GetTargetType(RenderViewHost*) OVERRIDE {
     return kTargetTypeTab;
   }
   virtual std::string GetViewDescription(content::RenderViewHost*) OVERRIDE {
-    return std::string();
+    return "";
   }
 };
 
@@ -98,9 +98,9 @@ TEST_F(DevToolsHttpHandlerTest, TestStartStop) {
   base::RunLoop run_loop, run_loop_2;
   content::DevToolsHttpHandler* devtools_http_handler_ =
       content::DevToolsHttpHandler::Start(
-          new DummyListenSocketFactory(run_loop.QuitClosure(),
-                                       run_loop_2.QuitClosure()),
-          std::string(),
+          new DummyListenSocketFactory(
+              run_loop.QuitClosure(), run_loop_2.QuitClosure()),
+          "",
           new DummyDelegate());
   // Our dummy socket factory will post a quit message once the server will
   // become ready.
diff --git a/content/browser/devtools/renderer_overrides_handler.cc b/content/browser/devtools/renderer_overrides_handler.cc
index f7db2e8..94395d1 100644
--- a/content/browser/devtools/renderer_overrides_handler.cc
+++ b/content/browser/devtools/renderer_overrides_handler.cc
@@ -145,8 +145,8 @@ RendererOverridesHandler::PageNavigate(
   if (host) {
     WebContents* web_contents = host->GetDelegate()->GetAsWebContents();
     if (web_contents) {
-      web_contents->GetController()
-          .LoadURL(gurl, Referrer(), PAGE_TRANSITION_TYPED, std::string());
+      web_contents->GetController().LoadURL(
+          gurl, Referrer(), PAGE_TRANSITION_TYPED, "");
       return command->SuccessResponse(new base::DictionaryValue());
     }
   }
diff --git a/content/browser/download/base_file.cc b/content/browser/download/base_file.cc
index 0b1db97..b5ded45 100644
--- a/content/browser/download/base_file.cc
+++ b/content/browser/download/base_file.cc
@@ -232,11 +232,11 @@ bool BaseFile::GetHash(std::string* hash) {
 
 std::string BaseFile::GetHashState() {
   if (!calculate_hash_)
-    return std::string();
+    return "";
 
   Pickle hash_state;
   if (!secure_hash_->Serialize(&hash_state))
-    return std::string();
+    return "";
 
   return std::string(reinterpret_cast<const char*>(hash_state.data()),
                      hash_state.size());
diff --git a/content/browser/download/base_file_unittest.cc b/content/browser/download/base_file_unittest.cc
index 0e6239f..799076d 100644
--- a/content/browser/download/base_file_unittest.cc
+++ b/content/browser/download/base_file_unittest.cc
@@ -54,7 +54,7 @@ class BaseFileTest : public testing::Test {
                                   GURL(),
                                   0,
                                   false,
-                                  std::string(),
+                                  "",
                                   scoped_ptr<net::FileStream>(),
                                   net::BoundNetLog()));
   }
@@ -105,7 +105,7 @@ class BaseFileTest : public testing::Test {
                                   GURL(),
                                   0,
                                   true,
-                                  std::string(),
+                                  "",
                                   scoped_ptr<net::FileStream>(),
                                   net::BoundNetLog()));
   }
@@ -145,7 +145,7 @@ class BaseFileTest : public testing::Test {
                   GURL(),
                   0,
                   false,
-                  std::string(),
+                  "",
                   scoped_ptr<net::FileStream>(),
                   net::BoundNetLog());
 
@@ -171,7 +171,7 @@ class BaseFileTest : public testing::Test {
                             GURL(),
                             0,
                             false,
-                            std::string(),
+                            "",
                             scoped_ptr<net::FileStream>(),
                             net::BoundNetLog());
     EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
@@ -503,7 +503,7 @@ TEST_F(BaseFileTest, MultipleWritesWithError) {
                                 GURL(),
                                 0,
                                 false,
-                                std::string(),
+                                "",
                                 mock_file_stream_scoped_ptr.Pass(),
                                 net::BoundNetLog()));
   ASSERT_TRUE(InitializeFile());
@@ -550,7 +550,7 @@ TEST_F(BaseFileTest, AppendToBaseFile) {
                                 GURL(),
                                 kTestDataLength4,
                                 false,
-                                std::string(),
+                                "",
                                 scoped_ptr<net::FileStream>(),
                                 net::BoundNetLog()));
 
@@ -584,7 +584,7 @@ TEST_F(BaseFileTest, ReadonlyBaseFile) {
                                 GURL(),
                                 0,
                                 false,
-                                std::string(),
+                                "",
                                 scoped_ptr<net::FileStream>(),
                                 net::BoundNetLog()));
 
@@ -609,7 +609,7 @@ TEST_F(BaseFileTest, IsEmptyHash) {
   EXPECT_TRUE(BaseFile::IsEmptyHash(empty));
   std::string not_empty(BaseFile::kSha256HashLen, '\x01');
   EXPECT_FALSE(BaseFile::IsEmptyHash(not_empty));
-  EXPECT_FALSE(BaseFile::IsEmptyHash(std::string()));
+  EXPECT_FALSE(BaseFile::IsEmptyHash(""));
 }
 
 // Test that calculating speed after no writes.
diff --git a/content/browser/download/download_file_impl.cc b/content/browser/download/download_file_impl.cc
index 5286e0c..ab95900 100644
--- a/content/browser/download/download_file_impl.cc
+++ b/content/browser/download/download_file_impl.cc
@@ -108,8 +108,8 @@ void DownloadFileImpl::RenameAndUniquify(
 
   base::FilePath new_path(full_path);
 
-  int uniquifier = file_util::GetUniquePathNumber(
-      new_path, base::FilePath::StringType());
+  int uniquifier =
+      file_util::GetUniquePathNumber(new_path, FILE_PATH_LITERAL(""));
   if (uniquifier > 0) {
     new_path = new_path.InsertBeforeExtensionASCII(
         base::StringPrintf(" (%d)", uniquifier));
diff --git a/content/browser/download/download_item_impl_unittest.cc b/content/browser/download/download_item_impl_unittest.cc
index caee4ae..83b0cf0 100644
--- a/content/browser/download/download_item_impl_unittest.cc
+++ b/content/browser/download/download_item_impl_unittest.cc
@@ -344,7 +344,7 @@ TEST_F(DownloadItemTest, NotificationAfterUpdate) {
   DownloadItemImpl* item = CreateDownloadItem();
   MockObserver observer(item);
 
-  item->UpdateProgress(kDownloadChunkSize, kDownloadSpeed, std::string());
+  item->UpdateProgress(kDownloadChunkSize, kDownloadSpeed, "");
   ASSERT_TRUE(observer.CheckUpdated());
   EXPECT_EQ(kDownloadSpeed, item->CurrentSpeed());
 }
@@ -545,7 +545,7 @@ TEST_F(DownloadItemTest, NotificationAfterOnContentCheckCompleted) {
   DownloadItemImpl* safe_item = CreateDownloadItem();
   MockObserver safe_observer(safe_item);
 
-  safe_item->OnAllDataSaved(std::string());
+  safe_item->OnAllDataSaved("");
   EXPECT_TRUE(safe_observer.CheckUpdated());
   safe_item->OnContentCheckCompleted(DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS);
   EXPECT_TRUE(safe_observer.CheckUpdated());
@@ -555,7 +555,7 @@ TEST_F(DownloadItemTest, NotificationAfterOnContentCheckCompleted) {
       CreateDownloadItem();
   MockObserver unsafeurl_observer(unsafeurl_item);
 
-  unsafeurl_item->OnAllDataSaved(std::string());
+  unsafeurl_item->OnAllDataSaved("");
   EXPECT_TRUE(unsafeurl_observer.CheckUpdated());
   unsafeurl_item->OnContentCheckCompleted(DOWNLOAD_DANGER_TYPE_DANGEROUS_URL);
   EXPECT_TRUE(unsafeurl_observer.CheckUpdated());
@@ -567,7 +567,7 @@ TEST_F(DownloadItemTest, NotificationAfterOnContentCheckCompleted) {
       CreateDownloadItem();
   MockObserver unsafefile_observer(unsafefile_item);
 
-  unsafefile_item->OnAllDataSaved(std::string());
+  unsafefile_item->OnAllDataSaved("");
   EXPECT_TRUE(unsafefile_observer.CheckUpdated());
   unsafefile_item->OnContentCheckCompleted(DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE);
   EXPECT_TRUE(unsafefile_observer.CheckUpdated());
@@ -697,7 +697,7 @@ TEST_F(DownloadItemTest, CallbackAfterRename) {
       .WillOnce(ScheduleRenameCallback(DOWNLOAD_INTERRUPT_REASON_NONE,
                                        final_path));
   EXPECT_CALL(*download_file, Detach());
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   RunAllPendingInMessageLoops();
   ::testing::Mock::VerifyAndClearExpectations(download_file);
   mock_delegate()->VerifyAndClearExpectations();
@@ -862,7 +862,7 @@ TEST_F(DownloadItemTest, EnabledActionsForNormalDownload) {
   EXPECT_CALL(*mock_delegate(), ShouldCompleteDownload(item, _))
       .WillOnce(Return(true));
   EXPECT_CALL(*download_file, Detach());
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   RunAllPendingInMessageLoops();
 
   ASSERT_TRUE(item->IsComplete());
@@ -889,7 +889,7 @@ TEST_F(DownloadItemTest, EnabledActionsForTemporaryDownload) {
       .WillOnce(ScheduleRenameCallback(DOWNLOAD_INTERRUPT_REASON_NONE,
                                        base::FilePath(kDummyPath)));
   EXPECT_CALL(*download_file, Detach());
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   RunAllPendingInMessageLoops();
 
   ASSERT_TRUE(item->IsComplete());
@@ -937,7 +937,7 @@ TEST_F(DownloadItemTest, CompleteDelegate_ReturnTrue) {
   // Drive the delegate interaction.
   EXPECT_CALL(*mock_delegate(), ShouldCompleteDownload(item, _))
       .WillOnce(Return(true));
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   EXPECT_EQ(DownloadItem::IN_PROGRESS, item->GetState());
   EXPECT_FALSE(item->IsDangerous());
 
@@ -966,7 +966,7 @@ TEST_F(DownloadItemTest, CompleteDelegate_BlockOnce) {
       .WillOnce(DoAll(SaveArg<1>(&delegate_callback),
                       Return(false)))
       .WillOnce(Return(true));
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   ASSERT_FALSE(delegate_callback.is_null());
   copy_delegate_callback = delegate_callback;
   delegate_callback.Reset();
@@ -1001,7 +1001,7 @@ TEST_F(DownloadItemTest, CompleteDelegate_SetDanger) {
       .WillOnce(DoAll(SaveArg<1>(&delegate_callback),
                       Return(false)))
       .WillOnce(Return(true));
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   ASSERT_FALSE(delegate_callback.is_null());
   copy_delegate_callback = delegate_callback;
   delegate_callback.Reset();
@@ -1047,7 +1047,7 @@ TEST_F(DownloadItemTest, CompleteDelegate_BlockTwice) {
       .WillOnce(DoAll(SaveArg<1>(&delegate_callback),
                       Return(false)))
       .WillOnce(Return(true));
-  item->DestinationObserverAsWeakPtr()->DestinationCompleted(std::string());
+  item->DestinationObserverAsWeakPtr()->DestinationCompleted("");
   ASSERT_FALSE(delegate_callback.is_null());
   copy_delegate_callback = delegate_callback;
   delegate_callback.Reset();
diff --git a/content/browser/download/download_manager_impl_unittest.cc b/content/browser/download/download_manager_impl_unittest.cc
index e08402e..4a33159 100644
--- a/content/browser/download/download_manager_impl_unittest.cc
+++ b/content/browser/download/download_manager_impl_unittest.cc
@@ -169,9 +169,7 @@ class MockDownloadItemImpl : public DownloadItemImpl {
   MOCK_CONST_METHOD0(GetUserVerifiedFilePath, base::FilePath());
   MOCK_METHOD0(NotifyRemoved, void());
   // May be called when vlog is on.
-  virtual std::string DebugString(bool verbose) const OVERRIDE {
-    return std::string();
-  }
+  virtual std::string DebugString(bool verbose) const OVERRIDE { return ""; }
 };
 
 class MockDownloadManagerDelegate : public DownloadManagerDelegate {
diff --git a/content/browser/download/download_stats.cc b/content/browser/download/download_stats.cc
index e13200e..cad6cbe 100644
--- a/content/browser/download/download_stats.cc
+++ b/content/browser/download/download_stats.cc
@@ -305,8 +305,8 @@ void RecordDownloadContentDisposition(
     const std::string& content_disposition_string) {
   if (content_disposition_string.empty())
     return;
-  net::HttpContentDisposition content_disposition(content_disposition_string,
-                                                  std::string());
+  net::HttpContentDisposition content_disposition(
+      content_disposition_string, "");
   int result = content_disposition.parse_result_flags();
 
   bool is_valid = !content_disposition.filename().empty();
diff --git a/content/browser/download/save_file.cc b/content/browser/download/save_file.cc
index 80caf13..3e7f7bd 100644
--- a/content/browser/download/save_file.cc
+++ b/content/browser/download/save_file.cc
@@ -20,7 +20,7 @@ SaveFile::SaveFile(const SaveFileCreateInfo* info, bool calculate_hash)
             GURL(),
             0,
             calculate_hash,
-            std::string(),
+            "",
             scoped_ptr<net::FileStream>(),
             net::BoundNetLog()),
       info_(info) {
diff --git a/content/browser/download/save_package.cc b/content/browser/download/save_package.cc
index f97d2d6..cbff60a 100644
--- a/content/browser/download/save_package.cc
+++ b/content/browser/download/save_package.cc
@@ -365,7 +365,7 @@ void SavePackage::OnMHTMLGenerated(const base::FilePath& path, int64 size) {
   // with SavePackage flow.
   if (download_->IsInProgress()) {
     download_->SetTotalBytes(size);
-    download_->UpdateProgress(size, 0, std::string());
+    download_->UpdateProgress(size, 0, "");
     // Must call OnAllDataSaved here in order for
     // GDataDownloadObserver::ShouldUpload() to return true.
     // ShouldCompleteDownload() may depend on the gdata uploader to finish.
@@ -449,11 +449,7 @@ bool SavePackage::GenerateFileName(const std::string& disposition,
                                    base::FilePath::StringType* generated_name) {
   // TODO(jungshik): Figure out the referrer charset when having one
   // makes sense and pass it to GenerateFileName.
-  base::FilePath file_path = net::GenerateFileName(url,
-                                                   disposition,
-                                                   std::string(),
-                                                   std::string(),
-                                                   std::string(),
+  base::FilePath file_path = net::GenerateFileName(url, disposition, "", "", "",
                                                    kDefaultSaveName);
 
   DCHECK(!file_path.empty());
@@ -792,8 +788,7 @@ void SavePackage::Finish() {
     // with SavePackage flow.
     if (download_->IsInProgress()) {
       if (save_type_ != SAVE_PAGE_TYPE_AS_MHTML) {
-        download_->UpdateProgress(
-            all_save_items_count_, CurrentSpeed(), std::string());
+        download_->UpdateProgress(all_save_items_count_, CurrentSpeed(), "");
         download_->OnAllDataSaved(DownloadItem::kEmptyFileHash);
       }
       download_->MarkAsComplete();
@@ -823,7 +818,7 @@ void SavePackage::SaveFinished(int32 save_id, int64 size, bool is_success) {
   // TODO(rdsmith/benjhayden): Integrate canceling on DownloadItem
   // with SavePackage flow.
   if (download_ && download_->IsInProgress())
-    download_->UpdateProgress(completed_count(), CurrentSpeed(), std::string());
+    download_->UpdateProgress(completed_count(), CurrentSpeed(), "");
 
   if (save_item->save_source() == SaveFileCreateInfo::SAVE_FILE_FROM_DOM &&
       save_item->url() == page_url_ && !save_item->received_bytes()) {
@@ -868,7 +863,7 @@ void SavePackage::SaveFailed(const GURL& save_url) {
   // TODO(rdsmith/benjhayden): Integrate canceling on DownloadItem
   // with SavePackage flow.
   if (download_ && download_->IsInProgress())
-    download_->UpdateProgress(completed_count(), CurrentSpeed(), std::string());
+    download_->UpdateProgress(completed_count(), CurrentSpeed(), "");
 
   if ((save_type_ == SAVE_PAGE_TYPE_AS_ONLY_HTML) ||
       (save_type_ == SAVE_PAGE_TYPE_AS_MHTML) ||
diff --git a/content/browser/download/save_package_unittest.cc b/content/browser/download/save_package_unittest.cc
index e40af08..b5a07ae 100644
--- a/content/browser/download/save_package_unittest.cc
+++ b/content/browser/download/save_package_unittest.cc
@@ -221,21 +221,20 @@ TEST_F(SavePackageTest, MAYBE_TestLongSavePackageFilename) {
 
   base::FilePath::StringType filename;
   // Test that the filename is successfully shortened to fit.
-  ASSERT_TRUE(GetGeneratedFilename(true, std::string(), url, false, &filename));
+  ASSERT_TRUE(GetGeneratedFilename(true, "", url, false, &filename));
   EXPECT_TRUE(filename.length() < long_file.length());
   EXPECT_FALSE(HasOrdinalNumber(filename));
 
   // Test that the filename is successfully shortened to fit, and gets an
   // an ordinal appended.
-  ASSERT_TRUE(GetGeneratedFilename(true, std::string(), url, false, &filename));
+  ASSERT_TRUE(GetGeneratedFilename(true, "", url, false, &filename));
   EXPECT_TRUE(filename.length() < long_file.length());
   EXPECT_TRUE(HasOrdinalNumber(filename));
 
   // Test that the filename is successfully shortened to fit, and gets a
   // different ordinal appended.
   base::FilePath::StringType filename2;
-  ASSERT_TRUE(
-      GetGeneratedFilename(true, std::string(), url, false, &filename2));
+  ASSERT_TRUE(GetGeneratedFilename(true, "", url, false, &filename2));
   EXPECT_TRUE(filename2.length() < long_file.length());
   EXPECT_TRUE(HasOrdinalNumber(filename2));
   EXPECT_NE(filename, filename2);
diff --git a/content/browser/geolocation/network_location_provider_unittest.cc b/content/browser/geolocation/network_location_provider_unittest.cc
index 3b91466..fb01795 100644
--- a/content/browser/geolocation/network_location_provider_unittest.cc
+++ b/content/browser/geolocation/network_location_provider_unittest.cc
@@ -344,7 +344,7 @@ TEST_F(GeolocationNetworkProviderTest, StartProvider) {
   EXPECT_TRUE(provider->StartProvider(false));
   net::TestURLFetcher* fetcher = get_url_fetcher_and_advance_id();
   ASSERT_TRUE(fetcher != NULL);
-  CheckRequestIsValid(*fetcher, 0, 0, 0, std::string());
+  CheckRequestIsValid(*fetcher, 0, 0, 0, "");
 }
 
 TEST_F(GeolocationNetworkProviderTest, StartProviderDefaultUrl) {
@@ -353,9 +353,10 @@ TEST_F(GeolocationNetworkProviderTest, StartProviderDefaultUrl) {
   EXPECT_TRUE(provider->StartProvider(false));
   net::TestURLFetcher* fetcher = get_url_fetcher_and_advance_id();
   ASSERT_TRUE(fetcher != NULL);
-  CheckRequestIsValid(*fetcher, 0, 0, 0, std::string());
+  CheckRequestIsValid(*fetcher, 0, 0, 0, "");
 }
 
+
 TEST_F(GeolocationNetworkProviderTest, StartProviderLongRequest) {
   scoped_ptr<LocationProviderBase> provider(CreateProvider(true));
   EXPECT_TRUE(provider->StartProvider(false));
@@ -368,7 +369,7 @@ TEST_F(GeolocationNetworkProviderTest, StartProviderLongRequest) {
   // in length by not including access points with the lowest signal strength
   // in the request.
   EXPECT_LT(fetcher->GetOriginalURL().spec().size(), size_t(2048));
-  CheckRequestIsValid(*fetcher, 0, 16, 4, std::string());
+  CheckRequestIsValid(*fetcher, 0, 16, 4, "");
 }
 
 TEST_F(GeolocationNetworkProviderTest, MultiRegistrations) {
@@ -417,7 +418,7 @@ TEST_F(GeolocationNetworkProviderTest, MultipleWifiScansComplete) {
   fetcher = get_url_fetcher_and_advance_id();
   ASSERT_TRUE(fetcher != NULL);
   // The request should have the wifi data.
-  CheckRequestIsValid(*fetcher, 0, kFirstScanAps, 0, std::string());
+  CheckRequestIsValid(*fetcher, 0, kFirstScanAps, 0, "");
 
   // Send a reply with good position fix.
   const char* kReferenceNetworkResponse =
@@ -471,7 +472,7 @@ TEST_F(GeolocationNetworkProviderTest, MultipleWifiScansComplete) {
   fetcher->set_url(test_server_url_);
   fetcher->set_status(net::URLRequestStatus(net::URLRequestStatus::FAILED, -1));
   fetcher->set_response_code(200);  // should be ignored
-  fetcher->SetResponseString(std::string());
+  fetcher->SetResponseString("");
   fetcher->delegate()->OnURLFetchComplete(fetcher);
 
   // Error means we now no longer have a fix.
diff --git a/content/browser/geolocation/wifi_data_provider_linux.cc b/content/browser/geolocation/wifi_data_provider_linux.cc
index c8d68ac..709063a 100644
--- a/content/browser/geolocation/wifi_data_provider_linux.cc
+++ b/content/browser/geolocation/wifi_data_provider_linux.cc
@@ -270,7 +270,7 @@ bool NetworkManagerWlanApi::GetAccessPointsForAdapter(
         continue;
       }
 
-      ReplaceSubstringsAfterOffset(&mac, 0U, ":", std::string());
+      ReplaceSubstringsAfterOffset(&mac, 0U, ":", "");
       std::vector<uint8> mac_bytes;
       if (!base::HexStringToBytes(mac, &mac_bytes) || mac_bytes.size() != 6) {
         LOG(WARNING) << "Can't parse mac address (found " << mac_bytes.size()
diff --git a/content/browser/gpu/gpu_control_list.cc b/content/browser/gpu/gpu_control_list.cc
index 0fba7c8..3592505 100644
--- a/content/browser/gpu/gpu_control_list.cc
+++ b/content/browser/gpu/gpu_control_list.cc
@@ -217,8 +217,8 @@ GpuControlList::OsInfo::OsInfo(const std::string& os,
                              const std::string& version_string2) {
   type_ = StringToOsType(os);
   if (type_ != kOsUnknown) {
-    version_info_.reset(new VersionInfo(
-        version_op, std::string(), version_string, version_string2));
+    version_info_.reset(
+        new VersionInfo(version_op, "", version_string, version_string2));
   }
 }
 
@@ -265,8 +265,8 @@ GpuControlList::MachineModelInfo::MachineModelInfo(
     const std::string& version_string,
     const std::string& version_string2) {
   name_info_.reset(new StringInfo(name_op, name_value));
-  version_info_.reset(new VersionInfo(
-      version_op, std::string(), version_string, version_string2));
+  version_info_.reset(
+      new VersionInfo(version_op, "", version_string, version_string2));
 }
 
 GpuControlList::MachineModelInfo::~MachineModelInfo() {}
@@ -864,7 +864,7 @@ bool GpuControlList::GpuControlListEntry::SetDriverDateInfo(
     const std::string& date_string,
     const std::string& date_string2) {
   driver_date_info_.reset(
-      new VersionInfo(date_op, std::string(), date_string, date_string2));
+      new VersionInfo(date_op, "", date_string, date_string2));
   return driver_date_info_->IsValid();
 }
 
@@ -1348,8 +1348,8 @@ GpuControlList::IsEntrySupportedByCurrentBrowserVersion(
     browser_version_value->GetString("number", &version_string);
     browser_version_value->GetString("number2", &version_string2);
     scoped_ptr<VersionInfo> browser_version_info;
-    browser_version_info.reset(new VersionInfo(
-        version_op, std::string(), version_string, version_string2));
+    browser_version_info.reset(
+        new VersionInfo(version_op, "", version_string, version_string2));
     if (!browser_version_info->IsValid())
       return kMalformed;
     if (browser_version_info->Contains(browser_version_))
diff --git a/content/browser/gpu/gpu_control_list_machine_model_info_unittest.cc b/content/browser/gpu/gpu_control_list_machine_model_info_unittest.cc
index 8d00a33..b8c3b1f 100644
--- a/content/browser/gpu/gpu_control_list_machine_model_info_unittest.cc
+++ b/content/browser/gpu/gpu_control_list_machine_model_info_unittest.cc
@@ -47,7 +47,8 @@ TEST_F(MachineModelInfoTest, ValidModelInfo) {
 }
 
 TEST_F(MachineModelInfoTest, ModelComparison) {
-  MachineModelInfo info("=", "model_a", ">", "3.4", std::string());
+  MachineModelInfo info("=", "model_a",
+                        ">", "3.4", "");
   EXPECT_TRUE(info.Contains("model_a", "4"));
   EXPECT_FALSE(info.Contains("model_b", "4"));
   EXPECT_FALSE(info.Contains("model_a", "3.2"));
diff --git a/content/browser/gpu/gpu_control_list_number_info_unittest.cc b/content/browser/gpu/gpu_control_list_number_info_unittest.cc
index 0cb72a7..f4e0ba6 100644
--- a/content/browser/gpu/gpu_control_list_number_info_unittest.cc
+++ b/content/browser/gpu/gpu_control_list_number_info_unittest.cc
@@ -46,7 +46,7 @@ TEST_F(NumberInfoTest, ValidFloatInfo) {
     "-2.14",
   };
   for (size_t i = 0; i < arraysize(value); ++i) {
-    FloatInfo info("=", value[i], std::string());
+    FloatInfo info("=", value[i], "");
     EXPECT_TRUE(info.IsValid());
   }
 }
@@ -60,11 +60,11 @@ TEST_F(NumberInfoTest, InvalidFloatInfo) {
     ">=",
   };
   for (size_t i = 0; i < arraysize(op); ++i) {
-    FloatInfo info(op[i], std::string(), std::string());
+    FloatInfo info(op[i], "", "");
     EXPECT_FALSE(info.IsValid());
   }
   {
-    FloatInfo info("between", "3.14", std::string());
+    FloatInfo info("between", "3.14", "");
     EXPECT_FALSE(info.IsValid());
   }
   const std::string value[] = {
@@ -75,33 +75,33 @@ TEST_F(NumberInfoTest, InvalidFloatInfo) {
     "- 2.14",
   };
   for (size_t i = 0; i < arraysize(value); ++i) {
-    FloatInfo info("=", value[i], std::string());
+    FloatInfo info("=", value[i], "");
     EXPECT_FALSE(info.IsValid());
   }
 }
 
 TEST_F(NumberInfoTest, FloatComparison) {
   {
-    FloatInfo info("=", "3.14", std::string());
+    FloatInfo info("=", "3.14", "");
     EXPECT_TRUE(info.Contains(3.14f));
     EXPECT_TRUE(info.Contains(3.1400f));
     EXPECT_FALSE(info.Contains(3.1f));
     EXPECT_FALSE(info.Contains(3));
   }
   {
-    FloatInfo info(">", "3.14", std::string());
+    FloatInfo info(">", "3.14", "");
     EXPECT_FALSE(info.Contains(3.14f));
     EXPECT_TRUE(info.Contains(3.141f));
     EXPECT_FALSE(info.Contains(3.1f));
   }
   {
-    FloatInfo info("<=", "3.14", std::string());
+    FloatInfo info("<=", "3.14", "");
     EXPECT_TRUE(info.Contains(3.14f));
     EXPECT_FALSE(info.Contains(3.141f));
     EXPECT_TRUE(info.Contains(3.1f));
   }
   {
-    FloatInfo info("any", std::string(), std::string());
+    FloatInfo info("any", "", "");
     EXPECT_TRUE(info.Contains(3.14f));
   }
   {
@@ -140,7 +140,7 @@ TEST_F(NumberInfoTest, ValidIntInfo) {
     "-12",
   };
   for (size_t i = 0; i < arraysize(value); ++i) {
-    IntInfo info("=", value[i], std::string());
+    IntInfo info("=", value[i], "");
     EXPECT_TRUE(info.IsValid());
   }
 }
@@ -154,11 +154,11 @@ TEST_F(NumberInfoTest, InvalidIntInfo) {
     ">=",
   };
   for (size_t i = 0; i < arraysize(op); ++i) {
-    IntInfo info(op[i], std::string(), std::string());
+    IntInfo info(op[i], "", "");
     EXPECT_FALSE(info.IsValid());
   }
   {
-    IntInfo info("between", "3", std::string());
+    IntInfo info("between", "3", "");
     EXPECT_FALSE(info.IsValid());
   }
   const std::string value[] = {
@@ -169,31 +169,31 @@ TEST_F(NumberInfoTest, InvalidIntInfo) {
     "3.14"
   };
   for (size_t i = 0; i < arraysize(value); ++i) {
-    IntInfo info("=", value[i], std::string());
+    IntInfo info("=", value[i], "");
     EXPECT_FALSE(info.IsValid());
   }
 }
 
 TEST_F(NumberInfoTest, IntComparison) {
   {
-    IntInfo info("=", "3", std::string());
+    IntInfo info("=", "3", "");
     EXPECT_TRUE(info.Contains(3));
     EXPECT_FALSE(info.Contains(4));
   }
   {
-    IntInfo info(">", "3", std::string());
+    IntInfo info(">", "3", "");
     EXPECT_FALSE(info.Contains(2));
     EXPECT_FALSE(info.Contains(3));
     EXPECT_TRUE(info.Contains(4));
   }
   {
-    IntInfo info("<=", "3", std::string());
+    IntInfo info("<=", "3", "");
     EXPECT_TRUE(info.Contains(2));
     EXPECT_TRUE(info.Contains(3));
     EXPECT_FALSE(info.Contains(4));
   }
   {
-    IntInfo info("any", std::string(), std::string());
+    IntInfo info("any", "", "");
     EXPECT_TRUE(info.Contains(3));
   }
   {
diff --git a/content/browser/gpu/gpu_control_list_os_info_unittest.cc b/content/browser/gpu/gpu_control_list_os_info_unittest.cc
index 5ea03b2..8aefb03 100644
--- a/content/browser/gpu/gpu_control_list_os_info_unittest.cc
+++ b/content/browser/gpu/gpu_control_list_os_info_unittest.cc
@@ -33,12 +33,12 @@ TEST_F(OsInfoTest, ValidOsInfo) {
     GpuControlList::kOsAny
   };
   for (size_t i = 0; i < arraysize(os); ++i) {
-    OsInfo info(os[i], "=", "10.6", std::string());
+    OsInfo info(os[i], "=", "10.6", "");
     EXPECT_TRUE(info.IsValid());
     EXPECT_EQ(os_type[i], info.type());
   }
   {
-    OsInfo info("any", "any", std::string(), std::string());
+    OsInfo info("any", "any", "", "");
     EXPECT_TRUE(info.IsValid());
   }
 }
@@ -54,15 +54,15 @@ TEST_F(OsInfoTest, InvalidOsInfo) {
   };
   for (size_t i = 0; i < arraysize(os); ++i) {
     {
-      OsInfo info(os[i], std::string(), std::string(), std::string());
+      OsInfo info(os[i], "", "", "");
       EXPECT_FALSE(info.IsValid());
     }
     {
-      OsInfo info(os[i], "=", std::string(), std::string());
+      OsInfo info(os[i], "=", "", "");
       EXPECT_FALSE(info.IsValid());
     }
     {
-      OsInfo info(os[i], std::string(), "10.6", std::string());
+      OsInfo info(os[i], "", "10.6", "");
       EXPECT_FALSE(info.IsValid());
     }
   }
@@ -74,32 +74,34 @@ TEST_F(OsInfoTest, InvalidOsInfo) {
     "Android",
   };
   for (size_t i = 0; i < arraysize(os_cap); ++i) {
-    OsInfo info(os_cap[i], "=", "10.6", std::string());
+    OsInfo info(os_cap[i], "=", "10.6", "");
     EXPECT_FALSE(info.IsValid());
   }
 }
 
 TEST_F(OsInfoTest, OsComparison) {
   {
-    OsInfo info("any", "any", std::string(), std::string());
+    OsInfo info("any", "any", "", "");
     const GpuControlList::OsType os_type[] = {
-      GpuControlList::kOsWin, GpuControlList::kOsLinux,
-      GpuControlList::kOsMacosx, GpuControlList::kOsChromeOS,
+      GpuControlList::kOsWin,
+      GpuControlList::kOsLinux,
+      GpuControlList::kOsMacosx,
+      GpuControlList::kOsChromeOS,
       GpuControlList::kOsAndroid,
     };
     for (size_t i = 0; i < arraysize(os_type); ++i) {
-      EXPECT_TRUE(info.Contains(os_type[i], std::string()));
+      EXPECT_TRUE(info.Contains(os_type[i], ""));
       EXPECT_TRUE(info.Contains(os_type[i], "7.8"));
     }
   }
   {
-    OsInfo info("win", ">=", "6", std::string());
+    OsInfo info("win", ">=", "6", "");
     EXPECT_FALSE(info.Contains(GpuControlList::kOsMacosx, "10.8.3"));
     EXPECT_FALSE(info.Contains(GpuControlList::kOsLinux, "10"));
     EXPECT_FALSE(info.Contains(GpuControlList::kOsChromeOS, "13"));
     EXPECT_FALSE(info.Contains(GpuControlList::kOsAndroid, "7"));
     EXPECT_FALSE(info.Contains(GpuControlList::kOsAny, "7"));
-    EXPECT_FALSE(info.Contains(GpuControlList::kOsWin, std::string()));
+    EXPECT_FALSE(info.Contains(GpuControlList::kOsWin, ""));
     EXPECT_TRUE(info.Contains(GpuControlList::kOsWin, "6"));
     EXPECT_TRUE(info.Contains(GpuControlList::kOsWin, "6.1"));
     EXPECT_TRUE(info.Contains(GpuControlList::kOsWin, "7"));
diff --git a/content/browser/gpu/gpu_control_list_string_info_unittest.cc b/content/browser/gpu/gpu_control_list_string_info_unittest.cc
index c2c8009..43bb952 100644
--- a/content/browser/gpu/gpu_control_list_string_info_unittest.cc
+++ b/content/browser/gpu/gpu_control_list_string_info_unittest.cc
@@ -24,7 +24,7 @@ TEST_F(StringInfoTest, ValidStringInfo) {
   };
   for (size_t i = 0; i < arraysize(op); ++i) {
     {
-      StringInfo info(op[i], std::string());
+      StringInfo info(op[i], "");
       EXPECT_TRUE(info.IsValid());
     }
     {
diff --git a/content/browser/gpu/gpu_control_list_version_info_unittest.cc b/content/browser/gpu/gpu_control_list_version_info_unittest.cc
index eb18648..f05d71c 100644
--- a/content/browser/gpu/gpu_control_list_version_info_unittest.cc
+++ b/content/browser/gpu/gpu_control_list_version_info_unittest.cc
@@ -32,7 +32,7 @@ TEST_F(VersionInfoTest, ValidVersionInfo) {
       string1 = "8.9";
     if (op[i] == "between")
       string2 = "9.0";
-    VersionInfo info(op[i], std::string(), string1, string2);
+    VersionInfo info(op[i], "", string1, string2);
     EXPECT_TRUE(info.IsValid());
   }
 
@@ -42,7 +42,7 @@ TEST_F(VersionInfoTest, ValidVersionInfo) {
     ""  // Default, same as "numerical"
   };
   for (size_t i =0; i < arraysize(style); ++i) {
-    VersionInfo info("=", style[i], "8.9", std::string());
+    VersionInfo info("=", style[i], "8.9", "");
     EXPECT_TRUE(info.IsValid());
     if (style[i] == "lexical")
       EXPECT_TRUE(info.IsLexical());
@@ -65,7 +65,7 @@ TEST_F(VersionInfoTest, ValidVersionInfo) {
     "10. 9",
   };
   for (size_t i =0; i < arraysize(number); ++i) {
-    VersionInfo info("=", std::string(), number[i], std::string());
+    VersionInfo info("=", "", number[i], "");
     EXPECT_TRUE(info.IsValid());
   }
 }
@@ -82,21 +82,21 @@ TEST_F(VersionInfoTest, InvalidVersionInfo) {
   };
   for (size_t i = 0; i < arraysize(op); ++i) {
     {
-      VersionInfo info(op[i], std::string(), "8.9", std::string());
+      VersionInfo info(op[i], "", "8.9", "");
       if (op[i] == "between")
         EXPECT_FALSE(info.IsValid());
       else
         EXPECT_TRUE(info.IsValid());
     }
     {
-      VersionInfo info(op[i], std::string(), std::string(), std::string());
+      VersionInfo info(op[i], "", "", "");
       if (op[i] == "any")
         EXPECT_TRUE(info.IsValid());
       else
         EXPECT_FALSE(info.IsValid());
     }
     {
-      VersionInfo info(op[i], std::string(), "8.9", "9.0");
+      VersionInfo info(op[i], "", "8.9", "9.0");
       EXPECT_TRUE(info.IsValid());
     }
   }
@@ -106,34 +106,34 @@ TEST_F(VersionInfoTest, InvalidVersionInfo) {
     "8-9",
   };
   for (size_t i = 0; i < arraysize(number); ++i) {
-    VersionInfo info("=", std::string(), number[i], std::string());
+    VersionInfo info("=", "", number[i], "");
     EXPECT_FALSE(info.IsValid());
   }
 }
 
 TEST_F(VersionInfoTest, VersionComparison) {
   {
-    VersionInfo info("any", std::string(), std::string(), std::string());
+    VersionInfo info("any", "", "", "");
     EXPECT_TRUE(info.Contains("0"));
     EXPECT_TRUE(info.Contains("8.9"));
     EXPECT_TRUE(info.Contains("100"));
   }
   {
-    VersionInfo info(">", std::string(), "8.9", std::string());
+    VersionInfo info(">", "", "8.9", "");
     EXPECT_FALSE(info.Contains("7"));
     EXPECT_FALSE(info.Contains("8.9"));
     EXPECT_FALSE(info.Contains("8.9.1"));
     EXPECT_TRUE(info.Contains("9"));
   }
   {
-    VersionInfo info(">=", std::string(), "8.9", std::string());
+    VersionInfo info(">=", "", "8.9", "");
     EXPECT_FALSE(info.Contains("7"));
     EXPECT_TRUE(info.Contains("8.9"));
     EXPECT_TRUE(info.Contains("8.9.1"));
     EXPECT_TRUE(info.Contains("9"));
   }
   {
-    VersionInfo info("=", std::string(), "8.9", std::string());
+    VersionInfo info("=", "", "8.9", "");
     EXPECT_FALSE(info.Contains("7"));
     EXPECT_TRUE(info.Contains("8"));
     EXPECT_TRUE(info.Contains("8.9"));
@@ -141,7 +141,7 @@ TEST_F(VersionInfoTest, VersionComparison) {
     EXPECT_FALSE(info.Contains("9"));
   }
   {
-    VersionInfo info("<", std::string(), "8.9", std::string());
+    VersionInfo info("<", "", "8.9", "");
     EXPECT_TRUE(info.Contains("7"));
     EXPECT_TRUE(info.Contains("8.8"));
     EXPECT_FALSE(info.Contains("8"));
@@ -150,7 +150,7 @@ TEST_F(VersionInfoTest, VersionComparison) {
     EXPECT_FALSE(info.Contains("9"));
   }
   {
-    VersionInfo info("<=", std::string(), "8.9", std::string());
+    VersionInfo info("<=", "", "8.9", "");
     EXPECT_TRUE(info.Contains("7"));
     EXPECT_TRUE(info.Contains("8.8"));
     EXPECT_TRUE(info.Contains("8"));
@@ -159,7 +159,7 @@ TEST_F(VersionInfoTest, VersionComparison) {
     EXPECT_FALSE(info.Contains("9"));
   }
   {
-    VersionInfo info("between", std::string(), "8.9", "9.1");
+    VersionInfo info("between", "", "8.9", "9.1");
     EXPECT_FALSE(info.Contains("7"));
     EXPECT_FALSE(info.Contains("8.8"));
     EXPECT_TRUE(info.Contains("8"));
@@ -177,14 +177,14 @@ TEST_F(VersionInfoTest, DateComparison) {
   // When we use '-' as splitter, we assume a format of mm-dd-yyyy
   // or mm-yyyy, i.e., a date.
   {
-    VersionInfo info("=", std::string(), "1976.3.21", std::string());
+    VersionInfo info("=", "", "1976.3.21", "");
     EXPECT_TRUE(info.Contains("3-21-1976", '-'));
     EXPECT_TRUE(info.Contains("3-1976", '-'));
     EXPECT_TRUE(info.Contains("03-1976", '-'));
     EXPECT_FALSE(info.Contains("21-3-1976", '-'));
   }
   {
-    VersionInfo info(">", std::string(), "1976.3.21", std::string());
+    VersionInfo info(">", "", "1976.3.21", "");
     EXPECT_TRUE(info.Contains("3-22-1976", '-'));
     EXPECT_TRUE(info.Contains("4-1976", '-'));
     EXPECT_TRUE(info.Contains("04-1976", '-'));
@@ -192,7 +192,7 @@ TEST_F(VersionInfoTest, DateComparison) {
     EXPECT_FALSE(info.Contains("2-1976", '-'));
   }
   {
-    VersionInfo info("between", std::string(), "1976.3.21", "2012.12.25");
+    VersionInfo info("between", "", "1976.3.21", "2012.12.25");
     EXPECT_FALSE(info.Contains("3-20-1976", '-'));
     EXPECT_TRUE(info.Contains("3-21-1976", '-'));
     EXPECT_TRUE(info.Contains("3-22-1976", '-'));
@@ -215,7 +215,7 @@ TEST_F(VersionInfoTest, LexicalComparison) {
   // When we use lexical style, we assume a format major.minor.*.
   // We apply numerical comparison to major, lexical comparison to others.
   {
-    VersionInfo info("<", "lexical", "8.201", std::string());
+    VersionInfo info("<", "lexical", "8.201", "");
     EXPECT_TRUE(info.Contains("8.001.100"));
     EXPECT_TRUE(info.Contains("8.109"));
     EXPECT_TRUE(info.Contains("8.10900"));
@@ -234,7 +234,7 @@ TEST_F(VersionInfoTest, LexicalComparison) {
     EXPECT_FALSE(info.Contains("12.201"));
   }
   {
-    VersionInfo info("<", "lexical", "9.002", std::string());
+    VersionInfo info("<", "lexical", "9.002", "");
     EXPECT_TRUE(info.Contains("8.001.100"));
     EXPECT_TRUE(info.Contains("8.109"));
     EXPECT_TRUE(info.Contains("8.10900"));
diff --git a/content/browser/gpu/gpu_data_manager_impl.cc b/content/browser/gpu/gpu_data_manager_impl.cc
index 467cc21..675222b 100644
--- a/content/browser/gpu/gpu_data_manager_impl.cc
+++ b/content/browser/gpu/gpu_data_manager_impl.cc
@@ -117,7 +117,7 @@ void GpuDataManagerImpl::InitializeForTesting(
   // This function is for testing only, so disable histograms.
   update_histograms_ = false;
 
-  InitializeImpl(gpu_blacklist_json, std::string(), std::string(), gpu_info);
+  InitializeImpl(gpu_blacklist_json, "", "", gpu_info);
 }
 
 bool GpuDataManagerImpl::IsFeatureBlacklisted(int feature) const {
@@ -350,7 +350,7 @@ void GpuDataManagerImpl::UpdateGpuInfo(const GPUInfo& gpu_info) {
 
   if (gpu_blacklist_.get()) {
     std::set<int> features = gpu_blacklist_->MakeDecision(
-        GpuControlList::kOsAny, std::string(), my_gpu_info);
+        GpuControlList::kOsAny, "", my_gpu_info);
     if (update_histograms_)
       UpdateStats(gpu_blacklist_.get(), features);
 
@@ -358,7 +358,7 @@ void GpuDataManagerImpl::UpdateGpuInfo(const GPUInfo& gpu_info) {
   }
   if (gpu_switching_list_.get()) {
     std::set<int> option = gpu_switching_list_->MakeDecision(
-        GpuControlList::kOsAny, std::string(), my_gpu_info);
+        GpuControlList::kOsAny, "", my_gpu_info);
     if (option.size() == 1) {
       // Blacklist decision should not overwrite commandline switch from users.
       CommandLine* command_line = CommandLine::ForCurrentProcess();
@@ -368,7 +368,7 @@ void GpuDataManagerImpl::UpdateGpuInfo(const GPUInfo& gpu_info) {
   }
   if (gpu_driver_bug_list_.get())
     gpu_driver_bugs_ = gpu_driver_bug_list_->MakeDecision(
-        GpuControlList::kOsAny, std::string(), my_gpu_info);
+        GpuControlList::kOsAny, "", my_gpu_info);
 
   // We have to update GpuFeatureType before notify all the observers.
   NotifyGpuInfoUpdate();
diff --git a/content/browser/gpu/gpu_memory_test.cc b/content/browser/gpu/gpu_memory_test.cc
index 832b947..36584c3 100644
--- a/content/browser/gpu/gpu_memory_test.cc
+++ b/content/browser/gpu/gpu_memory_test.cc
@@ -116,8 +116,12 @@ class GpuMemoryTest : public ContentBrowserTest {
     js_call << mb_to_use;
     js_call << ");";
     std::string message;
-    ASSERT_TRUE(ExecuteScriptInFrameAndExtractString(
-        tab_to_load->web_contents(), std::string(), js_call.str(), &message));
+    ASSERT_TRUE(
+        ExecuteScriptInFrameAndExtractString(
+        tab_to_load->web_contents(),
+        "",
+        js_call.str(),
+        &message));
     EXPECT_EQ("DONE_USE_GPU_MEMORY", message);
   }
 
@@ -192,8 +196,12 @@ class GpuMemoryTest : public ContentBrowserTest {
             "  domAutomationController.send(\"DONE_RAF\");"
             "})");
         std::string message;
-        ASSERT_TRUE(ExecuteScriptInFrameAndExtractString(
-            (*it)->web_contents(), std::string(), js_call, &message));
+        ASSERT_TRUE(
+            ExecuteScriptInFrameAndExtractString(
+            (*it)->web_contents(),
+            "",
+            js_call,
+            &message));
         EXPECT_EQ("DONE_RAF", message);
       }
       // TODO(ccameron): send an IPC from Browser -> Renderer (delay it until
diff --git a/content/browser/gpu/gpu_pixel_browsertest.cc b/content/browser/gpu/gpu_pixel_browsertest.cc
index 758d2b4..e146a08 100644
--- a/content/browser/gpu/gpu_pixel_browsertest.cc
+++ b/content/browser/gpu/gpu_pixel_browsertest.cc
@@ -147,7 +147,7 @@ class GpuPixelBrowserTest : public ContentBrowserTest {
         "DISABLED_", "FLAKY_", "FAILS_", "MANUAL_"};
     for (size_t i = 0; i < arraysize(test_status_prefixes); ++i) {
       ReplaceFirstSubstringAfterOffset(
-          &test_name_, 0, test_status_prefixes[i], std::string());
+          &test_name_, 0, test_status_prefixes[i], "");
     }
 
     ui::DisableTestCompositor();
diff --git a/content/browser/media/media_internals_unittest.cc b/content/browser/media/media_internals_unittest.cc
index 591a287..0db2580 100644
--- a/content/browser/media/media_internals_unittest.cc
+++ b/content/browser/media/media_internals_unittest.cc
@@ -41,7 +41,7 @@ class MediaInternalsTest : public testing::Test {
 
   void UpdateItem(const std::string& item, const std::string& property,
                   base::Value* value) {
-    internals_->UpdateItem(std::string(), item, property, value);
+    internals_->UpdateItem("", item, property, value);
   }
 
   void SendUpdate(const std::string& function, base::Value* value) {
diff --git a/content/browser/plugin_service_impl.cc b/content/browser/plugin_service_impl.cc
index a800ec2..4ae318a 100644
--- a/content/browser/plugin_service_impl.cc
+++ b/content/browser/plugin_service_impl.cc
@@ -178,7 +178,7 @@ void PluginServiceImpl::Init() {
   if (command_line->HasSwitch(switches::kSitePerProcess)) {
     webkit::WebPluginInfo webview_plugin(
         ASCIIToUTF16("WebView Tag"),
-        base::FilePath(),
+        base::FilePath(FILE_PATH_LITERAL("")),
         ASCIIToUTF16("1.2.3.4"),
         ASCIIToUTF16("Browser Plugin."));
     webview_plugin.type = webkit::WebPluginInfo::PLUGIN_TYPE_NPAPI;
diff --git a/content/browser/ppapi_plugin_process_host.cc b/content/browser/ppapi_plugin_process_host.cc
index 9956326..a315130 100644
--- a/content/browser/ppapi_plugin_process_host.cc
+++ b/content/browser/ppapi_plugin_process_host.cc
@@ -317,7 +317,7 @@ bool PpapiPluginProcessHost::Init(const PepperPluginInfo& info) {
 #if defined(OS_POSIX)
   bool use_zygote = !is_broker_ && plugin_launcher.empty() && info.is_sandboxed;
   if (!info.is_sandboxed)
-    cmd_line->AppendSwitchASCII(switches::kNoSandbox, std::string());
+    cmd_line->AppendSwitchASCII(switches::kNoSandbox, "");
 #endif  // OS_POSIX
   process_->Launch(
 #if defined(OS_WIN)
diff --git a/content/browser/renderer_host/gtk_key_bindings_handler.cc b/content/browser/renderer_host/gtk_key_bindings_handler.cc
index e86ea60..756bcc3 100644
--- a/content/browser/renderer_host/gtk_key_bindings_handler.cc
+++ b/content/browser/renderer_host/gtk_key_bindings_handler.cc
@@ -132,16 +132,15 @@ GtkKeyBindingsHandler* GtkKeyBindingsHandler::GetHandlerOwner(
 }
 
 void GtkKeyBindingsHandler::BackSpace(GtkTextView* text_view) {
-  GetHandlerOwner(text_view)
-      ->EditCommandMatched("DeleteBackward", std::string());
+  GetHandlerOwner(text_view)->EditCommandMatched("DeleteBackward", "");
 }
 
 void GtkKeyBindingsHandler::CopyClipboard(GtkTextView* text_view) {
-  GetHandlerOwner(text_view)->EditCommandMatched("Copy", std::string());
+  GetHandlerOwner(text_view)->EditCommandMatched("Copy", "");
 }
 
 void GtkKeyBindingsHandler::CutClipboard(GtkTextView* text_view) {
-  GetHandlerOwner(text_view)->EditCommandMatched("Cut", std::string());
+  GetHandlerOwner(text_view)->EditCommandMatched("Cut", "");
 }
 
 void GtkKeyBindingsHandler::DeleteFromCursor(
@@ -192,7 +191,7 @@ void GtkKeyBindingsHandler::DeleteFromCursor(
     count = -count;
   for (; count > 0; --count) {
     for (const char* const* p = commands; *p; ++p)
-      owner->EditCommandMatched(*p, std::string());
+      owner->EditCommandMatched(*p, "");
   }
 }
 
@@ -248,7 +247,7 @@ void GtkKeyBindingsHandler::MoveCursor(
   if (count < 0)
     count = -count;
   for (; count > 0; --count)
-    owner->EditCommandMatched(command, std::string());
+    owner->EditCommandMatched(command, "");
 }
 
 void GtkKeyBindingsHandler::MoveViewport(
@@ -257,18 +256,18 @@ void GtkKeyBindingsHandler::MoveViewport(
 }
 
 void GtkKeyBindingsHandler::PasteClipboard(GtkTextView* text_view) {
-  GetHandlerOwner(text_view)->EditCommandMatched("Paste", std::string());
+  GetHandlerOwner(text_view)->EditCommandMatched("Paste", "");
 }
 
 void GtkKeyBindingsHandler::SelectAll(GtkTextView* text_view, gboolean select) {
   if (select)
-    GetHandlerOwner(text_view)->EditCommandMatched("SelectAll", std::string());
+    GetHandlerOwner(text_view)->EditCommandMatched("SelectAll", "");
   else
-    GetHandlerOwner(text_view)->EditCommandMatched("Unselect", std::string());
+    GetHandlerOwner(text_view)->EditCommandMatched("Unselect", "");
 }
 
 void GtkKeyBindingsHandler::SetAnchor(GtkTextView* text_view) {
-  GetHandlerOwner(text_view)->EditCommandMatched("SetMark", std::string());
+  GetHandlerOwner(text_view)->EditCommandMatched("SetMark", "");
 }
 
 void GtkKeyBindingsHandler::ToggleCursorVisible(GtkTextView* text_view) {
diff --git a/content/browser/renderer_host/pepper/pepper_host_resolver_private_message_filter.cc b/content/browser/renderer_host/pepper/pepper_host_resolver_private_message_filter.cc
index e4bb14c..d42cb56 100644
--- a/content/browser/renderer_host/pepper/pepper_host_resolver_private_message_filter.cc
+++ b/content/browser/renderer_host/pepper/pepper_host_resolver_private_message_filter.cc
@@ -122,9 +122,9 @@ int32_t PepperHostResolverPrivateMessageFilter::OnMsgResolve(
 
   // Check plugin permissions.
   SocketPermissionRequest request(
-      content::SocketPermissionRequest::NONE, std::string(), 0);
-  RenderViewHost* render_view_host =
-      RenderViewHost::FromID(render_process_id_, render_view_id_);
+      content::SocketPermissionRequest::NONE, "", 0);
+  RenderViewHost* render_view_host = RenderViewHost::FromID(render_process_id_,
+                                                            render_view_id_);
   if (!render_view_host ||
       !pepper_socket_utils::CanUseSocketAPIs(external_plugin_,
                                              request,
diff --git a/content/browser/renderer_host/pepper/pepper_udp_socket_private_message_filter.cc b/content/browser/renderer_host/pepper/pepper_udp_socket_private_message_filter.cc
index 4799d66..08384e78 100644
--- a/content/browser/renderer_host/pepper/pepper_udp_socket_private_message_filter.cc
+++ b/content/browser/renderer_host/pepper/pepper_udp_socket_private_message_filter.cc
@@ -380,9 +380,7 @@ void PepperUDPSocketPrivateMessageFilter::SendBindError(
 void PepperUDPSocketPrivateMessageFilter::SendRecvFromError(
     const ppapi::host::ReplyMessageContext& context,
     int32_t result) {
-  SendRecvFromReply(context,
-                    result,
-                    std::string(),
+  SendRecvFromReply(context, result, "",
                     NetAddressPrivateImpl::kInvalidNetAddress);
 }
 
diff --git a/content/browser/renderer_host/render_sandbox_host_linux.cc b/content/browser/renderer_host/render_sandbox_host_linux.cc
index 78eba83..0cc3638 100644
--- a/content/browser/renderer_host/render_sandbox_host_linux.cc
+++ b/content/browser/renderer_host/render_sandbox_host_linux.cc
@@ -278,7 +278,7 @@ class SandboxIPCProcess  {
     if (family.name.data()) {
       reply.WriteString(family.name.data());
     } else {
-      reply.WriteString(std::string());
+      reply.WriteString("");
     }
     reply.WriteBool(family.isBold);
     reply.WriteBool(family.isItalic);
diff --git a/content/browser/speech/google_one_shot_remote_engine_unittest.cc b/content/browser/speech/google_one_shot_remote_engine_unittest.cc
index 694e246..efcf84f 100644
--- a/content/browser/speech/google_one_shot_remote_engine_unittest.cc
+++ b/content/browser/speech/google_one_shot_remote_engine_unittest.cc
@@ -104,7 +104,7 @@ TEST_F(GoogleOneShotRemoteEngineTest, BasicTest) {
   EXPECT_EQ(0U, result().hypotheses.size());
 
   // Http failure case.
-  CreateAndTestRequest(false, std::string());
+  CreateAndTestRequest(false, "");
   EXPECT_EQ(error_, SPEECH_RECOGNITION_ERROR_NETWORK);
   EXPECT_EQ(0U, result().hypotheses.size());
 
diff --git a/content/browser/speech/speech_recognition_manager_impl.cc b/content/browser/speech/speech_recognition_manager_impl.cc
index 2dc6cf8..8f9c3e1 100644
--- a/content/browser/speech/speech_recognition_manager_impl.cc
+++ b/content/browser/speech/speech_recognition_manager_impl.cc
@@ -100,8 +100,7 @@ int SpeechRecognitionManagerImpl::CreateSession(
   remote_engine_config.interim_results = config.interim_results;
   remote_engine_config.max_hypotheses = config.max_hypotheses;
   remote_engine_config.hardware_info = hardware_info;
-  remote_engine_config.origin_url =
-      can_report_metrics ? config.origin_url : std::string();
+  remote_engine_config.origin_url = can_report_metrics ? config.origin_url : "";
 
   SpeechRecognitionEngine* google_remote_engine;
   if (config.is_legacy_api) {
diff --git a/content/browser/speech/speech_recognizer_unittest.cc b/content/browser/speech/speech_recognizer_unittest.cc
index 4c061c2..2cc4db3 100644
--- a/content/browser/speech/speech_recognizer_unittest.cc
+++ b/content/browser/speech/speech_recognizer_unittest.cc
@@ -305,7 +305,7 @@ TEST_F(SpeechRecognizerTest, ConnectionError) {
   status.set_error(net::ERR_CONNECTION_REFUSED);
   fetcher->set_status(status);
   fetcher->set_response_code(0);
-  fetcher->SetResponseString(std::string());
+  fetcher->SetResponseString("");
   fetcher->delegate()->OnURLFetchComplete(fetcher);
   MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(recognition_ended_);
diff --git a/content/browser/storage_partition_impl_map_unittest.cc b/content/browser/storage_partition_impl_map_unittest.cc
index 04127cc..1c44fcc 100644
--- a/content/browser/storage_partition_impl_map_unittest.cc
+++ b/content/browser/storage_partition_impl_map_unittest.cc
@@ -13,18 +13,13 @@ class StoragePartitionConfigTest : public testing::Test {
 // Test that the Less comparison function is implemented properly to uniquely
 // identify storage partitions used as keys in a std::map.
 TEST_F(StoragePartitionConfigTest, OperatorLess) {
-  StoragePartitionImplMap::StoragePartitionConfig c1(
-      std::string(), std::string(), false);
-  StoragePartitionImplMap::StoragePartitionConfig c2(
-      std::string(), std::string(), false);
-  StoragePartitionImplMap::StoragePartitionConfig c3(
-      std::string(), std::string(), true);
-  StoragePartitionImplMap::StoragePartitionConfig c4("a", std::string(), true);
-  StoragePartitionImplMap::StoragePartitionConfig c5("b", std::string(), true);
-  StoragePartitionImplMap::StoragePartitionConfig c6(
-      std::string(), "abc", false);
-  StoragePartitionImplMap::StoragePartitionConfig c7(
-      std::string(), "abc", true);
+  StoragePartitionImplMap::StoragePartitionConfig c1("", "", false);
+  StoragePartitionImplMap::StoragePartitionConfig c2("", "", false);
+  StoragePartitionImplMap::StoragePartitionConfig c3("", "", true);
+  StoragePartitionImplMap::StoragePartitionConfig c4("a", "", true);
+  StoragePartitionImplMap::StoragePartitionConfig c5("b", "", true);
+  StoragePartitionImplMap::StoragePartitionConfig c6("", "abc", false);
+  StoragePartitionImplMap::StoragePartitionConfig c7("", "abc", true);
   StoragePartitionImplMap::StoragePartitionConfig c8("a", "abc", false);
   StoragePartitionImplMap::StoragePartitionConfig c9("a", "abc", true);
 
diff --git a/content/browser/streams/stream_url_request_job_unittest.cc b/content/browser/streams/stream_url_request_job_unittest.cc
index bed96fa..10a02c9 100644
--- a/content/browser/streams/stream_url_request_job_unittest.cc
+++ b/content/browser/streams/stream_url_request_job_unittest.cc
@@ -169,7 +169,7 @@ TEST_F(StreamURLRequestJobTest, TestInvalidRangeDataRequest) {
 
   net::HttpRequestHeaders extra_headers;
   extra_headers.SetHeader(net::HttpRequestHeaders::kRange, "bytes=1-3");
-  TestRequest("GET", kStreamURL, extra_headers, 405, std::string());
+  TestRequest("GET", kStreamURL, extra_headers, 405, "");
 }
 
 }  // namespace content
diff --git a/content/browser/tracing/tracing_ui.cc b/content/browser/tracing/tracing_ui.cc
index 40bbee3..aa2e529 100644
--- a/content/browser/tracing/tracing_ui.cc
+++ b/content/browser/tracing/tracing_ui.cc
@@ -317,11 +317,8 @@ void TracingMessageHandler::OnLoadTraceFile(const base::ListValue* list) {
       ui::SelectFileDialog::SELECT_OPEN_FILE,
       string16(),
       base::FilePath(),
-      NULL,
-      0,
-      base::FilePath::StringType(),
-      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
-      NULL);
+      NULL, 0, FILE_PATH_LITERAL(""),
+      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(), NULL);
 }
 
 void TracingMessageHandler::LoadTraceFileComplete(string16* contents) {
@@ -370,11 +367,8 @@ void TracingMessageHandler::OnSaveTraceFile(const base::ListValue* list) {
       ui::SelectFileDialog::SELECT_SAVEAS_FILE,
       string16(),
       base::FilePath(),
-      NULL,
-      0,
-      base::FilePath::StringType(),
-      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(),
-      NULL);
+      NULL, 0, FILE_PATH_LITERAL(""),
+      web_ui()->GetWebContents()->GetView()->GetTopLevelNativeWindow(), NULL);
 }
 
 void TracingMessageHandler::SaveTraceFileComplete() {
diff --git a/content/browser/web_contents/navigation_entry_impl_unittest.cc b/content/browser/web_contents/navigation_entry_impl_unittest.cc
index 8bc5de1..00857ed 100644
--- a/content/browser/web_contents/navigation_entry_impl_unittest.cc
+++ b/content/browser/web_contents/navigation_entry_impl_unittest.cc
@@ -61,23 +61,23 @@ TEST_F(NavigationEntryTest, NavigationEntryURLs) {
 
   EXPECT_EQ(GURL(), entry1_->GetURL());
   EXPECT_EQ(GURL(), entry1_->GetVirtualURL());
-  EXPECT_TRUE(entry1_->GetTitleForDisplay(std::string()).empty());
+  EXPECT_TRUE(entry1_->GetTitleForDisplay("").empty());
 
   // Setting URL affects virtual_url and GetTitleForDisplay
   entry1_->SetURL(GURL("http://www.google.com"));
   EXPECT_EQ(GURL("http://www.google.com"), entry1_->GetURL());
   EXPECT_EQ(GURL("http://www.google.com"), entry1_->GetVirtualURL());
   EXPECT_EQ(ASCIIToUTF16("www.google.com"),
-            entry1_->GetTitleForDisplay(std::string()));
+            entry1_->GetTitleForDisplay(""));
 
   // file:/// URLs should only show the filename.
   entry1_->SetURL(GURL("file:///foo/bar baz.txt"));
   EXPECT_EQ(ASCIIToUTF16("bar baz.txt"),
-            entry1_->GetTitleForDisplay(std::string()));
+            entry1_->GetTitleForDisplay(""));
 
   // Title affects GetTitleForDisplay
   entry1_->SetTitle(ASCIIToUTF16("Google"));
-  EXPECT_EQ(ASCIIToUTF16("Google"), entry1_->GetTitleForDisplay(std::string()));
+  EXPECT_EQ(ASCIIToUTF16("Google"), entry1_->GetTitleForDisplay(""));
 
   // Setting virtual_url doesn't affect URL
   entry2_->SetVirtualURL(GURL("display:url"));
@@ -86,7 +86,7 @@ TEST_F(NavigationEntryTest, NavigationEntryURLs) {
   EXPECT_EQ(GURL("display:url"), entry2_->GetVirtualURL());
 
   // Having a title set in constructor overrides virtual URL
-  EXPECT_EQ(ASCIIToUTF16("title"), entry2_->GetTitleForDisplay(std::string()));
+  EXPECT_EQ(ASCIIToUTF16("title"), entry2_->GetTitleForDisplay(""));
 
   // User typed URL is independent of the others
   EXPECT_EQ(GURL(), entry1_->GetUserTypedURL());
diff --git a/content/browser/webui/web_ui_data_source_unittest.cc b/content/browser/webui/web_ui_data_source_unittest.cc
index bece8d0..24d1d2b 100644
--- a/content/browser/webui/web_ui_data_source_unittest.cc
+++ b/content/browser/webui/web_ui_data_source_unittest.cc
@@ -141,7 +141,7 @@ TEST_F(WebUIDataSourceTest, NamedResource) {
 TEST_F(WebUIDataSourceTest, MimeType) {
   const char* html = "text/html";
   const char* js = "application/javascript";
-  EXPECT_EQ(GetMimeType(std::string()), html);
+  EXPECT_EQ(GetMimeType(""), html);
   EXPECT_EQ(GetMimeType("foo"), html);
   EXPECT_EQ(GetMimeType("foo.html"), html);
   EXPECT_EQ(GetMimeType(".js"), js);
diff --git a/content/browser/worker_host/test/worker_browsertest.cc b/content/browser/worker_host/test/worker_browsertest.cc
index 3e67d7f..1be3007 100644
--- a/content/browser/worker_host/test/worker_browsertest.cc
+++ b/content/browser/worker_host/test/worker_browsertest.cc
@@ -300,11 +300,11 @@ class WorkerTest : public ContentBrowserTest {
 };
 
 IN_PROC_BROWSER_TEST_F(WorkerTest, SingleWorker) {
-  RunTest("single_worker.html", std::string());
+  RunTest("single_worker.html", "");
 }
 
 IN_PROC_BROWSER_TEST_F(WorkerTest, MultipleWorkers) {
-  RunTest("multi_worker.html", std::string());
+  RunTest("multi_worker.html", "");
 }
 
 IN_PROC_BROWSER_TEST_F(WorkerTest, SingleSharedWorker) {
@@ -320,10 +320,10 @@ IN_PROC_BROWSER_TEST_F(WorkerTest, MultipleSharedWorkers) {
 // http://crbug.com/30021
 IN_PROC_BROWSER_TEST_F(WorkerTest, IncognitoSharedWorkers) {
   // Load a non-incognito tab and have it create a shared worker
-  RunTest("incognito_worker.html", std::string());
+  RunTest("incognito_worker.html", "");
 
   // Incognito worker should not share with non-incognito
-  RunTest(CreateOffTheRecordBrowser(), "incognito_worker.html", std::string());
+  RunTest(CreateOffTheRecordBrowser(), "incognito_worker.html", "");
 }
 
 // Make sure that auth dialog is displayed from worker context.
@@ -399,7 +399,7 @@ IN_PROC_BROWSER_TEST_F(WorkerTest, LimitTotal) {
 
 // Flaky, http://crbug.com/59786.
 IN_PROC_BROWSER_TEST_F(WorkerTest, WorkerClose) {
-  RunTest("worker_close.html", std::string());
+  RunTest("worker_close.html", "");
   ASSERT_TRUE(WaitForWorkerProcessCount(0));
 }
 
diff --git a/content/gpu/gpu_info_collector.cc b/content/gpu/gpu_info_collector.cc
index d3f5867..86fb0c5 100644
--- a/content/gpu/gpu_info_collector.cc
+++ b/content/gpu/gpu_info_collector.cc
@@ -53,7 +53,7 @@ std::string GetGLString(unsigned int pname) {
       reinterpret_cast<const char*>(glGetString(pname));
   if (gl_string)
     return std::string(gl_string);
-  return std::string();
+  return "";
 }
 
 // Return a version string in the format of "major.minor".
@@ -71,7 +71,7 @@ std::string GetVersionFromString(const std::string& version_string) {
     if (pieces.size() >= 2)
       return pieces[0] + "." + pieces[1];
   }
-  return std::string();
+  return "";
 }
 
 }  // namespace anonymous
diff --git a/content/public/test/test_launcher.cc b/content/public/test/test_launcher.cc
index f4635ec..40545d5 100644
--- a/content/public/test/test_launcher.cc
+++ b/content/public/test/test_launcher.cc
@@ -454,7 +454,7 @@ bool RunTests(TestLauncherDelegate* launcher_delegate,
   // Split --gtest_filter at '-', if there is one, to separate into
   // positive filter and negative filter portions.
   std::string positive_filter = filter;
-  std::string negative_filter;
+  std::string negative_filter = "";
   size_t dash_pos = filter.find('-');
   if (dash_pos != std::string::npos) {
     positive_filter = filter.substr(0, dash_pos);  // Everything up to the dash.
diff --git a/content/renderer/browser_plugin/browser_plugin.cc b/content/renderer/browser_plugin/browser_plugin.cc
index 62c973318..9fe3191 100644
--- a/content/renderer/browser_plugin/browser_plugin.cc
+++ b/content/renderer/browser_plugin/browser_plugin.cc
@@ -110,7 +110,7 @@ static std::string PermissionTypeToString(BrowserPluginPermissionType type) {
       NOTREACHED();
       break;
   }
-  return std::string();
+  return "";
 }
 
 typedef std::map<WebKit::WebPluginContainer*,
@@ -227,7 +227,7 @@ void BrowserPlugin::RemoveDOMAttribute(const std::string& attribute_name) {
 std::string BrowserPlugin::GetDOMAttributeValue(
     const std::string& attribute_name) const {
   if (!container())
-    return std::string();
+    return "";
 
   return container()->element().getAttribute(
       WebKit::WebString::fromUTF8(attribute_name)).utf8();
diff --git a/content/renderer/date_time_formatter.cc b/content/renderer/date_time_formatter.cc
index 1adb0de..d3c16e3 100644
--- a/content/renderer/date_time_formatter.cc
+++ b/content/renderer/date_time_formatter.cc
@@ -95,7 +95,7 @@ const std::string DateTimeFormatter::FormatString() const {
   UErrorCode success = U_ZERO_ERROR;
   if (year_ == 0 && month_ == 0 && day_ == 0 &&
       hour_ == 0 && minute_ == 0 && second_ == 0) {
-    return std::string();
+    return "";
   }
 
   std::string result;
@@ -113,7 +113,7 @@ const std::string DateTimeFormatter::FormatString() const {
       return result;
   }
   LOG(WARNING) << "Calendar not created: error " <<  success;
-  return std::string();
+  return "";
 }
 
 void DateTimeFormatter::ExtractType(
diff --git a/content/renderer/media/mock_media_stream_dependency_factory.cc b/content/renderer/media/mock_media_stream_dependency_factory.cc
index f2656c0..af3177f 100644
--- a/content/renderer/media/mock_media_stream_dependency_factory.cc
+++ b/content/renderer/media/mock_media_stream_dependency_factory.cc
@@ -203,7 +203,7 @@ cricket::VideoRenderer* MockLocalVideoTrack::FrameInput() {
 
 std::string MockLocalVideoTrack::kind() const {
   NOTIMPLEMENTED();
-  return std::string();
+  return "";
 }
 
 std::string MockLocalVideoTrack::id() const { return id_; }
@@ -239,7 +239,7 @@ VideoSourceInterface* MockLocalVideoTrack::GetSource() const {
 
 std::string MockLocalAudioTrack::kind() const {
   NOTIMPLEMENTED();
-  return std::string();
+  return "";
 }
 
 std::string MockLocalAudioTrack::id() const { return id_; }
@@ -292,11 +292,11 @@ class MockSessionDescription : public SessionDescriptionInterface {
   }
   virtual std::string session_id() const OVERRIDE {
     NOTIMPLEMENTED();
-    return std::string();
+    return "";
   }
   virtual std::string session_version() const OVERRIDE {
     NOTIMPLEMENTED();
-    return std::string();
+    return "";
   }
   virtual std::string type() const OVERRIDE {
     return type_;
diff --git a/content/renderer/media/peer_connection_tracker.cc b/content/renderer/media/peer_connection_tracker.cc
index 82f3c58..095d85f 100644
--- a/content/renderer/media/peer_connection_tracker.cc
+++ b/content/renderer/media/peer_connection_tracker.cc
@@ -376,7 +376,7 @@ void PeerConnectionTracker::TrackCreateDataChannel(
 }
 
 void PeerConnectionTracker::TrackStop(RTCPeerConnectionHandler* pc_handler) {
-  SendPeerConnectionUpdate(pc_handler, "stop", std::string());
+  SendPeerConnectionUpdate(pc_handler, "stop", "");
 }
 
 void PeerConnectionTracker::TrackSignalingStateChange(
@@ -430,7 +430,7 @@ void PeerConnectionTracker::TrackSessionDescriptionCallback(
 
 void PeerConnectionTracker::TrackOnRenegotiationNeeded(
     RTCPeerConnectionHandler* pc_handler) {
-  SendPeerConnectionUpdate(pc_handler, "onRenegotiationNeeded", std::string());
+  SendPeerConnectionUpdate(pc_handler, "onRenegotiationNeeded", "");
 }
 
 void PeerConnectionTracker::TrackCreateDTMFSender(
diff --git a/content/renderer/p2p/port_allocator.cc b/content/renderer/p2p/port_allocator.cc
index 7380113..7d06f6e 100644
--- a/content/renderer/p2p/port_allocator.cc
+++ b/content/renderer/p2p/port_allocator.cc
@@ -282,8 +282,8 @@ void P2PPortAllocatorSession::ParseRelayResponse() {
 }
 
 void P2PPortAllocatorSession::AddConfig() {
-  cricket::PortConfiguration* config = new cricket::PortConfiguration(
-      stun_server_address_, std::string(), std::string());
+  cricket::PortConfiguration* config =
+      new cricket::PortConfiguration(stun_server_address_, "", "");
 
   if (allocator_->config_.legacy_relay) {
     // Passing empty credentials for legacy google relay.
diff --git a/content/renderer/pepper/pepper_device_enumeration_event_handler.cc b/content/renderer/pepper/pepper_device_enumeration_event_handler.cc
index 7a8dce6..b23df8a 100644
--- a/content/renderer/pepper/pepper_device_enumeration_event_handler.cc
+++ b/content/renderer/pepper/pepper_device_enumeration_event_handler.cc
@@ -78,7 +78,7 @@ void PepperDeviceEnumerationEventHandler::OnDeviceOpened(
 }
 
 void PepperDeviceEnumerationEventHandler::OnDeviceOpenFailed(int request_id) {
-  NotifyDeviceOpened(request_id, false, std::string());
+  NotifyDeviceOpened(request_id, false, "");
 }
 
 // static
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 3e06f1f..0c4212b 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -180,7 +180,7 @@ std::string HostToCustomHistogramSuffix(const std::string& host) {
     return ".docs";
   if (host == "plus.google.com")
     return ".plus";
-  return std::string();
+  return "";
 }
 
 void* CreateHistogram(
diff --git a/content/renderer/v8_value_converter_impl_unittest.cc b/content/renderer/v8_value_converter_impl_unittest.cc
index 1f6b9bf..df68e80 100644
--- a/content/renderer/v8_value_converter_impl_unittest.cc
+++ b/content/renderer/v8_value_converter_impl_unittest.cc
@@ -70,7 +70,7 @@ class V8ValueConverterImplTest : public testing::Test {
     std::string temp;
     if (!value->GetString(key, &temp)) {
       ADD_FAILURE();
-      return std::string();
+      return "";
     }
     return temp;
   }
@@ -80,7 +80,7 @@ class V8ValueConverterImplTest : public testing::Test {
         value->Get(v8::String::New(key.c_str())).As<v8::String>();
     if (temp.IsEmpty()) {
       ADD_FAILURE();
-      return std::string();
+      return "";
     }
     v8::String::Utf8Value utf8(temp);
     return std::string(*utf8, utf8.length());
@@ -90,7 +90,7 @@ class V8ValueConverterImplTest : public testing::Test {
     std::string temp;
     if (!value->GetString(static_cast<size_t>(index), &temp)) {
       ADD_FAILURE();
-      return std::string();
+      return "";
     }
     return temp;
   }
@@ -99,7 +99,7 @@ class V8ValueConverterImplTest : public testing::Test {
     v8::Handle<v8::String> temp = value->Get(index).As<v8::String>();
     if (temp.IsEmpty()) {
       ADD_FAILURE();
-      return std::string();
+      return "";
     }
     v8::String::Utf8Value utf8(temp);
     return std::string(*utf8, utf8.length());
diff --git a/content/shell/shell_devtools_delegate.cc b/content/shell/shell_devtools_delegate.cc
index 07ebbde..58182f1 100644
--- a/content/shell/shell_devtools_delegate.cc
+++ b/content/shell/shell_devtools_delegate.cc
@@ -30,11 +30,12 @@ ShellDevToolsDelegate::ShellDevToolsDelegate(BrowserContext* browser_context,
   devtools_http_handler_ = DevToolsHttpHandler::Start(
 #if defined(OS_ANDROID)
       new net::UnixDomainSocketWithAbstractNamespaceFactory(
-          kSocketName, base::Bind(&CanUserConnectToDevTools)),
+          kSocketName,
+          base::Bind(&CanUserConnectToDevTools)),
 #else
       new net::TCPListenSocketFactory("127.0.0.1", port),
 #endif
-      std::string(),
+      "",
       this);
 }
 
@@ -60,7 +61,7 @@ base::FilePath ShellDevToolsDelegate::GetDebugFrontendDir() {
 }
 
 std::string ShellDevToolsDelegate::GetPageThumbnailData(const GURL& url) {
-  return std::string();
+  return "";
 }
 
 RenderViewHost* ShellDevToolsDelegate::CreateNewTarget() {
@@ -79,7 +80,7 @@ ShellDevToolsDelegate::GetTargetType(RenderViewHost*) {
 
 std::string ShellDevToolsDelegate::GetViewDescription(
     content::RenderViewHost*) {
-  return std::string();
+  return "";
 }
 
 }  // namespace content
diff --git a/content/test/gpu/gpu_test_config_unittest.cc b/content/test/gpu/gpu_test_config_unittest.cc
index a87d215..f58139f 100644
--- a/content/test/gpu/gpu_test_config_unittest.cc
+++ b/content/test/gpu/gpu_test_config_unittest.cc
@@ -148,7 +148,7 @@ TEST_F(GPUTestConfigTest, StringMatches) {
   config.set_gpu_device_id(0x0640);
   EXPECT_TRUE(config.IsValid());
 
-  EXPECT_TRUE(config.Matches(std::string()));
+  EXPECT_TRUE(config.Matches(""));
 
   // os matching
   EXPECT_TRUE(config.Matches("WIN"));
diff --git a/content/test/layout_browsertest.cc b/content/test/layout_browsertest.cc
index 431e890..4c34a38 100644
--- a/content/test/layout_browsertest.cc
+++ b/content/test/layout_browsertest.cc
@@ -155,8 +155,8 @@ void InProcessBrowserLayoutTest::RunLayoutTestInternal(
   test_controller_->set_printer(printer.release());
 
   LOG(INFO) << "Navigating to URL " << url << " and blocking.";
-  ASSERT_TRUE(test_controller_->PrepareForLayoutTest(
-      url, layout_test_dir_, false, std::string()));
+  ASSERT_TRUE(
+      test_controller_->PrepareForLayoutTest(url, layout_test_dir_, false, ""));
   base::RunLoop run_loop;
   run_loop.Run();
   LOG(INFO) << "Navigation completed.";
@@ -195,10 +195,9 @@ void InProcessBrowserLayoutTest::RunLayoutTestInternal(
 std::string InProcessBrowserLayoutTest::SaveResults(const std::string& expected,
                                                     const std::string& actual) {
   base::FilePath cwd;
-  EXPECT_TRUE(file_util::CreateNewTempDirectory(
-      base::FilePath::StringType(), &cwd));
-  base::FilePath expected_filename =
-      cwd.Append(FILE_PATH_LITERAL("expected.txt"));
+  EXPECT_TRUE(file_util::CreateNewTempDirectory(FILE_PATH_LITERAL(""), &cwd));
+  base::FilePath expected_filename = cwd.Append(
+      FILE_PATH_LITERAL("expected.txt"));
   base::FilePath actual_filename = cwd.Append(FILE_PATH_LITERAL("actual.txt"));
   EXPECT_NE(-1, file_util::WriteFile(expected_filename,
                                      expected.c_str(),
diff --git a/courgette/bsdiff_memory_unittest.cc b/courgette/bsdiff_memory_unittest.cc
index fe9fae6..f1718e2 100644
--- a/courgette/bsdiff_memory_unittest.cc
+++ b/courgette/bsdiff_memory_unittest.cc
@@ -51,15 +51,15 @@ std::string BSDiffMemoryTest::GenerateSyntheticInput(size_t length, int seed)
 }
 
 TEST_F(BSDiffMemoryTest, TestEmpty) {
-  GenerateAndTestPatch(std::string(), std::string());
+  GenerateAndTestPatch("", "");
 }
 
 TEST_F(BSDiffMemoryTest, TestEmptyVsNonempty) {
-  GenerateAndTestPatch(std::string(), "xxx");
+  GenerateAndTestPatch("", "xxx");
 }
 
 TEST_F(BSDiffMemoryTest, TestNonemptyVsEmpty) {
-  GenerateAndTestPatch("xxx", std::string());
+  GenerateAndTestPatch("xxx", "");
 }
 
 TEST_F(BSDiffMemoryTest, TestSmallInputsWithSmallChanges) {
diff --git a/crypto/ec_private_key_unittest.cc b/crypto/ec_private_key_unittest.cc
index d2ec256..a052a9a 100644
--- a/crypto/ec_private_key_unittest.cc
+++ b/crypto/ec_private_key_unittest.cc
@@ -23,7 +23,7 @@ TEST(ECPrivateKeyUnitTest, OpenSSLStub) {
 // back the same exact public key, and the private key should have the same
 // value and elliptic curve params.
 TEST(ECPrivateKeyUnitTest, InitRandomTest) {
-  const std::string password1;
+  const std::string password1 = "";
   const std::string password2 = "test";
 
   scoped_ptr<crypto::ECPrivateKey> keypair1(
@@ -86,7 +86,7 @@ TEST(ECPrivateKeyUnitTest, InitRandomTest) {
 }
 
 TEST(ECPrivateKeyUnitTest, BadPasswordTest) {
-  const std::string password1;
+  const std::string password1 = "";
   const std::string password2 = "test";
 
   scoped_ptr<crypto::ECPrivateKey> keypair1(
diff --git a/crypto/ec_signature_creator_unittest.cc b/crypto/ec_signature_creator_unittest.cc
index b34022b..df73bec 100644
--- a/crypto/ec_signature_creator_unittest.cc
+++ b/crypto/ec_signature_creator_unittest.cc
@@ -30,14 +30,13 @@ TEST(ECSignatureCreatorTest, BasicTest) {
   ASSERT_TRUE(key_original.get());
 
   std::vector<uint8> key_info;
-  ASSERT_TRUE(
-      key_original->ExportEncryptedPrivateKey(std::string(), 1000, &key_info));
+  ASSERT_TRUE(key_original->ExportEncryptedPrivateKey("", 1000, &key_info));
   std::vector<uint8> pubkey_info;
   ASSERT_TRUE(key_original->ExportPublicKey(&pubkey_info));
 
   scoped_ptr<crypto::ECPrivateKey> key(
-      crypto::ECPrivateKey::CreateFromEncryptedPrivateKeyInfo(
-          std::string(), key_info, pubkey_info));
+      crypto::ECPrivateKey::CreateFromEncryptedPrivateKeyInfo("", key_info,
+                                                              pubkey_info));
   ASSERT_TRUE(key.get());
   ASSERT_TRUE(key->key() != NULL);
 
diff --git a/dbus/end_to_end_async_unittest.cc b/dbus/end_to_end_async_unittest.cc
index 6943494..0a3446e 100644
--- a/dbus/end_to_end_async_unittest.cc
+++ b/dbus/end_to_end_async_unittest.cc
@@ -185,7 +185,7 @@ class EndToEndAsyncTest : public testing::Test {
       ASSERT_TRUE(reader.PopString(&response_string));
       response_strings_.push_back(response_string);
     } else {
-      response_strings_.push_back(std::string());
+      response_strings_.push_back("");
     }
     message_loop_.Quit();
   };
@@ -205,7 +205,7 @@ class EndToEndAsyncTest : public testing::Test {
       ASSERT_NE("", error->GetErrorName());
       error_names_.push_back(error->GetErrorName());
     } else {
-      error_names_.push_back(std::string());
+      error_names_.push_back("");
     }
     message_loop_.Quit();
   }
diff --git a/dbus/message.cc b/dbus/message.cc
index 737b0c4..ce53a48 100644
--- a/dbus/message.cc
+++ b/dbus/message.cc
@@ -87,7 +87,7 @@ std::string Message::GetMessageTypeAsString() {
       return "MESSAGE_ERROR";
   }
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 std::string Message::ToStringInternal(const std::string& indent,
@@ -251,7 +251,7 @@ std::string Message::ToStringInternal(const std::string& indent,
 // ...
 std::string Message::ToString() {
   if (!raw_message_)
-    return std::string();
+    return "";
 
   // Generate headers first.
   std::string headers;
@@ -268,7 +268,7 @@ std::string Message::ToString() {
 
   // Generate the payload.
   MessageReader reader(this);
-  return headers + "\n" + ToStringInternal(std::string(), &reader);
+  return headers + "\n" + ToStringInternal("", &reader);
 }
 
 bool Message::SetDestination(const std::string& destination) {
diff --git a/dbus/message_unittest.cc b/dbus/message_unittest.cc
index 383e1c1..7e4455a8 100644
--- a/dbus/message_unittest.cc
+++ b/dbus/message_unittest.cc
@@ -557,7 +557,7 @@ TEST(MessageTest, GetAndSetHeaders) {
   scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
 
   EXPECT_EQ("", message->GetDestination());
-  EXPECT_EQ(dbus::ObjectPath(std::string()), message->GetPath());
+  EXPECT_EQ(dbus::ObjectPath(""), message->GetPath());
   EXPECT_EQ("", message->GetInterface());
   EXPECT_EQ("", message->GetMember());
   EXPECT_EQ("", message->GetErrorName());
@@ -587,7 +587,7 @@ TEST(MessageTest, GetAndSetHeaders) {
 TEST(MessageTest, SetInvalidHeaders) {
   scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
   EXPECT_EQ("", message->GetDestination());
-  EXPECT_EQ(dbus::ObjectPath(std::string()), message->GetPath());
+  EXPECT_EQ(dbus::ObjectPath(""), message->GetPath());
   EXPECT_EQ("", message->GetInterface());
   EXPECT_EQ("", message->GetMember());
   EXPECT_EQ("", message->GetErrorName());
@@ -607,7 +607,7 @@ TEST(MessageTest, SetInvalidHeaders) {
   EXPECT_FALSE(message->SetSender("?!#*"));
 
   EXPECT_EQ("", message->GetDestination());
-  EXPECT_EQ(dbus::ObjectPath(std::string()), message->GetPath());
+  EXPECT_EQ(dbus::ObjectPath(""), message->GetPath());
   EXPECT_EQ("", message->GetInterface());
   EXPECT_EQ("", message->GetMember());
   EXPECT_EQ("", message->GetErrorName());
diff --git a/dbus/string_util_unittest.cc b/dbus/string_util_unittest.cc
index 99eb691..76bdfcb 100644
--- a/dbus/string_util_unittest.cc
+++ b/dbus/string_util_unittest.cc
@@ -10,7 +10,7 @@ TEST(StringUtilTest, IsValidObjectPath) {
   EXPECT_TRUE(dbus::IsValidObjectPath("/foo/bar"));
   EXPECT_TRUE(dbus::IsValidObjectPath("/hoge_fuga/piyo123"));
   // Empty string.
-  EXPECT_FALSE(dbus::IsValidObjectPath(std::string()));
+  EXPECT_FALSE(dbus::IsValidObjectPath(""));
   // Emptyr elemnt.
   EXPECT_FALSE(dbus::IsValidObjectPath("//"));
   EXPECT_FALSE(dbus::IsValidObjectPath("/foo//bar"));
diff --git a/dbus/values_util.cc b/dbus/values_util.cc
index 7574f39..2e2d8e3 100644
--- a/dbus/values_util.cc
+++ b/dbus/values_util.cc
@@ -79,7 +79,7 @@ std::string GetTypeSignature(const base::Value& value) {
       return "a{sv}";
     default:
       DLOG(ERROR) << "Unexpected type " << value.GetType();
-      return std::string();
+      return "";
   }
 }
 
diff --git a/device/bluetooth/bluetooth_utils.cc b/device/bluetooth/bluetooth_utils.cc
index 4f30202..1e7b827 100644
--- a/device/bluetooth/bluetooth_utils.cc
+++ b/device/bluetooth/bluetooth_utils.cc
@@ -21,18 +21,18 @@ namespace bluetooth_utils {
 
 std::string CanonicalUuid(std::string uuid) {
   if (uuid.empty())
-    return std::string();
+    return "";
 
   if (uuid.size() < 11 && uuid.find("0x") == 0)
     uuid = uuid.substr(2);
 
   if (!(uuid.size() == 4 || uuid.size() == 8 || uuid.size() == 36))
-    return std::string();
+    return "";
 
   if (uuid.size() == 4 || uuid.size() == 8) {
     for (size_t i = 0; i < uuid.size(); ++i) {
       if (!IsHexDigit(uuid[i]))
-        return std::string();
+        return "";
     }
 
     if (uuid.size() == 4)
@@ -45,10 +45,10 @@ std::string CanonicalUuid(std::string uuid) {
   for (int i = 0; i < kUuidSize; ++i) {
     if (i == 8 || i == 13 || i == 18 || i == 23) {
       if (uuid[i] != '-')
-        return std::string();
+        return "";
     } else {
       if (!IsHexDigit(uuid[i]))
-        return std::string();
+        return "";
       uuid_result[i] = tolower(uuid[i]);
     }
   }
diff --git a/device/media_transfer_protocol/media_transfer_protocol_manager.cc b/device/media_transfer_protocol/media_transfer_protocol_manager.cc
index d3fce03..bbd13b3 100644
--- a/device/media_transfer_protocol/media_transfer_protocol_manager.cc
+++ b/device/media_transfer_protocol/media_transfer_protocol_manager.cc
@@ -111,7 +111,7 @@ class MediaTransferProtocolManagerImpl : public MediaTransferProtocolManager {
                            const OpenStorageCallback& callback) OVERRIDE {
     DCHECK(thread_checker_.CalledOnValidThread());
     if (!ContainsKey(storage_info_map_, storage_name)) {
-      callback.Run(std::string(), true);
+      callback.Run("", true);
       return;
     }
     open_storage_callbacks_.push(callback);
@@ -333,13 +333,13 @@ class MediaTransferProtocolManagerImpl : public MediaTransferProtocolManager {
       open_storage_callbacks_.front().Run(handle, false);
     } else {
       NOTREACHED();
-      open_storage_callbacks_.front().Run(std::string(), true);
+      open_storage_callbacks_.front().Run("", true);
     }
     open_storage_callbacks_.pop();
   }
 
   void OnOpenStorageError() {
-    open_storage_callbacks_.front().Run(std::string(), true);
+    open_storage_callbacks_.front().Run("", true);
     open_storage_callbacks_.pop();
   }
 
diff --git a/extensions/common/extension_resource_unittest.cc b/extensions/common/extension_resource_unittest.cc
index 3791b14..132e718 100644
--- a/extensions/common/extension_resource_unittest.cc
+++ b/extensions/common/extension_resource_unittest.cc
@@ -131,8 +131,7 @@ TEST(ExtensionResourceTest, CreateWithAllResourcesOnDisk) {
   ASSERT_TRUE(file_util::CreateDirectory(l10n_path));
 
   std::vector<std::string> locales;
-  l10n_util::GetParentLocales(l10n_util::GetApplicationLocale(std::string()),
-                              &locales);
+  l10n_util::GetParentLocales(l10n_util::GetApplicationLocale(""), &locales);
   ASSERT_FALSE(locales.empty());
   for (size_t i = 0; i < locales.size(); i++) {
     base::FilePath make_path;
diff --git a/extensions/common/matcher/substring_set_matcher_unittest.cc b/extensions/common/matcher/substring_set_matcher_unittest.cc
index fde65bf..4152ff9 100644
--- a/extensions/common/matcher/substring_set_matcher_unittest.cc
+++ b/extensions/common/matcher/substring_set_matcher_unittest.cc
@@ -117,7 +117,7 @@ TEST(SubstringSetMatcherTest, TestMatcher) {
   // String    abcde
   // Pattern 1
   // Pattern 2 abcdef
-  TestTwoPatterns("abcde", std::string(), "abcdef", true, false);
+  TestTwoPatterns("abcde", "", "abcdef", true, false);
 }
 
 TEST(SubstringSetMatcherTest, RegisterAndRemove) {
diff --git a/extensions/common/matcher/url_matcher.cc b/extensions/common/matcher/url_matcher.cc
index b599293..d7779a2 100644
--- a/extensions/common/matcher/url_matcher.cc
+++ b/extensions/common/matcher/url_matcher.cc
@@ -256,8 +256,8 @@ URLMatcherConditionFactory::~URLMatcherConditionFactory() {
 std::string URLMatcherConditionFactory::CanonicalizeURLForComponentSearches(
     const GURL& url) const {
   return kBeginningOfURL + CanonicalizeHostname(url.host()) + kEndOfDomain +
-         url.path() + kEndOfPath +
-         (url.has_query() ? "?" + url.query() : std::string()) + kEndOfURL;
+      url.path() + kEndOfPath + (url.has_query() ? "?" + url.query() : "") +
+      kEndOfURL;
 }
 
 URLMatcherCondition URLMatcherConditionFactory::CreateHostPrefixCondition(
diff --git a/extensions/common/matcher/url_matcher_factory.cc b/extensions/common/matcher/url_matcher_factory.cc
index 3ca4aa2..cdd08ba 100644
--- a/extensions/common/matcher/url_matcher_factory.cc
+++ b/extensions/common/matcher/url_matcher_factory.cc
@@ -151,8 +151,7 @@ URLMatcherFactory::CreateFromURLFilterDictionary(
   // matched.
   if (url_matcher_conditions.empty()) {
     url_matcher_conditions.insert(
-        url_matcher_condition_factory->CreateHostPrefixCondition(
-            std::string()));
+        url_matcher_condition_factory->CreateHostPrefixCondition(""));
   }
 
   scoped_refptr<URLMatcherConditionSet> url_matcher_condition_set(
diff --git a/extensions/common/matcher/url_matcher_unittest.cc b/extensions/common/matcher/url_matcher_unittest.cc
index b17c13c..09fc562 100644
--- a/extensions/common/matcher/url_matcher_unittest.cc
+++ b/extensions/common/matcher/url_matcher_unittest.cc
@@ -247,7 +247,7 @@ TEST(URLMatcherConditionFactoryTest, TestComponentSearches) {
   std::string url = factory.CanonicalizeURLForComponentSearches(gurl);
 
   // Test host component.
-  EXPECT_TRUE(Matches(factory.CreateHostPrefixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateHostPrefixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreateHostPrefixCondition("www.goog"), url));
   EXPECT_TRUE(
       Matches(factory.CreateHostPrefixCondition("www.google.com"), url));
@@ -258,7 +258,7 @@ TEST(URLMatcherConditionFactoryTest, TestComponentSearches) {
       Matches(factory.CreateHostPrefixCondition("www.google.com/"), url));
   EXPECT_FALSE(Matches(factory.CreateHostPrefixCondition("webhp"), url));
 
-  EXPECT_TRUE(Matches(factory.CreateHostSuffixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateHostSuffixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreateHostSuffixCondition("com"), url));
   EXPECT_TRUE(Matches(factory.CreateHostSuffixCondition(".com"), url));
   EXPECT_TRUE(
@@ -270,7 +270,7 @@ TEST(URLMatcherConditionFactoryTest, TestComponentSearches) {
       Matches(factory.CreateHostSuffixCondition("www.google.com/"), url));
   EXPECT_FALSE(Matches(factory.CreateHostSuffixCondition("webhp"), url));
 
-  EXPECT_FALSE(Matches(factory.CreateHostEqualsCondition(std::string()), url));
+  EXPECT_FALSE(Matches(factory.CreateHostEqualsCondition(""), url));
   EXPECT_FALSE(Matches(factory.CreateHostEqualsCondition("www"), url));
   EXPECT_TRUE(
       Matches(factory.CreateHostEqualsCondition("www.google.com"), url));
@@ -279,14 +279,14 @@ TEST(URLMatcherConditionFactoryTest, TestComponentSearches) {
 
 
   // Test path component.
-  EXPECT_TRUE(Matches(factory.CreatePathPrefixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreatePathPrefixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreatePathPrefixCondition("/web"), url));
   EXPECT_TRUE(Matches(factory.CreatePathPrefixCondition("/webhp"), url));
   EXPECT_FALSE(Matches(factory.CreatePathPrefixCondition("webhp"), url));
   EXPECT_FALSE(Matches(factory.CreatePathPrefixCondition("/webhp?"), url));
   EXPECT_FALSE(Matches(factory.CreatePathPrefixCondition("?sourceid"), url));
 
-  EXPECT_TRUE(Matches(factory.CreatePathSuffixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreatePathSuffixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreatePathSuffixCondition("webhp"), url));
   EXPECT_TRUE(Matches(factory.CreatePathSuffixCondition("/webhp"), url));
   EXPECT_FALSE(Matches(factory.CreatePathSuffixCondition("/web"), url));
@@ -300,12 +300,12 @@ TEST(URLMatcherConditionFactoryTest, TestComponentSearches) {
 
 
   // Test query component.
-  EXPECT_TRUE(Matches(factory.CreateQueryPrefixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateQueryPrefixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreateQueryPrefixCondition("sourceid"), url));
   // The '?' at the beginning is just ignored.
   EXPECT_TRUE(Matches(factory.CreateQueryPrefixCondition("?sourceid"), url));
 
-  EXPECT_TRUE(Matches(factory.CreateQuerySuffixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateQuerySuffixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreateQuerySuffixCondition("ion=1"), url));
   EXPECT_FALSE(Matches(factory.CreateQuerySuffixCondition("www"), url));
   // "Suffix" condition + pattern starting with '?' = "equals" condition.
@@ -330,26 +330,21 @@ TEST(URLMatcherConditionFactoryTest, TestComponentSearches) {
   // Test adjacent components
   EXPECT_TRUE(Matches(factory.CreateHostSuffixPathPrefixCondition(
       "google.com", "/webhp"), url));
-  EXPECT_TRUE(Matches(
-      factory.CreateHostSuffixPathPrefixCondition(std::string(), "/webhp"),
-      url));
-  EXPECT_TRUE(Matches(
-      factory.CreateHostSuffixPathPrefixCondition("google.com", std::string()),
-      url));
-  EXPECT_FALSE(Matches(
-      factory.CreateHostSuffixPathPrefixCondition("www", std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateHostSuffixPathPrefixCondition(
+      "", "/webhp"), url));
+  EXPECT_TRUE(Matches(factory.CreateHostSuffixPathPrefixCondition(
+      "google.com", ""), url));
+  EXPECT_FALSE(Matches(factory.CreateHostSuffixPathPrefixCondition(
+      "www", ""), url));
 
   EXPECT_TRUE(Matches(factory.CreateHostEqualsPathPrefixCondition(
       "www.google.com", "/webhp"), url));
-  EXPECT_FALSE(Matches(
-      factory.CreateHostEqualsPathPrefixCondition(std::string(), "/webhp"),
-      url));
+  EXPECT_FALSE(Matches(factory.CreateHostEqualsPathPrefixCondition(
+      "", "/webhp"), url));
   EXPECT_TRUE(Matches(factory.CreateHostEqualsPathPrefixCondition(
-                          "www.google.com", std::string()),
-                      url));
-  EXPECT_FALSE(Matches(
-      factory.CreateHostEqualsPathPrefixCondition("google.com", std::string()),
-      url));
+      "www.google.com", ""), url));
+  EXPECT_FALSE(Matches(factory.CreateHostEqualsPathPrefixCondition(
+      "google.com", ""), url));
 }
 
 TEST(URLMatcherConditionFactoryTest, TestFullSearches) {
@@ -359,9 +354,9 @@ TEST(URLMatcherConditionFactoryTest, TestFullSearches) {
   URLMatcherConditionFactory factory;
   std::string url = factory.CanonicalizeURLForFullSearches(gurl);
 
-  EXPECT_TRUE(Matches(factory.CreateURLPrefixCondition(std::string()), url));
-  EXPECT_TRUE(
-      Matches(factory.CreateURLPrefixCondition("https://www.goog"), url));
+  EXPECT_TRUE(Matches(factory.CreateURLPrefixCondition(""), url));
+  EXPECT_TRUE(Matches(factory.CreateURLPrefixCondition(
+      "https://www.goog"), url));
   EXPECT_TRUE(Matches(factory.CreateURLPrefixCondition(
       "https://www.google.com"), url));
   EXPECT_TRUE(Matches(factory.CreateURLPrefixCondition(
@@ -370,11 +365,11 @@ TEST(URLMatcherConditionFactoryTest, TestFullSearches) {
       "http://www.google.com"), url));
   EXPECT_FALSE(Matches(factory.CreateURLPrefixCondition("webhp"), url));
 
-  EXPECT_TRUE(Matches(factory.CreateURLSuffixCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateURLSuffixCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreateURLSuffixCondition("ion=1"), url));
   EXPECT_FALSE(Matches(factory.CreateURLSuffixCondition("www"), url));
 
-  EXPECT_TRUE(Matches(factory.CreateURLContainsCondition(std::string()), url));
+  EXPECT_TRUE(Matches(factory.CreateURLContainsCondition(""), url));
   EXPECT_TRUE(Matches(factory.CreateURLContainsCondition("www.goog"), url));
   EXPECT_TRUE(Matches(factory.CreateURLContainsCondition("webhp"), url));
   EXPECT_TRUE(Matches(factory.CreateURLContainsCondition("?"), url));
diff --git a/google_apis/gaia/gaia_auth_fetcher.cc b/google_apis/gaia/gaia_auth_fetcher.cc
index 15aa78a..9354447 100644
--- a/google_apis/gaia/gaia_auth_fetcher.cc
+++ b/google_apis/gaia/gaia_auth_fetcher.cc
@@ -617,7 +617,7 @@ void GaiaAuthFetcher::StartClientLogin(
                                       allow_hosted_accounts);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    client_login_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -635,7 +635,7 @@ void GaiaAuthFetcher::StartIssueAuthToken(const std::string& sid,
   request_body_ = MakeIssueAuthTokenBody(sid, lsid, service);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    issue_auth_token_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -669,7 +669,7 @@ void GaiaAuthFetcher::StartRevokeOAuth2Token(const std::string& auth_token) {
   request_body_ = MakeRevokeTokenBody(auth_token);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    oauth2_revoke_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -692,7 +692,7 @@ void GaiaAuthFetcher::StartCookieForOAuthLoginTokenExchange(
 
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    client_login_to_oauth2_gurl_,
                                    net::LOAD_NORMAL,
                                    this));
@@ -708,7 +708,7 @@ void GaiaAuthFetcher::StartAuthCodeForOAuth2TokenExchange(
   request_body_ = MakeGetTokenPairBody(auth_code);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    oauth2_token_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -723,7 +723,7 @@ void GaiaAuthFetcher::StartGetUserInfo(const std::string& lsid) {
   request_body_ = MakeGetUserInfoBody(lsid);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    get_user_info_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -748,7 +748,7 @@ void GaiaAuthFetcher::StartMergeSession(const std::string& uber_token) {
   request_body_ = MakeMergeSessionBody(uber_token, continue_url, source_);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    merge_session_gurl_,
                                    net::LOAD_NORMAL,
                                    this));
@@ -765,7 +765,7 @@ void GaiaAuthFetcher::StartTokenFetchForUberAuthExchange(
   std::string authentication_header =
       base::StringPrintf(kOAuthHeaderFormat, access_token.c_str());
   fetcher_.reset(CreateGaiaFetcher(getter_,
-                                   std::string(),
+                                   "",
                                    authentication_header,
                                    uberauth_token_gurl_,
                                    kLoadFlagsIgnoreCookies,
@@ -785,7 +785,7 @@ void GaiaAuthFetcher::StartClientOAuth(const std::string& username,
                                       source_, locale);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    client_oauth_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -814,7 +814,7 @@ void GaiaAuthFetcher::StartClientOAuthChallengeResponse(
   request_body_ = MakeClientOAuthChallengeResponseBody(name, token, solution);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   std::string(),
+                                   "",
                                    client_oauth_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
diff --git a/google_apis/gaia/gaia_auth_fetcher_unittest.cc b/google_apis/gaia/gaia_auth_fetcher_unittest.cc
index 47b6d15..226ee1a 100644
--- a/google_apis/gaia/gaia_auth_fetcher_unittest.cc
+++ b/google_apis/gaia/gaia_auth_fetcher_unittest.cc
@@ -311,10 +311,10 @@ TEST_F(GaiaAuthFetcherTest, ParseRequest) {
   RunParsingTest("SID=sid\nLSID=lsid\nAuth=auth\n", "sid", "lsid", "auth");
   RunParsingTest("LSID=lsid\nSID=sid\nAuth=auth\n", "sid", "lsid", "auth");
   RunParsingTest("SID=sid\nLSID=lsid\nAuth=auth", "sid", "lsid", "auth");
-  RunParsingTest("SID=sid\nAuth=auth\n", "sid", std::string(), "auth");
-  RunParsingTest("LSID=lsid\nAuth=auth\n", std::string(), "lsid", "auth");
-  RunParsingTest("\nAuth=auth\n", std::string(), std::string(), "auth");
-  RunParsingTest("SID=sid", "sid", std::string(), std::string());
+  RunParsingTest("SID=sid\nAuth=auth\n", "sid", "", "auth");
+  RunParsingTest("LSID=lsid\nAuth=auth\n", "", "lsid", "auth");
+  RunParsingTest("\nAuth=auth\n", "", "", "auth");
+  RunParsingTest("SID=sid", "sid", "", "");
 }
 
 TEST_F(GaiaAuthFetcherTest, ParseErrorRequest) {
@@ -588,11 +588,7 @@ TEST_F(GaiaAuthFetcherTest, FullTokenFailure) {
   MockFetcher mock_fetcher(
       issue_auth_token_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_FORBIDDEN,
-      cookies_,
-      std::string(),
-      net::URLFetcher::GET,
-      &auth);
+      net::HTTP_FORBIDDEN, cookies_, "", net::URLFetcher::GET, &auth);
   auth.OnURLFetchComplete(&mock_fetcher);
   EXPECT_FALSE(auth.HasPendingFetch());
 }
@@ -617,11 +613,8 @@ TEST_F(GaiaAuthFetcherTest, OAuthLoginTokenSuccess) {
   MockFetcher mock_fetcher1(
       client_login_to_oauth2_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_OK,
-      cookies,
-      std::string(),
-      net::URLFetcher::POST,
-      &auth);
+      net::HTTP_OK, cookies, "",
+      net::URLFetcher::POST, &auth);
   auth.OnURLFetchComplete(&mock_fetcher1);
   EXPECT_TRUE(auth.HasPendingFetch());
   MockFetcher mock_fetcher2(
@@ -659,11 +652,8 @@ TEST_F(GaiaAuthFetcherTest, OAuthLoginTokenClientLoginToOAuth2Failure) {
   MockFetcher mock_fetcher(
       client_login_to_oauth2_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_FORBIDDEN,
-      cookies,
-      std::string(),
-      net::URLFetcher::POST,
-      &auth);
+      net::HTTP_FORBIDDEN, cookies, "",
+      net::URLFetcher::POST, &auth);
   auth.OnURLFetchComplete(&mock_fetcher);
   EXPECT_FALSE(auth.HasPendingFetch());
 }
@@ -684,21 +674,15 @@ TEST_F(GaiaAuthFetcherTest, OAuthLoginTokenOAuth2TokenPairFailure) {
   MockFetcher mock_fetcher1(
       client_login_to_oauth2_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_OK,
-      cookies,
-      std::string(),
-      net::URLFetcher::POST,
-      &auth);
+      net::HTTP_OK, cookies, "",
+      net::URLFetcher::POST, &auth);
   auth.OnURLFetchComplete(&mock_fetcher1);
   EXPECT_TRUE(auth.HasPendingFetch());
   MockFetcher mock_fetcher2(
       oauth2_token_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_FORBIDDEN,
-      cookies_,
-      std::string(),
-      net::URLFetcher::POST,
-      &auth);
+      net::HTTP_FORBIDDEN, cookies_, "",
+      net::URLFetcher::POST, &auth);
   auth.OnURLFetchComplete(&mock_fetcher2);
   EXPECT_FALSE(auth.HasPendingFetch());
 }
@@ -826,7 +810,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthSuccess) {
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
   scopes.push_back("https://some.other.scope.com");
-  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
+  auth.StartClientOAuth("username", "password", scopes, "", "en");
 
   std::string expected_text = base::StringPrintf(
       "{"
@@ -858,8 +842,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthWithQuote) {
   GaiaAuthFetcher auth(&consumer, "te\"sts", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back("https://some.\"other.scope.com");
-  auth.StartClientOAuth(
-      "user\"name", "pass\"word", scopes, std::string(), "e\"n");
+  auth.StartClientOAuth("user\"name", "pass\"word", scopes, "", "e\"n");
 
   std::string expected_text = base::StringPrintf(
       "{"
@@ -896,7 +879,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthBadAuth) {
   GaiaAuthFetcher auth(&consumer, "tests", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
-  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
+  auth.StartClientOAuth("username", "password", scopes, "", "en");
 }
 
 TEST_F(GaiaAuthFetcherTest, ClientOAuthCaptchaChallenge) {
@@ -925,7 +908,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthCaptchaChallenge) {
   GaiaAuthFetcher auth(&consumer, "tests", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
-  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
+  auth.StartClientOAuth("username", "password", scopes, "", "en");
 }
 
 TEST_F(GaiaAuthFetcherTest, ClientOAuthTwoFactorChallenge) {
@@ -953,7 +936,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthTwoFactorChallenge) {
   GaiaAuthFetcher auth(&consumer, "tests", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
-  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
+  auth.StartClientOAuth("username", "password", scopes, "", "en");
 }
 
 TEST_F(GaiaAuthFetcherTest, ClientOAuthChallengeSuccess) {
diff --git a/google_apis/gaia/google_service_auth_error.cc b/google_apis/gaia/google_service_auth_error.cc
index 96fc063..8beeb4d 100644
--- a/google_apis/gaia/google_service_auth_error.cc
+++ b/google_apis/gaia/google_service_auth_error.cc
@@ -225,7 +225,7 @@ DictionaryValue* GoogleServiceAuthError::ToValue() const {
 std::string GoogleServiceAuthError::ToString() const {
   switch (state_) {
     case NONE:
-      return std::string();
+      return "";
     case INVALID_GAIA_CREDENTIALS:
       return "Invalid credentials.";
     case USER_NOT_SIGNED_UP:
diff --git a/google_apis/gaia/google_service_auth_error_unittest.cc b/google_apis/gaia/google_service_auth_error_unittest.cc
index 15155b6..59aa510 100644
--- a/google_apis/gaia/google_service_auth_error_unittest.cc
+++ b/google_apis/gaia/google_service_auth_error_unittest.cc
@@ -64,7 +64,7 @@ TEST_F(GoogleServiceAuthErrorTest, CaptchaChallenge) {
   EXPECT_TRUE(value->GetDictionary("captcha", &captcha_value));
   ASSERT_TRUE(captcha_value);
   ExpectDictStringValue("captcha_token", *captcha_value, "token");
-  ExpectDictStringValue(std::string(), *captcha_value, "audioUrl");
+  ExpectDictStringValue("", *captcha_value, "audioUrl");
   ExpectDictStringValue("http://www.google.com/", *captcha_value, "imageUrl");
   ExpectDictStringValue("http://www.bing.com/", *captcha_value, "unlockUrl");
   ExpectDictIntegerValue(0, *captcha_value, "imageWidth");
diff --git a/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc b/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc
index 7c761c7..feb8020 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc
+++ b/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc
@@ -120,7 +120,7 @@ class OAuth2AccessTokenFetcherTest : public testing::Test {
 
 // These four tests time out, see http://crbug.com/113446.
 TEST_F(OAuth2AccessTokenFetcherTest, DISABLED_GetAccessTokenRequestFailure) {
-  TestURLFetcher* url_fetcher = SetupGetAccessToken(false, 0, std::string());
+  TestURLFetcher* url_fetcher = SetupGetAccessToken(false, 0, "");
   EXPECT_CALL(consumer_, OnGetTokenFailure(_)).Times(1);
   fetcher_.Start("client_id", "client_secret", "refresh_token", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
@@ -129,7 +129,7 @@ TEST_F(OAuth2AccessTokenFetcherTest, DISABLED_GetAccessTokenRequestFailure) {
 TEST_F(OAuth2AccessTokenFetcherTest,
        DISABLED_GetAccessTokenResponseCodeFailure) {
   TestURLFetcher* url_fetcher =
-      SetupGetAccessToken(true, net::HTTP_FORBIDDEN, std::string());
+      SetupGetAccessToken(true, net::HTTP_FORBIDDEN, "");
   EXPECT_CALL(consumer_, OnGetTokenFailure(_)).Times(1);
   fetcher_.Start("client_id", "client_secret", "refresh_token", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
diff --git a/google_apis/gaia/oauth2_api_call_flow_unittest.cc b/google_apis/gaia/oauth2_api_call_flow_unittest.cc
index 4e8692e..137eaeb 100644
--- a/google_apis/gaia/oauth2_api_call_flow_unittest.cc
+++ b/google_apis/gaia/oauth2_api_call_flow_unittest.cc
@@ -158,8 +158,8 @@ class OAuth2ApiCallFlowTest : public testing::Test {
     GURL url(CreateApiUrl());
     EXPECT_CALL(*flow_, CreateApiCallBody()).WillOnce(Return(body));
     EXPECT_CALL(*flow_, CreateApiCallUrl()).WillOnce(Return(url));
-    TestURLFetcher* url_fetcher =
-        CreateURLFetcher(url, succeeds, status, std::string());
+    TestURLFetcher* url_fetcher = CreateURLFetcher(
+        url, succeeds, status, "");
     EXPECT_CALL(factory_, CreateURLFetcher(_, url, _, _))
         .WillOnce(Return(url_fetcher));
     return url_fetcher;
@@ -240,7 +240,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenFirstApiCallSucceeds) {
   std::string at = "access_token";
   std::vector<std::string> scopes(CreateTestScopes());
 
-  CreateFlow(rt, std::string(), scopes);
+  CreateFlow(rt, "", scopes);
   SetupAccessTokenFetcher(rt, scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(true, net::HTTP_OK);
   EXPECT_CALL(*flow_, ProcessApiCallSuccess(url_fetcher));
@@ -256,7 +256,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenApiCallFails) {
   std::string at = "access_token";
   std::vector<std::string> scopes(CreateTestScopes());
 
-  CreateFlow(rt, std::string(), scopes);
+  CreateFlow(rt, "", scopes);
   SetupAccessTokenFetcher(rt, scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(false, net::HTTP_BAD_GATEWAY);
   EXPECT_CALL(*flow_, ProcessApiCallFailure(url_fetcher));
@@ -272,7 +272,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenNewTokenGenerationFails) {
   std::string at = "access_token";
   std::vector<std::string> scopes(CreateTestScopes());
 
-  CreateFlow(rt, std::string(), scopes);
+  CreateFlow(rt, "", scopes);
   SetupAccessTokenFetcher(rt, scopes);
   GoogleServiceAuthError error(
       GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS);
diff --git a/google_apis/gaia/oauth2_mint_token_flow.cc b/google_apis/gaia/oauth2_mint_token_flow.cc
index 169d187..42fc4ef 100644
--- a/google_apis/gaia/oauth2_mint_token_flow.cc
+++ b/google_apis/gaia/oauth2_mint_token_flow.cc
@@ -89,16 +89,17 @@ OAuth2MintTokenFlow::Parameters::Parameters(
 
 OAuth2MintTokenFlow::Parameters::~Parameters() {}
 
-OAuth2MintTokenFlow::OAuth2MintTokenFlow(URLRequestContextGetter* context,
-                                         Delegate* delegate,
-                                         const Parameters& parameters)
-    : OAuth2ApiCallFlow(context,
-                        parameters.login_refresh_token,
-                        std::string(),
-                        std::vector<std::string>()),
+OAuth2MintTokenFlow::OAuth2MintTokenFlow(
+    URLRequestContextGetter* context,
+    Delegate* delegate,
+    const Parameters& parameters)
+    : OAuth2ApiCallFlow(
+          context, parameters.login_refresh_token,
+          "", std::vector<std::string>()),
       delegate_(delegate),
       parameters_(parameters),
-      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {}
+      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {
+}
 
 OAuth2MintTokenFlow::~OAuth2MintTokenFlow() { }
 
diff --git a/google_apis/gaia/oauth2_mint_token_flow_unittest.cc b/google_apis/gaia/oauth2_mint_token_flow_unittest.cc
index 3206601..e213984 100644
--- a/google_apis/gaia/oauth2_mint_token_flow_unittest.cc
+++ b/google_apis/gaia/oauth2_mint_token_flow_unittest.cc
@@ -272,7 +272,7 @@ TEST_F(OAuth2MintTokenFlowTest, ParseIssueAdviceResponse) {
 TEST_F(OAuth2MintTokenFlowTest, ProcessApiCallSuccess) {
   {  // No body.
     TestURLFetcher url_fetcher(1, GURL("http://www.google.com"), NULL);
-    url_fetcher.SetResponseString(std::string());
+    url_fetcher.SetResponseString("");
     CreateFlow(OAuth2MintTokenFlow::MODE_MINT_TOKEN_NO_FORCE);
     EXPECT_CALL(delegate_, OnMintTokenFailure(_));
     flow_->ProcessApiCallSuccess(&url_fetcher);
diff --git a/google_apis/gaia/oauth_request_signer.cc b/google_apis/gaia/oauth_request_signer.cc
index 9952a6f..b5d138f 100644
--- a/google_apis/gaia/oauth_request_signer.cc
+++ b/google_apis/gaia/oauth_request_signer.cc
@@ -89,7 +89,7 @@ std::string BuildBaseString(const GURL& request_base_url,
 
 std::string BuildBaseStringParameters(
     const OAuthRequestSigner::Parameters& parameters) {
-  std::string result;
+  std::string result = "";
   OAuthRequestSigner::Parameters::const_iterator cursor;
   OAuthRequestSigner::Parameters::const_iterator limit;
   bool first = true;
@@ -297,7 +297,7 @@ bool SignParameters(const GURL& request_base_url,
 // static
 bool OAuthRequestSigner::Decode(const std::string& text,
                                 std::string* decoded_text) {
-  std::string accumulator;
+  std::string accumulator = "";
   std::string::const_iterator cursor;
   std::string::const_iterator limit;
   for (limit = text.end(), cursor = text.begin(); cursor != limit; ++cursor) {
@@ -335,7 +335,7 @@ bool OAuthRequestSigner::Decode(const std::string& text,
 
 // static
 std::string OAuthRequestSigner::Encode(const std::string& text) {
-  std::string result;
+  std::string result = "";
   std::string::const_iterator cursor;
   std::string::const_iterator limit;
   for (limit = text.end(), cursor = text.begin(); cursor != limit; ++cursor) {
diff --git a/google_apis/gaia/oauth_request_signer_unittest.cc b/google_apis/gaia/oauth_request_signer_unittest.cc
index 40206f6..5cf2dc2 100644
--- a/google_apis/gaia/oauth_request_signer_unittest.cc
+++ b/google_apis/gaia/oauth_request_signer_unittest.cc
@@ -109,15 +109,15 @@ TEST(OAuthRequestSignerTest, SignGet2) {
   parameters["oauth_nonce"] = "4d4hZW9DygWQujP2tz06UN";
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::SignURL(
-      request_url,
-      parameters,
-      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-      OAuthRequestSigner::GET_METHOD,
-      "anonymous",                       // oauth_consumer_key
-      "anonymous",                       // consumer secret
-      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-      std::string(),                     // token secret
-      &signed_text));
+                  request_url,
+                  parameters,
+                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+                  OAuthRequestSigner::GET_METHOD,
+                  "anonymous",  // oauth_consumer_key
+                  "anonymous",  // consumer secret
+                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+                  "", // token secret
+                  &signed_text));
   ASSERT_EQ(signed_text,
             "https://accounts.google.com/OAuthGetAccessToken"
             "?oauth_consumer_key=anonymous"
@@ -137,14 +137,14 @@ TEST(OAuthRequestSignerTest, ParseAndSignGet1) {
                    "&oauth_timestamp=1308152953");
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::ParseAndSign(
-      request_url,
-      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-      OAuthRequestSigner::GET_METHOD,
-      "anonymous",                       // oauth_consumer_key
-      "anonymous",                       // consumer secret
-      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-      std::string(),                     // token secret
-      &signed_text));
+                  request_url,
+                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+                  OAuthRequestSigner::GET_METHOD,
+                  "anonymous",  // oauth_consumer_key
+                  "anonymous",  // consumer secret
+                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+                  "", // token secret
+                  &signed_text));
   ASSERT_EQ("https://www.google.com/accounts/o8/GetOAuthToken"
             "?oauth_consumer_key=anonymous"
             "&oauth_nonce=2oiE_aHdk5qRTz0L9C8Lq0g"
@@ -164,14 +164,14 @@ TEST(OAuthRequestSignerTest, ParseAndSignGet2) {
                    "&oauth_nonce=4d4hZW9DygWQujP2tz06UN");
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::ParseAndSign(
-      request_url,
-      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-      OAuthRequestSigner::GET_METHOD,
-      "anonymous",                       // oauth_consumer_key
-      "anonymous",                       // consumer secret
-      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-      std::string(),                     // token secret
-      &signed_text));
+                  request_url,
+                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+                  OAuthRequestSigner::GET_METHOD,
+                  "anonymous",  // oauth_consumer_key
+                  "anonymous",  // consumer secret
+                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+                  "", // token secret
+                  &signed_text));
   ASSERT_EQ(signed_text,
             "https://accounts.google.com/OAuthGetAccessToken"
             "?oauth_consumer_key=anonymous"
@@ -220,15 +220,15 @@ TEST(OAuthRequestSignerTest, SignPost2) {
   parameters["oauth_nonce"] = "17171717171717171";
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::SignURL(
-      request_url,
-      parameters,
-      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-      OAuthRequestSigner::POST_METHOD,
-      "anonymous",                       // oauth_consumer_key
-      "anonymous",                       // consumer secret
-      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-      std::string(),                     // token secret
-      &signed_text));
+                  request_url,
+                  parameters,
+                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+                  OAuthRequestSigner::POST_METHOD,
+                  "anonymous",  // oauth_consumer_key
+                  "anonymous",  // consumer secret
+                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+                  "", // token secret
+                  &signed_text));
   ASSERT_EQ(signed_text,
             "oauth_consumer_key=anonymous"
             "&oauth_nonce=17171717171717171"
@@ -273,14 +273,14 @@ TEST(OAuthRequestSignerTest, ParseAndSignPost2) {
                    "&oauth_nonce=17171717171717171");
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::ParseAndSign(
-      request_url,
-      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-      OAuthRequestSigner::POST_METHOD,
-      "anonymous",                       // oauth_consumer_key
-      "anonymous",                       // consumer secret
-      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-      std::string(),                     // token secret
-      &signed_text));
+                  request_url,
+                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+                  OAuthRequestSigner::POST_METHOD,
+                  "anonymous",  // oauth_consumer_key
+                  "anonymous",  // consumer secret
+                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+                  "", // token secret
+                  &signed_text));
   ASSERT_EQ(signed_text,
             "oauth_consumer_key=anonymous"
             "&oauth_nonce=17171717171717171"
diff --git a/google_apis/google_api_keys.cc b/google_apis/google_api_keys.cc
index c05435e..cd13b9e 100644
--- a/google_apis/google_api_keys.cc
+++ b/google_apis/google_api_keys.cc
@@ -98,25 +98,22 @@ class APIKeyCache {
 
     api_key_ = CalculateKeyValue(GOOGLE_API_KEY,
                                  STRINGIZE_NO_EXPANSION(GOOGLE_API_KEY),
-                                 NULL,
-                                 std::string(),
+                                 NULL, "",
                                  environment.get(),
                                  command_line);
 
-    std::string default_client_id =
-        CalculateKeyValue(GOOGLE_DEFAULT_CLIENT_ID,
-                          STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_ID),
-                          NULL,
-                          std::string(),
-                          environment.get(),
-                          command_line);
-    std::string default_client_secret =
-        CalculateKeyValue(GOOGLE_DEFAULT_CLIENT_SECRET,
-                          STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_SECRET),
-                          NULL,
-                          std::string(),
-                          environment.get(),
-                          command_line);
+    std::string default_client_id = CalculateKeyValue(
+        GOOGLE_DEFAULT_CLIENT_ID,
+        STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_ID),
+        NULL, "",
+        environment.get(),
+        command_line);
+    std::string default_client_secret = CalculateKeyValue(
+        GOOGLE_DEFAULT_CLIENT_SECRET,
+        STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_SECRET),
+        NULL, "",
+        environment.get(),
+        command_line);
 
     // We currently only allow overriding the baked-in values for the
     // default OAuth2 client ID and secret using a command-line
diff --git a/gpu/command_buffer/service/program_manager.cc b/gpu/command_buffer/service/program_manager.cc
index 5c31f14..747d157 100644
--- a/gpu/command_buffer/service/program_manager.cc
+++ b/gpu/command_buffer/service/program_manager.cc
@@ -445,8 +445,8 @@ void ProgramManager::DoCompileShader(Shader* shader,
                                      FeatureInfo* feature_info) {
   TimeTicks before = TimeTicks::HighResNow();
   if (program_cache_ &&
-      program_cache_->GetShaderCompilationStatus(
-          shader->source() ? *shader->source() : std::string()) ==
+      program_cache_->GetShaderCompilationStatus(shader->source() ?
+                                                 *shader->source() : "") ==
           ProgramCache::COMPILATION_SUCCEEDED) {
     shader->SetStatus(true, "", translator);
     shader->FlagSourceAsCompiled(false);
@@ -525,9 +525,9 @@ void ProgramManager::ForceCompileShader(const std::string* source,
     LOG_IF(ERROR, translator)
         << "Shader translator allowed/produced an invalid shader "
         << "unless the driver is buggy:"
-        << "\n--original-shader--\n" << (source ? *source : std::string())
-        << "\n--translated-shader--\n" << shader_src << "\n--info-log--\n"
-        << *shader->log_info();
+        << "\n--original-shader--\n" << (source ? *source : "")
+        << "\n--translated-shader--\n" << shader_src
+        << "\n--info-log--\n" << *shader->log_info();
   }
 }
 
diff --git a/ipc/ipc_channel_factory.cc b/ipc/ipc_channel_factory.cc
index 3d5c866..d355328 100644
--- a/ipc/ipc_channel_factory.cc
+++ b/ipc/ipc_channel_factory.cc
@@ -64,8 +64,7 @@ void ChannelFactory::OnFileCanReadWithoutBlocking(int fd) {
   if (!IsPeerAuthorized(new_fd))
     return;
 
-  ChannelHandle handle(std::string(),
-                       base::FileDescriptor(*scoped_fd.release(), true));
+  ChannelHandle handle("", base::FileDescriptor(*scoped_fd.release(), true));
   delegate_->OnClientConnected(handle);
 }
 
diff --git a/jingle/glue/channel_socket_adapter_unittest.cc b/jingle/glue/channel_socket_adapter_unittest.cc
index d90cbca..c9b0bb7 100644
--- a/jingle/glue/channel_socket_adapter_unittest.cc
+++ b/jingle/glue/channel_socket_adapter_unittest.cc
@@ -29,7 +29,8 @@ const int kTestError = -32123;
 
 class MockTransportChannel : public cricket::TransportChannel {
  public:
-  MockTransportChannel() : cricket::TransportChannel(std::string(), 0) {
+  MockTransportChannel()
+      : cricket::TransportChannel("", 0) {
     set_writable(true);
     set_readable(true);
   }
diff --git a/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc b/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
index f7ddf8d..24aa6a9 100644
--- a/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
+++ b/jingle/notifier/base/gaia_token_pre_xmpp_auth.cc
@@ -101,10 +101,9 @@ std::string GaiaTokenPreXmppAuth::GetAuthMechanism() const {
 
 std::string GaiaTokenPreXmppAuth::ChooseBestSaslMechanism(
     const std::vector<std::string> & mechanisms, bool encrypted) {
-  return (std::find(mechanisms.begin(), mechanisms.end(), auth_mechanism_) !=
-              mechanisms.end())
-             ? auth_mechanism_
-             : std::string();
+  return (std::find(mechanisms.begin(),
+                    mechanisms.end(), auth_mechanism_) !=
+          mechanisms.end()) ? auth_mechanism_ : "";
 }
 
 buzz::SaslMechanism* GaiaTokenPreXmppAuth::CreateSaslMechanism(
diff --git a/jingle/notifier/communicator/single_login_attempt.cc b/jingle/notifier/communicator/single_login_attempt.cc
index 49fcdee..dda0cfe 100644
--- a/jingle/notifier/communicator/single_login_attempt.cc
+++ b/jingle/notifier/communicator/single_login_attempt.cc
@@ -85,9 +85,9 @@ net::HostPortPair ParseRedirectText(const std::string& redirect_text) {
 void SingleLoginAttempt::OnError(buzz::XmppEngine::Error error, int subcode,
                                  const buzz::XmlElement* stream_error) {
   DVLOG(1) << "Error: " << error << ", subcode: " << subcode
-           << (stream_error
-                   ? (", stream error: " + XmlElementToString(*stream_error))
-                   : std::string());
+           << (stream_error ?
+               (", stream error: " + XmlElementToString(*stream_error)) :
+               "");
 
   DCHECK_EQ(error == buzz::XmppEngine::ERROR_STREAM, stream_error != NULL);
 
diff --git a/jingle/notifier/communicator/single_login_attempt_unittest.cc b/jingle/notifier/communicator/single_login_attempt_unittest.cc
index 4d009c2..582b808 100644
--- a/jingle/notifier/communicator/single_login_attempt_unittest.cc
+++ b/jingle/notifier/communicator/single_login_attempt_unittest.cc
@@ -219,7 +219,7 @@ TEST_F(SingleLoginAttemptTest, RedirectInvalidPort) {
 // Fire an empty redirect and make sure the delegate does not get a
 // redirect.
 TEST_F(SingleLoginAttemptTest, RedirectEmpty) {
-  scoped_ptr<buzz::XmlElement> redirect_error(MakeRedirectError(std::string()));
+  scoped_ptr<buzz::XmlElement> redirect_error(MakeRedirectError(""));
   FireRedirect(redirect_error.get());
   EXPECT_EQ(IDLE, fake_delegate_.state());
 }
@@ -227,7 +227,7 @@ TEST_F(SingleLoginAttemptTest, RedirectEmpty) {
 // Fire a redirect with a missing text element and make sure the
 // delegate does not get a redirect.
 TEST_F(SingleLoginAttemptTest, RedirectMissingText) {
-  scoped_ptr<buzz::XmlElement> redirect_error(MakeRedirectError(std::string()));
+  scoped_ptr<buzz::XmlElement> redirect_error(MakeRedirectError(""));
   redirect_error->RemoveChildAfter(redirect_error->FirstChild());
   FireRedirect(redirect_error.get());
   EXPECT_EQ(IDLE, fake_delegate_.state());
@@ -236,7 +236,7 @@ TEST_F(SingleLoginAttemptTest, RedirectMissingText) {
 // Fire a redirect with a missing see-other-host element and make sure
 // the delegate does not get a redirect.
 TEST_F(SingleLoginAttemptTest, RedirectMissingSeeOtherHost) {
-  scoped_ptr<buzz::XmlElement> redirect_error(MakeRedirectError(std::string()));
+  scoped_ptr<buzz::XmlElement> redirect_error(MakeRedirectError(""));
   redirect_error->RemoveChildAfter(NULL);
   FireRedirect(redirect_error.get());
   EXPECT_EQ(IDLE, fake_delegate_.state());
diff --git a/media/audio/linux/alsa_output.cc b/media/audio/linux/alsa_output.cc
index f3c3f91..4615d01 100644
--- a/media/audio/linux/alsa_output.cc
+++ b/media/audio/linux/alsa_output.cc
@@ -523,7 +523,7 @@ std::string AlsaPcmOutputStream::FindDeviceForChannels(uint32 channels) {
 
   const char* wanted_device = GuessSpecificDeviceName(channels);
   if (!wanted_device)
-    return std::string();
+    return "";
 
   std::string guessed_device;
   void** hints = NULL;
diff --git a/media/audio/null_audio_sink.cc b/media/audio/null_audio_sink.cc
index 40db453..5c4f67a 100644
--- a/media/audio/null_audio_sink.cc
+++ b/media/audio/null_audio_sink.cc
@@ -85,7 +85,7 @@ void NullAudioSink::StartAudioHashForTesting() {
 }
 
 std::string NullAudioSink::GetAudioHashForTesting() {
-  return audio_hash_ ? audio_hash_->ToString() : std::string();
+  return audio_hash_ ? audio_hash_->ToString() : "";
 }
 
 }  // namespace media
diff --git a/media/crypto/aes_decryptor.cc b/media/crypto/aes_decryptor.cc
index 430568c..e214b06 100644
--- a/media/crypto/aes_decryptor.cc
+++ b/media/crypto/aes_decryptor.cc
@@ -152,7 +152,7 @@ bool AesDecryptor::GenerateKeyRequest(const std::string& key_system,
                           init_data_length);
   }
 
-  key_message_cb_.Run(key_system, session_id_string, message, std::string());
+  key_message_cb_.Run(key_system, session_id_string, message, "");
   return true;
 }
 
diff --git a/media/crypto/aes_decryptor_unittest.cc b/media/crypto/aes_decryptor_unittest.cc
index abc7e6e..f882150 100644
--- a/media/crypto/aes_decryptor_unittest.cc
+++ b/media/crypto/aes_decryptor_unittest.cc
@@ -242,13 +242,11 @@ class AesDecryptorTest : public testing::Test {
   void GenerateKeyRequest(const uint8* key_id, int key_id_size) {
     std::string key_id_string(reinterpret_cast<const char*>(key_id),
                               key_id_size);
-    EXPECT_CALL(
-        *this,
-        KeyMessage(
-            kClearKeySystem, StrNe(std::string()), StrEq(key_id_string), ""))
+    EXPECT_CALL(*this, KeyMessage(kClearKeySystem,
+                                  StrNe(""), StrEq(key_id_string), ""))
         .WillOnce(SaveArg<1>(&session_id_string_));
-    EXPECT_TRUE(decryptor_.GenerateKeyRequest(
-        kClearKeySystem, std::string(), key_id, key_id_size));
+    EXPECT_TRUE(decryptor_.GenerateKeyRequest(kClearKeySystem, "",
+                                              key_id, key_id_size));
   }
 
   void AddKeyAndExpectToSucceed(const uint8* key_id, int key_id_size,
@@ -327,9 +325,8 @@ class AesDecryptorTest : public testing::Test {
 };
 
 TEST_F(AesDecryptorTest, GenerateKeyRequestWithNullInitData) {
-  EXPECT_CALL(*this, KeyMessage(kClearKeySystem, StrNe(std::string()), "", ""));
-  EXPECT_TRUE(
-      decryptor_.GenerateKeyRequest(kClearKeySystem, std::string(), NULL, 0));
+  EXPECT_CALL(*this, KeyMessage(kClearKeySystem, StrNe(""), "", ""));
+  EXPECT_TRUE(decryptor_.GenerateKeyRequest(kClearKeySystem, "", NULL, 0));
 }
 
 TEST_F(AesDecryptorTest, NormalWebMDecryption) {
diff --git a/media/filters/pipeline_integration_test.cc b/media/filters/pipeline_integration_test.cc
index 2945db2..5244376 100644
--- a/media/filters/pipeline_integration_test.cc
+++ b/media/filters/pipeline_integration_test.cc
@@ -316,8 +316,7 @@ class MockMediaSource {
     DCHECK(init_data.get());
     DCHECK_GT(init_data_size, 0);
     CHECK(!need_key_cb_.is_null());
-    need_key_cb_.Run(
-        std::string(), std::string(), type, init_data.Pass(), init_data_size);
+    need_key_cb_.Run("", "", type, init_data.Pass(), init_data_size);
   }
 
  private:
diff --git a/media/filters/pipeline_integration_test_base.cc b/media/filters/pipeline_integration_test_base.cc
index 1b650d5..68b648e 100644
--- a/media/filters/pipeline_integration_test_base.cc
+++ b/media/filters/pipeline_integration_test_base.cc
@@ -67,8 +67,7 @@ void PipelineIntegrationTestBase::DemuxerNeedKeyCB(
   DCHECK(init_data.get());
   DCHECK_GT(init_data_size, 0);
   CHECK(!need_key_cb_.is_null());
-  need_key_cb_.Run(
-      std::string(), std::string(), type, init_data.Pass(), init_data_size);
+  need_key_cb_.Run("", "", type, init_data.Pass(), init_data_size);
 }
 
 void PipelineIntegrationTestBase::OnEnded() {
diff --git a/media/webm/webm_cluster_parser_unittest.cc b/media/webm/webm_cluster_parser_unittest.cc
index baa35f2..dc73329 100644
--- a/media/webm/webm_cluster_parser_unittest.cc
+++ b/media/webm/webm_cluster_parser_unittest.cc
@@ -203,14 +203,13 @@ static void AppendToEnd(const WebMClusterParser::BufferQueue& src,
 class WebMClusterParserTest : public testing::Test {
  public:
   WebMClusterParserTest()
-      : parser_(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      std::set<int>(),
-                                      std::set<int64>(),
-                                      std::string(),
-                                      std::string(),
-                                      LogCB())) {}
+      : parser_(new WebMClusterParser(
+          kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+          std::set<int>(),
+          std::set<int64>(),
+          "", "",
+          LogCB())) {
+  }
 
  protected:
   scoped_ptr<WebMClusterParser> parser_;
@@ -335,14 +334,11 @@ TEST_F(WebMClusterParserTest, IgnoredTracks) {
   std::set<int64> ignored_tracks;
   ignored_tracks.insert(kTextTrackNum);
 
-  parser_.reset(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      std::set<int>(),
-                                      ignored_tracks,
-                                      std::string(),
-                                      std::string(),
-                                      LogCB()));
+  parser_.reset(new WebMClusterParser(
+      kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+      std::set<int>(),
+      ignored_tracks, "", "",
+      LogCB()));
 
   const BlockInfo kInputBlockInfo[] = {
     { kAudioTrackNum, 0,  23, true },
@@ -375,14 +371,11 @@ TEST_F(WebMClusterParserTest, ParseTextTracks) {
   std::set<int> text_tracks;
   text_tracks.insert(kTextTrackNum);
 
-  parser_.reset(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      text_tracks,
-                                      std::set<int64>(),
-                                      std::string(),
-                                      std::string(),
-                                      LogCB()));
+  parser_.reset(new WebMClusterParser(
+      kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+      text_tracks,
+      std::set<int64>(), "", "",
+      LogCB()));
 
   const BlockInfo kInputBlockInfo[] = {
     { kAudioTrackNum, 0,  23, true },
@@ -407,14 +400,11 @@ TEST_F(WebMClusterParserTest, TextTracksSimpleBlock) {
   std::set<int> text_tracks;
   text_tracks.insert(kTextTrackNum);
 
-  parser_.reset(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      text_tracks,
-                                      std::set<int64>(),
-                                      std::string(),
-                                      std::string(),
-                                      LogCB()));
+  parser_.reset(new WebMClusterParser(
+      kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+      text_tracks,
+      std::set<int64>(), "", "",
+      LogCB()));
 
   const BlockInfo kInputBlockInfo[] = {
     { kTextTrackNum,  33, 42, true },
@@ -438,14 +428,11 @@ TEST_F(WebMClusterParserTest, ParseMultipleTextTracks) {
   text_tracks.insert(kSubtitleTextTrackNum);
   text_tracks.insert(kCaptionTextTrackNum);
 
-  parser_.reset(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      text_tracks,
-                                      std::set<int64>(),
-                                      std::string(),
-                                      std::string(),
-                                      LogCB()));
+  parser_.reset(new WebMClusterParser(
+      kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+      text_tracks,
+      std::set<int64>(), "", "",
+      LogCB()));
 
   const BlockInfo kInputBlockInfo[] = {
     { kAudioTrackNum, 0,  23, true },
@@ -483,14 +470,11 @@ TEST_F(WebMClusterParserTest, ParseMultipleTextTracks) {
 TEST_F(WebMClusterParserTest, ParseEncryptedBlock) {
   scoped_ptr<Cluster> cluster(CreateEncryptedCluster(sizeof(kEncryptedFrame)));
 
-  parser_.reset(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      std::set<int>(),
-                                      std::set<int64>(),
-                                      std::string(),
-                                      "video_key_id",
-                                      LogCB()));
+  parser_.reset(new WebMClusterParser(
+      kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+      std::set<int>(),
+      std::set<int64>(), "", "video_key_id",
+      LogCB()));
   int result = parser_->Parse(cluster->data(), cluster->size());
   EXPECT_EQ(cluster->size(), result);
   ASSERT_EQ(1UL, parser_->video_buffers().size());
@@ -502,14 +486,11 @@ TEST_F(WebMClusterParserTest, ParseBadEncryptedBlock) {
   scoped_ptr<Cluster> cluster(
       CreateEncryptedCluster(sizeof(kEncryptedFrame) - 1));
 
-  parser_.reset(new WebMClusterParser(kTimecodeScale,
-                                      kAudioTrackNum,
-                                      kVideoTrackNum,
-                                      std::set<int>(),
-                                      std::set<int64>(),
-                                      std::string(),
-                                      "video_key_id",
-                                      LogCB()));
+  parser_.reset(new WebMClusterParser(
+      kTimecodeScale, kAudioTrackNum, kVideoTrackNum,
+      std::set<int>(),
+      std::set<int64>(), "", "video_key_id",
+      LogCB()));
   int result = parser_->Parse(cluster->data(), cluster->size());
   EXPECT_EQ(-1, result);
 }
diff --git a/net/base/dns_util.cc b/net/base/dns_util.cc
index b94eff8..816095b 100644
--- a/net/base/dns_util.cc
+++ b/net/base/dns_util.cc
@@ -62,16 +62,16 @@ std::string DNSDomainToString(const base::StringPiece& domain) {
   for (unsigned i = 0; i < domain.size() && domain[i]; i += domain[i] + 1) {
 #if CHAR_MIN < 0
     if (domain[i] < 0)
-      return std::string();
+      return "";
 #endif
     if (domain[i] > 63)
-      return std::string();
+      return "";
 
     if (i)
       ret += ".";
 
     if (static_cast<unsigned>(domain[i]) + i + 1 > domain.size())
-      return std::string();
+      return "";
 
     domain.substr(i + 1, domain[i]).AppendToString(&ret);
   }
diff --git a/net/base/host_mapping_rules_unittest.cc b/net/base/host_mapping_rules_unittest.cc
index 8d8f7b1..9ecd4b7 100644
--- a/net/base/host_mapping_rules_unittest.cc
+++ b/net/base/host_mapping_rules_unittest.cc
@@ -72,7 +72,7 @@ TEST(HostMappingRulesTest, ParseInvalidRules) {
   HostMappingRules rules;
 
   EXPECT_FALSE(rules.AddRuleFromString("xyz"));
-  EXPECT_FALSE(rules.AddRuleFromString(std::string()));
+  EXPECT_FALSE(rules.AddRuleFromString(""));
   EXPECT_FALSE(rules.AddRuleFromString(" "));
   EXPECT_FALSE(rules.AddRuleFromString("EXCLUDE"));
   EXPECT_FALSE(rules.AddRuleFromString("EXCLUDE foo bar"));
diff --git a/net/base/mime_sniffer_unittest.cc b/net/base/mime_sniffer_unittest.cc
index 7865350..a4bde0f 100644
--- a/net/base/mime_sniffer_unittest.cc
+++ b/net/base/mime_sniffer_unittest.cc
@@ -304,14 +304,13 @@ TEST(MimeSnifferTest, FlashTest) {
 TEST(MimeSnifferTest, XMLTest) {
   // An easy feed to identify.
   EXPECT_EQ("application/atom+xml",
-            SniffMimeType("<?xml?><feed", std::string(), "text/xml"));
+            SniffMimeType("<?xml?><feed", "", "text/xml"));
   // Don't sniff out of plain text.
   EXPECT_EQ("text/plain",
-            SniffMimeType("<?xml?><feed", std::string(), "text/plain"));
+            SniffMimeType("<?xml?><feed", "", "text/plain"));
   // Simple RSS.
   EXPECT_EQ("application/rss+xml",
-            SniffMimeType(
-                "<?xml version='1.0'?>\r\n<rss", std::string(), "text/xml"));
+            SniffMimeType("<?xml version='1.0'?>\r\n<rss", "", "text/xml"));
 
   // The top of CNN's RSS feed, which we'd like to recognize as RSS.
   static const char kCNNRSS[] =
@@ -324,43 +323,39 @@ TEST(MimeSnifferTest, XMLTest) {
       "version=\"2.0\">";
   // CNN's RSS
   EXPECT_EQ("application/rss+xml",
-            SniffMimeType(kCNNRSS, std::string(), "text/xml"));
-  EXPECT_EQ("text/plain", SniffMimeType(kCNNRSS, std::string(), "text/plain"));
+            SniffMimeType(kCNNRSS, "", "text/xml"));
+  EXPECT_EQ("text/plain",
+            SniffMimeType(kCNNRSS, "", "text/plain"));
 
   // Don't sniff random XML as something different.
   EXPECT_EQ("text/xml",
-            SniffMimeType("<?xml?><notafeed", std::string(), "text/xml"));
+            SniffMimeType("<?xml?><notafeed", "", "text/xml"));
   // Don't sniff random plain-text as something different.
   EXPECT_EQ("text/plain",
-            SniffMimeType("<?xml?><notafeed", std::string(), "text/plain"));
+            SniffMimeType("<?xml?><notafeed", "", "text/plain"));
 
   // Positive test for the two instances we upgrade to XHTML.
   EXPECT_EQ("application/xhtml+xml",
             SniffMimeType("<html xmlns=\"http://www.w3.org/1999/xhtml\">",
-                          std::string(),
-                          "text/xml"));
+                          "", "text/xml"));
   EXPECT_EQ("application/xhtml+xml",
             SniffMimeType("<html xmlns=\"http://www.w3.org/1999/xhtml\">",
-                          std::string(),
-                          "application/xml"));
+                          "", "application/xml"));
 
   // Following our behavior with HTML, don't call other mime types XHTML.
   EXPECT_EQ("text/plain",
             SniffMimeType("<html xmlns=\"http://www.w3.org/1999/xhtml\">",
-                          std::string(),
-                          "text/plain"));
+                          "", "text/plain"));
   EXPECT_EQ("application/rss+xml",
             SniffMimeType("<html xmlns=\"http://www.w3.org/1999/xhtml\">",
-                          std::string(),
-                          "application/rss+xml"));
+                          "", "application/rss+xml"));
 
   // Don't sniff other HTML-looking bits as HTML.
   EXPECT_EQ("text/xml",
-            SniffMimeType("<html><head>", std::string(), "text/xml"));
+            SniffMimeType("<html><head>", "", "text/xml"));
   EXPECT_EQ("text/xml",
             SniffMimeType("<foo><html xmlns=\"http://www.w3.org/1999/xhtml\">",
-                          std::string(),
-                          "text/xml"));
+                          "", "text/xml"));
 
 }
 
diff --git a/net/base/mime_util.cc b/net/base/mime_util.cc
index b3053a6..21a05bf 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -967,7 +967,7 @@ const std::string GetIANAMediaType(const std::string& mime_type) {
       return kIanaMediaTypes[i].name;
     }
   }
-  return std::string();
+  return "";
 }
 
 CertificateMimeType GetCertificateMimeTypeForMimeType(
diff --git a/net/base/mime_util_unittest.cc b/net/base/mime_util_unittest.cc
index 565f9de..ee6663b 100644
--- a/net/base/mime_util_unittest.cc
+++ b/net/base/mime_util_unittest.cc
@@ -93,11 +93,11 @@ TEST(MimeUtilTest, MatchesMimeType) {
                                    "application/html+xml"));
   EXPECT_TRUE(MatchesMimeType("application/*+xml", "application/+xml"));
   EXPECT_TRUE(MatchesMimeType("aaa*aaa", "aaaaaa"));
-  EXPECT_TRUE(MatchesMimeType("*", std::string()));
+  EXPECT_TRUE(MatchesMimeType("*", ""));
   EXPECT_FALSE(MatchesMimeType("video/", "video/x-mpeg"));
-  EXPECT_FALSE(MatchesMimeType(std::string(), "video/x-mpeg"));
-  EXPECT_FALSE(MatchesMimeType(std::string(), std::string()));
-  EXPECT_FALSE(MatchesMimeType("video/x-mpeg", std::string()));
+  EXPECT_FALSE(MatchesMimeType("", "video/x-mpeg"));
+  EXPECT_FALSE(MatchesMimeType("", ""));
+  EXPECT_FALSE(MatchesMimeType("video/x-mpeg", ""));
   EXPECT_FALSE(MatchesMimeType("application/*+xml", "application/xml"));
   EXPECT_FALSE(MatchesMimeType("application/*+xml",
                                     "application/html+xmlz"));
@@ -219,7 +219,7 @@ TEST(MimeUtilTest, TestIsMimeType) {
 TEST(MimeUtilTest, TestToIANAMediaType) {
   EXPECT_EQ("", GetIANAMediaType("texting/driving"));
   EXPECT_EQ("", GetIANAMediaType("ham/sandwich"));
-  EXPECT_EQ("", GetIANAMediaType(std::string()));
+  EXPECT_EQ("", GetIANAMediaType(""));
   EXPECT_EQ("", GetIANAMediaType("/application/hamsandwich"));
 
   EXPECT_EQ("application", GetIANAMediaType("application/poodle-wrestler"));
diff --git a/net/base/net_util.cc b/net/base/net_util.cc
index 18d00fe..066812c 100644
--- a/net/base/net_util.cc
+++ b/net/base/net_util.cc
@@ -1433,7 +1433,7 @@ std::string NetAddressToString(const struct sockaddr* sa,
   if (!GetIPAddressFromSockAddr(sa, sock_addr_len, &address,
                                 &address_len, NULL)) {
     NOTREACHED();
-    return std::string();
+    return "";
   }
   return IPAddressToString(address, address_len);
 }
@@ -1446,7 +1446,7 @@ std::string NetAddressToStringWithPort(const struct sockaddr* sa,
   if (!GetIPAddressFromSockAddr(sa, sock_addr_len, &address,
                                 &address_len, &port)) {
     NOTREACHED();
-    return std::string();
+    return "";
   }
   return IPAddressToStringWithPort(address, address_len, port);
 }
diff --git a/net/base/net_util_unittest.cc b/net/base/net_util_unittest.cc
index ab8a236..8512d09 100644
--- a/net/base/net_util_unittest.cc
+++ b/net/base/net_util_unittest.cc
@@ -2596,14 +2596,10 @@ TEST(NetUtilTest, FormatUrlParsed) {
       formatted.substr(parsed.ref.begin, parsed.ref.len));
 
   // View-source case.
-  formatted =
-      FormatUrl(GURL("view-source:http://user:passwd@host:81/path?query#ref"),
-                std::string(),
-                kFormatUrlOmitUsernamePassword,
-                UnescapeRule::NORMAL,
-                &parsed,
-                NULL,
-                NULL);
+  formatted = FormatUrl(
+      GURL("view-source:http://user:passwd@host:81/path?query#ref"),
+      "", kFormatUrlOmitUsernamePassword, UnescapeRule::NORMAL, &parsed,
+      NULL, NULL);
   EXPECT_EQ(WideToUTF16(L"view-source:http://host:81/path?query#ref"),
       formatted);
   EXPECT_EQ(WideToUTF16(L"view-source:http"),
@@ -2622,13 +2618,9 @@ TEST(NetUtilTest, FormatUrlParsed) {
       formatted.substr(parsed.ref.begin, parsed.ref.len));
 
   // omit http case.
-  formatted = FormatUrl(GURL("http://host:8000/a?b=c#d"),
-                        std::string(),
-                        kFormatUrlOmitHTTP,
-                        UnescapeRule::NORMAL,
-                        &parsed,
-                        NULL,
-                        NULL);
+  formatted = FormatUrl(
+      GURL("http://host:8000/a?b=c#d"),
+      "", kFormatUrlOmitHTTP, UnescapeRule::NORMAL, &parsed, NULL, NULL);
   EXPECT_EQ(WideToUTF16(L"host:8000/a?b=c#d"), formatted);
   EXPECT_FALSE(parsed.scheme.is_valid());
   EXPECT_FALSE(parsed.username.is_valid());
@@ -2645,13 +2637,9 @@ TEST(NetUtilTest, FormatUrlParsed) {
       formatted.substr(parsed.ref.begin, parsed.ref.len));
 
   // omit http starts with ftp case.
-  formatted = FormatUrl(GURL("http://ftp.host:8000/a?b=c#d"),
-                        std::string(),
-                        kFormatUrlOmitHTTP,
-                        UnescapeRule::NORMAL,
-                        &parsed,
-                        NULL,
-                        NULL);
+  formatted = FormatUrl(
+      GURL("http://ftp.host:8000/a?b=c#d"),
+      "", kFormatUrlOmitHTTP, UnescapeRule::NORMAL, &parsed, NULL, NULL);
   EXPECT_EQ(WideToUTF16(L"http://ftp.host:8000/a?b=c#d"), formatted);
   EXPECT_TRUE(parsed.scheme.is_valid());
   EXPECT_FALSE(parsed.username.is_valid());
@@ -2670,13 +2658,9 @@ TEST(NetUtilTest, FormatUrlParsed) {
       formatted.substr(parsed.ref.begin, parsed.ref.len));
 
   // omit http starts with 'f' case.
-  formatted = FormatUrl(GURL("http://f/"),
-                        std::string(),
-                        kFormatUrlOmitHTTP,
-                        UnescapeRule::NORMAL,
-                        &parsed,
-                        NULL,
-                        NULL);
+  formatted = FormatUrl(
+      GURL("http://f/"),
+      "", kFormatUrlOmitHTTP, UnescapeRule::NORMAL, &parsed, NULL, NULL);
   EXPECT_EQ(WideToUTF16(L"f/"), formatted);
   EXPECT_FALSE(parsed.scheme.is_valid());
   EXPECT_FALSE(parsed.username.is_valid());
@@ -2698,13 +2682,9 @@ TEST(NetUtilTest, FormatUrlRoundTripPathASCII) {
     GURL url(std::string("http://www.google.com/") +
              static_cast<char>(test_char));
     size_t prefix_len;
-    base::string16 formatted = FormatUrl(url,
-                                         std::string(),
-                                         kFormatUrlOmitUsernamePassword,
-                                         UnescapeRule::NORMAL,
-                                         NULL,
-                                         &prefix_len,
-                                         NULL);
+    base::string16 formatted = FormatUrl(
+        url, "", kFormatUrlOmitUsernamePassword, UnescapeRule::NORMAL, NULL,
+        &prefix_len, NULL);
     EXPECT_EQ(url.spec(), GURL(formatted).spec());
   }
 }
@@ -2719,13 +2699,9 @@ TEST(NetUtilTest, FormatUrlRoundTripPathEscaped) {
 
     GURL url(original_url);
     size_t prefix_len;
-    base::string16 formatted = FormatUrl(url,
-                                         std::string(),
-                                         kFormatUrlOmitUsernamePassword,
-                                         UnescapeRule::NORMAL,
-                                         NULL,
-                                         &prefix_len,
-                                         NULL);
+    base::string16 formatted = FormatUrl(
+        url, "", kFormatUrlOmitUsernamePassword, UnescapeRule::NORMAL, NULL,
+        &prefix_len, NULL);
     EXPECT_EQ(url.spec(), GURL(formatted).spec());
   }
 }
@@ -2737,13 +2713,9 @@ TEST(NetUtilTest, FormatUrlRoundTripQueryASCII) {
     GURL url(std::string("http://www.google.com/?") +
              static_cast<char>(test_char));
     size_t prefix_len;
-    base::string16 formatted = FormatUrl(url,
-                                         std::string(),
-                                         kFormatUrlOmitUsernamePassword,
-                                         UnescapeRule::NORMAL,
-                                         NULL,
-                                         &prefix_len,
-                                         NULL);
+    base::string16 formatted = FormatUrl(
+        url, "", kFormatUrlOmitUsernamePassword, UnescapeRule::NORMAL, NULL,
+        &prefix_len, NULL);
     EXPECT_EQ(url.spec(), GURL(formatted).spec());
   }
 }
@@ -2762,13 +2734,9 @@ TEST(NetUtilTest, FormatUrlRoundTripQueryEscaped) {
 
     GURL url(original_url);
     size_t prefix_len;
-    base::string16 formatted = FormatUrl(url,
-                                         std::string(),
-                                         kFormatUrlOmitUsernamePassword,
-                                         UnescapeRule::NORMAL,
-                                         NULL,
-                                         &prefix_len,
-                                         NULL);
+    base::string16 formatted = FormatUrl(
+        url, "", kFormatUrlOmitUsernamePassword, UnescapeRule::NORMAL, NULL,
+        &prefix_len, NULL);
 
     if (test_char &&
         strchr(kUnescapedCharacters, static_cast<char>(test_char))) {
@@ -3068,7 +3036,7 @@ TEST(NetUtilTest, ParseIPLiteralToNumber_FailParse) {
 
   EXPECT_FALSE(ParseIPLiteralToNumber("bad value", &number));
   EXPECT_FALSE(ParseIPLiteralToNumber("bad:value", &number));
-  EXPECT_FALSE(ParseIPLiteralToNumber(std::string(), &number));
+  EXPECT_FALSE(ParseIPLiteralToNumber("", &number));
   EXPECT_FALSE(ParseIPLiteralToNumber("192.168.0.1:30", &number));
   EXPECT_FALSE(ParseIPLiteralToNumber("  192.168.0.1  ", &number));
   EXPECT_FALSE(ParseIPLiteralToNumber("[::1]", &number));
diff --git a/net/base/registry_controlled_domains/registry_controlled_domain_unittest.cc b/net/base/registry_controlled_domains/registry_controlled_domain_unittest.cc
index 8ad8a55..7ae5da4 100644
--- a/net/base/registry_controlled_domains/registry_controlled_domain_unittest.cc
+++ b/net/base/registry_controlled_domains/registry_controlled_domain_unittest.cc
@@ -79,7 +79,7 @@ TEST_F(RegistryControlledDomainTest, TestGetDomainAndRegistry) {
   EXPECT_EQ("baz.com", GetDomainFromURL("http://baz.com"));              // none
   EXPECT_EQ("baz.com.", GetDomainFromURL("http://baz.com."));            // none
 
-  EXPECT_EQ("", GetDomainFromURL(std::string()));
+  EXPECT_EQ("", GetDomainFromURL(""));
   EXPECT_EQ("", GetDomainFromURL("http://"));
   EXPECT_EQ("", GetDomainFromURL("file:///C:/file.html"));
   EXPECT_EQ("", GetDomainFromURL("http://foo.com.."));
@@ -108,7 +108,7 @@ TEST_F(RegistryControlledDomainTest, TestGetDomainAndRegistry) {
   EXPECT_EQ("baz.com", GetDomainFromHost("baz.com"));                  // none
   EXPECT_EQ("baz.com.", GetDomainFromHost("baz.com."));                // none
 
-  EXPECT_EQ("", GetDomainFromHost(std::string()));
+  EXPECT_EQ("", GetDomainFromHost(""));
   EXPECT_EQ("", GetDomainFromHost("foo.com.."));
   EXPECT_EQ("", GetDomainFromHost("..."));
   EXPECT_EQ("", GetDomainFromHost("192.168.0.1"));
@@ -143,7 +143,7 @@ TEST_F(RegistryControlledDomainTest, TestGetRegistryLength) {
   EXPECT_EQ(3U, GetRegistryLengthFromURL("http://baz.com", true));      // none
   EXPECT_EQ(4U, GetRegistryLengthFromURL("http://baz.com.", true));     // none
 
-  EXPECT_EQ(std::string::npos, GetRegistryLengthFromURL(std::string(), false));
+  EXPECT_EQ(std::string::npos, GetRegistryLengthFromURL("", false));
   EXPECT_EQ(std::string::npos, GetRegistryLengthFromURL("http://", false));
   EXPECT_EQ(std::string::npos,
             GetRegistryLengthFromURL("file:///C:/file.html", false));
@@ -177,7 +177,7 @@ TEST_F(RegistryControlledDomainTest, TestGetRegistryLength) {
   EXPECT_EQ(3U, GetRegistryLengthFromHost("baz.com", true));            // none
   EXPECT_EQ(4U, GetRegistryLengthFromHost("baz.com.", true));           // none
 
-  EXPECT_EQ(std::string::npos, GetRegistryLengthFromHost(std::string(), false));
+  EXPECT_EQ(std::string::npos, GetRegistryLengthFromHost("", false));
   EXPECT_EQ(0U, GetRegistryLengthFromHost("foo.com..", false));
   EXPECT_EQ(0U, GetRegistryLengthFromHost("..", false));
   EXPECT_EQ(0U, GetRegistryLengthFromHost("192.168.0.1", false));
diff --git a/net/base/sdch_filter_unittest.cc b/net/base/sdch_filter_unittest.cc
index 1cc70cb..2e0f5ec 100644
--- a/net/base/sdch_filter_unittest.cc
+++ b/net/base/sdch_filter_unittest.cc
@@ -1346,7 +1346,7 @@ TEST_F(SdchFilterTest, PathMatch) {
   // Make sure less that sufficient prefix match is false.
   EXPECT_FALSE(PathMatch("/sear", "/search"));
   EXPECT_FALSE(PathMatch("/", "/search"));
-  EXPECT_FALSE(PathMatch(std::string(), "/search"));
+  EXPECT_FALSE(PathMatch("", "/search"));
 
   // Add examples with several levels of direcories in the restriction.
   EXPECT_FALSE(PathMatch("/search/something", "search/s"));
diff --git a/net/cookies/canonical_cookie_unittest.cc b/net/cookies/canonical_cookie_unittest.cc
index 161b27f..d7c25d188 100644
--- a/net/cookies/canonical_cookie_unittest.cc
+++ b/net/cookies/canonical_cookie_unittest.cc
@@ -55,16 +55,8 @@ TEST(CanonicalCookieTest, Constructor) {
   EXPECT_EQ("/test", cookie.Path());
   EXPECT_FALSE(cookie.IsSecure());
 
-  CanonicalCookie cookie2(url,
-                          "A",
-                          "2",
-                          std::string(),
-                          std::string(),
-                          current_time,
-                          base::Time(),
-                          current_time,
-                          false,
-                          false);
+  CanonicalCookie cookie2(url, "A", "2", "", "", current_time, base::Time(),
+                          current_time, false, false);
   EXPECT_EQ(url.GetOrigin().spec(), cookie.Source());
   EXPECT_EQ("A", cookie2.Name());
   EXPECT_EQ("2", cookie2.Value());
@@ -295,7 +287,7 @@ TEST(CanonicalCookieTest, IsOnPath) {
   EXPECT_TRUE(cookie->IsOnPath("/test/bar.html"));
 
   // Test the empty string edge case.
-  EXPECT_FALSE(cookie->IsOnPath(std::string()));
+  EXPECT_FALSE(cookie->IsOnPath(""));
 
   cookie.reset(
       CanonicalCookie::Create(GURL("http://www.example.com/test/foo.html"),
diff --git a/net/cookies/cookie_monster_unittest.cc b/net/cookies/cookie_monster_unittest.cc
index b3688c3..116d486 100644
--- a/net/cookies/cookie_monster_unittest.cc
+++ b/net/cookies/cookie_monster_unittest.cc
@@ -233,44 +233,20 @@ class CookieMonsterTest : public CookieStoreTest<CookieMonsterTestTraits> {
                                           base::Time(), false, false));
 
     // Host cookies
-    EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_1,
-                                           "host_1",
-                                           "X",
-                                           std::string(),
-                                           "/",
-                                           base::Time(),
-                                           false,
-                                           false));
-    EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_2,
-                                           "host_2",
-                                           "X",
-                                           std::string(),
-                                           "/",
-                                           base::Time(),
-                                           false,
-                                           false));
-    EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_3,
-                                           "host_3",
-                                           "X",
-                                           std::string(),
-                                           "/",
-                                           base::Time(),
-                                           false,
-                                           false));
+    EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_1,
+                                          "host_1", "X", "", "/",
+                                          base::Time(), false, false));
+    EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_2,
+                                          "host_2", "X", "", "/",
+                                          base::Time(), false, false));
+    EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_3,
+                                          "host_3", "X", "", "/",
+                                          base::Time(), false, false));
 
     // Http_only cookie
-    EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_2,
-                                           "httpo_check",
-                                           "X",
-                                           std::string(),
-                                           "/",
-                                           base::Time(),
-                                           false,
-                                           true));
+    EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_2,
+                                          "httpo_check", "X", "", "/",
+                                          base::Time(), false, true));
 
     // Secure cookies
     EXPECT_TRUE(this->SetCookieWithDetails(cm,
@@ -278,14 +254,9 @@ class CookieMonsterTest : public CookieStoreTest<CookieMonsterTestTraits> {
                                          "sec_dom", "X", ".math.harvard.edu",
                                          "/", base::Time(), true, false));
     EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_2_secure,
-                                           "sec_host",
-                                           "X",
-                                           std::string(),
-                                           "/",
-                                           base::Time(),
-                                           true,
-                                           false));
+                                          url_top_level_domain_plus_2_secure,
+                                          "sec_host", "X", "", "/",
+                                          base::Time(), true, false));
 
     // Domain path cookies
     EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_2,
@@ -298,24 +269,14 @@ class CookieMonsterTest : public CookieStoreTest<CookieMonsterTestTraits> {
                                           base::Time(), false, false));
 
     // Host path cookies
-    EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_2,
-                                           "host_path_1",
-                                           "X",
-                                           std::string(),
-                                           "/dir1",
-                                           base::Time(),
-                                           false,
-                                           false));
-    EXPECT_TRUE(this->SetCookieWithDetails(cm,
-                                           url_top_level_domain_plus_2,
-                                           "host_path_2",
-                                           "X",
-                                           std::string(),
-                                           "/dir1/dir2",
-                                           base::Time(),
-                                           false,
-                                           false));
+    EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_2,
+                                          "host_path_1", "X",
+                                          "", "/dir1",
+                                          base::Time(), false, false));
+    EXPECT_TRUE(this->SetCookieWithDetails(cm, url_top_level_domain_plus_2,
+                                          "host_path_2", "X",
+                                          "", "/dir1/dir2",
+                                          base::Time(), false, false));
 
     EXPECT_EQ(13U, this->GetAllCookies(cm).size());
   }
@@ -2244,7 +2205,7 @@ TEST_F(CookieMonsterTest, PersisentCookieStorageTest) {
   EXPECT_EQ(CookieStoreCommand::ADD, store->commands()[0].type);
   // Remove it.
   EXPECT_TRUE(SetCookie(cm, url_google_,"A=B; max-age=0"));
-  this->MatchCookieLines(std::string(), GetCookies(cm, url_google_));
+  this->MatchCookieLines("", GetCookies(cm, url_google_));
   ASSERT_EQ(2u, store->commands().size());
   EXPECT_EQ(CookieStoreCommand::REMOVE, store->commands()[1].type);
 
diff --git a/net/cookies/cookie_store_test_helpers.cc b/net/cookies/cookie_store_test_helpers.cc
index 6ae4357d..e499538 100644
--- a/net/cookies/cookie_store_test_helpers.cc
+++ b/net/cookies/cookie_store_test_helpers.cc
@@ -90,7 +90,7 @@ std::string DelayedCookieMonster::GetCookiesWithOptions(
     const GURL& url,
     const CookieOptions& options) {
   ADD_FAILURE();
-  return std::string();
+  return "";
 }
 
 void DelayedCookieMonster::DeleteCookie(const GURL& url,
diff --git a/net/cookies/cookie_store_unittest.h b/net/cookies/cookie_store_unittest.h
index 0d2d7ed..134a193 100644
--- a/net/cookies/cookie_store_unittest.h
+++ b/net/cookies/cookie_store_unittest.h
@@ -275,10 +275,9 @@ TYPED_TEST_P(CookieStoreTest, DomainTest) {
 
   // Test domain enforcement, should fail on a sub-domain or something too deep.
   EXPECT_FALSE(this->SetCookie(cs, this->url_google_, "I=J; domain=.izzle"));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, GURL("http://a.izzle")));
-  EXPECT_FALSE(this->SetCookie(
-      cs, this->url_google_, "K=L; domain=.bla.www.google.izzle"));
+  this->MatchCookieLines("", this->GetCookies(cs, GURL("http://a.izzle")));
+  EXPECT_FALSE(this->SetCookie(cs, this->url_google_,
+                               "K=L; domain=.bla.www.google.izzle"));
   this->MatchCookieLines("C=D; E=F; G=H",
       this->GetCookies(cs, GURL("http://bla.www.google.izzle")));
   this->MatchCookieLines("A=B; C=D; E=F; G=H",
@@ -293,8 +292,7 @@ TYPED_TEST_P(CookieStoreTest, DomainWithTrailingDotTest) {
                                "a=1; domain=.www.google.com."));
   EXPECT_FALSE(this->SetCookie(cs, this->url_google_,
                                "b=2; domain=.www.google.com.."));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
 }
 
 // Test that cookies can bet set on higher level domains.
@@ -368,7 +366,7 @@ TYPED_TEST_P(CookieStoreTest, InvalidDomainTest) {
     EXPECT_FALSE(this->SetCookie(cs, url_foobar,
                                  "o=15; domain=.foo.bar.com#sup"));
 
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url_foobar));
+    this->MatchCookieLines("", this->GetCookies(cs, url_foobar));
   }
 
   {
@@ -379,7 +377,7 @@ TYPED_TEST_P(CookieStoreTest, InvalidDomainTest) {
     GURL url_foocom("http://foo.com.com");
     EXPECT_FALSE(this->SetCookie(cs, url_foocom,
                                  "a=1; domain=.foo.com.com.com"));
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url_foocom));
+    this->MatchCookieLines("", this->GetCookies(cs, url_foocom));
   }
 }
 
@@ -404,8 +402,8 @@ TYPED_TEST_P(CookieStoreTest, DomainWithoutLeadingDotTest) {
     this->MatchCookieLines("a=1", this->GetCookies(cs, url));
     this->MatchCookieLines("a=1",
         this->GetCookies(cs, GURL("http://sub.www.google.com")));
-    this->MatchCookieLines(
-        std::string(), this->GetCookies(cs, GURL("http://something-else.com")));
+    this->MatchCookieLines("",
+        this->GetCookies(cs, GURL("http://something-else.com")));
   }
 }
 
@@ -431,11 +429,11 @@ TYPED_TEST_P(CookieStoreTest, TestIpAddress) {
     scoped_refptr<CookieStore> cs(this->GetCookieStore());
     EXPECT_FALSE(this->SetCookie(cs, url_ip, "b=2; domain=.1.2.3.4"));
     EXPECT_FALSE(this->SetCookie(cs, url_ip, "c=3; domain=.3.4"));
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url_ip));
+    this->MatchCookieLines("", this->GetCookies(cs, url_ip));
     // It should be allowed to set a cookie if domain= matches the IP address
     // exactly.  This matches IE/Firefox, even though it seems a bit wrong.
     EXPECT_FALSE(this->SetCookie(cs, url_ip, "b=2; domain=1.2.3.3"));
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url_ip));
+    this->MatchCookieLines("", this->GetCookies(cs, url_ip));
     EXPECT_TRUE(this->SetCookie(cs, url_ip, "b=2; domain=1.2.3.4"));
     this->MatchCookieLines("b=2", this->GetCookies(cs, url_ip));
   }
@@ -453,12 +451,10 @@ TYPED_TEST_P(CookieStoreTest, TestNonDottedAndTLD) {
     this->MatchCookieLines("a=1", this->GetCookies(cs, url));
     // Make sure it doesn't show up for a normal .com, it should be a host
     // not a domain cookie.
-    this->MatchCookieLines(
-        std::string(),
+    this->MatchCookieLines("",
         this->GetCookies(cs, GURL("http://hopefully-no-cookies.com/")));
     if (TypeParam::supports_non_dotted_domains) {
-      this->MatchCookieLines(std::string(),
-                             this->GetCookies(cs, GURL("http://.com/")));
+      this->MatchCookieLines("", this->GetCookies(cs, GURL("http://.com/")));
     }
   }
 
@@ -469,8 +465,7 @@ TYPED_TEST_P(CookieStoreTest, TestNonDottedAndTLD) {
     if (TypeParam::supports_trailing_dots) {
       EXPECT_TRUE(this->SetCookie(cs, url, "a=1"));
       this->MatchCookieLines("a=1", this->GetCookies(cs, url));
-      this->MatchCookieLines(
-          std::string(),
+      this->MatchCookieLines("",
           this->GetCookies(cs, GURL("http://hopefully-no-cookies.com./")));
     } else {
       EXPECT_FALSE(this->SetCookie(cs, url, "a=1"));
@@ -482,7 +477,7 @@ TYPED_TEST_P(CookieStoreTest, TestNonDottedAndTLD) {
     GURL url("http://a.b");
     EXPECT_FALSE(this->SetCookie(cs, url, "a=1; domain=.b"));
     EXPECT_FALSE(this->SetCookie(cs, url, "b=2; domain=b"));
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url));
+    this->MatchCookieLines("", this->GetCookies(cs, url));
   }
 
   {  // Same test as above, but explicitly on a known TLD (com).
@@ -490,7 +485,7 @@ TYPED_TEST_P(CookieStoreTest, TestNonDottedAndTLD) {
     GURL url("http://google.com");
     EXPECT_FALSE(this->SetCookie(cs, url, "a=1; domain=.com"));
     EXPECT_FALSE(this->SetCookie(cs, url, "b=2; domain=com"));
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url));
+    this->MatchCookieLines("", this->GetCookies(cs, url));
   }
 
   {  // Make sure can't set cookie on TLD which is dotted.
@@ -498,12 +493,11 @@ TYPED_TEST_P(CookieStoreTest, TestNonDottedAndTLD) {
     GURL url("http://google.co.uk");
     EXPECT_FALSE(this->SetCookie(cs, url, "a=1; domain=.co.uk"));
     EXPECT_FALSE(this->SetCookie(cs, url, "b=2; domain=.uk"));
-    this->MatchCookieLines(std::string(), this->GetCookies(cs, url));
-    this->MatchCookieLines(
-        std::string(),
+    this->MatchCookieLines("", this->GetCookies(cs, url));
+    this->MatchCookieLines("",
         this->GetCookies(cs, GURL("http://something-else.co.uk")));
-    this->MatchCookieLines(
-        std::string(), this->GetCookies(cs, GURL("http://something-else.uk")));
+    this->MatchCookieLines("",
+        this->GetCookies(cs, GURL("http://something-else.uk")));
   }
 
   {  // Intranet URLs should only be able to set host cookies.
@@ -539,11 +533,9 @@ TYPED_TEST_P(CookieStoreTest, TestHostEndsWithDot) {
   }
 
   // Make sure there weren't any side effects.
-  this->MatchCookieLines(
-      std::string(),
+  this->MatchCookieLines("",
       this->GetCookies(cs, GURL("http://hopefully-no-cookies.com/")));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, GURL("http://.com/")));
+  this->MatchCookieLines("", this->GetCookies(cs, GURL("http://.com/")));
 }
 
 TYPED_TEST_P(CookieStoreTest, InvalidScheme) {
@@ -560,7 +552,7 @@ TYPED_TEST_P(CookieStoreTest, InvalidScheme_Read) {
 
   scoped_refptr<CookieStore> cs(this->GetCookieStore());
   EXPECT_TRUE(this->SetCookie(cs, GURL(kUrlGoogle), kValidDomainCookieLine));
-  this->MatchCookieLines(std::string(), this->GetCookies(cs, GURL(kUrlFtp)));
+  this->MatchCookieLines("", this->GetCookies(cs, GURL(kUrlFtp)));
 }
 
 TYPED_TEST_P(CookieStoreTest, PathTest) {
@@ -573,9 +565,8 @@ TYPED_TEST_P(CookieStoreTest, PathTest) {
   this->MatchCookieLines("A=B",
       this->GetCookies(cs, GURL(url + "/wee/war/more/more")));
   if (!TypeParam::has_path_prefix_bug)
-    this->MatchCookieLines(std::string(),
-                           this->GetCookies(cs, GURL(url + "/weehee")));
-  this->MatchCookieLines(std::string(), this->GetCookies(cs, GURL(url + "/")));
+    this->MatchCookieLines("", this->GetCookies(cs, GURL(url + "/weehee")));
+  this->MatchCookieLines("", this->GetCookies(cs, GURL(url + "/")));
 
   // If we add a 0 length path, it should default to /
   EXPECT_TRUE(this->SetCookie(cs, GURL(url), "A=C; path="));
@@ -621,17 +612,15 @@ TYPED_TEST_P(CookieStoreTest, HttpOnlyTest) {
                                          options));
 
   // Check httponly read protection.
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
-  this->MatchCookieLines(
-      "A=B", this->GetCookiesWithOptions(cs, this->url_google_, options));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("A=B",
+      this->GetCookiesWithOptions(cs, this->url_google_, options));
 
   // Check httponly overwrite protection.
   EXPECT_FALSE(this->SetCookie(cs, this->url_google_, "A=C"));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
-  this->MatchCookieLines(
-      "A=B", this->GetCookiesWithOptions(cs, this->url_google_, options));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("A=B",
+      this->GetCookiesWithOptions(cs, this->url_google_, options));
   EXPECT_TRUE(this->SetCookieWithOptions(cs, this->url_google_, "A=C",
                                          options));
   this->MatchCookieLines("A=C", this->GetCookies(cs, this->url_google_));
@@ -656,7 +645,7 @@ TYPED_TEST_P(CookieStoreTest, TestCookieDeletion) {
   // Delete it via Max-Age.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
                               std::string(kValidCookieLine) + "; max-age=0"));
-  this->MatchCookieLineWithTimeout(cs, this->url_google_, std::string());
+  this->MatchCookieLineWithTimeout(cs, this->url_google_, "");
 
   // Create a session cookie.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_, kValidCookieLine));
@@ -665,8 +654,7 @@ TYPED_TEST_P(CookieStoreTest, TestCookieDeletion) {
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
                               std::string(kValidCookieLine) +
                               "; expires=Mon, 18-Apr-1977 22:50:13 GMT"));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
 
   // Create a persistent cookie.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
@@ -677,7 +665,7 @@ TYPED_TEST_P(CookieStoreTest, TestCookieDeletion) {
   // Delete it via Max-Age.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
                               std::string(kValidCookieLine) + "; max-age=0"));
-  this->MatchCookieLineWithTimeout(cs, this->url_google_, std::string());
+  this->MatchCookieLineWithTimeout(cs, this->url_google_, "");
 
   // Create a persistent cookie.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
@@ -688,8 +676,7 @@ TYPED_TEST_P(CookieStoreTest, TestCookieDeletion) {
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
                               std::string(kValidCookieLine) +
                               "; expires=Mon, 18-Apr-1977 22:50:13 GMT"));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
 
   // Create a persistent cookie.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
@@ -716,8 +703,7 @@ TYPED_TEST_P(CookieStoreTest, TestCookieDeletion) {
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_,
                               std::string(kValidCookieLine) +
                               "; expires=Thu, 1-Jan-1970 00:00:00 GMT"));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
 }
 
 TYPED_TEST_P(CookieStoreTest, TestDeleteAllCreatedBetween) {
@@ -745,8 +731,7 @@ TYPED_TEST_P(CookieStoreTest, TestDeleteAllCreatedBetween) {
   // Remove the cookie with an interval defined by two dates.
   EXPECT_EQ(1, this->DeleteCreatedBetween(cs, last_minute, next_minute));
   // Check that the cookie disappeared.
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
 
   // Add another cookie.
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_, "C=D"));
@@ -756,8 +741,7 @@ TYPED_TEST_P(CookieStoreTest, TestDeleteAllCreatedBetween) {
   // Remove the cookie with a null ending time.
   EXPECT_EQ(1, this->DeleteCreatedBetween(cs, last_minute, base::Time()));
   // Check that the cookie disappeared.
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
 }
 
 TYPED_TEST_P(CookieStoreTest, TestSecure) {
@@ -769,13 +753,11 @@ TYPED_TEST_P(CookieStoreTest, TestSecure) {
 
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_secure_, "A=B; secure"));
   // The secure should overwrite the non-secure.
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
   this->MatchCookieLines("A=B", this->GetCookies(cs, this->url_google_secure_));
 
   EXPECT_TRUE(this->SetCookie(cs, this->url_google_secure_, "D=E; secure"));
-  this->MatchCookieLines(std::string(),
-                         this->GetCookies(cs, this->url_google_));
+  this->MatchCookieLines("", this->GetCookies(cs, this->url_google_));
   this->MatchCookieLines("A=B; D=E",
                          this->GetCookies(cs, this->url_google_secure_));
 
diff --git a/net/cookies/parsed_cookie.cc b/net/cookies/parsed_cookie.cc
index ecb8712..5cd542d 100644
--- a/net/cookies/parsed_cookie.cc
+++ b/net/cookies/parsed_cookie.cc
@@ -424,7 +424,7 @@ bool ParsedCookie::SetBool(size_t* index,
     ClearAttributePair(*index);
     return true;
   } else {
-    return SetAttributePair(index, key, std::string());
+    return SetAttributePair(index, key, "");
   }
 }
 
diff --git a/net/cookies/parsed_cookie_unittest.cc b/net/cookies/parsed_cookie_unittest.cc
index 57de115..3729650 100644
--- a/net/cookies/parsed_cookie_unittest.cc
+++ b/net/cookies/parsed_cookie_unittest.cc
@@ -208,7 +208,7 @@ TEST(ParsedCookieTest, InvalidTooLong) {
 }
 
 TEST(ParsedCookieTest, InvalidEmpty) {
-  ParsedCookie pc((std::string()));
+  ParsedCookie pc("");
   EXPECT_FALSE(pc.IsValid());
 }
 
@@ -259,7 +259,7 @@ TEST(ParsedCookieTest, SerializeCookieLine) {
 
 
 TEST(ParsedCookieTest, SetNameAndValue) {
-  ParsedCookie empty((std::string()));
+  ParsedCookie empty("");
   EXPECT_FALSE(empty.IsValid());
   EXPECT_FALSE(empty.SetDomain("foobar.com"));
   EXPECT_TRUE(empty.SetName("name"));
@@ -282,7 +282,7 @@ TEST(ParsedCookieTest, SetNameAndValue) {
   EXPECT_EQ("name=value", pc.ToCookieLine());
   EXPECT_TRUE(pc.IsValid());
 
-  EXPECT_FALSE(pc.SetName(std::string()));
+  EXPECT_FALSE(pc.SetName(""));
   EXPECT_EQ("name=value", pc.ToCookieLine());
   EXPECT_TRUE(pc.IsValid());
 
@@ -303,7 +303,7 @@ TEST(ParsedCookieTest, SetNameAndValue) {
   EXPECT_EQ("test=\"foobar\"", pc.ToCookieLine());
   EXPECT_TRUE(pc.IsValid());
 
-  EXPECT_TRUE(pc.SetValue(std::string()));
+  EXPECT_TRUE(pc.SetValue(""));
   EXPECT_EQ("test=", pc.ToCookieLine());
   EXPECT_TRUE(pc.IsValid());
 }
@@ -313,7 +313,7 @@ TEST(ParsedCookieTest, SetAttributes) {
   EXPECT_TRUE(pc.IsValid());
 
   // Clear an unset attribute.
-  EXPECT_TRUE(pc.SetDomain(std::string()));
+  EXPECT_TRUE(pc.SetDomain(""));
   EXPECT_FALSE(pc.HasDomain());
   EXPECT_EQ("name=value", pc.ToCookieLine());
   EXPECT_TRUE(pc.IsValid());
@@ -355,10 +355,10 @@ TEST(ParsedCookieTest, SetAttributes) {
             pc.ToCookieLine());
 
   // Clear the rest and change the name and value.
-  EXPECT_TRUE(pc.SetDomain(std::string()));
-  EXPECT_TRUE(pc.SetPath(std::string()));
-  EXPECT_TRUE(pc.SetExpires(std::string()));
-  EXPECT_TRUE(pc.SetMaxAge(std::string()));
+  EXPECT_TRUE(pc.SetDomain(""));
+  EXPECT_TRUE(pc.SetPath(""));
+  EXPECT_TRUE(pc.SetExpires(""));
+  EXPECT_TRUE(pc.SetMaxAge(""));
   EXPECT_TRUE(pc.SetIsSecure(false));
   EXPECT_TRUE(pc.SetIsHttpOnly(false));
   EXPECT_TRUE(pc.SetName("name2"));
diff --git a/net/dns/host_resolver_impl_unittest.cc b/net/dns/host_resolver_impl_unittest.cc
index 26bebeb..c9ebec0 100644
--- a/net/dns/host_resolver_impl_unittest.cc
+++ b/net/dns/host_resolver_impl_unittest.cc
@@ -107,7 +107,7 @@ class MockHostResolverProc : public HostResolverProc {
   void AddRule(const std::string& hostname, AddressFamily family,
                const std::string& ip_list) {
     AddressList result;
-    int rv = ParseAddressList(ip_list, std::string(), &result);
+    int rv = ParseAddressList(ip_list, "", &result);
     DCHECK_EQ(OK, rv);
     AddRule(hostname, family, result);
   }
@@ -115,7 +115,7 @@ class MockHostResolverProc : public HostResolverProc {
   void AddRuleForAllFamilies(const std::string& hostname,
                              const std::string& ip_list) {
     AddressList result;
-    int rv = ParseAddressList(ip_list, std::string(), &result);
+    int rv = ParseAddressList(ip_list, "", &result);
     DCHECK_EQ(OK, rv);
     AddRule(hostname, ADDRESS_FAMILY_UNSPECIFIED, result);
     AddRule(hostname, ADDRESS_FAMILY_IPV4, result);
@@ -137,7 +137,7 @@ class MockHostResolverProc : public HostResolverProc {
     --num_slots_available_;
     --num_requests_waiting_;
     if (rules_.empty()) {
-      int rv = ParseAddressList("127.0.0.1", std::string(), addrlist);
+      int rv = ParseAddressList("127.0.0.1", "", addrlist);
       DCHECK_EQ(OK, rv);
       return OK;
     }
@@ -527,8 +527,7 @@ TEST_F(HostResolverImplTest, AsynchronousLookup) {
 }
 
 TEST_F(HostResolverImplTest, FailedAsynchronousLookup) {
-  proc_->AddRuleForAllFamilies(std::string(),
-                               "0.0.0.0");  // Default to failures.
+  proc_->AddRuleForAllFamilies("", "0.0.0.0");  // Default to failures.
   proc_->SignalMultiple(1u);
 
   Request* req = CreateRequest("just.testing", 80);
@@ -583,7 +582,7 @@ TEST_F(HostResolverImplTest, NumericIPv6Address) {
 }
 
 TEST_F(HostResolverImplTest, EmptyHost) {
-  Request* req = CreateRequest(std::string(), 5555);
+  Request* req = CreateRequest("", 5555);
   EXPECT_EQ(ERR_NAME_NOT_RESOLVED, req->Resolve());
 }
 
@@ -1345,8 +1344,7 @@ TEST_F(HostResolverImplDnsTest, ServeFromHosts) {
   DnsConfig config = CreateValidDnsConfig();
   ChangeDnsConfig(config);
 
-  proc_->AddRuleForAllFamilies(std::string(),
-                               std::string());  // Default to failures.
+  proc_->AddRuleForAllFamilies("", "");  // Default to failures.
   proc_->SignalMultiple(1u);  // For the first request which misses.
 
   Request* req0 = CreateRequest("er_ipv4", 80);
@@ -1398,8 +1396,7 @@ TEST_F(HostResolverImplDnsTest, ServeFromHosts) {
 TEST_F(HostResolverImplDnsTest, BypassDnsTask) {
   ChangeDnsConfig(CreateValidDnsConfig());
 
-  proc_->AddRuleForAllFamilies(std::string(),
-                               std::string());  // Default to failures.
+  proc_->AddRuleForAllFamilies("", "");  // Default to failures.
 
   EXPECT_EQ(ERR_IO_PENDING, CreateRequest("ok.local", 80)->Resolve());
   EXPECT_EQ(ERR_IO_PENDING, CreateRequest("ok.local.", 80)->Resolve());
@@ -1419,8 +1416,7 @@ TEST_F(HostResolverImplDnsTest, BypassDnsTask) {
 TEST_F(HostResolverImplDnsTest, DisableDnsClientOnPersistentFailure) {
   ChangeDnsConfig(CreateValidDnsConfig());
 
-  proc_->AddRuleForAllFamilies(std::string(),
-                               std::string());  // Default to failures.
+  proc_->AddRuleForAllFamilies("", "");  // Default to failures.
 
   // Check that DnsTask works.
   Request* req = CreateRequest("ok_1", 80);
@@ -1474,7 +1470,7 @@ TEST_F(HostResolverImplDnsTest, DontDisableDnsClientOnSporadicFailure) {
     EXPECT_EQ(OK, requests_[i]->WaitForResult()) << i;
 
   // Make |proc_| default to failures.
-  proc_->AddRuleForAllFamilies(std::string(), std::string());
+  proc_->AddRuleForAllFamilies("", "");
 
   // DnsTask should still be enabled.
   Request* req = CreateRequest("ok_last", 80);
diff --git a/net/dns/mapped_host_resolver_unittest.cc b/net/dns/mapped_host_resolver_unittest.cc
index d859466..8da95e1 100644
--- a/net/dns/mapped_host_resolver_unittest.cc
+++ b/net/dns/mapped_host_resolver_unittest.cc
@@ -18,7 +18,7 @@ namespace {
 
 std::string FirstAddress(const AddressList& address_list) {
   if (address_list.empty())
-    return std::string();
+    return "";
   return address_list.front().ToString();
 }
 
@@ -171,7 +171,7 @@ TEST(MappedHostResolverTest, ParseInvalidRules) {
       new MappedHostResolver(scoped_ptr<HostResolver>()));
 
   EXPECT_FALSE(resolver->AddRuleFromString("xyz"));
-  EXPECT_FALSE(resolver->AddRuleFromString(std::string()));
+  EXPECT_FALSE(resolver->AddRuleFromString(""));
   EXPECT_FALSE(resolver->AddRuleFromString(" "));
   EXPECT_FALSE(resolver->AddRuleFromString("EXCLUDE"));
   EXPECT_FALSE(resolver->AddRuleFromString("EXCLUDE foo bar"));
diff --git a/net/dns/mock_host_resolver.cc b/net/dns/mock_host_resolver.cc
index e6ecf59..fb03836 100644
--- a/net/dns/mock_host_resolver.cc
+++ b/net/dns/mock_host_resolver.cc
@@ -256,13 +256,8 @@ void RuleBasedHostResolverProc::AddRuleForAddressFamily(
   DCHECK(!replacement.empty());
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeSystem,
-            host_pattern,
-            address_family,
-            flags,
-            replacement,
-            std::string(),
-            0);
+  Rule rule(Rule::kResolverTypeSystem, host_pattern, address_family, flags,
+            replacement, "", 0);
   rules_.push_back(rule);
 }
 
@@ -291,13 +286,8 @@ void RuleBasedHostResolverProc::AddRuleWithLatency(
   DCHECK(!replacement.empty());
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeSystem,
-            host_pattern,
-            ADDRESS_FAMILY_UNSPECIFIED,
-            flags,
-            replacement,
-            std::string(),
-            latency_ms);
+  Rule rule(Rule::kResolverTypeSystem, host_pattern, ADDRESS_FAMILY_UNSPECIFIED,
+            flags, replacement, "", latency_ms);
   rules_.push_back(rule);
 }
 
@@ -305,13 +295,8 @@ void RuleBasedHostResolverProc::AllowDirectLookup(
     const std::string& host_pattern) {
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeSystem,
-            host_pattern,
-            ADDRESS_FAMILY_UNSPECIFIED,
-            flags,
-            std::string(),
-            std::string(),
-            0);
+  Rule rule(Rule::kResolverTypeSystem, host_pattern, ADDRESS_FAMILY_UNSPECIFIED,
+            flags, "", "", 0);
   rules_.push_back(rule);
 }
 
@@ -319,13 +304,8 @@ void RuleBasedHostResolverProc::AddSimulatedFailure(
     const std::string& host_pattern) {
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeFail,
-            host_pattern,
-            ADDRESS_FAMILY_UNSPECIFIED,
-            flags,
-            std::string(),
-            std::string(),
-            0);
+  Rule rule(Rule::kResolverTypeFail, host_pattern, ADDRESS_FAMILY_UNSPECIFIED,
+            flags, "", "", 0);
   rules_.push_back(rule);
 }
 
diff --git a/net/dns/single_request_host_resolver_unittest.cc b/net/dns/single_request_host_resolver_unittest.cc
index 1b0198f..3e2ea1e 100644
--- a/net/dns/single_request_host_resolver_unittest.cc
+++ b/net/dns/single_request_host_resolver_unittest.cc
@@ -68,7 +68,7 @@ TEST(SingleRequestHostResolverTest, NormalResolve) {
   // Create a host resolver dependency that returns address "199.188.1.166"
   // for resolutions of "watsup".
   MockHostResolver resolver;
-  resolver.rules()->AddIPLiteralRule("watsup", "199.188.1.166", std::string());
+  resolver.rules()->AddIPLiteralRule("watsup", "199.188.1.166", "");
 
   SingleRequestHostResolver single_request_resolver(&resolver);
 
diff --git a/net/ftp/ftp_util.cc b/net/ftp/ftp_util.cc
index 68307a2..0eab465 100644
--- a/net/ftp/ftp_util.cc
+++ b/net/ftp/ftp_util.cc
@@ -107,7 +107,7 @@ std::string FtpUtil::VMSPathToUnix(const std::string& vms_path) {
   std::string result(vms_path);
   if (vms_path[0] == '[') {
     // It's a relative path.
-    ReplaceFirstSubstringAfterOffset(&result, 0, "[.", std::string());
+    ReplaceFirstSubstringAfterOffset(&result, 0, "[.", "");
   } else {
     // It's an absolute path.
     result.insert(0, "/");
diff --git a/net/http/http_auth.cc b/net/http/http_auth.cc
index 9e9410b..fb7fc5d 100644
--- a/net/http/http_auth.cc
+++ b/net/http/http_auth.cc
@@ -146,7 +146,7 @@ std::string HttpAuth::GetChallengeHeaderName(Target target) {
       return "WWW-Authenticate";
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
@@ -159,7 +159,7 @@ std::string HttpAuth::GetAuthorizationHeaderName(Target target) {
       return HttpRequestHeaders::kAuthorization;
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
@@ -172,7 +172,7 @@ std::string HttpAuth::GetAuthTargetString(Target target) {
       return "server";
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
diff --git a/net/http/http_auth_cache_unittest.cc b/net/http/http_auth_cache_unittest.cc
index 0bdb280..af3b25c 100644
--- a/net/http/http_auth_cache_unittest.cc
+++ b/net/http/http_auth_cache_unittest.cc
@@ -106,13 +106,11 @@ TEST(HttpAuthCacheTest, Basic) {
       new MockAuthHandler(HttpAuth::AUTH_SCHEME_BASIC,
                           kRealm3,
                           HttpAuth::AUTH_PROXY));
-  cache.Add(
-      origin,
-      realm3_basic_handler->realm(),
-      realm3_basic_handler->auth_scheme(),
-      "Basic realm=Realm3",
-      CreateASCIICredentials("realm3-basic-user", "realm3-basic-password"),
-      std::string());
+  cache.Add(origin, realm3_basic_handler->realm(),
+            realm3_basic_handler->auth_scheme(), "Basic realm=Realm3",
+            CreateASCIICredentials("realm3-basic-user",
+                                   "realm3-basic-password"),
+            "");
 
   scoped_ptr<HttpAuthHandler> realm3_digest_handler(
       new MockAuthHandler(HttpAuth::AUTH_SCHEME_DIGEST,
@@ -207,7 +205,7 @@ TEST(HttpAuthCacheTest, Basic) {
   // Negative tests:
   entry = cache.LookupByPath(origin, "/foo3/index.html");
   EXPECT_FALSE(realm2_entry == entry);
-  entry = cache.LookupByPath(origin, std::string());
+  entry = cache.LookupByPath(origin, "");
   EXPECT_FALSE(realm2_entry == entry);
 
   // Confirm we find the same realm, different auth scheme by path lookup
@@ -233,7 +231,7 @@ TEST(HttpAuthCacheTest, Basic) {
   EXPECT_FALSE(realm3DigestEntry == entry);
 
   // Lookup using empty path (may be used for proxy).
-  entry = cache.LookupByPath(origin, std::string());
+  entry = cache.LookupByPath(origin, "");
   EXPECT_FALSE(NULL == entry);
   EXPECT_EQ(HttpAuth::AUTH_SCHEME_BASIC, entry->scheme());
   EXPECT_EQ(kRealm3, entry->realm());
@@ -542,10 +540,7 @@ class HttpAuthCacheEvictionTest : public testing::Test {
   }
 
   void AddPathToRealm(int realm_i, int path_i) {
-    cache_.Add(origin_,
-               GenerateRealm(realm_i),
-               HttpAuth::AUTH_SCHEME_BASIC,
-               std::string(),
+    cache_.Add(origin_, GenerateRealm(realm_i), HttpAuth::AUTH_SCHEME_BASIC, "",
                AuthCredentials(kUsername, kPassword),
                GeneratePath(realm_i, path_i));
   }
diff --git a/net/http/http_auth_filter_unittest.cc b/net/http/http_auth_filter_unittest.cc
index e6891dd..0aab9d4 100644
--- a/net/http/http_auth_filter_unittest.cc
+++ b/net/http/http_auth_filter_unittest.cc
@@ -35,17 +35,22 @@ struct UrlData {
 };
 
 static const UrlData urls[] = {
-  { GURL(std::string()), HttpAuth::AUTH_NONE, false, 0 },
-  { GURL("http://foo.cn"), HttpAuth::AUTH_PROXY, true, ALL_SERVERS_MATCH },
-  { GURL("http://foo.cn"), HttpAuth::AUTH_SERVER, false, 0 },
-  { GURL("http://slashdot.org"), HttpAuth::AUTH_NONE, false, 0 },
-  { GURL("http://www.google.com"), HttpAuth::AUTH_SERVER, true, 1 << 0 },
-  { GURL("http://www.google.com"), HttpAuth::AUTH_PROXY, true,
-    ALL_SERVERS_MATCH },
+  { GURL(""),
+    HttpAuth::AUTH_NONE, false, 0 },
+  { GURL("http://foo.cn"),
+    HttpAuth::AUTH_PROXY, true, ALL_SERVERS_MATCH },
+  { GURL("http://foo.cn"),
+    HttpAuth::AUTH_SERVER, false, 0 },
+  { GURL("http://slashdot.org"),
+    HttpAuth::AUTH_NONE, false, 0 },
+  { GURL("http://www.google.com"),
+    HttpAuth::AUTH_SERVER, true, 1 << 0 },
+  { GURL("http://www.google.com"),
+    HttpAuth::AUTH_PROXY, true, ALL_SERVERS_MATCH },
   { GURL("https://login.facebook.com/login.php?login_attempt=1"),
     HttpAuth::AUTH_NONE, false, 0 },
-  { GURL("http://codereview.chromium.org/634002/show"), HttpAuth::AUTH_SERVER,
-    true, 1 << 3 },
+  { GURL("http://codereview.chromium.org/634002/show"),
+    HttpAuth::AUTH_SERVER, true, 1 << 3 },
   { GURL("http://code.google.com/p/chromium/issues/detail?id=34505"),
     HttpAuth::AUTH_SERVER, true, 1 << 0 },
   { GURL("http://code.google.com/p/chromium/issues/list?can=2&q=label:"
@@ -72,7 +77,7 @@ static const UrlData urls[] = {
 
 TEST(HttpAuthFilterTest, EmptyFilter) {
   // Create an empty filter
-  HttpAuthFilterWhitelist filter((std::string()));
+  HttpAuthFilterWhitelist filter("");
   for (size_t i = 0; i < arraysize(urls); i++) {
     EXPECT_EQ(urls[i].target == HttpAuth::AUTH_PROXY,
               filter.IsValid(urls[i].url, urls[i].target))
diff --git a/net/http/http_auth_gssapi_posix_unittest.cc b/net/http/http_auth_gssapi_posix_unittest.cc
index 1c3d12b..cbf4d3d 100644
--- a/net/http/http_auth_gssapi_posix_unittest.cc
+++ b/net/http/http_auth_gssapi_posix_unittest.cc
@@ -76,7 +76,7 @@ TEST(HttpAuthGSSAPIPOSIXTest, GSSAPIStartup) {
   // TODO(ahendrickson): Manipulate the libraries and paths to test each of the
   // libraries we expect, and also whether or not they have the interface
   // functions we want.
-  scoped_ptr<GSSAPILibrary> gssapi(new GSSAPISharedLibrary(std::string()));
+  scoped_ptr<GSSAPILibrary> gssapi(new GSSAPISharedLibrary(""));
   DCHECK(gssapi.get());
   EXPECT_TRUE(gssapi.get()->Init());
 }
diff --git a/net/http/http_auth_handler_digest.cc b/net/http/http_auth_handler_digest.cc
index cc90b52..bfc8312 100644
--- a/net/http/http_auth_handler_digest.cc
+++ b/net/http/http_auth_handler_digest.cc
@@ -270,12 +270,12 @@ bool HttpAuthHandlerDigest::ParseChallengeProperty(const std::string& name,
 std::string HttpAuthHandlerDigest::QopToString(QualityOfProtection qop) {
   switch (qop) {
     case QOP_UNSPECIFIED:
-      return std::string();
+      return "";
     case QOP_AUTH:
       return "auth";
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
@@ -284,14 +284,14 @@ std::string HttpAuthHandlerDigest::AlgorithmToString(
     DigestAlgorithm algorithm) {
   switch (algorithm) {
     case ALGORITHM_UNSPECIFIED:
-      return std::string();
+      return "";
     case ALGORITHM_MD5:
       return "MD5";
     case ALGORITHM_MD5_SESS:
       return "MD5-sess";
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
diff --git a/net/http/http_auth_unittest.cc b/net/http/http_auth_unittest.cc
index ff63c9b..88c7f95 100644
--- a/net/http/http_auth_unittest.cc
+++ b/net/http/http_auth_unittest.cc
@@ -304,7 +304,7 @@ TEST(HttpAuthTest, ChallengeTokenizerMismatchedQuotesNoValue) {
   EXPECT_TRUE(parameters.GetNext());
   EXPECT_TRUE(parameters.valid());
   EXPECT_EQ(std::string("realm"), parameters.name());
-  EXPECT_EQ(std::string(), parameters.value());
+  EXPECT_EQ(std::string(""), parameters.value());
   EXPECT_FALSE(parameters.GetNext());
 }
 
diff --git a/net/http/http_cache.cc b/net/http/http_cache.cc
index 27c591d..a2a9dfc 100644
--- a/net/http/http_cache.cc
+++ b/net/http/http_cache.cc
@@ -445,7 +445,7 @@ int HttpCache::CreateBackend(disk_cache::Backend** backend,
 
   // This is the only operation that we can do that is not related to any given
   // entry, so we use an empty key for it.
-  PendingOp* pending_op = GetPendingOp(std::string());
+  PendingOp* pending_op = GetPendingOp("");
   if (pending_op->writer) {
     if (!callback.is_null())
       pending_op->pending_queue.push_back(item.release());
@@ -477,7 +477,7 @@ int HttpCache::GetBackendForTransaction(Transaction* trans) {
 
   WorkItem* item = new WorkItem(
       WI_CREATE_BACKEND, trans, net::CompletionCallback(), NULL);
-  PendingOp* pending_op = GetPendingOp(std::string());
+  PendingOp* pending_op = GetPendingOp("");
   DCHECK(pending_op->writer);
   pending_op->pending_queue.push_back(item);
   return ERR_IO_PENDING;
@@ -896,7 +896,7 @@ void HttpCache::RemovePendingTransaction(Transaction* trans) {
     return;
 
   if (building_backend_) {
-    PendingOpsMap::const_iterator j = pending_ops_.find(std::string());
+    PendingOpsMap::const_iterator j = pending_ops_.find("");
     if (j != pending_ops_.end())
       found = RemovePendingTransactionFromPendingOp(j->second, trans);
 
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index 467eb94..54d79f3 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -929,7 +929,7 @@ int HttpNetworkTransaction::DoReadHeadersComplete(int result) {
   // We treat any other 1xx in this same way (although in practice getting
   // a 1xx that isn't a 100 is rare).
   if (response_.headers->response_code() / 100 == 1) {
-    response_.headers = new HttpResponseHeaders(std::string());
+    response_.headers = new HttpResponseHeaders("");
     next_state_ = STATE_READ_HEADERS;
     return OK;
   }
diff --git a/net/http/http_network_transaction_spdy2_unittest.cc b/net/http/http_network_transaction_spdy2_unittest.cc
index 0da9f2e..3f81030 100644
--- a/net/http/http_network_transaction_spdy2_unittest.cc
+++ b/net/http/http_network_transaction_spdy2_unittest.cc
@@ -461,24 +461,12 @@ CaptureGroupNameHttpProxySocketPool::CaptureGroupNameSocketPool(
     CertVerifier* /* cert_verifier */)
     : HttpProxyClientSocketPool(0, 0, NULL, host_resolver, NULL, NULL, NULL) {}
 
-template <>
+template<>
 CaptureGroupNameSSLSocketPool::CaptureGroupNameSocketPool(
     HostResolver* host_resolver,
     CertVerifier* cert_verifier)
-    : SSLClientSocketPool(0,
-                          0,
-                          NULL,
-                          host_resolver,
-                          cert_verifier,
-                          NULL,
-                          NULL,
-                          std::string(),
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL) {}
+    : SSLClientSocketPool(0, 0, NULL, host_resolver, cert_verifier, NULL,
+                          NULL, "", NULL, NULL, NULL, NULL, NULL, NULL) {}
 
 //-----------------------------------------------------------------------------
 
@@ -8863,10 +8851,7 @@ TEST_F(HttpNetworkTransactionSpdy2Test,
   SSLClientSocketContext context;
   context.cert_verifier = session_deps.cert_verifier.get();
   ssl_connection->set_socket(session_deps.socket_factory->CreateSSLClientSocket(
-      connection.release(),
-      HostPortPair(std::string(), 443),
-      ssl_config,
-      context));
+      connection.release(), HostPortPair("" , 443), ssl_config, context));
   EXPECT_EQ(ERR_IO_PENDING,
             ssl_connection->socket()->Connect(callback.callback()));
   EXPECT_EQ(OK, callback.WaitForResult());
diff --git a/net/http/http_network_transaction_spdy3_unittest.cc b/net/http/http_network_transaction_spdy3_unittest.cc
index 8a90c7b..3076326 100644
--- a/net/http/http_network_transaction_spdy3_unittest.cc
+++ b/net/http/http_network_transaction_spdy3_unittest.cc
@@ -461,24 +461,12 @@ CaptureGroupNameHttpProxySocketPool::CaptureGroupNameSocketPool(
     CertVerifier* /* cert_verifier */)
     : HttpProxyClientSocketPool(0, 0, NULL, host_resolver, NULL, NULL, NULL) {}
 
-template <>
+template<>
 CaptureGroupNameSSLSocketPool::CaptureGroupNameSocketPool(
     HostResolver* host_resolver,
     CertVerifier* cert_verifier)
-    : SSLClientSocketPool(0,
-                          0,
-                          NULL,
-                          host_resolver,
-                          cert_verifier,
-                          NULL,
-                          NULL,
-                          std::string(),
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL) {}
+    : SSLClientSocketPool(0, 0, NULL, host_resolver, cert_verifier, NULL,
+                          NULL, "", NULL, NULL, NULL, NULL, NULL, NULL) {}
 
 //-----------------------------------------------------------------------------
 
@@ -8839,10 +8827,7 @@ TEST_F(HttpNetworkTransactionSpdy3Test,
   SSLClientSocketContext context;
   context.cert_verifier = session_deps.cert_verifier.get();
   ssl_connection->set_socket(session_deps.socket_factory->CreateSSLClientSocket(
-      connection.release(),
-      HostPortPair(std::string(), 443),
-      ssl_config,
-      context));
+      connection.release(), HostPortPair("" , 443), ssl_config, context));
   EXPECT_EQ(ERR_IO_PENDING,
             ssl_connection->socket()->Connect(callback.callback()));
   EXPECT_EQ(OK, callback.WaitForResult());
diff --git a/net/http/http_proxy_client_socket_pool_spdy2_unittest.cc b/net/http/http_proxy_client_socket_pool_spdy2_unittest.cc
index 48ac42c..77ccbed 100644
--- a/net/http/http_proxy_client_socket_pool_spdy2_unittest.cc
+++ b/net/http/http_proxy_client_socket_pool_spdy2_unittest.cc
@@ -47,37 +47,26 @@ class HttpProxyClientSocketPoolSpdy2Test : public TestWithHttpParam {
  protected:
   HttpProxyClientSocketPoolSpdy2Test()
       : ssl_config_(),
-        ignored_transport_socket_params_(
-            new TransportSocketParams(HostPortPair("proxy", 80),
-                                      LOWEST,
-                                      false,
-                                      false,
-                                      OnHostResolutionCallback())),
-        ignored_ssl_socket_params_(
-            new SSLSocketParams(ignored_transport_socket_params_,
-                                NULL,
-                                NULL,
-                                ProxyServer::SCHEME_DIRECT,
-                                HostPortPair("www.google.com", 443),
-                                ssl_config_,
-                                0,
-                                false,
-                                false)),
+        ignored_transport_socket_params_(new TransportSocketParams(
+            HostPortPair("proxy", 80), LOWEST, false, false,
+            OnHostResolutionCallback())),
+        ignored_ssl_socket_params_(new SSLSocketParams(
+            ignored_transport_socket_params_, NULL, NULL,
+            ProxyServer::SCHEME_DIRECT, HostPortPair("www.google.com", 443),
+            ssl_config_, 0, false, false)),
         tcp_histograms_("MockTCP"),
         transport_socket_pool_(
-            kMaxSockets,
-            kMaxSocketsPerGroup,
+            kMaxSockets, kMaxSocketsPerGroup,
             &tcp_histograms_,
             session_deps_.deterministic_socket_factory.get()),
         ssl_histograms_("MockSSL"),
-        ssl_socket_pool_(kMaxSockets,
-                         kMaxSocketsPerGroup,
+        ssl_socket_pool_(kMaxSockets, kMaxSocketsPerGroup,
                          &ssl_histograms_,
                          session_deps_.host_resolver.get(),
                          session_deps_.cert_verifier.get(),
                          NULL /* server_bound_cert_store */,
                          NULL /* transport_security_state */,
-                         std::string() /* ssl_session_cache_shard */,
+                         ""   /* ssl_session_cache_shard */,
                          session_deps_.deterministic_socket_factory.get(),
                          &transport_socket_pool_,
                          NULL,
@@ -88,13 +77,13 @@ class HttpProxyClientSocketPoolSpdy2Test : public TestWithHttpParam {
         http_proxy_histograms_("HttpProxyUnitTest"),
         ssl_data_(NULL),
         data_(NULL),
-        pool_(kMaxSockets,
-              kMaxSocketsPerGroup,
+        pool_(kMaxSockets, kMaxSocketsPerGroup,
               &http_proxy_histograms_,
               NULL,
               &transport_socket_pool_,
               &ssl_socket_pool_,
-              NULL) {}
+              NULL) {
+  }
 
   virtual ~HttpProxyClientSocketPoolSpdy2Test() {
   }
@@ -126,16 +115,17 @@ class HttpProxyClientSocketPoolSpdy2Test : public TestWithHttpParam {
   // Returns the a correctly constructed HttpProxyParms
   // for the HTTP or HTTPS proxy.
   scoped_refptr<HttpProxySocketParams> GetParams(bool tunnel) {
-    return scoped_refptr<HttpProxySocketParams>(new HttpProxySocketParams(
-        GetTcpParams(),
-        GetSslParams(),
-        GURL(tunnel ? "https://www.google.com/" : "http://www.google.com"),
-        std::string(),
-        HostPortPair("www.google.com", tunnel ? 443 : 80),
-        session_->http_auth_cache(),
-        session_->http_auth_handler_factory(),
-        session_->spdy_session_pool(),
-        tunnel));
+    return scoped_refptr<HttpProxySocketParams>(
+        new HttpProxySocketParams(
+            GetTcpParams(),
+            GetSslParams(),
+            GURL(tunnel ? "https://www.google.com/" : "http://www.google.com"),
+            "",
+            HostPortPair("www.google.com", tunnel ? 443 : 80),
+            session_->http_auth_cache(),
+            session_->http_auth_handler_factory(),
+            session_->spdy_session_pool(),
+            tunnel));
   }
 
   scoped_refptr<HttpProxySocketParams> GetTunnelParams() {
diff --git a/net/http/http_proxy_client_socket_pool_spdy3_unittest.cc b/net/http/http_proxy_client_socket_pool_spdy3_unittest.cc
index 36e5869..86924fc 100644
--- a/net/http/http_proxy_client_socket_pool_spdy3_unittest.cc
+++ b/net/http/http_proxy_client_socket_pool_spdy3_unittest.cc
@@ -47,37 +47,26 @@ class HttpProxyClientSocketPoolSpdy3Test : public TestWithHttpParam {
  protected:
   HttpProxyClientSocketPoolSpdy3Test()
       : ssl_config_(),
-        ignored_transport_socket_params_(
-            new TransportSocketParams(HostPortPair("proxy", 80),
-                                      LOWEST,
-                                      false,
-                                      false,
-                                      OnHostResolutionCallback())),
-        ignored_ssl_socket_params_(
-            new SSLSocketParams(ignored_transport_socket_params_,
-                                NULL,
-                                NULL,
-                                ProxyServer::SCHEME_DIRECT,
-                                HostPortPair("www.google.com", 443),
-                                ssl_config_,
-                                0,
-                                false,
-                                false)),
+        ignored_transport_socket_params_(new TransportSocketParams(
+            HostPortPair("proxy", 80), LOWEST, false, false,
+            OnHostResolutionCallback())),
+        ignored_ssl_socket_params_(new SSLSocketParams(
+            ignored_transport_socket_params_, NULL, NULL,
+            ProxyServer::SCHEME_DIRECT, HostPortPair("www.google.com", 443),
+            ssl_config_, 0, false, false)),
         tcp_histograms_("MockTCP"),
         transport_socket_pool_(
-            kMaxSockets,
-            kMaxSocketsPerGroup,
+            kMaxSockets, kMaxSocketsPerGroup,
             &tcp_histograms_,
             session_deps_.deterministic_socket_factory.get()),
         ssl_histograms_("MockSSL"),
-        ssl_socket_pool_(kMaxSockets,
-                         kMaxSocketsPerGroup,
+        ssl_socket_pool_(kMaxSockets, kMaxSocketsPerGroup,
                          &ssl_histograms_,
                          session_deps_.host_resolver.get(),
                          session_deps_.cert_verifier.get(),
                          NULL /* server_bound_cert_store */,
                          NULL /* transport_security_state */,
-                         std::string() /* ssl_session_cache_shard */,
+                         ""   /* ssl_session_cache_shard */,
                          session_deps_.deterministic_socket_factory.get(),
                          &transport_socket_pool_,
                          NULL,
@@ -88,13 +77,13 @@ class HttpProxyClientSocketPoolSpdy3Test : public TestWithHttpParam {
         http_proxy_histograms_("HttpProxyUnitTest"),
         ssl_data_(NULL),
         data_(NULL),
-        pool_(kMaxSockets,
-              kMaxSocketsPerGroup,
+        pool_(kMaxSockets, kMaxSocketsPerGroup,
               &http_proxy_histograms_,
               NULL,
               &transport_socket_pool_,
               &ssl_socket_pool_,
-              NULL) {}
+              NULL) {
+  }
 
   virtual ~HttpProxyClientSocketPoolSpdy3Test() {
   }
@@ -126,16 +115,17 @@ class HttpProxyClientSocketPoolSpdy3Test : public TestWithHttpParam {
   // Returns the a correctly constructed HttpProxyParms
   // for the HTTP or HTTPS proxy.
   scoped_refptr<HttpProxySocketParams> GetParams(bool tunnel) {
-    return scoped_refptr<HttpProxySocketParams>(new HttpProxySocketParams(
-        GetTcpParams(),
-        GetSslParams(),
-        GURL(tunnel ? "https://www.google.com/" : "http://www.google.com"),
-        std::string(),
-        HostPortPair("www.google.com", tunnel ? 443 : 80),
-        session_->http_auth_cache(),
-        session_->http_auth_handler_factory(),
-        session_->spdy_session_pool(),
-        tunnel));
+    return scoped_refptr<HttpProxySocketParams>(
+        new HttpProxySocketParams(
+            GetTcpParams(),
+            GetSslParams(),
+            GURL(tunnel ? "https://www.google.com/" : "http://www.google.com"),
+            "",
+            HostPortPair("www.google.com", tunnel ? 443 : 80),
+            session_->http_auth_cache(),
+            session_->http_auth_handler_factory(),
+            session_->spdy_session_pool(),
+            tunnel));
   }
 
   scoped_refptr<HttpProxySocketParams> GetTunnelParams() {
diff --git a/net/http/http_security_headers_unittest.cc b/net/http/http_security_headers_unittest.cc
index 4f1e580..a142486 100644
--- a/net/http/http_security_headers_unittest.cc
+++ b/net/http/http_security_headers_unittest.cc
@@ -51,8 +51,7 @@ TEST_F(HttpSecurityHeadersTest, BogusHeaders) {
   base::Time expiry = now;
   bool include_subdomains = false;
 
-  EXPECT_FALSE(
-      ParseHSTSHeader(now, std::string(), &expiry, &include_subdomains));
+  EXPECT_FALSE(ParseHSTSHeader(now, "", &expiry, &include_subdomains));
   EXPECT_FALSE(ParseHSTSHeader(now, "    ", &expiry, &include_subdomains));
   EXPECT_FALSE(ParseHSTSHeader(now, "abc", &expiry, &include_subdomains));
   EXPECT_FALSE(ParseHSTSHeader(now, "  abc", &expiry, &include_subdomains));
@@ -136,8 +135,7 @@ static void TestBogusPinsHeaders(HashValueTag tag) {
   std::string good_pin = GetTestPin(2, tag);
   std::string backup_pin = GetTestPin(4, tag);
 
-  EXPECT_FALSE(
-      ParseHPKPHeader(now, std::string(), chain_hashes, &expiry, &hashes));
+  EXPECT_FALSE(ParseHPKPHeader(now, "", chain_hashes, &expiry, &hashes));
   EXPECT_FALSE(ParseHPKPHeader(now, "    ", chain_hashes, &expiry, &hashes));
   EXPECT_FALSE(ParseHPKPHeader(now, "abc", chain_hashes, &expiry, &hashes));
   EXPECT_FALSE(ParseHPKPHeader(now, "  abc", chain_hashes, &expiry, &hashes));
diff --git a/net/http/http_server_properties_impl_unittest.cc b/net/http/http_server_properties_impl_unittest.cc
index b9ef0bf..8dc9de3 100644
--- a/net/http/http_server_properties_impl_unittest.cc
+++ b/net/http/http_server_properties_impl_unittest.cc
@@ -65,7 +65,7 @@ TEST_F(SpdyServerPropertiesTest, Initialize) {
 }
 
 TEST_F(SpdyServerPropertiesTest, SupportsSpdyTest) {
-  HostPortPair spdy_server_empty(std::string(), 443);
+  HostPortPair spdy_server_empty("", 443);
   EXPECT_FALSE(impl_.SupportsSpdy(spdy_server_empty));
 
   // Add www.google.com:443 as supporting SPDY.
@@ -89,7 +89,7 @@ TEST_F(SpdyServerPropertiesTest, SupportsSpdyTest) {
 }
 
 TEST_F(SpdyServerPropertiesTest, SetSupportsSpdy) {
-  HostPortPair spdy_server_empty(std::string(), 443);
+  HostPortPair spdy_server_empty("", 443);
   impl_.SetSupportsSpdy(spdy_server_empty, true);
   EXPECT_FALSE(impl_.SupportsSpdy(spdy_server_empty));
 
@@ -134,7 +134,7 @@ TEST_F(SpdyServerPropertiesTest, GetSpdyServerList) {
   EXPECT_EQ(0U, spdy_server_list.GetSize());
 
   // Check empty server is not added.
-  HostPortPair spdy_server_empty(std::string(), 443);
+  HostPortPair spdy_server_empty("", 443);
   impl_.SetSupportsSpdy(spdy_server_empty, true);
   impl_.GetSpdyServerList(&spdy_server_list);
   EXPECT_EQ(0U, spdy_server_list.GetSize());
@@ -303,7 +303,7 @@ TEST_F(SpdySettingsServerPropertiesTest, Initialize) {
 }
 
 TEST_F(SpdySettingsServerPropertiesTest, SetSpdySetting) {
-  HostPortPair spdy_server_empty(std::string(), 443);
+  HostPortPair spdy_server_empty("", 443);
   const SettingsMap& settings_map0 = impl_.GetSpdySettings(spdy_server_empty);
   EXPECT_EQ(0U, settings_map0.size());  // Returns kEmptySettingsMap.
 
diff --git a/net/http/http_stream_factory_impl_unittest.cc b/net/http/http_stream_factory_impl_unittest.cc
index f228d9a..0a9437f 100644
--- a/net/http/http_stream_factory_impl_unittest.cc
+++ b/net/http/http_stream_factory_impl_unittest.cc
@@ -271,24 +271,11 @@ CapturePreconnectsHttpProxySocketPool::CapturePreconnectsSocketPool(
     : HttpProxyClientSocketPool(0, 0, NULL, host_resolver, NULL, NULL, NULL),
       last_num_streams_(-1) {}
 
-template <>
+template<>
 CapturePreconnectsSSLSocketPool::CapturePreconnectsSocketPool(
-    HostResolver* host_resolver,
-    CertVerifier* cert_verifier)
-    : SSLClientSocketPool(0,
-                          0,
-                          NULL,
-                          host_resolver,
-                          cert_verifier,
-                          NULL,
-                          NULL,
-                          std::string(),
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL,
-                          NULL),
+    HostResolver* host_resolver, CertVerifier* cert_verifier)
+    : SSLClientSocketPool(0, 0, NULL, host_resolver, cert_verifier, NULL,
+                          NULL, "", NULL, NULL, NULL, NULL, NULL, NULL),
       last_num_streams_(-1) {}
 
 TEST(HttpStreamFactoryTest, PreconnectDirect) {
diff --git a/net/http/http_util_unittest.cc b/net/http/http_util_unittest.cc
index f86821c..083343d 100644
--- a/net/http/http_util_unittest.cc
+++ b/net/http/http_util_unittest.cc
@@ -966,12 +966,12 @@ TEST(HttpUtilTest, NameValuePairsIteratorCopyAndAssign) {
 }
 
 TEST(HttpUtilTest, NameValuePairsIteratorEmptyInput) {
-  std::string data;
+  std::string data = "";
   HttpUtil::NameValuePairsIterator parser(data.begin(), data.end(), ';');
 
   EXPECT_TRUE(parser.valid());
-  ASSERT_NO_FATAL_FAILURE(CheckNextNameValuePair(
-      &parser, false, true, std::string(), std::string()));
+  ASSERT_NO_FATAL_FAILURE(
+      CheckNextNameValuePair(&parser, false, true, "", ""));
 }
 
 TEST(HttpUtilTest, NameValuePairsIterator) {
@@ -997,19 +997,19 @@ TEST(HttpUtilTest, NameValuePairsIterator) {
   ASSERT_NO_FATAL_FAILURE(
       CheckNextNameValuePair(&parser, true, true, "f", "'hello world'"));
   ASSERT_NO_FATAL_FAILURE(
-      CheckNextNameValuePair(&parser, true, true, "g", std::string()));
+      CheckNextNameValuePair(&parser, true, true, "g", ""));
   ASSERT_NO_FATAL_FAILURE(
       CheckNextNameValuePair(&parser, true, true, "h", "hello"));
-  ASSERT_NO_FATAL_FAILURE(CheckNextNameValuePair(
-      &parser, false, true, std::string(), std::string()));
+  ASSERT_NO_FATAL_FAILURE(
+      CheckNextNameValuePair(&parser, false, true, "", ""));
 }
 
 TEST(HttpUtilTest, NameValuePairsIteratorIllegalInputs) {
   ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair("alpha=1", "; beta"));
-  ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair(std::string(), "beta"));
+  ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair("", "beta"));
 
   ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair("alpha=1", "; 'beta'=2"));
-  ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair(std::string(), "'beta'=2"));
+  ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair("", "'beta'=2"));
   ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair("alpha=1", ";beta="));
   ASSERT_NO_FATAL_FAILURE(CheckInvalidNameValuePair("alpha=1",
                                                     ";beta=;cappa=2"));
@@ -1033,8 +1033,8 @@ TEST(HttpUtilTest, NameValuePairsIteratorExtraSeparators) {
       CheckNextNameValuePair(&parser, true, true, "beta", "2"));
   ASSERT_NO_FATAL_FAILURE(
       CheckNextNameValuePair(&parser, true, true, "cappa", "3"));
-  ASSERT_NO_FATAL_FAILURE(CheckNextNameValuePair(
-      &parser, false, true, std::string(), std::string()));
+  ASSERT_NO_FATAL_FAILURE(
+      CheckNextNameValuePair(&parser, false, true, "", ""));
 }
 
 // See comments on the implementation of NameValuePairsIterator::GetNext
@@ -1046,6 +1046,6 @@ TEST(HttpUtilTest, NameValuePairsIteratorMissingEndQuote) {
 
   ASSERT_NO_FATAL_FAILURE(
       CheckNextNameValuePair(&parser, true, true, "name", "value"));
-  ASSERT_NO_FATAL_FAILURE(CheckNextNameValuePair(
-      &parser, false, true, std::string(), std::string()));
+  ASSERT_NO_FATAL_FAILURE(
+      CheckNextNameValuePair(&parser, false, true, "", ""));
 }
diff --git a/net/http/http_vary_data.cc b/net/http/http_vary_data.cc
index 51b74a4..c716ca0 100644
--- a/net/http/http_vary_data.cc
+++ b/net/http/http_vary_data.cc
@@ -105,7 +105,7 @@ std::string HttpVaryData::GetRequestValue(
   if (request_info.extra_headers.GetHeader(request_header, &result))
     return result;
 
-  return std::string();
+  return "";
 }
 
 // static
diff --git a/net/http/http_vary_data_unittest.cc b/net/http/http_vary_data_unittest.cc
index 93ee4f45..38e4e32 100644
--- a/net/http/http_vary_data_unittest.cc
+++ b/net/http/http_vary_data_unittest.cc
@@ -41,7 +41,7 @@ TEST(HttpVaryDataTest, IsInvalid) {
 
   for (size_t i = 0; i < arraysize(kTestResponses); ++i) {
     TestTransaction t;
-    t.Init(std::string(), kTestResponses[i]);
+    t.Init("", kTestResponses[i]);
 
     net::HttpVaryData v;
     EXPECT_FALSE(v.is_valid());
diff --git a/net/proxy/dhcp_proxy_script_fetcher.cc b/net/proxy/dhcp_proxy_script_fetcher.cc
index 1771be0..4771d9d 100644
--- a/net/proxy/dhcp_proxy_script_fetcher.cc
+++ b/net/proxy/dhcp_proxy_script_fetcher.cc
@@ -9,7 +9,7 @@
 namespace net {
 
 std::string DhcpProxyScriptFetcher::GetFetcherName() const {
-  return std::string();
+  return "";
 }
 
 DhcpProxyScriptFetcher::DhcpProxyScriptFetcher() {}
diff --git a/net/proxy/proxy_resolver_v8_tracing_unittest.cc b/net/proxy/proxy_resolver_v8_tracing_unittest.cc
index 5e0e108..b5503e5 100644
--- a/net/proxy/proxy_resolver_v8_tracing_unittest.cc
+++ b/net/proxy/proxy_resolver_v8_tracing_unittest.cc
@@ -282,8 +282,7 @@ TEST_F(ProxyResolverV8TracingTest, Dns) {
 
   host_resolver.rules()->AddRuleForAddressFamily(
       "host1", ADDRESS_FAMILY_IPV4, "166.155.144.44");
-  host_resolver.rules()
-      ->AddIPLiteralRule("host1", "::1,192.168.1.1", std::string());
+  host_resolver.rules()->AddIPLiteralRule("host1", "::1,192.168.1.1", "");
   host_resolver.rules()->AddSimulatedFailure("host2");
   host_resolver.rules()->AddRule("host3", "166.155.144.33");
   host_resolver.rules()->AddRule("host5", "166.155.144.55");
@@ -996,8 +995,7 @@ TEST_F(ProxyResolverV8TracingTest, MultipleResolvers) {
   MockHostResolver host_resolver0;
   host_resolver0.rules()->AddRuleForAddressFamily(
       "host1", ADDRESS_FAMILY_IPV4, "166.155.144.44");
-  host_resolver0.rules()
-      ->AddIPLiteralRule("host1", "::1,192.168.1.1", std::string());
+  host_resolver0.rules()->AddIPLiteralRule("host1", "::1,192.168.1.1", "");
   host_resolver0.rules()->AddSimulatedFailure("host2");
   host_resolver0.rules()->AddRule("host3", "166.155.144.33");
   host_resolver0.rules()->AddRule("host5", "166.155.144.55");
diff --git a/net/proxy/proxy_service_unittest.cc b/net/proxy/proxy_service_unittest.cc
index 53cc326..ec4a0fa 100644
--- a/net/proxy/proxy_service_unittest.cc
+++ b/net/proxy/proxy_service_unittest.cc
@@ -1723,7 +1723,7 @@ TEST_F(ProxyServiceTest, FallbackFromAutodetectToCustomPac) {
   // the script download.
   EXPECT_TRUE(fetcher->has_pending_request());
   EXPECT_EQ(GURL("http://wpad/wpad.dat"), fetcher->pending_request_url());
-  fetcher->NotifyFetchCompletion(ERR_FAILED, std::string());
+  fetcher->NotifyFetchCompletion(ERR_FAILED, "");
 
   // Next it should be trying the custom PAC url.
   EXPECT_TRUE(fetcher->has_pending_request());
@@ -1872,12 +1872,12 @@ TEST_F(ProxyServiceTest, FallbackFromAutodetectToCustomToManual) {
   // It should be trying to auto-detect first -- fail the download.
   EXPECT_TRUE(fetcher->has_pending_request());
   EXPECT_EQ(GURL("http://wpad/wpad.dat"), fetcher->pending_request_url());
-  fetcher->NotifyFetchCompletion(ERR_FAILED, std::string());
+  fetcher->NotifyFetchCompletion(ERR_FAILED, "");
 
   // Next it should be trying the custom PAC url -- fail the download.
   EXPECT_TRUE(fetcher->has_pending_request());
   EXPECT_EQ(GURL("http://foopy/proxy.pac"), fetcher->pending_request_url());
-  fetcher->NotifyFetchCompletion(ERR_FAILED, std::string());
+  fetcher->NotifyFetchCompletion(ERR_FAILED, "");
 
   // Since we never managed to initialize a ProxyResolver, nothing should have
   // been sent to it.
@@ -2251,7 +2251,7 @@ TEST_F(ProxyServiceTest, PACScriptRefetchAfterFailure) {
   //
   // We simulate a failed download attempt, the proxy service should now
   // fall-back to DIRECT connections.
-  fetcher->NotifyFetchCompletion(ERR_FAILED, std::string());
+  fetcher->NotifyFetchCompletion(ERR_FAILED, "");
 
   ASSERT_TRUE(resolver->pending_requests().empty());
 
@@ -2604,7 +2604,7 @@ TEST_F(ProxyServiceTest, PACScriptRefetchAfterSuccess) {
   // to download the script.
   EXPECT_TRUE(fetcher->has_pending_request());
   EXPECT_EQ(GURL("http://foopy/proxy.pac"), fetcher->pending_request_url());
-  fetcher->NotifyFetchCompletion(ERR_FAILED, std::string());
+  fetcher->NotifyFetchCompletion(ERR_FAILED, "");
 
   MessageLoop::current()->RunUntilIdle();
 
@@ -2771,7 +2771,7 @@ TEST_F(ProxyServiceTest, PACScriptRefetchAfterActivity) {
   EXPECT_EQ(GURL("http://foopy/proxy.pac"), fetcher->pending_request_url());
 
   // This time we will fail the download, to simulate a PAC script change.
-  fetcher->NotifyFetchCompletion(ERR_FAILED, std::string());
+  fetcher->NotifyFetchCompletion(ERR_FAILED, "");
 
   // Drain the message loop, so ProxyService is notified of the change
   // and has a chance to re-configure itself.
diff --git a/net/quic/quic_http_stream_test.cc b/net/quic/quic_http_stream_test.cc
index 1370ced..f3f4c33 100644
--- a/net/quic/quic_http_stream_test.cc
+++ b/net/quic/quic_http_stream_test.cc
@@ -348,7 +348,7 @@ TEST_F(QuicHttpStreamTest, GetRequest) {
             stream_->ReadResponseHeaders(callback_.callback()));
 
   // Send the response without a body.
-  SetResponseString("404 Not Found", std::string());
+  SetResponseString("404 Not Found", "");
   scoped_ptr<QuicEncryptedPacket> resp(
       ConstructDataPacket(2, false, kFin, 0, response_data_));
   ProcessPacket(*resp);
@@ -440,7 +440,7 @@ TEST_F(QuicHttpStreamTest, SendPostRequest) {
   ProcessPacket(*ack);
 
   // Send the response headers (but not the body).
-  SetResponseString("200 OK", std::string());
+  SetResponseString("200 OK", "");
   scoped_ptr<QuicEncryptedPacket> resp(
       ConstructDataPacket(2, false, !kFin, 0, response_data_));
   ProcessPacket(*resp);
@@ -502,7 +502,7 @@ TEST_F(QuicHttpStreamTest, SendChunkedPostRequest) {
   ProcessPacket(*ack);
 
   // Send the response headers (but not the body).
-  SetResponseString("200 OK", std::string());
+  SetResponseString("200 OK", "");
   scoped_ptr<QuicEncryptedPacket> resp(
       ConstructDataPacket(2, false, !kFin, 0, response_data_));
   ProcessPacket(*resp);
diff --git a/net/quic/quic_packet_creator_test.cc b/net/quic/quic_packet_creator_test.cc
index 2f4e2e9..5e7ed61 100644
--- a/net/quic/quic_packet_creator_test.cc
+++ b/net/quic/quic_packet_creator_test.cc
@@ -180,7 +180,7 @@ TEST_F(QuicPacketCreatorTest, CreateStreamFrameFinOnly) {
   QuicFrame frame;
   size_t consumed = creator_.CreateStreamFrame(1u, "", 0u, true, &frame);
   EXPECT_EQ(0u, consumed);
-  CheckStreamFrame(frame, 1u, std::string(), 0u, true);
+  CheckStreamFrame(frame, 1u, "", 0u, true);
   delete frame.stream_frame;
 }
 
diff --git a/net/quic/quic_packet_generator_test.cc b/net/quic/quic_packet_generator_test.cc
index 4e84d0b..c7e2918 100644
--- a/net/quic/quic_packet_generator_test.cc
+++ b/net/quic/quic_packet_generator_test.cc
@@ -120,7 +120,7 @@ class QuicPacketGeneratorTest : public ::testing::Test {
   }
 
   QuicGoAwayFrame* CreateGoAwayFrame() {
-    return new QuicGoAwayFrame(QUIC_NO_ERROR, 1, std::string());
+    return new QuicGoAwayFrame(QUIC_NO_ERROR, 1, "");
   }
 
   void CheckPacketContains(const PacketContents& contents,
diff --git a/net/server/http_server.cc b/net/server/http_server.cc
index a0c9a3a..4f1fb08 100644
--- a/net/server/http_server.cc
+++ b/net/server/http_server.cc
@@ -62,7 +62,7 @@ void HttpServer::Send200(int connection_id,
 }
 
 void HttpServer::Send404(int connection_id) {
-  Send(connection_id, HTTP_NOT_FOUND, std::string(), "text/html");
+  Send(connection_id, HTTP_NOT_FOUND, "", "text/html");
 }
 
 void HttpServer::Send500(int connection_id, const std::string& message) {
diff --git a/net/server/http_server_request_info.cc b/net/server/http_server_request_info.cc
index 08b925f..eda597a 100644
--- a/net/server/http_server_request_info.cc
+++ b/net/server/http_server_request_info.cc
@@ -16,7 +16,7 @@ std::string HttpServerRequestInfo::GetHeaderValue(
       headers.find(header_name);
   if (it != headers.end())
     return it->second;
-  return std::string();
+  return "";
 }
 
 }  // namespace net
diff --git a/net/socket/client_socket_pool_base_unittest.cc b/net/socket/client_socket_pool_base_unittest.cc
index bc64306..0628d91 100644
--- a/net/socket/client_socket_pool_base_unittest.cc
+++ b/net/socket/client_socket_pool_base_unittest.cc
@@ -274,7 +274,7 @@ class TestConnectJob : public ConnectJob {
       // Set all of the additional error state fields in some way.
       handle->set_is_ssl_error(true);
       HttpResponseInfo info;
-      info.headers = new HttpResponseHeaders(std::string());
+      info.headers = new HttpResponseHeaders("");
       handle->set_ssl_error_response_info(info);
     }
   }
@@ -846,7 +846,7 @@ TEST_F(ClientSocketPoolBaseTest, InitConnectionFailure) {
   // Set the additional error state members to ensure that they get cleared.
   handle.set_is_ssl_error(true);
   HttpResponseInfo info;
-  info.headers = new HttpResponseHeaders(std::string());
+  info.headers = new HttpResponseHeaders("");
   handle.set_ssl_error_response_info(info);
   EXPECT_EQ(ERR_CONNECTION_FAILED,
             handle.Init("a",
@@ -1720,7 +1720,7 @@ TEST_F(ClientSocketPoolBaseTest,
   // Set the additional error state members to ensure that they get cleared.
   handle.set_is_ssl_error(true);
   HttpResponseInfo info;
-  info.headers = new HttpResponseHeaders(std::string());
+  info.headers = new HttpResponseHeaders("");
   handle.set_ssl_error_response_info(info);
   EXPECT_EQ(ERR_IO_PENDING, handle.Init("a",
                                         params_,
diff --git a/net/socket/deterministic_socket_data_unittest.cc b/net/socket/deterministic_socket_data_unittest.cc
index aea8160..a007e36 100644
--- a/net/socket/deterministic_socket_data_unittest.cc
+++ b/net/socket/deterministic_socket_data_unittest.cc
@@ -77,8 +77,9 @@ DeterministicSocketDataTest::DeterministicSocketDataTest()
                                             false,
                                             false,
                                             OnHostResolutionCallback())),
-      histograms_(std::string()),
-      socket_pool_(10, 10, &histograms_, &socket_factory_) {}
+      histograms_(""),
+      socket_pool_(10, 10, &histograms_, &socket_factory_) {
+}
 
 void DeterministicSocketDataTest::TearDown() {
   // Empty the current queue.
diff --git a/net/socket/ssl_client_socket_pool_unittest.cc b/net/socket/ssl_client_socket_pool_unittest.cc
index fe7e3d2..c188a80 100644
--- a/net/socket/ssl_client_socket_pool_unittest.cc
+++ b/net/socket/ssl_client_socket_pool_unittest.cc
@@ -79,54 +79,46 @@ class SSLClientSocketPoolTest : public testing::Test {
   SSLClientSocketPoolTest()
       : proxy_service_(ProxyService::CreateDirect()),
         ssl_config_service_(new SSLConfigServiceDefaults),
-        http_auth_handler_factory_(
-            HttpAuthHandlerFactory::CreateDefault(&host_resolver_)),
+        http_auth_handler_factory_(HttpAuthHandlerFactory::CreateDefault(
+            &host_resolver_)),
         session_(CreateNetworkSession()),
-        direct_transport_socket_params_(
-            new TransportSocketParams(HostPortPair("host", 443),
-                                      MEDIUM,
-                                      false,
-                                      false,
-                                      OnHostResolutionCallback())),
+        direct_transport_socket_params_(new TransportSocketParams(
+            HostPortPair("host", 443), MEDIUM, false, false,
+            OnHostResolutionCallback())),
         transport_histograms_("MockTCP"),
-        transport_socket_pool_(kMaxSockets,
-                               kMaxSocketsPerGroup,
-                               &transport_histograms_,
-                               &socket_factory_),
-        proxy_transport_socket_params_(
-            new TransportSocketParams(HostPortPair("proxy", 443),
-                                      MEDIUM,
-                                      false,
-                                      false,
-                                      OnHostResolutionCallback())),
-        socks_socket_params_(
-            new SOCKSSocketParams(proxy_transport_socket_params_,
-                                  true,
-                                  HostPortPair("sockshost", 443),
-                                  MEDIUM)),
+        transport_socket_pool_(
+            kMaxSockets,
+            kMaxSocketsPerGroup,
+            &transport_histograms_,
+            &socket_factory_),
+        proxy_transport_socket_params_(new TransportSocketParams(
+            HostPortPair("proxy", 443), MEDIUM, false, false,
+            OnHostResolutionCallback())),
+        socks_socket_params_(new SOCKSSocketParams(
+            proxy_transport_socket_params_, true,
+            HostPortPair("sockshost", 443), MEDIUM)),
         socks_histograms_("MockSOCKS"),
-        socks_socket_pool_(kMaxSockets,
-                           kMaxSocketsPerGroup,
-                           &socks_histograms_,
-                           &transport_socket_pool_),
-        http_proxy_socket_params_(
-            new HttpProxySocketParams(proxy_transport_socket_params_,
-                                      NULL,
-                                      GURL("http://host"),
-                                      std::string(),
-                                      HostPortPair("host", 80),
-                                      session_->http_auth_cache(),
-                                      session_->http_auth_handler_factory(),
-                                      session_->spdy_session_pool(),
-                                      true)),
+        socks_socket_pool_(
+            kMaxSockets,
+            kMaxSocketsPerGroup,
+            &socks_histograms_,
+            &transport_socket_pool_),
+        http_proxy_socket_params_(new HttpProxySocketParams(
+            proxy_transport_socket_params_, NULL, GURL("http://host"), "",
+            HostPortPair("host", 80),
+            session_->http_auth_cache(),
+            session_->http_auth_handler_factory(),
+            session_->spdy_session_pool(),
+            true)),
         http_proxy_histograms_("MockHttpProxy"),
-        http_proxy_socket_pool_(kMaxSockets,
-                                kMaxSocketsPerGroup,
-                                &http_proxy_histograms_,
-                                &host_resolver_,
-                                &transport_socket_pool_,
-                                NULL,
-                                NULL) {
+        http_proxy_socket_pool_(
+            kMaxSockets,
+            kMaxSocketsPerGroup,
+            &http_proxy_histograms_,
+            &host_resolver_,
+            &transport_socket_pool_,
+            NULL,
+            NULL) {
     scoped_refptr<SSLConfigService> ssl_config_service(
         new SSLConfigServiceDefaults);
     ssl_config_service->GetSSLConfig(&ssl_config_);
@@ -142,7 +134,7 @@ class SSLClientSocketPoolTest : public testing::Test {
         NULL /* cert_verifier */,
         NULL /* server_bound_cert_service */,
         NULL /* transport_security_state */,
-        std::string() /* ssl_session_cache_shard */,
+        ""   /* ssl_session_cache_shard */,
         &socket_factory_,
         transport_pool ? &transport_socket_pool_ : NULL,
         socks_pool ? &socks_socket_pool_ : NULL,
@@ -730,8 +722,8 @@ TEST_F(SSLClientSocketPoolTest, IPPooling) {
 
   host_resolver_.set_synchronous_mode(true);
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_hosts); i++) {
-    host_resolver_.rules()->AddIPLiteralRule(
-        test_hosts[i].name, test_hosts[i].iplist, std::string());
+    host_resolver_.rules()->AddIPLiteralRule(test_hosts[i].name,
+        test_hosts[i].iplist, "");
 
     // This test requires that the HostResolver cache be populated.  Normal
     // code would have done this already, but we do it manually.
@@ -813,8 +805,8 @@ void SSLClientSocketPoolTest::TestIPPoolingDisabled(
   TestCompletionCallback callback;
   int rv;
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_hosts); i++) {
-    host_resolver_.rules()->AddIPLiteralRule(
-        test_hosts[i].name, test_hosts[i].iplist, std::string());
+    host_resolver_.rules()->AddIPLiteralRule(test_hosts[i].name,
+        test_hosts[i].iplist, "");
 
     // This test requires that the HostResolver cache be populated.  Normal
     // code would have done this already, but we do it manually.
diff --git a/net/socket/transport_client_socket_pool_unittest.cc b/net/socket/transport_client_socket_pool_unittest.cc
index 9d95a1b..eba7c26 100644
--- a/net/socket/transport_client_socket_pool_unittest.cc
+++ b/net/socket/transport_client_socket_pool_unittest.cc
@@ -1210,8 +1210,8 @@ TEST_F(TransportClientSocketPoolTest, IPv6FallbackSocketIPv4FinishesFirst) {
   client_socket_factory_.set_client_socket_types(case_types, 2);
 
   // Resolve an AddressList with a IPv6 address first and then a IPv4 address.
-  host_resolver_->rules()
-      ->AddIPLiteralRule("*", "2:abcd::3:4:ff,2.2.2.2", std::string());
+  host_resolver_->rules()->AddIPLiteralRule(
+      "*", "2:abcd::3:4:ff,2.2.2.2", "");
 
   TestCompletionCallback callback;
   ClientSocketHandle handle;
@@ -1255,8 +1255,8 @@ TEST_F(TransportClientSocketPoolTest, IPv6FallbackSocketIPv6FinishesFirst) {
       TransportConnectJob::kIPv6FallbackTimerInMs + 50));
 
   // Resolve an AddressList with a IPv6 address first and then a IPv4 address.
-  host_resolver_->rules()
-      ->AddIPLiteralRule("*", "2:abcd::3:4:ff,2.2.2.2", std::string());
+  host_resolver_->rules()->AddIPLiteralRule(
+      "*", "2:abcd::3:4:ff,2.2.2.2", "");
 
   TestCompletionCallback callback;
   ClientSocketHandle handle;
@@ -1289,8 +1289,8 @@ TEST_F(TransportClientSocketPoolTest, IPv6NoIPv4AddressesToFallbackTo) {
       MockClientSocketFactory::MOCK_DELAYED_CLIENT_SOCKET);
 
   // Resolve an AddressList with only IPv6 addresses.
-  host_resolver_->rules()
-      ->AddIPLiteralRule("*", "2:abcd::3:4:ff,3:abcd::3:4:ff", std::string());
+  host_resolver_->rules()->AddIPLiteralRule(
+      "*", "2:abcd::3:4:ff,3:abcd::3:4:ff", "");
 
   TestCompletionCallback callback;
   ClientSocketHandle handle;
@@ -1323,7 +1323,8 @@ TEST_F(TransportClientSocketPoolTest, IPv4HasNoFallback) {
       MockClientSocketFactory::MOCK_DELAYED_CLIENT_SOCKET);
 
   // Resolve an AddressList with only IPv4 addresses.
-  host_resolver_->rules()->AddIPLiteralRule("*", "1.1.1.1", std::string());
+  host_resolver_->rules()->AddIPLiteralRule(
+      "*", "1.1.1.1", "");
 
   TestCompletionCallback callback;
   ClientSocketHandle handle;
diff --git a/net/spdy/spdy_framer_test.cc b/net/spdy/spdy_framer_test.cc
index 3ae8871a..46d44c9 100644
--- a/net/spdy/spdy_framer_test.cc
+++ b/net/spdy/spdy_framer_test.cc
@@ -1826,7 +1826,7 @@ TEST_P(SpdyFramerTest, CreateSynStreamUncompressed) {
         "max stream ID";
 
     SpdyHeaderBlock headers;
-    headers[std::string()] = "foo";
+    headers[""] = "foo";
     headers["foo"] = "bar";
 
     const unsigned char kV2FrameData[] = {
@@ -2103,7 +2103,7 @@ TEST_P(SpdyFramerTest, CreateSynReplyUncompressed) {
         "SYN_REPLY frame with a 0-length header name, FIN, max stream ID";
 
     SpdyHeaderBlock headers;
-    headers[std::string()] = "foo";
+    headers[""] = "foo";
     headers["foo"] = "bar";
 
     const unsigned char kV2FrameData[] = {
@@ -2619,7 +2619,7 @@ TEST_P(SpdyFramerTest, CreateHeadersUncompressed) {
         "HEADERS frame with a 0-length header name, FIN, max stream ID";
 
     SpdyHeaderBlock headers;
-    headers[std::string()] = "foo";
+    headers[""] = "foo";
     headers["foo"] = "bar";
 
     const unsigned char kV2FrameData[] = {
diff --git a/net/spdy/spdy_http_utils.cc b/net/spdy/spdy_http_utils.cc
index 49fb8ca..41647c1 100644
--- a/net/spdy/spdy_http_utils.cc
+++ b/net/spdy/spdy_http_utils.cc
@@ -188,9 +188,8 @@ GURL GetUrlFromHeaderBlock(const SpdyHeaderBlock& headers,
   if (it != headers.end())
     path = it->second;
 
-  std::string url = (scheme.empty() || host_port.empty() || path.empty())
-                        ? std::string()
-                        : scheme + "://" + host_port + path;
+  std::string url =  (scheme.empty() || host_port.empty() || path.empty())
+      ? "" : scheme + "://" + host_port + path;
   return GURL(url);
 }
 
diff --git a/net/spdy/spdy_session_spdy2_unittest.cc b/net/spdy/spdy_session_spdy2_unittest.cc
index 1d7026f..0b93815 100644
--- a/net/spdy/spdy_session_spdy2_unittest.cc
+++ b/net/spdy/spdy_session_spdy2_unittest.cc
@@ -678,8 +678,8 @@ void IPPoolingTest(SpdyPoolCloseSessionsType close_sessions_type) {
   SpdySessionDependencies session_deps;
   session_deps.host_resolver->set_synchronous_mode(true);
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_hosts); i++) {
-    session_deps.host_resolver->rules()->AddIPLiteralRule(
-        test_hosts[i].name, test_hosts[i].iplist, std::string());
+    session_deps.host_resolver->rules()->AddIPLiteralRule(test_hosts[i].name,
+        test_hosts[i].iplist, "");
 
     // This test requires that the HostResolver cache be populated.  Normal
     // code would have done this already, but we do it manually.
@@ -1139,7 +1139,7 @@ TEST_F(SpdySessionSpdy2Test, CloseSessionWithTwoCreatedStreams) {
   EXPECT_EQ(0u, spdy_stream2->stream_id());
 
   // Ensure we don't crash while closing the session.
-  session->CloseSessionOnError(ERR_ABORTED, true, std::string());
+  session->CloseSessionOnError(ERR_ABORTED, true, "");
 
   EXPECT_TRUE(spdy_stream1->closed());
   EXPECT_TRUE(spdy_stream2->closed());
diff --git a/net/spdy/spdy_session_spdy3_unittest.cc b/net/spdy/spdy_session_spdy3_unittest.cc
index eaf23ffe..c790251 100644
--- a/net/spdy/spdy_session_spdy3_unittest.cc
+++ b/net/spdy/spdy_session_spdy3_unittest.cc
@@ -704,8 +704,8 @@ void IPPoolingTest(SpdyPoolCloseSessionsType close_sessions_type) {
   SpdySessionDependencies session_deps;
   session_deps.host_resolver->set_synchronous_mode(true);
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_hosts); i++) {
-    session_deps.host_resolver->rules()->AddIPLiteralRule(
-        test_hosts[i].name, test_hosts[i].iplist, std::string());
+    session_deps.host_resolver->rules()->AddIPLiteralRule(test_hosts[i].name,
+        test_hosts[i].iplist, "");
 
     // This test requires that the HostResolver cache be populated.  Normal
     // code would have done this already, but we do it manually.
@@ -1140,7 +1140,7 @@ TEST_F(SpdySessionSpdy3Test, CloseSessionWithTwoCreatedStreams) {
   EXPECT_EQ(0u, spdy_stream2->stream_id());
 
   // Ensure we don't crash while closing the session.
-  session->CloseSessionOnError(ERR_ABORTED, true, std::string());
+  session->CloseSessionOnError(ERR_ABORTED, true, "");
 
   EXPECT_TRUE(spdy_stream1->closed());
   EXPECT_TRUE(spdy_stream2->closed());
diff --git a/net/spdy/spdy_stream.cc b/net/spdy/spdy_stream.cc
index 70412dd..5725253 100644
--- a/net/spdy/spdy_stream.cc
+++ b/net/spdy/spdy_stream.cc
@@ -534,7 +534,7 @@ void SpdyStream::Cancel() {
 
   cancelled_ = true;
   if (session_->IsStreamActive(stream_id_))
-    session_->ResetStream(stream_id_, RST_STREAM_CANCEL, std::string());
+    session_->ResetStream(stream_id_, RST_STREAM_CANCEL, "");
   else if (stream_id_ == 0)
     session_->CloseCreatedStream(this, RST_STREAM_CANCEL);
 }
diff --git a/net/spdy/spdy_stream_test_util.cc b/net/spdy/spdy_stream_test_util.cc
index 00a58df..3b2235f 100644
--- a/net/spdy/spdy_stream_test_util.cc
+++ b/net/spdy/spdy_stream_test_util.cc
@@ -101,7 +101,7 @@ int StreamDelegateBase::WaitForClose() {
 std::string StreamDelegateBase::GetResponseHeaderValue(
     const std::string& name) const {
   SpdyHeaderBlock::const_iterator it = response_.find(name);
-  return (it == response_.end()) ? std::string() : it->second;
+  return (it == response_.end()) ? "" : it->second;
 }
 
 StreamDelegateSendImmediate::StreamDelegateSendImmediate(
diff --git a/net/spdy/spdy_write_queue_unittest.cc b/net/spdy/spdy_write_queue_unittest.cc
index 26029e4..c295db8 100644
--- a/net/spdy/spdy_write_queue_unittest.cc
+++ b/net/spdy/spdy_write_queue_unittest.cc
@@ -60,8 +60,7 @@ int ProducerToInt(scoped_ptr<SpdyFrameProducer> producer) {
 // -- be careful to not call any functions that expect the session to
 // be there.
 SpdyStream* MakeTestStream(RequestPriority priority) {
-  return new SpdyStream(
-      NULL, std::string(), priority, 0, 0, false, BoundNetLog());
+  return new SpdyStream(NULL, "", priority, 0, 0, false, BoundNetLog());
 }
 
 // Add some frame producers of different priority. The producers
diff --git a/net/ssl/server_bound_cert_service.cc b/net/ssl/server_bound_cert_service.cc
index 3a50ed6..bed97cf 100644
--- a/net/ssl/server_bound_cert_service.cc
+++ b/net/ssl/server_bound_cert_service.cc
@@ -579,11 +579,8 @@ void ServerBoundCertService::GotServerBoundCert(
     delete worker;
     // TODO(rkn): Log to the NetLog.
     LOG(ERROR) << "ServerBoundCertServiceWorker couldn't be started.";
-    HandleResult(ERR_INSUFFICIENT_RESOURCES,
-                 server_identifier,
-                 CLIENT_CERT_INVALID_TYPE,
-                 std::string(),
-                 std::string());
+    HandleResult(ERR_INSUFFICIENT_RESOURCES, server_identifier,
+                 CLIENT_CERT_INVALID_TYPE, "", "");
     return;
   }
 }
@@ -613,11 +610,7 @@ void ServerBoundCertService::GeneratedServerBoundCert(
     HandleResult(error, server_identifier, cert->type(), cert->private_key(),
                  cert->cert());
   } else {
-    HandleResult(error,
-                 server_identifier,
-                 CLIENT_CERT_INVALID_TYPE,
-                 std::string(),
-                 std::string());
+    HandleResult(error, server_identifier, CLIENT_CERT_INVALID_TYPE, "", "");
   }
 }
 
diff --git a/net/test/base_test_server.cc b/net/test/base_test_server.cc
index ab9b121..3a2dc11 100644
--- a/net/test/base_test_server.cc
+++ b/net/test/base_test_server.cc
@@ -92,7 +92,7 @@ base::FilePath BaseTestServer::SSLOptions::GetCertificateFile() const {
 
 std::string BaseTestServer::SSLOptions::GetOCSPArgument() const {
   if (server_certificate != CERT_AUTO)
-    return std::string();
+    return "";
 
   switch (ocsp_status) {
     case OCSP_OK:
@@ -107,7 +107,7 @@ std::string BaseTestServer::SSLOptions::GetOCSPArgument() const {
       return "unknown";
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
diff --git a/net/tools/dump_cache/url_to_filename_encoder_unittest.cc b/net/tools/dump_cache/url_to_filename_encoder_unittest.cc
index 23bbc6d..2e09e0b 100644
--- a/net/tools/dump_cache/url_to_filename_encoder_unittest.cc
+++ b/net/tools/dump_cache/url_to_filename_encoder_unittest.cc
@@ -57,8 +57,7 @@ class UrlToFilenameEncoderTest : public ::testing::Test {
 
   void Validate(const string& in_word, const string& gold_word) {
     string escaped_word, url;
-    UrlToFilenameEncoder::EncodeSegment(
-        std::string(), in_word, '/', &escaped_word);
+    UrlToFilenameEncoder::EncodeSegment("", in_word, '/', &escaped_word);
     EXPECT_EQ(gold_word, escaped_word);
     CheckSegmentLength(escaped_word);
     CheckValidChars(escaped_word, '\\');
@@ -68,8 +67,7 @@ class UrlToFilenameEncoderTest : public ::testing::Test {
 
   void ValidateAllSegmentsSmall(const string& in_word) {
     string escaped_word, url;
-    UrlToFilenameEncoder::EncodeSegment(
-        std::string(), in_word, '/', &escaped_word);
+    UrlToFilenameEncoder::EncodeSegment("", in_word, '/', &escaped_word);
     CheckSegmentLength(escaped_word);
     CheckValidChars(escaped_word, '\\');
     UrlToFilenameEncoder::Decode(escaped_word, '/', &url);
@@ -108,13 +106,13 @@ class UrlToFilenameEncoderTest : public ::testing::Test {
 
   void ValidateUrlOldNew(const string& url, const string& gold_old_filename,
                          const string& gold_new_filename) {
-    ValidateUrl(url, std::string(), true, gold_old_filename);
-    ValidateUrl(url, std::string(), false, gold_new_filename);
+    ValidateUrl(url, "", true, gold_old_filename);
+    ValidateUrl(url, "", false, gold_new_filename);
   }
 
   void ValidateEncodeSame(const string& url1, const string& url2) {
-    string filename1 = UrlToFilenameEncoder::Encode(url1, std::string(), false);
-    string filename2 = UrlToFilenameEncoder::Encode(url2, std::string(), false);
+    string filename1 = UrlToFilenameEncoder::Encode(url1, "", false);
+    string filename2 = UrlToFilenameEncoder::Encode(url2, "", false);
     EXPECT_EQ(filename1, filename2);
   }
 
@@ -123,7 +121,7 @@ class UrlToFilenameEncoderTest : public ::testing::Test {
 };
 
 TEST_F(UrlToFilenameEncoderTest, DoesNotEscape) {
-  ValidateNoChange(std::string());
+  ValidateNoChange("");
   ValidateNoChange("abcdefg");
   ValidateNoChange("abcdefghijklmnopqrstuvwxyz");
   ValidateNoChange("ZYXWVUT");
@@ -195,8 +193,7 @@ TEST_F(UrlToFilenameEncoderTest, EncodeUrlCorrectly) {
 
   // From bug: Double slash preserved.
   ValidateUrl("http://www.foo.com/u?site=http://www.google.com/index.html",
-              std::string(),
-              false,
+              "", false,
               "www.foo.com" + dir_sep_ + "u" + escape_ + "3Fsite=http" +
               escape_ + "3A" + dir_sep_ + escape_ + "2Fwww.google.com" +
               dir_sep_ + "index.html" + escape_);
@@ -329,8 +326,7 @@ TEST_F(UrlToFilenameEncoderTest, BackslashSeparator) {
   string long_word;
   string escaped_word;
   long_word.append(UrlToFilenameEncoder::kMaximumSubdirectoryLength + 1, 'x');
-  UrlToFilenameEncoder::EncodeSegment(
-      std::string(), long_word, '\\', &escaped_word);
+  UrlToFilenameEncoder::EncodeSegment("", long_word, '\\', &escaped_word);
 
   // check that one backslash, plus the escape ",-", and the ending , got added.
   EXPECT_EQ(long_word.size() + 4, escaped_word.size());
diff --git a/net/tools/fetch/fetch_server.cc b/net/tools/fetch/fetch_server.cc
index 34c7c83..830cd18 100644
--- a/net/tools/fetch/fetch_server.cc
+++ b/net/tools/fetch/fetch_server.cc
@@ -36,8 +36,7 @@ int main(int argc, char**argv) {
 
   // Do work here.
   MessageLoop loop;
-  HttpServer server(std::string(),
-                    80);  // TODO(mbelshe): make port configurable
+  HttpServer server("", 80);   // TODO(mbelshe): make port configurable
   MessageLoop::current()->Run();
 
   if (parsed_command_line.HasSwitch("stats")) {
diff --git a/net/tools/flip_server/acceptor_thread.cc b/net/tools/flip_server/acceptor_thread.cc
index ed8a3ec..b16d181 100644
--- a/net/tools/flip_server/acceptor_thread.cc
+++ b/net/tools/flip_server/acceptor_thread.cc
@@ -105,9 +105,7 @@ void SMAcceptorThread::HandleConnection(int server_fd,
                                       NULL,
                                       &epoll_server_,
                                       server_fd,
-                                      std::string(),
-                                      std::string(),
-                                      remote_ip,
+                                      "", "", remote_ip,
                                       use_ssl_);
   if (server_connection->initialized())
     active_server_connections_.push_back(server_connection);
diff --git a/net/tools/flip_server/flip_in_mem_edsm_server.cc b/net/tools/flip_server/flip_in_mem_edsm_server.cc
index 15fb9644..8ba1505 100644
--- a/net/tools/flip_server/flip_in_mem_edsm_server.cc
+++ b/net/tools/flip_server/flip_in_mem_edsm_server.cc
@@ -335,16 +335,11 @@ int main (int argc, char**argv)
     std::string value = cl.GetSwitchValueASCII("spdy-server");
     std::vector<std::string> valueArgs = split(value, ',');
     while (valueArgs.size() < 4)
-      valueArgs.push_back(std::string());
+      valueArgs.push_back("");
     g_proxy_config.AddAcceptor(net::FLIP_HANDLER_SPDY_SERVER,
-                               valueArgs[0],
-                               valueArgs[1],
-                               valueArgs[2],
-                               valueArgs[3],
-                               std::string(),
-                               std::string(),
-                               std::string(),
-                               std::string(),
+                               valueArgs[0], valueArgs[1],
+                               valueArgs[2], valueArgs[3],
+                               "", "", "", "",
                                0,
                                FLAGS_accept_backlog_size,
                                FLAGS_disable_nagle,
@@ -361,16 +356,11 @@ int main (int argc, char**argv)
     std::string value = cl.GetSwitchValueASCII("http-server");
     std::vector<std::string> valueArgs = split(value, ',');
     while (valueArgs.size() < 4)
-      valueArgs.push_back(std::string());
+      valueArgs.push_back("");
     g_proxy_config.AddAcceptor(net::FLIP_HANDLER_HTTP_SERVER,
-                               valueArgs[0],
-                               valueArgs[1],
-                               valueArgs[2],
-                               valueArgs[3],
-                               std::string(),
-                               std::string(),
-                               std::string(),
-                               std::string(),
+                               valueArgs[0], valueArgs[1],
+                               valueArgs[2], valueArgs[3],
+                               "", "", "", "",
                                0,
                                FLAGS_accept_backlog_size,
                                FLAGS_disable_nagle,
diff --git a/net/tools/flip_server/spdy_interface.cc b/net/tools/flip_server/spdy_interface.cc
index 649e99e..1c34e79 100644
--- a/net/tools/flip_server/spdy_interface.cc
+++ b/net/tools/flip_server/spdy_interface.cc
@@ -112,14 +112,9 @@ SMInterface* SpdySM::FindOrMakeNewSMConnectionInterface(
   }
 
   sm_http_interface->InitSMInterface(this, server_idx);
-  sm_http_interface->InitSMConnection(NULL,
-                                      sm_http_interface,
-                                      epoll_server_,
-                                      -1,
-                                      server_ip,
-                                      server_port,
-                                      std::string(),
-                                      false);
+  sm_http_interface->InitSMConnection(NULL, sm_http_interface,
+                                      epoll_server_, -1,
+                                      server_ip, server_port, "", false);
 
   return sm_http_interface;
 }
diff --git a/net/tools/flip_server/streamer_interface.cc b/net/tools/flip_server/streamer_interface.cc
index b1612e7..9e6e6c8 100644
--- a/net/tools/flip_server/streamer_interface.cc
+++ b/net/tools/flip_server/streamer_interface.cc
@@ -131,13 +131,11 @@ int StreamerSM::PostAcceptHook() {
   }
   // The Streamer interface is used to stream HTTPS connections, so we
   // will always use the https_server_ip/port here.
-  sm_other_interface_->InitSMConnection(NULL,
-                                        sm_other_interface_,
-                                        epoll_server_,
-                                        -1,
+  sm_other_interface_->InitSMConnection(NULL, sm_other_interface_,
+                                        epoll_server_, -1,
                                         acceptor_->https_server_ip_,
                                         acceptor_->https_server_port_,
-                                        std::string(),
+                                        "",
                                         false);
 
   return 1;
diff --git a/net/tools/quic/end_to_end_test.cc b/net/tools/quic/end_to_end_test.cc
index cb14db8..e98c4ea 100644
--- a/net/tools/quic/end_to_end_test.cc
+++ b/net/tools/quic/end_to_end_test.cc
@@ -234,7 +234,7 @@ TEST_F(EndToEndTest, SeparateFinPacket) {
 
   client_->SendMessage(request);
 
-  client_->SendData(std::string(), true);
+  client_->SendData("", true);
 
   client_->WaitForResponse();
   EXPECT_EQ(kFooResponseBody, client_->response_body());
@@ -243,7 +243,7 @@ TEST_F(EndToEndTest, SeparateFinPacket) {
   request.AddBody("foo", true);
 
   client_->SendMessage(request);
-  client_->SendData(std::string(), true);
+  client_->SendData("", true);
   client_->WaitForResponse();
   EXPECT_EQ(kFooResponseBody, client_->response_body());
   EXPECT_EQ(200ul, client_->response_headers()->parsed_response_code());
diff --git a/net/tools/quic/quic_client.cc b/net/tools/quic/quic_client.cc
index 8acb85a..4a61ab4 100644
--- a/net/tools/quic/quic_client.cc
+++ b/net/tools/quic/quic_client.cc
@@ -43,8 +43,8 @@ QuicClient::QuicClient(IPEndPoint server_address,
 
 QuicClient::~QuicClient() {
   if (connected()) {
-    session()->connection()
-        ->SendConnectionClosePacket(QUIC_PEER_GOING_AWAY, std::string());
+    session()->connection()->SendConnectionClosePacket(
+        QUIC_PEER_GOING_AWAY, "");
   }
 }
 
diff --git a/net/tools/quic/test_tools/quic_test_client.cc b/net/tools/quic/test_tools/quic_test_client.cc
index 843af2f..53bc057 100644
--- a/net/tools/quic/test_tools/quic_test_client.cc
+++ b/net/tools/quic/test_tools/quic_test_client.cc
@@ -85,7 +85,7 @@ string QuicTestClient::SendCustomSynchronousRequest(
 string QuicTestClient::SendSynchronousRequest(const string& uri) {
   if (SendRequest(uri) == 0) {
     DLOG(ERROR) << "Failed to the request for uri:" << uri;
-    return std::string();
+    return "";
   }
   WaitForResponse();
   return response_;
diff --git a/net/udp/udp_socket_unittest.cc b/net/udp/udp_socket_unittest.cc
index 09a2806..c2085ad 100644
--- a/net/udp/udp_socket_unittest.cc
+++ b/net/udp/udp_socket_unittest.cc
@@ -38,7 +38,7 @@ class UDPSocketTest : public PlatformTest {
     if (rv == ERR_IO_PENDING)
       rv = callback.WaitForResult();
     if (rv < 0)
-      return std::string();  // error!
+      return "";  // error!
     return std::string(buffer_->data(), rv);
   }
 
@@ -82,7 +82,7 @@ class UDPSocketTest : public PlatformTest {
     if (rv == ERR_IO_PENDING)
       rv = callback.WaitForResult();
     if (rv < 0)
-      return std::string();  // error!
+      return "";  // error!
     return std::string(buffer_->data(), rv);
   }
 
diff --git a/net/url_request/url_fetcher_impl_unittest.cc b/net/url_request/url_fetcher_impl_unittest.cc
index c8cbd1a..98a3a11 100644
--- a/net/url_request/url_fetcher_impl_unittest.cc
+++ b/net/url_request/url_fetcher_impl_unittest.cc
@@ -441,16 +441,11 @@ class CancelTestURLRequestContextGetter
       // The initial backoff is 2 seconds and maximum backoff is 4 seconds.
       // Maximum retries allowed is set to 2.
       scoped_refptr<URLRequestThrottlerEntry> entry(
-          new URLRequestThrottlerEntry(context_->throttler_manager(),
-                                       std::string(),
-                                       200,
-                                       3,
-                                       2000,
-                                       2.0,
-                                       0.0,
-                                       4000));
-      context_->throttler_manager()
-          ->OverrideEntryForTests(throttle_for_url_, entry);
+          new URLRequestThrottlerEntry(
+              context_->throttler_manager(),
+              "", 200, 3, 2000, 2.0, 0.0, 4000));
+      context_->throttler_manager()->OverrideEntryForTests(
+          throttle_for_url_, entry);
 
       context_created_.Signal();
     }
@@ -558,7 +553,7 @@ void URLFetcherEmptyPostTest::CreateFetcher(const GURL& url) {
   fetcher_ = new URLFetcherImpl(url, URLFetcher::POST, this);
   fetcher_->SetRequestContext(new TestURLRequestContextGetter(
       io_message_loop_proxy()));
-  fetcher_->SetUploadData("text/plain", std::string());
+  fetcher_->SetUploadData("text/plain", "");
   fetcher_->Start();
 }
 
@@ -1168,14 +1163,9 @@ TEST_F(URLFetcherProtectTest, Overload) {
   // Registers an entry for test url. It only allows 3 requests to be sent
   // in 200 milliseconds.
   scoped_refptr<URLRequestThrottlerEntry> entry(
-      new URLRequestThrottlerEntry(request_context()->throttler_manager(),
-                                   std::string(),
-                                   200,
-                                   3,
-                                   1,
-                                   2.0,
-                                   0.0,
-                                   256));
+      new URLRequestThrottlerEntry(
+          request_context()->throttler_manager(),
+          "", 200, 3, 1, 2.0, 0.0, 256));
   request_context()->throttler_manager()->OverrideEntryForTests(url, entry);
 
   CreateFetcher(url);
@@ -1196,14 +1186,9 @@ TEST_F(URLFetcherProtectTest, ServerUnavailable) {
   // and maximum backoff time is 256 milliseconds.
   // Maximum retries allowed is set to 11.
   scoped_refptr<URLRequestThrottlerEntry> entry(
-      new URLRequestThrottlerEntry(request_context()->throttler_manager(),
-                                   std::string(),
-                                   200,
-                                   3,
-                                   1,
-                                   2.0,
-                                   0.0,
-                                   256));
+      new URLRequestThrottlerEntry(
+          request_context()->throttler_manager(),
+          "", 200, 3, 1, 2.0, 0.0, 256));
   request_context()->throttler_manager()->OverrideEntryForTests(url, entry);
 
   CreateFetcher(url);
@@ -1224,14 +1209,9 @@ TEST_F(URLFetcherProtectTestPassedThrough, ServerUnavailablePropagateResponse) {
   // and maximum backoff time is 150000 milliseconds.
   // Maximum retries allowed is set to 11.
   scoped_refptr<URLRequestThrottlerEntry> entry(
-      new URLRequestThrottlerEntry(request_context()->throttler_manager(),
-                                   std::string(),
-                                   200,
-                                   3,
-                                   100,
-                                   2.0,
-                                   0.0,
-                                   150000));
+      new URLRequestThrottlerEntry(
+          request_context()->throttler_manager(),
+          "", 200, 3, 100, 2.0, 0.0, 150000));
   // Total time if *not* for not doing automatic backoff would be 150s.
   // In reality it should be "as soon as server responds".
   request_context()->throttler_manager()->OverrideEntryForTests(url, entry);
@@ -1288,14 +1268,9 @@ TEST_F(URLFetcherCancelTest, CancelWhileDelayedStartTaskPending) {
   // Using a sliding window of 4 seconds, and max of 1 request, under a fast
   // run we expect to have a 4 second delay when posting the Start task.
   scoped_refptr<URLRequestThrottlerEntry> entry(
-      new URLRequestThrottlerEntry(request_context()->throttler_manager(),
-                                   std::string(),
-                                   4000,
-                                   1,
-                                   2000,
-                                   2.0,
-                                   0.0,
-                                   4000));
+      new URLRequestThrottlerEntry(
+          request_context()->throttler_manager(),
+          "", 4000, 1, 2000, 2.0, 0.0, 4000));
   request_context()->throttler_manager()->OverrideEntryForTests(url, entry);
   // Fake that a request has just started.
   entry->ReserveSendingTimeForNextRequest(base::TimeTicks());
diff --git a/net/url_request/url_request_throttler_simulation_unittest.cc b/net/url_request/url_request_throttler_simulation_unittest.cc
index cbb8be8..3a5a399 100644
--- a/net/url_request/url_request_throttler_simulation_unittest.cc
+++ b/net/url_request/url_request_throttler_simulation_unittest.cc
@@ -297,9 +297,11 @@ class Server : public DiscreteTimeSimulation::Actor {
 // Mock throttler entry used by Requester class.
 class MockURLRequestThrottlerEntry : public URLRequestThrottlerEntry {
  public:
-  explicit MockURLRequestThrottlerEntry(URLRequestThrottlerManager* manager)
-      : URLRequestThrottlerEntry(manager, std::string()),
-        mock_backoff_entry_(&backoff_policy_) {}
+  explicit MockURLRequestThrottlerEntry(
+      URLRequestThrottlerManager* manager)
+      : URLRequestThrottlerEntry(manager, ""),
+        mock_backoff_entry_(&backoff_policy_) {
+  }
 
   virtual const BackoffEntry* GetBackoffEntry() const OVERRIDE {
     return &mock_backoff_entry_;
@@ -431,7 +433,7 @@ class Requester : public DiscreteTimeSimulation::Actor {
       if (!throttler_entry_->ShouldRejectRequest(server_->mock_request())) {
         int status_code = server_->HandleRequest();
         MockURLRequestThrottlerHeaderAdapter response_headers(status_code);
-        throttler_entry_->UpdateWithResponse(std::string(), &response_headers);
+        throttler_entry_->UpdateWithResponse("", &response_headers);
 
         if (status_code == 200) {
           if (results_)
diff --git a/net/url_request/url_request_throttler_test_support.cc b/net/url_request/url_request_throttler_test_support.cc
index 9d3f4e2..b6088ec 100644
--- a/net/url_request/url_request_throttler_test_support.cc
+++ b/net/url_request/url_request_throttler_test_support.cc
@@ -48,7 +48,7 @@ std::string MockURLRequestThrottlerHeaderAdapter::GetNormalizedValue(
     return fake_opt_out_value_;
   }
 
-  return std::string();
+  return "";
 }
 
 int MockURLRequestThrottlerHeaderAdapter::GetResponseCode() const {
diff --git a/net/url_request/url_request_throttler_unittest.cc b/net/url_request/url_request_throttler_unittest.cc
index ed3eb87..cb20a95 100644
--- a/net/url_request/url_request_throttler_unittest.cc
+++ b/net/url_request/url_request_throttler_unittest.cc
@@ -37,7 +37,7 @@ class MockURLRequestThrottlerEntry : public URLRequestThrottlerEntry {
  public:
   explicit MockURLRequestThrottlerEntry(
       net::URLRequestThrottlerManager* manager)
-      : net::URLRequestThrottlerEntry(manager, std::string()),
+      : net::URLRequestThrottlerEntry(manager, ""),
         mock_backoff_entry_(&backoff_policy_) {
     InitPolicy();
   }
@@ -46,7 +46,7 @@ class MockURLRequestThrottlerEntry : public URLRequestThrottlerEntry {
       const TimeTicks& exponential_backoff_release_time,
       const TimeTicks& sliding_window_release_time,
       const TimeTicks& fake_now)
-      : net::URLRequestThrottlerEntry(manager, std::string()),
+      : net::URLRequestThrottlerEntry(manager, ""),
         fake_time_now_(fake_now),
         mock_backoff_entry_(&backoff_policy_) {
     InitPolicy();
@@ -279,14 +279,14 @@ TEST_F(URLRequestThrottlerEntryTest, InterfaceNotDuringExponentialBackoff) {
 
 TEST_F(URLRequestThrottlerEntryTest, InterfaceUpdateFailure) {
   MockURLRequestThrottlerHeaderAdapter failure_response(503);
-  entry_->UpdateWithResponse(std::string(), &failure_response);
+  entry_->UpdateWithResponse("", &failure_response);
   EXPECT_GT(entry_->GetExponentialBackoffReleaseTime(), entry_->fake_time_now_)
       << "A failure should increase the release_time";
 }
 
 TEST_F(URLRequestThrottlerEntryTest, InterfaceUpdateSuccess) {
   MockURLRequestThrottlerHeaderAdapter success_response(200);
-  entry_->UpdateWithResponse(std::string(), &success_response);
+  entry_->UpdateWithResponse("", &success_response);
   EXPECT_EQ(entry_->GetExponentialBackoffReleaseTime(), entry_->fake_time_now_)
       << "A success should not add any delay";
 }
@@ -294,11 +294,11 @@ TEST_F(URLRequestThrottlerEntryTest, InterfaceUpdateSuccess) {
 TEST_F(URLRequestThrottlerEntryTest, InterfaceUpdateSuccessThenFailure) {
   MockURLRequestThrottlerHeaderAdapter failure_response(503);
   MockURLRequestThrottlerHeaderAdapter success_response(200);
-  entry_->UpdateWithResponse(std::string(), &success_response);
-  entry_->UpdateWithResponse(std::string(), &failure_response);
+  entry_->UpdateWithResponse("", &success_response);
+  entry_->UpdateWithResponse("", &failure_response);
   EXPECT_GT(entry_->GetExponentialBackoffReleaseTime(), entry_->fake_time_now_)
       << "This scenario should add delay";
-  entry_->UpdateWithResponse(std::string(), &success_response);
+  entry_->UpdateWithResponse("", &success_response);
 }
 
 TEST_F(URLRequestThrottlerEntryTest, IsEntryReallyOutdated) {
@@ -324,7 +324,7 @@ TEST_F(URLRequestThrottlerEntryTest, IsEntryReallyOutdated) {
 TEST_F(URLRequestThrottlerEntryTest, MaxAllowedBackoff) {
   for (int i = 0; i < 30; ++i) {
     MockURLRequestThrottlerHeaderAdapter response_adapter(503);
-    entry_->UpdateWithResponse(std::string(), &response_adapter);
+    entry_->UpdateWithResponse("", &response_adapter);
   }
 
   TimeDelta delay = entry_->GetExponentialBackoffReleaseTime() - now_;
@@ -335,7 +335,7 @@ TEST_F(URLRequestThrottlerEntryTest, MaxAllowedBackoff) {
 TEST_F(URLRequestThrottlerEntryTest, MalformedContent) {
   MockURLRequestThrottlerHeaderAdapter response_adapter(503);
   for (int i = 0; i < 5; ++i)
-    entry_->UpdateWithResponse(std::string(), &response_adapter);
+    entry_->UpdateWithResponse("", &response_adapter);
 
   TimeTicks release_after_failures = entry_->GetExponentialBackoffReleaseTime();
 
@@ -346,7 +346,7 @@ TEST_F(URLRequestThrottlerEntryTest, MalformedContent) {
   // response must also have been received).
   entry_->ReceivedContentWasMalformed(200);
   MockURLRequestThrottlerHeaderAdapter success_adapter(200);
-  entry_->UpdateWithResponse(std::string(), &success_adapter);
+  entry_->UpdateWithResponse("", &success_adapter);
   EXPECT_GT(entry_->GetExponentialBackoffReleaseTime(), release_after_failures);
 }
 
@@ -475,7 +475,7 @@ void ExpectEntryAllowsAllOnErrorIfOptedOut(
   MockURLRequestThrottlerHeaderAdapter failure_adapter(503);
   for (int i = 0; i < 10; ++i) {
     // Host doesn't really matter in this scenario so we skip it.
-    entry->UpdateWithResponse(std::string(), &failure_adapter);
+    entry->UpdateWithResponse("", &failure_adapter);
   }
   EXPECT_NE(opted_out, entry->ShouldRejectRequest(request));
 
@@ -500,7 +500,7 @@ TEST_F(URLRequestThrottlerManagerTest, OptOutHeader) {
 
   // Fake a response with the opt-out header.
   MockURLRequestThrottlerHeaderAdapter response_adapter(
-      std::string(),
+      "",
       MockURLRequestThrottlerEntry::kExponentialThrottlingDisableValue,
       200);
   entry->UpdateWithResponse("www.google.com", &response_adapter);
@@ -517,8 +517,7 @@ TEST_F(URLRequestThrottlerManagerTest, OptOutHeader) {
   // Fake a response with the opt-out header incorrectly specified.
   scoped_refptr<net::URLRequestThrottlerEntryInterface> no_opt_out_entry =
       manager.RegisterRequestUrl(GURL("http://www.nike.com/justdoit"));
-  MockURLRequestThrottlerHeaderAdapter wrong_adapter(
-      std::string(), "yesplease", 200);
+  MockURLRequestThrottlerHeaderAdapter wrong_adapter("", "yesplease", 200);
   no_opt_out_entry->UpdateWithResponse("www.nike.com", &wrong_adapter);
   ExpectEntryAllowsAllOnErrorIfOptedOut(no_opt_out_entry, false, request_);
 
@@ -536,7 +535,7 @@ TEST_F(URLRequestThrottlerManagerTest, ClearOnNetworkChange) {
     MockURLRequestThrottlerHeaderAdapter failure_adapter(503);
     for (int j = 0; j < 10; ++j) {
       // Host doesn't really matter in this scenario so we skip it.
-      entry_before->UpdateWithResponse(std::string(), &failure_adapter);
+      entry_before->UpdateWithResponse("", &failure_adapter);
     }
     EXPECT_TRUE(entry_before->ShouldRejectRequest(request_));
 
diff --git a/net/url_request/url_request_unittest.cc b/net/url_request/url_request_unittest.cc
index c3c68a1..494e6b3 100644
--- a/net/url_request/url_request_unittest.cc
+++ b/net/url_request/url_request_unittest.cc
@@ -2577,7 +2577,7 @@ TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequest) {
       &network_delegate);
 
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &context);
+    URLRequest r(test_server_.GetURL(""), &d, &context);
 
     r.Start();
     MessageLoop::current()->Run();
@@ -2626,21 +2626,21 @@ TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequestSynchronously1) {
   ASSERT_TRUE(test_server_.Start());
   NetworkDelegateCancelRequest(BlockingNetworkDelegate::SYNCHRONOUS,
                                BlockingNetworkDelegate::ON_BEFORE_URL_REQUEST,
-                               test_server_.GetURL(std::string()));
+                               test_server_.GetURL(""));
 }
 
 TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequestSynchronously2) {
   ASSERT_TRUE(test_server_.Start());
   NetworkDelegateCancelRequest(BlockingNetworkDelegate::SYNCHRONOUS,
                                BlockingNetworkDelegate::ON_BEFORE_SEND_HEADERS,
-                               test_server_.GetURL(std::string()));
+                               test_server_.GetURL(""));
 }
 
 TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequestSynchronously3) {
   ASSERT_TRUE(test_server_.Start());
   NetworkDelegateCancelRequest(BlockingNetworkDelegate::SYNCHRONOUS,
                                BlockingNetworkDelegate::ON_HEADERS_RECEIVED,
-                               test_server_.GetURL(std::string()));
+                               test_server_.GetURL(""));
 }
 
 // The following 3 tests check that the network delegate can cancel a request
@@ -2649,21 +2649,21 @@ TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequestAsynchronously1) {
   ASSERT_TRUE(test_server_.Start());
   NetworkDelegateCancelRequest(BlockingNetworkDelegate::AUTO_CALLBACK,
                                BlockingNetworkDelegate::ON_BEFORE_URL_REQUEST,
-                               test_server_.GetURL(std::string()));
+                               test_server_.GetURL(""));
 }
 
 TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequestAsynchronously2) {
   ASSERT_TRUE(test_server_.Start());
   NetworkDelegateCancelRequest(BlockingNetworkDelegate::AUTO_CALLBACK,
                                BlockingNetworkDelegate::ON_BEFORE_SEND_HEADERS,
-                               test_server_.GetURL(std::string()));
+                               test_server_.GetURL(""));
 }
 
 TEST_F(URLRequestTestHTTP, NetworkDelegateCancelRequestAsynchronously3) {
   ASSERT_TRUE(test_server_.Start());
   NetworkDelegateCancelRequest(BlockingNetworkDelegate::AUTO_CALLBACK,
                                BlockingNetworkDelegate::ON_HEADERS_RECEIVED,
-                               test_server_.GetURL(std::string()));
+                               test_server_.GetURL(""));
 }
 
 // Tests that the network delegate can block and redirect a request to a new
@@ -2992,7 +2992,7 @@ TEST_F(URLRequestTestHTTP, NetworkDelegateCancelWhileWaiting1) {
   context.Init();
 
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &context);
+    URLRequest r(test_server_.GetURL(""), &d, &context);
 
     r.Start();
     MessageLoop::current()->Run();
@@ -3028,7 +3028,7 @@ TEST_F(URLRequestTestHTTP, NetworkDelegateCancelWhileWaiting2) {
   context.Init();
 
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &context);
+    URLRequest r(test_server_.GetURL(""), &d, &context);
 
     r.Start();
     MessageLoop::current()->Run();
@@ -3063,7 +3063,7 @@ TEST_F(URLRequestTestHTTP, NetworkDelegateCancelWhileWaiting3) {
   context.Init();
 
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &context);
+    URLRequest r(test_server_.GetURL(""), &d, &context);
 
     r.Start();
     MessageLoop::current()->Run();
@@ -3147,7 +3147,7 @@ TEST_F(URLRequestTestHTTP, GetTest_NoCache) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server_.GetURL(""), &d, &default_context_);
 
     r.Start();
     EXPECT_TRUE(r.is_pending());
@@ -3213,7 +3213,7 @@ TEST_F(URLRequestTestHTTP, GetTest) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server_.GetURL(""), &d, &default_context_);
 
     r.Start();
     EXPECT_TRUE(r.is_pending());
@@ -3235,7 +3235,7 @@ TEST_F(URLRequestTestHTTP, GetTestLoadTiming) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server_.GetURL(""), &d, &default_context_);
 
     r.Start();
     EXPECT_TRUE(r.is_pending());
@@ -3319,7 +3319,7 @@ TEST_F(URLRequestTestHTTP, HTTPSToHTTPRedirectNoRefererTest) {
   // An https server is sent a request with an https referer,
   // and responds with a redirect to an http url. The http
   // server should not be sent the referer.
-  GURL http_destination = test_server_.GetURL(std::string());
+  GURL http_destination = test_server_.GetURL("");
   TestDelegate d;
   URLRequest req(https_test_server.GetURL(
       "server-redirect?" + http_destination.spec()), &d, &default_context_);
@@ -3336,9 +3336,9 @@ TEST_F(URLRequestTestHTTP, HTTPSToHTTPRedirectNoRefererTest) {
 TEST_F(URLRequestTestHTTP, RedirectLoadTiming) {
   ASSERT_TRUE(test_server_.Start());
 
-  GURL destination_url = test_server_.GetURL(std::string());
-  GURL original_url =
-      test_server_.GetURL("server-redirect?" + destination_url.spec());
+  GURL destination_url = test_server_.GetURL("");
+  GURL original_url = test_server_.GetURL(
+      "server-redirect?" + destination_url.spec());
   TestDelegate d;
   URLRequest req(original_url, &d, &default_context_);
   req.Start();
@@ -3374,9 +3374,9 @@ TEST_F(URLRequestTestHTTP, RedirectLoadTiming) {
 TEST_F(URLRequestTestHTTP, MultipleRedirectTest) {
   ASSERT_TRUE(test_server_.Start());
 
-  GURL destination_url = test_server_.GetURL(std::string());
-  GURL middle_redirect_url =
-      test_server_.GetURL("server-redirect?" + destination_url.spec());
+  GURL destination_url = test_server_.GetURL("");
+  GURL middle_redirect_url = test_server_.GetURL(
+      "server-redirect?" + destination_url.spec());
   GURL original_url = test_server_.GetURL(
       "server-redirect?" + middle_redirect_url.spec());
   TestDelegate d;
@@ -3492,7 +3492,7 @@ TEST_F(URLRequestTestHTTP, CancelTest2) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server_.GetURL(""), &d, &default_context_);
 
     d.set_cancel_in_response_started(true);
 
@@ -3513,7 +3513,7 @@ TEST_F(URLRequestTestHTTP, CancelTest3) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server_.GetURL(""), &d, &default_context_);
 
     d.set_cancel_in_received_data(true);
 
@@ -3537,7 +3537,7 @@ TEST_F(URLRequestTestHTTP, CancelTest4) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server_.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server_.GetURL(""), &d, &default_context_);
 
     r.Start();
     EXPECT_TRUE(r.is_pending());
@@ -4496,7 +4496,7 @@ TEST_F(HTTPSRequestTest, HTTPSGetTest) {
 
   TestDelegate d;
   {
-    URLRequest r(test_server.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server.GetURL(""), &d, &default_context_);
     r.Start();
     EXPECT_TRUE(r.is_pending());
 
@@ -4526,7 +4526,7 @@ TEST_F(HTTPSRequestTest, HTTPSMismatchedTest) {
     TestDelegate d;
     {
       d.set_allow_certificate_errors(err_allowed);
-      URLRequest r(test_server.GetURL(std::string()), &d, &default_context_);
+      URLRequest r(test_server.GetURL(""), &d, &default_context_);
 
       r.Start();
       EXPECT_TRUE(r.is_pending());
@@ -4561,7 +4561,7 @@ TEST_F(HTTPSRequestTest, HTTPSExpiredTest) {
     TestDelegate d;
     {
       d.set_allow_certificate_errors(err_allowed);
-      URLRequest r(test_server.GetURL(std::string()), &d, &default_context_);
+      URLRequest r(test_server.GetURL(""), &d, &default_context_);
 
       r.Start();
       EXPECT_TRUE(r.is_pending());
@@ -4605,7 +4605,7 @@ TEST_F(HTTPSRequestTest, TLSv1Fallback) {
   TestURLRequestContext context(true);
   context.Init();
   d.set_allow_certificate_errors(true);
-  URLRequest r(test_server.GetURL(std::string()), &d, &context);
+  URLRequest r(test_server.GetURL(""), &d, &context);
   r.Start();
 
   MessageLoop::current()->Run();
@@ -4784,7 +4784,7 @@ TEST_F(HTTPSRequestTest, SSLv3Fallback) {
   TestURLRequestContext context(true);
   context.Init();
   d.set_allow_certificate_errors(true);
-  URLRequest r(test_server.GetURL(std::string()), &d, &context);
+  URLRequest r(test_server.GetURL(""), &d, &context);
   r.Start();
 
   MessageLoop::current()->Run();
@@ -4832,7 +4832,7 @@ TEST_F(HTTPSRequestTest, ClientAuthTest) {
 
   SSLClientAuthTestDelegate d;
   {
-    URLRequest r(test_server.GetURL(std::string()), &d, &default_context_);
+    URLRequest r(test_server.GetURL(""), &d, &default_context_);
 
     r.Start();
     EXPECT_TRUE(r.is_pending());
@@ -5072,7 +5072,7 @@ class HTTPSOCSPTest : public HTTPSRequestTest {
 
     TestDelegate d;
     d.set_allow_certificate_errors(true);
-    URLRequest r(test_server.GetURL(std::string()), &d, &context_);
+    URLRequest r(test_server.GetURL(""), &d, &context_);
     r.Start();
 
     MessageLoop::current()->Run();
diff --git a/net/websockets/websocket_net_log_params_unittest.cc b/net/websockets/websocket_net_log_params_unittest.cc
index 0519390f..e3c92a9 100644
--- a/net/websockets/websocket_net_log_params_unittest.cc
+++ b/net/websockets/websocket_net_log_params_unittest.cc
@@ -21,7 +21,7 @@ TEST(NetLogWebSocketHandshakeParameterTest, ToValue) {
   list->Append(new StringValue("Upgrade: WebSocket"));
   list->Append(new StringValue("Sec-WebSocket-Key1: 4 @1  46546xW%0l 1 5"));
   list->Append(new StringValue("Origin: http://example.com"));
-  list->Append(new StringValue(std::string()));
+  list->Append(new StringValue(""));
   list->Append(new StringValue("\\x00\\x01\\x0a\\x0d\\xff\\xfe\\x0d\\x0a"));
 
   DictionaryValue expected;
diff --git a/ppapi/cpp/dev/text_input_dev.cc b/ppapi/cpp/dev/text_input_dev.cc
index 657a0b3..3b38df8 100644
--- a/ppapi/cpp/dev/text_input_dev.cc
+++ b/ppapi/cpp/dev/text_input_dev.cc
@@ -54,7 +54,7 @@ TextInput_Dev::~TextInput_Dev() {
 
 void TextInput_Dev::RequestSurroundingText(uint32_t) {
   // Default implementation. Send a null range.
-  UpdateSurroundingText(std::string(), 0, 0);
+  UpdateSurroundingText("", 0, 0);
 }
 
 void TextInput_Dev::SetTextInputType(PP_TextInput_Type type) {
diff --git a/ppapi/examples/ime/ime.cc b/ppapi/examples/ime/ime.cc
index 6f3e655..f5e2e44 100644
--- a/ppapi/examples/ime/ime.cc
+++ b/ppapi/examples/ime/ime.cc
@@ -245,7 +245,7 @@ class MyTextField {
       int32_t target_segment,
       const std::pair<uint32_t, uint32_t>& selection) {
     if (HasSelection() && !text.empty())
-      InsertText(std::string());
+      InsertText("");
     composition_ = text;
     segments_ = segments;
     target_segment_ = target_segment;
@@ -344,7 +344,7 @@ class MyTextField {
     if (!Focused())
       return;
     if (HasSelection()) {
-      InsertText(std::string());
+      InsertText("");
     } else {
       size_t i = GetNextCharOffsetUtf8(utf8_text_, caret_pos_);
       utf8_text_.erase(caret_pos_, i - caret_pos_);
@@ -356,7 +356,7 @@ class MyTextField {
     if (!Focused())
       return;
     if (HasSelection()) {
-      InsertText(std::string());
+      InsertText("");
     } else if (caret_pos_ != 0) {
       size_t i = GetPrevCharOffsetUtf8(utf8_text_, caret_pos_);
       utf8_text_.erase(i, caret_pos_ - i);
@@ -565,10 +565,8 @@ class MyInstance : public pp::Instance {
          it != textfield_.end();
          ++it) {
       if (it->Focused()) {
-        it->SetComposition(std::string(),
-                           std::vector<std::pair<uint32_t, uint32_t> >(),
-                           0,
-                           std::make_pair(0, 0));
+        it->SetComposition("", std::vector< std::pair<uint32_t, uint32_t> >(),
+                           0, std::make_pair(0, 0));
         return true;
       }
     }
diff --git a/ppapi/native_client/src/trusted/plugin/plugin.cc b/ppapi/native_client/src/trusted/plugin/plugin.cc
index 7b2f0a9..e1f3ad9 100644
--- a/ppapi/native_client/src/trusted/plugin/plugin.cc
+++ b/ppapi/native_client/src/trusted/plugin/plugin.cc
@@ -677,6 +677,7 @@ bool Plugin::Init(uint32_t argc, const char* argn[], const char* argv[]) {
   return status;
 }
 
+
 Plugin::Plugin(PP_Instance pp_instance)
     : pp::InstancePrivate(pp_instance),
       scriptable_plugin_(NULL),
@@ -687,6 +688,7 @@ Plugin::Plugin(PP_Instance pp_instance)
       nacl_ready_state_(UNSENT),
       nexe_error_reported_(false),
       wrapper_factory_(NULL),
+      last_error_string_(""),
       enable_dev_interfaces_(false),
       is_installed_(false),
       init_time_(0),
diff --git a/ppapi/native_client/src/trusted/plugin/plugin_error.h b/ppapi/native_client/src/trusted/plugin/plugin_error.h
index f02ef83..90c0284 100644
--- a/ppapi/native_client/src/trusted/plugin/plugin_error.h
+++ b/ppapi/native_client/src/trusted/plugin/plugin_error.h
@@ -109,7 +109,7 @@ class ErrorInfo {
   }
 
   void Reset() {
-    SetReport(ERROR_UNKNOWN, std::string());
+    SetReport(ERROR_UNKNOWN, "");
   }
 
   void SetReport(PluginErrorCode error_code, const std::string& message) {
diff --git a/ppapi/native_client/src/trusted/plugin/pnacl_translate_thread.cc b/ppapi/native_client/src/trusted/plugin/pnacl_translate_thread.cc
index ff0982e..a7d3f24 100644
--- a/ppapi/native_client/src/trusted/plugin/pnacl_translate_thread.cc
+++ b/ppapi/native_client/src/trusted/plugin/pnacl_translate_thread.cc
@@ -224,7 +224,9 @@ void PnaclTranslateThread::DoTranslate() {
   }
   PLUGIN_PRINTF(("PnaclTranslateThread done with chunks\n"));
   // Finish llc.
-  if (!llc_subprocess_->InvokeSrpcMethod("StreamEnd", std::string(), &params)) {
+  if(!llc_subprocess_->InvokeSrpcMethod("StreamEnd",
+                                       "",
+                                       &params)) {
     PLUGIN_PRINTF(("PnaclTranslateThread StreamEnd failed\n"));
     if (llc_subprocess_->srpc_client()->GetLastError() ==
         NACL_SRPC_RESULT_APP_ERROR) {
diff --git a/ppapi/native_client/src/trusted/plugin/service_runtime.cc b/ppapi/native_client/src/trusted/plugin/service_runtime.cc
index 68a50d3..00f64c7 100644
--- a/ppapi/native_client/src/trusted/plugin/service_runtime.cc
+++ b/ppapi/native_client/src/trusted/plugin/service_runtime.cc
@@ -846,7 +846,7 @@ nacl::string ServiceRuntime::GetCrashLogOutput() {
   if (NULL != subprocess_.get()) {
     return subprocess_->GetCrashLogOutput();
   } else {
-    return std::string();
+    return "";
   }
 }
 
diff --git a/ppapi/proxy/audio_input_resource.cc b/ppapi/proxy/audio_input_resource.cc
index 4f321c2..5f700ec 100644
--- a/ppapi/proxy/audio_input_resource.cc
+++ b/ppapi/proxy/audio_input_resource.cc
@@ -217,10 +217,7 @@ void AudioInputResource::SetStreamInfo(
   shared_memory_size_ = shared_memory_size;
 
   if (!shared_memory_->Map(shared_memory_size_)) {
-    PpapiGlobals::Get()->LogWithSource(
-        pp_instance(),
-        PP_LOGLEVEL_WARNING,
-        std::string(),
+    PpapiGlobals::Get()->LogWithSource(pp_instance(), PP_LOGLEVEL_WARNING, "",
         "Failed to map shared memory for PPB_AudioInput_Shared.");
   }
 
diff --git a/ppapi/shared_impl/ppb_audio_shared.cc b/ppapi/shared_impl/ppb_audio_shared.cc
index f6d0cac..f275559 100644
--- a/ppapi/shared_impl/ppb_audio_shared.cc
+++ b/ppapi/shared_impl/ppb_audio_shared.cc
@@ -80,11 +80,8 @@ void PPB_Audio_Shared::SetStreamInfo(
 
   if (!shared_memory_->Map(
           media::TotalSharedMemorySizeInBytes(shared_memory_size_))) {
-    PpapiGlobals::Get()->LogWithSource(
-        instance,
-        PP_LOGLEVEL_WARNING,
-        std::string(),
-        "Failed to map shared memory for PPB_Audio_Shared.");
+    PpapiGlobals::Get()->LogWithSource(instance, PP_LOGLEVEL_WARNING, "",
+      "Failed to map shared memory for PPB_Audio_Shared.");
   } else {
     audio_bus_ = media::AudioBus::WrapMemory(
         kChannels, sample_frame_count, shared_memory_->memory());
diff --git a/ppapi/tests/test_file_ref.cc b/ppapi/tests/test_file_ref.cc
index f3217f9..2dfea85 100644
--- a/ppapi/tests/test_file_ref.cc
+++ b/ppapi/tests/test_file_ref.cc
@@ -85,7 +85,7 @@ void TestFileRef::RunTests(const std::string& filter) {
 std::string TestFileRef::TestCreate() {
   std::vector<std::string> invalid_paths;
   invalid_paths.push_back("invalid_path");  // no '/' at the first character
-  invalid_paths.push_back(std::string());   // empty path
+  invalid_paths.push_back("");  // empty path
   // The following are directory traversal checks
   invalid_paths.push_back("..");
   invalid_paths.push_back("/../invalid_path");
diff --git a/ppapi/tests/test_flash_clipboard.cc b/ppapi/tests/test_flash_clipboard.cc
index 8eb756b..e38c145 100644
--- a/ppapi/tests/test_flash_clipboard.cc
+++ b/ppapi/tests/test_flash_clipboard.cc
@@ -253,7 +253,7 @@ std::string TestFlashClipboard::TestInvalidFormat() {
 std::string TestFlashClipboard::TestRegisterCustomFormat() {
   // Test an empty name is rejected.
   uint32_t format_id =
-      pp::flash::Clipboard::RegisterCustomFormat(instance_, std::string());
+      pp::flash::Clipboard::RegisterCustomFormat(instance_, "");
   ASSERT_EQ(format_id, PP_FLASH_CLIPBOARD_FORMAT_INVALID);
 
   // Test a valid format name.
diff --git a/ppapi/tests/test_flash_file.cc b/ppapi/tests/test_flash_file.cc
index e5a8ee9..86100d9 100644
--- a/ppapi/tests/test_flash_file.cc
+++ b/ppapi/tests/test_flash_file.cc
@@ -285,10 +285,12 @@ std::string TestFlashFile::TestGetDirContents() {
   CloseFileHandle(file_handle);
   ASSERT_TRUE(FileModuleLocal::CreateDir(instance_, dirname));
 
-  ASSERT_TRUE(
-      FileModuleLocal::GetDirContents(instance_, std::string(), &result));
-  FileModuleLocal::DirEntry expected[] = { { "..", true }, { filename, false },
-                                           { dirname, true } };
+  ASSERT_TRUE(FileModuleLocal::GetDirContents(instance_, "", &result));
+  FileModuleLocal::DirEntry expected[] =
+    { {"..", true},
+      {filename, false},
+      {dirname, true}
+    };
   size_t expected_size = sizeof(expected) / sizeof(expected[0]);
 
   std::sort(expected, expected + expected_size, DirEntryLessThan);
@@ -327,8 +329,7 @@ std::string TestFlashFile::TestCreateTemporaryFile() {
 std::string TestFlashFile::GetItemCountUnderModuleLocalRoot(
     size_t* item_count) {
   std::vector<FileModuleLocal::DirEntry> contents;
-  ASSERT_TRUE(
-      FileModuleLocal::GetDirContents(instance_, std::string(), &contents));
+  ASSERT_TRUE(FileModuleLocal::GetDirContents(instance_, "", &contents));
   *item_count = contents.size();
   PASS();
 }
diff --git a/ppapi/tests/test_ime_input_event.cc b/ppapi/tests/test_ime_input_event.cc
index 500fcbb..804e17d7a 100644
--- a/ppapi/tests/test_ime_input_event.cc
+++ b/ppapi/tests/test_ime_input_event.cc
@@ -357,11 +357,11 @@ std::string TestImeInputEvent::TestImeCancel() {
   expected_events_.clear();
   expected_events_.push_back(CreateImeCompositionStartEvent());
   expected_events_.push_back(update_event);
-  expected_events_.push_back(CreateImeCompositionEndEvent(std::string()));
+  expected_events_.push_back(CreateImeCompositionEndEvent(""));
 
   // Simulate the case when IME canceled composition.
   ASSERT_TRUE(SimulateInputEvent(update_event));
-  ASSERT_TRUE(SimulateInputEvent(CreateImeCompositionEndEvent(std::string())));
+  ASSERT_TRUE(SimulateInputEvent(CreateImeCompositionEndEvent("")));
 
   ASSERT_TRUE(expected_events_.empty());
   PASS();
@@ -417,7 +417,7 @@ std::string TestImeInputEvent::TestImeUnawareCancel() {
 
   // Test for IME-unaware plugins. Cancel won't issue any events.
   ASSERT_TRUE(SimulateInputEvent(update_event));
-  ASSERT_TRUE(SimulateInputEvent(CreateImeCompositionEndEvent(std::string())));
+  ASSERT_TRUE(SimulateInputEvent(CreateImeCompositionEndEvent("")));
 
   ASSERT_TRUE(expected_events_.empty());
   PASS();
diff --git a/ppapi/tests/test_url_loader.cc b/ppapi/tests/test_url_loader.cc
index 320167a..112a483 100644
--- a/ppapi/tests/test_url_loader.cc
+++ b/ppapi/tests/test_url_loader.cc
@@ -375,7 +375,7 @@ std::string TestURLLoader::TestEmptyDataPOST() {
   request.SetURL("/echo");
   request.SetMethod("POST");
   request.AppendDataToBody("", 0);
-  return LoadAndCompareBody(request, std::string());
+  return LoadAndCompareBody(request, "");
 }
 
 std::string TestURLLoader::TestBinaryDataPOST() {
@@ -558,12 +558,11 @@ std::string TestURLLoader::TestUntrustedHttpRequests() {
   // valid token (containing special characters like CR, LF).
   // http://www.w3.org/TR/XMLHttpRequest/
   {
-    ASSERT_EQ(OpenUntrusted("cOnNeCt", std::string()), PP_ERROR_NOACCESS);
-    ASSERT_EQ(OpenUntrusted("tRaCk", std::string()), PP_ERROR_NOACCESS);
-    ASSERT_EQ(OpenUntrusted("tRaCe", std::string()), PP_ERROR_NOACCESS);
-    ASSERT_EQ(
-        OpenUntrusted("POST\x0d\x0ax-csrf-token:\x20test1234", std::string()),
-        PP_ERROR_NOACCESS);
+    ASSERT_EQ(OpenUntrusted("cOnNeCt", ""), PP_ERROR_NOACCESS);
+    ASSERT_EQ(OpenUntrusted("tRaCk", ""), PP_ERROR_NOACCESS);
+    ASSERT_EQ(OpenUntrusted("tRaCe", ""), PP_ERROR_NOACCESS);
+    ASSERT_EQ(OpenUntrusted("POST\x0d\x0ax-csrf-token:\x20test1234", ""),
+                            PP_ERROR_NOACCESS);
   }
   // HTTP methods are restricted only for untrusted loaders. Try all headers
   // that are forbidden by http://www.w3.org/TR/XMLHttpRequest/.
@@ -620,9 +619,9 @@ std::string TestURLLoader::TestUntrustedHttpRequests() {
 std::string TestURLLoader::TestTrustedHttpRequests() {
   // Trusted requests can use restricted methods.
   {
-    ASSERT_EQ(OpenTrusted("cOnNeCt", std::string()), PP_OK);
-    ASSERT_EQ(OpenTrusted("tRaCk", std::string()), PP_OK);
-    ASSERT_EQ(OpenTrusted("tRaCe", std::string()), PP_OK);
+    ASSERT_EQ(OpenTrusted("cOnNeCt", ""), PP_OK);
+    ASSERT_EQ(OpenTrusted("tRaCk", ""), PP_OK);
+    ASSERT_EQ(OpenTrusted("tRaCe", ""), PP_OK);
   }
   // Trusted requests can use restricted headers.
   {
diff --git a/ppapi/tests/test_websocket.cc b/ppapi/tests/test_websocket.cc
index 61a8e19..e61185d 100644
--- a/ppapi/tests/test_websocket.cc
+++ b/ppapi/tests/test_websocket.cc
@@ -350,18 +350,18 @@ std::string TestWebSocket::TestUninitializedPropertiesAccess() {
   ASSERT_EQ(0U, close_code);
 
   PP_Var close_reason = websocket_interface_->GetCloseReason(ws);
-  ASSERT_TRUE(AreEqualWithString(close_reason, std::string()));
+  ASSERT_TRUE(AreEqualWithString(close_reason, ""));
   ReleaseVar(close_reason);
 
   PP_Bool close_was_clean = websocket_interface_->GetCloseWasClean(ws);
   ASSERT_EQ(PP_FALSE, close_was_clean);
 
   PP_Var extensions = websocket_interface_->GetExtensions(ws);
-  ASSERT_TRUE(AreEqualWithString(extensions, std::string()));
+  ASSERT_TRUE(AreEqualWithString(extensions, ""));
   ReleaseVar(extensions);
 
   PP_Var protocol = websocket_interface_->GetProtocol(ws);
-  ASSERT_TRUE(AreEqualWithString(protocol, std::string()));
+  ASSERT_TRUE(AreEqualWithString(protocol, ""));
   ReleaseVar(protocol);
 
   PP_WebSocketReadyState ready_state =
@@ -369,7 +369,7 @@ std::string TestWebSocket::TestUninitializedPropertiesAccess() {
   ASSERT_EQ(PP_WEBSOCKETREADYSTATE_INVALID, ready_state);
 
   PP_Var url = websocket_interface_->GetURL(ws);
-  ASSERT_TRUE(AreEqualWithString(url, std::string()));
+  ASSERT_TRUE(AreEqualWithString(url, ""));
   ReleaseVar(url);
 
   core_interface_->ReleaseResource(ws);
@@ -398,7 +398,7 @@ std::string TestWebSocket::TestInvalidConnect() {
 
   for (int i = 0; kInvalidURLs[i]; ++i) {
     int32_t result;
-    ws = Connect(kInvalidURLs[i], &result, std::string());
+    ws = Connect(kInvalidURLs[i], &result, "");
     ASSERT_TRUE(ws);
     ASSERT_EQ(PP_ERROR_BADARGUMENT, result);
 
@@ -448,7 +448,7 @@ std::string TestWebSocket::TestProtocols() {
 std::string TestWebSocket::TestGetURL() {
   for (int i = 0; kInvalidURLs[i]; ++i) {
     int32_t result;
-    PP_Resource ws = Connect(kInvalidURLs[i], &result, std::string());
+    PP_Resource ws = Connect(kInvalidURLs[i], &result, "");
     ASSERT_TRUE(ws);
     PP_Var url = websocket_interface_->GetURL(ws);
     ASSERT_TRUE(AreEqualWithString(url, kInvalidURLs[i]));
@@ -463,11 +463,11 @@ std::string TestWebSocket::TestGetURL() {
 
 std::string TestWebSocket::TestValidConnect() {
   int32_t result;
-  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   PP_Var extensions = websocket_interface_->GetExtensions(ws);
-  ASSERT_TRUE(AreEqualWithString(extensions, std::string()));
+  ASSERT_TRUE(AreEqualWithString(extensions, ""));
   core_interface_->ReleaseResource(ws);
   ReleaseVar(extensions);
 
@@ -489,7 +489,7 @@ std::string TestWebSocket::TestInvalidClose() {
 
   // Close with bad arguments.
   int32_t result;
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   callback.WaitForResult(websocket_interface_->Close(
@@ -498,7 +498,7 @@ std::string TestWebSocket::TestInvalidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close with PP_VARTYPE_NULL.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   callback.WaitForResult(websocket_interface_->Close(
@@ -508,7 +508,7 @@ std::string TestWebSocket::TestInvalidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close with PP_VARTYPE_NULL and ongoing receive message.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   PP_Var receive_message_var;
@@ -532,7 +532,7 @@ std::string TestWebSocket::TestInvalidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close twice.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   result = websocket_interface_->Close(
@@ -569,7 +569,7 @@ std::string TestWebSocket::TestValidClose() {
 
   // Close.
   int32_t result;
-  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   callback.WaitForResult(websocket_interface_->Close(
@@ -580,7 +580,7 @@ std::string TestWebSocket::TestValidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close without code and reason.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   callback.WaitForResult(websocket_interface_->Close(
@@ -590,7 +590,7 @@ std::string TestWebSocket::TestValidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close with PP_VARTYPE_UNDEFINED.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   callback.WaitForResult(websocket_interface_->Close(
@@ -620,7 +620,7 @@ std::string TestWebSocket::TestValidClose() {
   // Close in closing.
   // The first close will be done successfully, then the second one failed with
   // with PP_ERROR_INPROGRESS immediately.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   result = websocket_interface_->Close(
@@ -636,7 +636,7 @@ std::string TestWebSocket::TestValidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close with ongoing receive message.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   PP_Var receive_message_var;
@@ -655,7 +655,7 @@ std::string TestWebSocket::TestValidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Close with PP_VARTYPE_UNDEFINED and ongoing receive message.
-  ws = Connect(GetFullURL(kEchoServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kEchoServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   result = websocket_interface_->ReceiveMessage(
@@ -673,8 +673,7 @@ std::string TestWebSocket::TestValidClose() {
   core_interface_->ReleaseResource(ws);
 
   // Server initiated closing handshake.
-  ws = Connect(
-      GetFullURL(kCloseWithCodeAndReasonServerURL), &result, std::string());
+  ws = Connect(GetFullURL(kCloseWithCodeAndReasonServerURL), &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   // Text messsage "1000 bye" requests the server to initiate closing handshake
@@ -721,8 +720,7 @@ std::string TestWebSocket::TestGetProtocol() {
 std::string TestWebSocket::TestTextSendReceive() {
   // Connect to test echo server.
   int32_t connect_result;
-  PP_Resource ws =
-      Connect(GetFullURL(kEchoServerURL), &connect_result, std::string());
+  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &connect_result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, connect_result);
 
@@ -749,8 +747,7 @@ std::string TestWebSocket::TestTextSendReceive() {
 std::string TestWebSocket::TestBinarySendReceive() {
   // Connect to test echo server.
   int32_t connect_result;
-  PP_Resource ws =
-      Connect(GetFullURL(kEchoServerURL), &connect_result, std::string());
+  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &connect_result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, connect_result);
 
@@ -779,8 +776,7 @@ std::string TestWebSocket::TestBinarySendReceive() {
 std::string TestWebSocket::TestStressedSendReceive() {
   // Connect to test echo server.
   int32_t connect_result;
-  PP_Resource ws =
-      Connect(GetFullURL(kEchoServerURL), &connect_result, std::string());
+  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &connect_result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, connect_result);
 
@@ -840,8 +836,7 @@ std::string TestWebSocket::TestStressedSendReceive() {
 std::string TestWebSocket::TestBufferedAmount() {
   // Connect to test echo server.
   int32_t connect_result;
-  PP_Resource ws =
-      Connect(GetFullURL(kEchoServerURL), &connect_result, std::string());
+  PP_Resource ws = Connect(GetFullURL(kEchoServerURL), &connect_result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, connect_result);
 
@@ -881,7 +876,7 @@ std::string TestWebSocket::TestBufferedAmount() {
 
   // After connection closure, all sending requests fail and just increase
   // the bufferedAmount property.
-  PP_Var empty_string = CreateVarString(std::string());
+  PP_Var empty_string = CreateVarString("");
   result = websocket_interface_->SendMessage(ws, empty_string);
   ASSERT_EQ(PP_ERROR_FAILED, result);
   buffered_amount = websocket_interface_->GetBufferedAmount(ws);
@@ -924,7 +919,7 @@ std::string TestWebSocket::TestAbortCallsWithCallback() {
   ASSERT_EQ(PP_ERROR_ABORTED, connect_callback.result());
 
   // Test the behavior for Close().
-  ws = Connect(url, &result, std::string());
+  ws = Connect(url, &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   PP_Var reason_var = CreateVarString("abort");
@@ -941,7 +936,7 @@ std::string TestWebSocket::TestAbortCallsWithCallback() {
 
   // Test the behavior for ReceiveMessage().
   // Make sure the simplest case to wait for data which never arrives, here.
-  ws = Connect(url, &result, std::string());
+  ws = Connect(url, &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   PP_Var receive_var;
@@ -957,7 +952,7 @@ std::string TestWebSocket::TestAbortCallsWithCallback() {
 
   // Release the resource in the aborting receive completion callback which is
   // introduced by calling Close().
-  ws = Connect(url, &result, std::string());
+  ws = Connect(url, &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   result = websocket_interface_->ReceiveMessage(
@@ -991,7 +986,7 @@ std::string TestWebSocket::TestAbortSendMessageCall() {
 
   int32_t result;
   std::string url = GetFullURL(kEchoServerURL);
-  PP_Resource ws = Connect(url, &result, std::string());
+  PP_Resource ws = Connect(url, &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   result = websocket_interface_->SendMessage(ws, large_var);
@@ -1006,7 +1001,7 @@ std::string TestWebSocket::TestAbortCloseCall() {
   // Release the resource in the close completion callback.
   int32_t result;
   std::string url = GetFullURL(kEchoServerURL);
-  PP_Resource ws = Connect(url, &result, std::string());
+  PP_Resource ws = Connect(url, &result, "");
   ASSERT_TRUE(ws);
   ASSERT_EQ(PP_OK, result);
   TestCompletionCallback close_callback(
@@ -1039,7 +1034,7 @@ std::string TestWebSocket::TestAbortReceiveMessageCall() {
   // released while the next message is going to be received.
   const int trial_count = 8;
   for (int trial = 1; trial <= trial_count; trial++) {
-    ws = Connect(url, &result, std::string());
+    ws = Connect(url, &result, "");
     ASSERT_TRUE(ws);
     ASSERT_EQ(PP_OK, result);
     for (int i = 0; i <= trial_count; ++i) {
@@ -1065,7 +1060,7 @@ std::string TestWebSocket::TestAbortReceiveMessageCall() {
   }
   // Same test, but the last receiving message is large message over 64KiB.
   for (int trial = 1; trial <= trial_count; trial++) {
-    ws = Connect(url, &result, std::string());
+    ws = Connect(url, &result, "");
     ASSERT_TRUE(ws);
     ASSERT_EQ(PP_OK, result);
     for (int i = 0; i <= trial_count; ++i) {
@@ -1107,12 +1102,12 @@ std::string TestWebSocket::TestCcInterfaces() {
   // Check uninitialized properties access.
   ASSERT_EQ(0, ws.GetBufferedAmount());
   ASSERT_EQ(0, ws.GetCloseCode());
-  ASSERT_TRUE(AreEqualWithString(ws.GetCloseReason().pp_var(), std::string()));
+  ASSERT_TRUE(AreEqualWithString(ws.GetCloseReason().pp_var(), ""));
   ASSERT_EQ(false, ws.GetCloseWasClean());
-  ASSERT_TRUE(AreEqualWithString(ws.GetExtensions().pp_var(), std::string()));
-  ASSERT_TRUE(AreEqualWithString(ws.GetProtocol().pp_var(), std::string()));
+  ASSERT_TRUE(AreEqualWithString(ws.GetExtensions().pp_var(), ""));
+  ASSERT_TRUE(AreEqualWithString(ws.GetProtocol().pp_var(), ""));
   ASSERT_EQ(PP_WEBSOCKETREADYSTATE_INVALID, ws.GetReadyState());
-  ASSERT_TRUE(AreEqualWithString(ws.GetURL().pp_var(), std::string()));
+  ASSERT_TRUE(AreEqualWithString(ws.GetURL().pp_var(), ""));
 
   // Check communication interfaces (connect, send, receive, and close).
   TestCompletionCallback connect_callback(
@@ -1168,7 +1163,7 @@ std::string TestWebSocket::TestCcInterfaces() {
   ASSERT_TRUE(
       AreEqualWithString(ws.GetCloseReason().pp_var(), reason.c_str()));
   ASSERT_EQ(true, ws.GetCloseWasClean());
-  ASSERT_TRUE(AreEqualWithString(ws.GetProtocol().pp_var(), std::string()));
+  ASSERT_TRUE(AreEqualWithString(ws.GetProtocol().pp_var(), ""));
   ASSERT_EQ(PP_WEBSOCKETREADYSTATE_CLOSED, ws.GetReadyState());
   ASSERT_TRUE(AreEqualWithString(
       ws.GetURL().pp_var(), GetFullURL(kCloseServerURL).c_str()));
@@ -1273,8 +1268,7 @@ std::string TestWebSocket::TestUtilityValidConnect() {
   const std::vector<WebSocketEvent>& events = websocket.GetSeenEvents();
   ASSERT_EQ(1U, events.size());
   ASSERT_EQ(WebSocketEvent::EVENT_OPEN, events[0].event_type);
-  ASSERT_TRUE(
-      AreEqualWithString(websocket.GetExtensions().pp_var(), std::string()));
+  ASSERT_TRUE(AreEqualWithString(websocket.GetExtensions().pp_var(), ""));
 
   PASS();
 }
@@ -1502,7 +1496,7 @@ std::string TestWebSocket::TestUtilityBufferedAmount() {
 
   // After connection closure, all sending requests fail and just increase
   // the bufferedAmount property.
-  result = websocket.Send(pp::Var(std::string()));
+  result = websocket.Send(pp::Var(std::string("")));
   ASSERT_EQ(PP_ERROR_FAILED, result);
   buffered_amount = websocket.GetBufferedAmount();
   ASSERT_EQ(base_buffered_amount + kMessageFrameOverhead, buffered_amount);
diff --git a/ppapi/tests/test_x509_certificate_private.cc b/ppapi/tests/test_x509_certificate_private.cc
index fab2f21..6aee30f 100644
--- a/ppapi/tests/test_x509_certificate_private.cc
+++ b/ppapi/tests/test_x509_certificate_private.cc
@@ -166,30 +166,22 @@ std::string TestX509CertificatePrivate::TestValidCertificate() {
       PP_X509CERTIFICATE_PRIVATE_SUBJECT_COUNTRY_NAME, "US"));
   ASSERT_TRUE(FieldMatchesString(certificate,
       PP_X509CERTIFICATE_PRIVATE_SUBJECT_ORGANIZATION_NAME, "Google Inc"));
-  ASSERT_TRUE(FieldMatchesString(
-      certificate,
-      PP_X509CERTIFICATE_PRIVATE_SUBJECT_ORGANIZATION_UNIT_NAME,
-      std::string()));
+  ASSERT_TRUE(FieldMatchesString(certificate,
+      PP_X509CERTIFICATE_PRIVATE_SUBJECT_ORGANIZATION_UNIT_NAME, ""));
 
   ASSERT_TRUE(FieldMatchesString(certificate,
       PP_X509CERTIFICATE_PRIVATE_ISSUER_COMMON_NAME, "Thawte SGC CA"));
-  ASSERT_TRUE(
-      FieldMatchesString(certificate,
-                         PP_X509CERTIFICATE_PRIVATE_ISSUER_LOCALITY_NAME,
-                         std::string()));
-  ASSERT_TRUE(FieldMatchesString(
-      certificate,
-      PP_X509CERTIFICATE_PRIVATE_ISSUER_STATE_OR_PROVINCE_NAME,
-      std::string()));
-  ASSERT_TRUE(FieldMatchesString(
-      certificate, PP_X509CERTIFICATE_PRIVATE_ISSUER_COUNTRY_NAME, "ZA"));
+  ASSERT_TRUE(FieldMatchesString(certificate,
+      PP_X509CERTIFICATE_PRIVATE_ISSUER_LOCALITY_NAME, ""));
+  ASSERT_TRUE(FieldMatchesString(certificate,
+      PP_X509CERTIFICATE_PRIVATE_ISSUER_STATE_OR_PROVINCE_NAME, ""));
+  ASSERT_TRUE(FieldMatchesString(certificate,
+      PP_X509CERTIFICATE_PRIVATE_ISSUER_COUNTRY_NAME, "ZA"));
   ASSERT_TRUE(FieldMatchesString(certificate,
       PP_X509CERTIFICATE_PRIVATE_ISSUER_ORGANIZATION_NAME,
       "Thawte Consulting (Pty) Ltd."));
-  ASSERT_TRUE(FieldMatchesString(
-      certificate,
-      PP_X509CERTIFICATE_PRIVATE_ISSUER_ORGANIZATION_UNIT_NAME,
-      std::string()));
+  ASSERT_TRUE(FieldMatchesString(certificate,
+      PP_X509CERTIFICATE_PRIVATE_ISSUER_ORGANIZATION_UNIT_NAME, ""));
 
   ASSERT_FALSE(FieldIsNull(certificate,
       PP_X509CERTIFICATE_PRIVATE_SERIAL_NUMBER));
diff --git a/remoting/client/plugin/chromoting_instance.cc b/remoting/client/plugin/chromoting_instance.cc
index 057c4a1..aff8c10 100644
--- a/remoting/client/plugin/chromoting_instance.cc
+++ b/remoting/client/plugin/chromoting_instance.cc
@@ -81,7 +81,7 @@ std::string ConnectionStateToString(protocol::ConnectionToHost::State state) {
       return "FAILED";
   }
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 // TODO(sergeyu): Ideally we should just pass ErrorCode to the webapp
@@ -115,7 +115,7 @@ std::string ConnectionErrorToString(protocol::ErrorCode error) {
       return "NETWORK_FAILURE";
   }
   DLOG(FATAL) << "Unknown error code" << error;
-  return std::string();
+  return  "";
 }
 
 // This flag blocks LOGs to the UI if we're already in the middle of logging
diff --git a/remoting/client/plugin/pepper_port_allocator.cc b/remoting/client/plugin/pepper_port_allocator.cc
index 423102a..62a5822 100644
--- a/remoting/client/plugin/pepper_port_allocator.cc
+++ b/remoting/client/plugin/pepper_port_allocator.cc
@@ -82,15 +82,9 @@ PepperPortAllocatorSession::PepperPortAllocatorSession(
     const std::vector<std::string>& relay_hosts,
     const std::string& relay_token,
     const pp::InstanceHandle& instance)
-    : HttpPortAllocatorSessionBase(allocator,
-                                   content_name,
-                                   component,
-                                   ice_username_fragment,
-                                   ice_password,
-                                   stun_hosts,
-                                   relay_hosts,
-                                   relay_token,
-                                   std::string()),
+    : HttpPortAllocatorSessionBase(
+        allocator, content_name, component, ice_username_fragment, ice_password,
+        stun_hosts, relay_hosts, relay_token, ""),
       instance_(instance),
       stun_address_resolver_(instance_),
       stun_port_(0),
@@ -135,7 +129,7 @@ void PepperPortAllocatorSession::GetPortConfigurations() {
   // Add an empty configuration synchronously, so a local connection
   // can be started immediately.
   ConfigReady(new cricket::PortConfiguration(
-      talk_base::SocketAddress(), std::string(), std::string()));
+      talk_base::SocketAddress(), "", ""));
 
   ResolveStunServerAddress();
   TryCreateRelaySession();
@@ -201,8 +195,7 @@ void PepperPortAllocatorSession::OnStunAddressResolved(int32_t result) {
     ReceiveSessionResponse(std::string(relay_response_body_.begin(),
                                        relay_response_body_.end()));
   } else {
-    ConfigReady(new cricket::PortConfiguration(
-        stun_address_, std::string(), std::string()));
+    ConfigReady(new cricket::PortConfiguration(stun_address_, "", ""));
   }
 }
 
@@ -311,9 +304,7 @@ PepperPortAllocator::PepperPortAllocator(
     const pp::InstanceHandle& instance,
     scoped_ptr<talk_base::NetworkManager> network_manager,
     scoped_ptr<talk_base::PacketSocketFactory> socket_factory)
-    : HttpPortAllocatorBase(network_manager.get(),
-                            socket_factory.get(),
-                            std::string()),
+    : HttpPortAllocatorBase(network_manager.get(), socket_factory.get(), ""),
       instance_(instance),
       network_manager_(network_manager.Pass()),
       socket_factory_(socket_factory.Pass()) {
diff --git a/remoting/host/desktop_process_unittest.cc b/remoting/host/desktop_process_unittest.cc
index bc50988..b861cf0 100644
--- a/remoting/host/desktop_process_unittest.cc
+++ b/remoting/host/desktop_process_unittest.cc
@@ -172,7 +172,7 @@ void DesktopProcessTest::ConnectNetworkChannel(
     IPC::PlatformFileForTransit desktop_process) {
 
 #if defined(OS_POSIX)
-  IPC::ChannelHandle channel_handle(std::string(), desktop_process);
+  IPC::ChannelHandle channel_handle("", desktop_process);
 #elif defined(OS_WIN)
   IPC::ChannelHandle channel_handle(desktop_process);
 #endif  // defined(OS_WIN)
diff --git a/remoting/host/desktop_session_proxy.cc b/remoting/host/desktop_session_proxy.cc
index 04add54..05a8188 100644
--- a/remoting/host/desktop_session_proxy.cc
+++ b/remoting/host/desktop_session_proxy.cc
@@ -143,7 +143,7 @@ bool DesktopSessionProxy::AttachToDesktop(
   // On posix: |desktop_pipe| is a valid file descriptor.
   DCHECK(desktop_pipe.auto_close);
 
-  IPC::ChannelHandle desktop_channel_handle(std::string(), desktop_pipe);
+  IPC::ChannelHandle desktop_channel_handle("", desktop_pipe);
 
 #else
 #error Unsupported platform.
diff --git a/remoting/host/heartbeat_sender_unittest.cc b/remoting/host/heartbeat_sender_unittest.cc
index ea5eeb8..99880b4 100644
--- a/remoting/host/heartbeat_sender_unittest.cc
+++ b/remoting/host/heartbeat_sender_unittest.cc
@@ -176,9 +176,9 @@ TEST_F(HeartbeatSenderTest, DoSendStanzaWithExpectedSequenceId) {
       .WillOnce(DoAll(SaveArg<0>(&sent_iq2), Return(true)));
 
   scoped_ptr<XmlElement> response(new XmlElement(buzz::QN_IQ));
-  response->AddAttr(QName(std::string(), "type"), "result");
-  XmlElement* result =
-      new XmlElement(QName(kChromotingXmlNamespace, "heartbeat-result"));
+  response->AddAttr(QName("", "type"), "result");
+  XmlElement* result = new XmlElement(
+      QName(kChromotingXmlNamespace, "heartbeat-result"));
   response->AddElement(result);
   XmlElement* expected_sequence_id = new XmlElement(
       QName(kChromotingXmlNamespace, "expected-sequence-id"));
@@ -200,7 +200,7 @@ TEST_F(HeartbeatSenderTest, DoSendStanzaWithExpectedSequenceId) {
 // Verify that ProcessResponse parses set-interval result.
 TEST_F(HeartbeatSenderTest, ProcessResponseSetInterval) {
   scoped_ptr<XmlElement> response(new XmlElement(buzz::QN_IQ));
-  response->AddAttr(QName(std::string(), "type"), "result");
+  response->AddAttr(QName("", "type"), "result");
 
   XmlElement* result = new XmlElement(
       QName(kChromotingXmlNamespace, "heartbeat-result"));
@@ -221,9 +221,9 @@ TEST_F(HeartbeatSenderTest, ProcessResponseSetInterval) {
 // Validate a heartbeat stanza.
 void HeartbeatSenderTest::ValidateHeartbeatStanza(
     XmlElement* stanza, const char* expectedSequenceId) {
-  EXPECT_EQ(stanza->Attr(buzz::QName(std::string(), "to")),
+  EXPECT_EQ(stanza->Attr(buzz::QName("", "to")),
             std::string(kTestBotJid));
-  EXPECT_EQ(stanza->Attr(buzz::QName(std::string(), "type")), "set");
+  EXPECT_EQ(stanza->Attr(buzz::QName("", "type")), "set");
   XmlElement* heartbeat_stanza =
       stanza->FirstNamed(QName(kChromotingXmlNamespace, "heartbeat"));
   ASSERT_TRUE(heartbeat_stanza != NULL);
diff --git a/remoting/host/host_change_notification_listener_unittest.cc b/remoting/host/host_change_notification_listener_unittest.cc
index 5ec6ff8..1f9305e 100644
--- a/remoting/host/host_change_notification_listener_unittest.cc
+++ b/remoting/host/host_change_notification_listener_unittest.cc
@@ -69,9 +69,9 @@ class HostChangeNotificationListenerTest : public testing::Test {
                                                std::string hostId,
                                                std::string botJid) {
     scoped_ptr<XmlElement> stanza(new XmlElement(buzz::QN_IQ));
-    stanza->AddAttr(QName(std::string(), "type"), "set");
-    XmlElement* host_changed =
-        new XmlElement(QName(kChromotingXmlNamespace, "host-changed"));
+    stanza->AddAttr(QName("", "type"), "set");
+    XmlElement* host_changed = new XmlElement(
+        QName(kChromotingXmlNamespace, "host-changed"));
     host_changed->AddAttr(QName(kChromotingXmlNamespace, "operation"),
                           operation);
     host_changed->AddAttr(QName(kChromotingXmlNamespace, "hostid"), hostId);
diff --git a/remoting/host/host_port_allocator.cc b/remoting/host/host_port_allocator.cc
index cf8a84c..ba53322 100644
--- a/remoting/host/host_port_allocator.cc
+++ b/remoting/host/host_port_allocator.cc
@@ -59,16 +59,11 @@ HostPortAllocatorSession::HostPortAllocatorSession(
     const std::vector<std::string>& relay_hosts,
     const std::string& relay,
     const scoped_refptr<net::URLRequestContextGetter>& url_context)
-    : HttpPortAllocatorSessionBase(allocator,
-                                   content_name,
-                                   component,
-                                   ice_username_fragment,
-                                   ice_password,
-                                   stun_hosts,
-                                   relay_hosts,
-                                   relay,
-                                   std::string()),
-      url_context_(url_context) {}
+    : HttpPortAllocatorSessionBase(
+        allocator, content_name, component, ice_username_fragment, ice_password,
+        stun_hosts, relay_hosts, relay, ""),
+      url_context_(url_context) {
+}
 
 HostPortAllocatorSession::~HostPortAllocatorSession() {
   STLDeleteElements(&url_fetchers_);
@@ -162,12 +157,11 @@ HostPortAllocator::HostPortAllocator(
     const scoped_refptr<net::URLRequestContextGetter>& url_context,
     scoped_ptr<talk_base::NetworkManager> network_manager,
     scoped_ptr<talk_base::PacketSocketFactory> socket_factory)
-    : HttpPortAllocatorBase(network_manager.get(),
-                            socket_factory.get(),
-                            std::string()),
+    : HttpPortAllocatorBase(network_manager.get(), socket_factory.get(), ""),
       url_context_(url_context),
       network_manager_(network_manager.Pass()),
-      socket_factory_(socket_factory.Pass()) {}
+      socket_factory_(socket_factory.Pass()) {
+}
 
 HostPortAllocator::~HostPortAllocator() {
 }
diff --git a/remoting/host/log_to_server_unittest.cc b/remoting/host/log_to_server_unittest.cc
index 99a51ec..1fb0500 100644
--- a/remoting/host/log_to_server_unittest.cc
+++ b/remoting/host/log_to_server_unittest.cc
@@ -36,12 +36,11 @@ const char kHostJid[] = "host@domain.com/1234";
 
 bool IsLogEntryForConnection(XmlElement* node, const char* connection_type) {
   return (node->Name() == QName(kChromotingNamespace, "entry") &&
-          node->Attr(QName(std::string(), "event-name")) == "session-state" &&
-          node->Attr(QName(std::string(), "session-state")) == "connected" &&
-          node->Attr(QName(std::string(), "role")) == "host" &&
-          node->Attr(QName(std::string(), "mode")) == "me2me" &&
-          node->Attr(QName(std::string(), "connection-type")) ==
-              connection_type);
+          node->Attr(QName("", "event-name")) == "session-state" &&
+          node->Attr(QName("", "session-state")) == "connected" &&
+          node->Attr(QName("", "role")) == "host" &&
+          node->Attr(QName("", "mode")) == "me2me" &&
+          node->Attr(QName("", "connection-type")) == connection_type);
 }
 
 MATCHER_P(IsClientConnected, connection_type, "") {
@@ -92,10 +91,10 @@ MATCHER_P2(IsTwoClientsConnected, connection_type1, connection_type2, "") {
 
 bool IsLogEntryForDisconnection(XmlElement* node) {
   return (node->Name() == QName(kChromotingNamespace, "entry") &&
-          node->Attr(QName(std::string(), "event-name")) == "session-state" &&
-          node->Attr(QName(std::string(), "session-state")) == "closed" &&
-          node->Attr(QName(std::string(), "role")) == "host" &&
-          node->Attr(QName(std::string(), "mode")) == "me2me");
+          node->Attr(QName("", "event-name")) == "session-state" &&
+          node->Attr(QName("", "session-state")) == "closed" &&
+          node->Attr(QName("", "role")) == "host" &&
+          node->Attr(QName("", "mode")) == "me2me");
 }
 
 MATCHER(IsClientDisconnected, "") {
diff --git a/remoting/host/policy_hack/policy_watcher_unittest.cc b/remoting/host/policy_hack/policy_watcher_unittest.cc
index ff1aa8a..d323718 100644
--- a/remoting/host/policy_hack/policy_watcher_unittest.cc
+++ b/remoting/host/policy_hack/policy_watcher_unittest.cc
@@ -29,8 +29,7 @@ class PolicyWatcherTest : public testing::Test {
     nat_true_.SetBoolean(PolicyWatcher::kNatPolicyName, true);
     nat_false_.SetBoolean(PolicyWatcher::kNatPolicyName, false);
     nat_one_.SetInteger(PolicyWatcher::kNatPolicyName, 1);
-    domain_empty_.SetString(PolicyWatcher::kHostDomainPolicyName,
-                            std::string());
+    domain_empty_.SetString(PolicyWatcher::kHostDomainPolicyName, "");
     domain_full_.SetString(PolicyWatcher::kHostDomainPolicyName, kHostDomain);
     SetDefaults(nat_true_others_default_);
     nat_true_others_default_.SetBoolean(PolicyWatcher::kNatPolicyName, true);
@@ -38,19 +37,17 @@ class PolicyWatcherTest : public testing::Test {
     nat_false_others_default_.SetBoolean(PolicyWatcher::kNatPolicyName, false);
     SetDefaults(domain_empty_others_default_);
     domain_empty_others_default_.SetString(PolicyWatcher::kHostDomainPolicyName,
-                                           std::string());
+                                           "");
     SetDefaults(domain_full_others_default_);
     domain_full_others_default_.SetString(PolicyWatcher::kHostDomainPolicyName,
                                           kHostDomain);
     nat_true_domain_empty_.SetBoolean(PolicyWatcher::kNatPolicyName, true);
-    nat_true_domain_empty_.SetString(PolicyWatcher::kHostDomainPolicyName,
-                                     std::string());
+    nat_true_domain_empty_.SetString(PolicyWatcher::kHostDomainPolicyName, "");
     nat_true_domain_full_.SetBoolean(PolicyWatcher::kNatPolicyName, true);
     nat_true_domain_full_.SetString(PolicyWatcher::kHostDomainPolicyName,
                                    kHostDomain);
     nat_false_domain_empty_.SetBoolean(PolicyWatcher::kNatPolicyName, false);
-    nat_false_domain_empty_.SetString(PolicyWatcher::kHostDomainPolicyName,
-                                      std::string());
+    nat_false_domain_empty_.SetString(PolicyWatcher::kHostDomainPolicyName, "");
     nat_false_domain_full_.SetBoolean(PolicyWatcher::kNatPolicyName, false);
     nat_false_domain_full_.SetString(PolicyWatcher::kHostDomainPolicyName,
                                     kHostDomain);
@@ -58,9 +55,9 @@ class PolicyWatcherTest : public testing::Test {
     nat_true_domain_empty_others_default_.SetBoolean(
         PolicyWatcher::kNatPolicyName, true);
     nat_true_domain_empty_others_default_.SetString(
-        PolicyWatcher::kHostDomainPolicyName, std::string());
-    unknown_policies_.SetString("UnknownPolicyOne", std::string());
-    unknown_policies_.SetString("UnknownPolicyTwo", std::string());
+        PolicyWatcher::kHostDomainPolicyName, "");
+    unknown_policies_.SetString("UnknownPolicyOne", "");
+    unknown_policies_.SetString("UnknownPolicyTwo", "");
 
     const char kOverrideNatTraversalToFalse[] =
       "{ \"RemoteAccessHostFirewallTraversal\": false }";
@@ -120,14 +117,13 @@ class PolicyWatcherTest : public testing::Test {
   void SetDefaults(base::DictionaryValue& dict) {
     dict.SetBoolean(PolicyWatcher::kNatPolicyName, true);
     dict.SetBoolean(PolicyWatcher::kHostRequireTwoFactorPolicyName, false);
-    dict.SetString(PolicyWatcher::kHostDomainPolicyName, std::string());
+    dict.SetString(PolicyWatcher::kHostDomainPolicyName, "");
     dict.SetBoolean(PolicyWatcher::kHostMatchUsernamePolicyName, false);
     dict.SetString(PolicyWatcher::kHostTalkGadgetPrefixPolicyName,
                    kDefaultHostTalkGadgetPrefix);
     dict.SetBoolean(PolicyWatcher::kHostRequireCurtainPolicyName, false);
-    dict.SetString(PolicyWatcher::kHostTokenUrlPolicyName, std::string());
-    dict.SetString(PolicyWatcher::kHostTokenValidationUrlPolicyName,
-                   std::string());
+    dict.SetString(PolicyWatcher::kHostTokenUrlPolicyName, "");
+    dict.SetString(PolicyWatcher::kHostTokenValidationUrlPolicyName, "");
 #if !defined(NDEBUG)
     dict.SetString(PolicyWatcher::kHostDebugOverridePoliciesName, "");
 #endif
diff --git a/remoting/host/register_support_host_request_unittest.cc b/remoting/host/register_support_host_request_unittest.cc
index 6080304..cd5da6e 100644
--- a/remoting/host/register_support_host_request_unittest.cc
+++ b/remoting/host/register_support_host_request_unittest.cc
@@ -99,9 +99,9 @@ TEST_F(RegisterSupportHostRequestTest, Send) {
   scoped_ptr<XmlElement> stanza(sent_iq);
   ASSERT_TRUE(stanza != NULL);
 
-  EXPECT_EQ(stanza->Attr(buzz::QName(std::string(), "to")),
+  EXPECT_EQ(stanza->Attr(buzz::QName("", "to")),
             std::string(kTestBotJid));
-  EXPECT_EQ(stanza->Attr(buzz::QName(std::string(), "type")), "set");
+  EXPECT_EQ(stanza->Attr(buzz::QName("", "type")), "set");
 
   EXPECT_EQ(QName(kChromotingXmlNamespace, "register-support-host"),
             stanza->FirstElement()->Name());
@@ -131,9 +131,9 @@ TEST_F(RegisterSupportHostRequestTest, Send) {
                                     base::TimeDelta::FromSeconds(300)));
 
   scoped_ptr<XmlElement> response(new XmlElement(buzz::QN_IQ));
-  response->AddAttr(QName(std::string(), "from"), kTestBotJid);
-  response->AddAttr(QName(std::string(), "type"), "result");
-  response->AddAttr(QName(std::string(), "id"), kStanzaId);
+  response->AddAttr(QName("", "from"), kTestBotJid);
+  response->AddAttr(QName("", "type"), "result");
+  response->AddAttr(QName("", "id"), kStanzaId);
 
   XmlElement* result = new XmlElement(
       QName(kChromotingXmlNamespace, "register-support-host-result"));
diff --git a/remoting/host/server_log_entry.cc b/remoting/host/server_log_entry.cc
index f18b2378..cf6f861 100644
--- a/remoting/host/server_log_entry.cc
+++ b/remoting/host/server_log_entry.cc
@@ -140,7 +140,7 @@ scoped_ptr<XmlElement> ServerLogEntry::ToStanza() const {
       kChromotingXmlNamespace, kLogEntry)));
   ValuesMap::const_iterator iter;
   for (iter = values_map_.begin(); iter != values_map_.end(); ++iter) {
-    stanza->AddAttr(QName(std::string(), iter->first), iter->second);
+    stanza->AddAttr(QName("", iter->first), iter->second);
   }
   return stanza.Pass();
 }
diff --git a/remoting/host/service_client.cc b/remoting/host/service_client.cc
index d487a97..6db1c6e 100644
--- a/remoting/host/service_client.cc
+++ b/remoting/host/service_client.cc
@@ -78,10 +78,7 @@ void ServiceClient::Core::RegisterHost(
   post_body.SetString("data.publicKey", public_key);
   std::string post_body_str;
   base::JSONWriter::Write(&post_body, &post_body_str);
-  MakeGaiaRequest(net::URLFetcher::POST,
-                  std::string(),
-                  post_body_str,
-                  oauth_access_token,
+  MakeGaiaRequest(net::URLFetcher::POST, "", post_body_str, oauth_access_token,
                   delegate);
 }
 
@@ -91,11 +88,8 @@ void ServiceClient::Core::UnregisterHost(
     Delegate* delegate) {
   DCHECK(pending_request_type_ == PENDING_REQUEST_NONE);
   pending_request_type_ = PENDING_REQUEST_UNREGISTER_HOST;
-  MakeGaiaRequest(net::URLFetcher::DELETE_REQUEST,
-                  host_id,
-                  std::string(),
-                  oauth_access_token,
-                  delegate);
+  MakeGaiaRequest(net::URLFetcher::DELETE_REQUEST, host_id, "",
+                  oauth_access_token, delegate);
 }
 
 void ServiceClient::Core::MakeGaiaRequest(
diff --git a/remoting/host/setup/daemon_controller_linux.cc b/remoting/host/setup/daemon_controller_linux.cc
index 216572f..f5076d4 100644
--- a/remoting/host/setup/daemon_controller_linux.cc
+++ b/remoting/host/setup/daemon_controller_linux.cc
@@ -318,7 +318,7 @@ void DaemonControllerLinux::DoGetVersion(
     const GetVersionCallback& done_callback) {
   base::FilePath script_path;
   if (!GetScriptPath(&script_path)) {
-    done_callback.Run(std::string());
+    done_callback.Run("");
     return;
   }
   CommandLine command_line(script_path);
@@ -331,14 +331,14 @@ void DaemonControllerLinux::DoGetVersion(
   if (!result || exit_code != 0) {
     LOG(ERROR) << "Failed to run \"" << command_line.GetCommandLineString()
                << "\". Exit code: " << exit_code;
-    done_callback.Run(std::string());
+    done_callback.Run("");
     return;
   }
 
   TrimWhitespaceASCII(version, TRIM_ALL, &version);
   if (!ContainsOnlyChars(version, "0123456789.")) {
     LOG(ERROR) << "Received invalid host version number: " << version;
-    done_callback.Run(std::string());
+    done_callback.Run("");
     return;
   }
 
diff --git a/remoting/host/setup/oauth_helper.cc b/remoting/host/setup/oauth_helper.cc
index 6ea46d5..6f110f6 100644
--- a/remoting/host/setup/oauth_helper.cc
+++ b/remoting/host/setup/oauth_helper.cc
@@ -14,7 +14,7 @@ namespace {
 std::string GetComponent(const std::string& url,
                          const url_parse::Component component) {
   if (component.len < 0) {
-    return std::string();
+    return "";
   }
   return url.substr(component.begin, component.len);
 }
@@ -60,11 +60,11 @@ std::string GetOauthCodeInUrl(const std::string& url,
                    &redirect_url_parsed);
   if (GetComponent(url, url_parsed.scheme) !=
       GetComponent(redirect_url, redirect_url_parsed.scheme)) {
-    return std::string();
+    return "";
   }
   if (GetComponent(url, url_parsed.host) !=
       GetComponent(redirect_url, redirect_url_parsed.host)) {
-    return std::string();
+    return "";
   }
   url_parse::Component query = url_parsed.query;
   url_parse::Component key;
@@ -74,7 +74,7 @@ std::string GetOauthCodeInUrl(const std::string& url,
       return GetComponent(url, value);
     }
   }
-  return std::string();
+  return "";
 }
 
 }  // namespace remoting
diff --git a/remoting/host/setup/start_host.cc b/remoting/host/setup/start_host.cc
index 256fb3c..4d8ba75 100644
--- a/remoting/host/setup/start_host.cc
+++ b/remoting/host/setup/start_host.cc
@@ -53,7 +53,7 @@ std::string ReadString(bool no_echo) {
     SetEcho(true);
   }
   if (!result)
-    return std::string();
+    return "";
   size_t newline_index = str.find('\n');
   if (newline_index != std::string::npos)
     str[newline_index] = '\0';
diff --git a/remoting/jingle_glue/iq_sender_unittest.cc b/remoting/jingle_glue/iq_sender_unittest.cc
index 2876735..b09f114 100644
--- a/remoting/jingle_glue/iq_sender_unittest.cc
+++ b/remoting/jingle_glue/iq_sender_unittest.cc
@@ -91,9 +91,9 @@ TEST_F(IqSenderTest, SendIq) {
   });
 
   scoped_ptr<XmlElement> response(new XmlElement(buzz::QN_IQ));
-  response->AddAttr(QName(std::string(), "type"), "result");
-  response->AddAttr(QName(std::string(), "id"), kStanzaId);
-  response->AddAttr(QName(std::string(), "from"), kTo);
+  response->AddAttr(QName("", "type"), "result");
+  response->AddAttr(QName("", "id"), kStanzaId);
+  response->AddAttr(QName("", "from"), kTo);
 
   XmlElement* result = new XmlElement(
       QName("test:namespace", "response-body"));
@@ -123,9 +123,9 @@ TEST_F(IqSenderTest, InvalidFrom) {
   });
 
   scoped_ptr<XmlElement> response(new XmlElement(buzz::QN_IQ));
-  response->AddAttr(QName(std::string(), "type"), "result");
-  response->AddAttr(QName(std::string(), "id"), kStanzaId);
-  response->AddAttr(QName(std::string(), "from"), "different_user@domain.com");
+  response->AddAttr(QName("", "type"), "result");
+  response->AddAttr(QName("", "id"), kStanzaId);
+  response->AddAttr(QName("", "from"), "different_user@domain.com");
 
   XmlElement* result = new XmlElement(
       QName("test:namespace", "response-body"));
@@ -143,9 +143,9 @@ TEST_F(IqSenderTest, IdMatchingHack) {
   });
 
   scoped_ptr<XmlElement> response(new XmlElement(buzz::QN_IQ));
-  response->AddAttr(QName(std::string(), "type"), "result");
-  response->AddAttr(QName(std::string(), "id"), "DIFFERENT_ID");
-  response->AddAttr(QName(std::string(), "from"), kTo);
+  response->AddAttr(QName("", "type"), "result");
+  response->AddAttr(QName("", "id"), "DIFFERENT_ID");
+  response->AddAttr(QName("", "from"), kTo);
 
   XmlElement* result = new XmlElement(
       QName("test:namespace", "response-body"));
diff --git a/remoting/jingle_glue/xmpp_signal_strategy.cc b/remoting/jingle_glue/xmpp_signal_strategy.cc
index 88fc9f3..51bbade 100644
--- a/remoting/jingle_glue/xmpp_signal_strategy.cc
+++ b/remoting/jingle_glue/xmpp_signal_strategy.cc
@@ -91,10 +91,9 @@ void XmppSignalStrategy::Connect() {
 
   task_runner_.reset(new jingle_glue::TaskPump());
   xmpp_client_ = new buzz::XmppClient(task_runner_.get());
-  xmpp_client_->Connect(
-      settings, std::string(), socket, CreatePreXmppAuth(settings));
-  xmpp_client_->SignalStateChange
-      .connect(this, &XmppSignalStrategy::OnConnectionStateChanged);
+  xmpp_client_->Connect(settings, "", socket, CreatePreXmppAuth(settings));
+  xmpp_client_->SignalStateChange.connect(
+      this, &XmppSignalStrategy::OnConnectionStateChanged);
   xmpp_client_->engine()->AddStanzaHandler(this, buzz::XmppEngine::HL_TYPE);
   xmpp_client_->Start();
 
@@ -157,7 +156,7 @@ std::string XmppSignalStrategy::GetNextId() {
   if (!xmpp_client_) {
     // If the connection has been terminated then it doesn't matter
     // what Id we return.
-    return std::string();
+    return "";
   }
   return xmpp_client_->NextId();
 }
diff --git a/remoting/protocol/jingle_messages.cc b/remoting/protocol/jingle_messages.cc
index e2408e0..7d82443 100644
--- a/remoting/protocol/jingle_messages.cc
+++ b/remoting/protocol/jingle_messages.cc
@@ -124,9 +124,10 @@ JingleMessage::NamedCandidate::NamedCandidate(
 
 // static
 bool JingleMessage::IsJingleMessage(const buzz::XmlElement* stanza) {
-  return stanza->Name() == QName(kJabberNamespace, "iq") &&
-         stanza->Attr(QName(std::string(), "type")) == "set" &&
-         stanza->FirstNamed(QName(kJingleNamespace, "jingle")) != NULL;
+  return
+      stanza->Name() == QName(kJabberNamespace, "iq") &&
+      stanza->Attr(QName("", "type")) == "set" &&
+      stanza->FirstNamed(QName(kJingleNamespace, "jingle")) != NULL;
 }
 
 // static
@@ -372,7 +373,7 @@ scoped_ptr<buzz::XmlElement> JingleMessageReply::ToXml(
 
   std::string type;
   std::string error_text;
-  QName name;
+  QName name("");
   switch (error_type) {
     case BAD_REQUEST:
       type = "modify";
diff --git a/remoting/protocol/jingle_session.cc b/remoting/protocol/jingle_session.cc
index 72985c2..c6a4f22 100644
--- a/remoting/protocol/jingle_session.cc
+++ b/remoting/protocol/jingle_session.cc
@@ -323,8 +323,7 @@ void JingleSession::OnMessageResponse(
     CloseInternal(SIGNALING_TIMEOUT);
     return;
   } else {
-    const std::string& type =
-        response->Attr(buzz::QName(std::string(), "type"));
+    const std::string& type = response->Attr(buzz::QName("", "type"));
     if (type != "result") {
       LOG(ERROR) << "Received error in response to " << type_str
                  << " message: \"" << response->Str()
@@ -384,7 +383,7 @@ void JingleSession::OnTransportInfoResponse(IqRequest* request,
     return;
   }
 
-  const std::string& type = response->Attr(buzz::QName(std::string(), "type"));
+  const std::string& type = response->Attr(buzz::QName("", "type"));
   if (type != "result") {
     LOG(ERROR) << "Received error in response to transport-info message: \""
                << response->Str() << "\". Terminating the session.";
diff --git a/remoting/protocol/jingle_session_unittest.cc b/remoting/protocol/jingle_session_unittest.cc
index 76aee23..433356b 100644
--- a/remoting/protocol/jingle_session_unittest.cc
+++ b/remoting/protocol/jingle_session_unittest.cc
@@ -323,7 +323,7 @@ TEST_F(JingleSessionTest, Connect) {
       initiate_xml->FirstNamed(buzz::QName(kJingleNamespace, "jingle"));
   ASSERT_TRUE(jingle_element);
   ASSERT_EQ(kClientJid,
-            jingle_element->Attr(buzz::QName(std::string(), "initiator")));
+            jingle_element->Attr(buzz::QName("", "initiator")));
 }
 
 // Verify that we can connect two endpoints with multi-step authentication.
diff --git a/remoting/protocol/libjingle_transport_factory.cc b/remoting/protocol/libjingle_transport_factory.cc
index 7a09d09..e27b619 100644
--- a/remoting/protocol/libjingle_transport_factory.cc
+++ b/remoting/protocol/libjingle_transport_factory.cc
@@ -139,7 +139,7 @@ void LibjingleStreamTransport::Connect(
   // Create P2PTransportChannel, attach signal handlers and connect it.
   // TODO(sergeyu): Specify correct component ID for the channel.
   channel_.reset(new cricket::P2PTransportChannel(
-      std::string(), 0, NULL, port_allocator_));
+      "", 0, NULL, port_allocator_));
   channel_->SetIceCredentials(ice_username_fragment_, ice_password_);
   channel_->SignalRequestSignaling.connect(
       this, &LibjingleStreamTransport::OnRequestSignaling);
diff --git a/remoting/protocol/third_party_authenticator_unittest.cc b/remoting/protocol/third_party_authenticator_unittest.cc
index 0298877..b787a62 100644
--- a/remoting/protocol/third_party_authenticator_unittest.cc
+++ b/remoting/protocol/third_party_authenticator_unittest.cc
@@ -153,8 +153,7 @@ TEST_F(ThirdPartyAuthenticatorTest, ClientNoSecret) {
   ASSERT_NO_FATAL_FAILURE(InitAuthenticators());
   ASSERT_NO_FATAL_FAILURE(RunHostInitiatedAuthExchange());
   ASSERT_EQ(Authenticator::PROCESSING_MESSAGE, client_->state());
-  ASSERT_NO_FATAL_FAILURE(
-      token_fetcher_->OnTokenFetched(kToken, std::string()));
+  ASSERT_NO_FATAL_FAILURE(token_fetcher_->OnTokenFetched(kToken, ""));
 
   // The end result is that the client rejected the connection, since it
   // couldn't fetch the secret.
@@ -168,7 +167,7 @@ TEST_F(ThirdPartyAuthenticatorTest, InvalidToken) {
   ASSERT_NO_FATAL_FAILURE(token_fetcher_->OnTokenFetched(
       kToken, kSharedSecret));
   ASSERT_EQ(Authenticator::PROCESSING_MESSAGE, host_->state());
-  ASSERT_NO_FATAL_FAILURE(token_validator_->OnTokenValidated(std::string()));
+  ASSERT_NO_FATAL_FAILURE(token_validator_->OnTokenValidated(""));
 
   // The end result is that the host rejected the token.
   ASSERT_EQ(Authenticator::REJECTED, host_->state());
@@ -178,8 +177,7 @@ TEST_F(ThirdPartyAuthenticatorTest, CannotFetchToken) {
   ASSERT_NO_FATAL_FAILURE(InitAuthenticators());
   ASSERT_NO_FATAL_FAILURE(RunHostInitiatedAuthExchange());
   ASSERT_EQ(Authenticator::PROCESSING_MESSAGE, client_->state());
-  ASSERT_NO_FATAL_FAILURE(
-      token_fetcher_->OnTokenFetched(std::string(), std::string()));
+  ASSERT_NO_FATAL_FAILURE(token_fetcher_->OnTokenFetched("", ""));
 
   // The end result is that the client rejected the connection, since it
   // couldn't fetch the token.
diff --git a/remoting/protocol/transport.cc b/remoting/protocol/transport.cc
index 13ed29f..4ccbcde 100644
--- a/remoting/protocol/transport.cc
+++ b/remoting/protocol/transport.cc
@@ -20,7 +20,7 @@ std::string TransportRoute::GetTypeString(RouteType type) {
       return "relay";
   }
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 TransportRoute::TransportRoute() : type(DIRECT) {
diff --git a/sandbox/linux/tests/unit_tests.cc b/sandbox/linux/tests/unit_tests.cc
index 5d6cf30..63fbb2b 100644
--- a/sandbox/linux/tests/unit_tests.cc
+++ b/sandbox/linux/tests/unit_tests.cc
@@ -16,7 +16,7 @@
 
 namespace {
 std::string TestFailedMessage(const std::string& msg) {
-  return msg.empty() ? std::string() : "Actual test failure: " + msg;
+  return msg.empty() ? "" : "Actual test failure: " + msg;
 }
 
 int GetSubProcessTimeoutTimeInSeconds() {
diff --git a/sql/statement.cc b/sql/statement.cc
index fe0accb..d92be01 100644
--- a/sql/statement.cc
+++ b/sql/statement.cc
@@ -210,7 +210,7 @@ double Statement::ColumnDouble(int col) const {
 
 std::string Statement::ColumnString(int col) const {
   if (!CheckValid())
-    return std::string();
+    return "";
 
   const char* str = reinterpret_cast<const char*>(
       sqlite3_column_text(ref_->stmt(), col));
diff --git a/sync/api/sync_data.cc b/sync/api/sync_data.cc
index e0b6f1a..b9e2ca9 100644
--- a/sync/api/sync_data.cc
+++ b/sync/api/sync_data.cc
@@ -59,7 +59,7 @@ SyncData SyncData::CreateLocalDelete(
     ModelType datatype) {
   sync_pb::EntitySpecifics specifics;
   AddDefaultFieldValue(datatype, &specifics);
-  return CreateLocalData(sync_tag, std::string(), specifics);
+  return CreateLocalData(sync_tag, "", specifics);
 }
 
 // Static.
diff --git a/sync/engine/syncer_unittest.cc b/sync/engine/syncer_unittest.cc
index 2dcc4b7..5ee9e47 100644
--- a/sync/engine/syncer_unittest.cc
+++ b/sync/engine/syncer_unittest.cc
@@ -1641,15 +1641,15 @@ TEST_F(SyncerTest, TestCommitListOrderingAndNewParentAndChild) {
 
 TEST_F(SyncerTest, UpdateWithZeroLengthName) {
   // One illegal update
-  mock_server_->AddUpdateDirectory(
-      1, 0, std::string(), 1, 10, foreign_cache_guid(), "-1");
+  mock_server_->AddUpdateDirectory(1, 0, "", 1, 10,
+                                   foreign_cache_guid(), "-1");
   // And one legal one that we're going to delete.
   mock_server_->AddUpdateDirectory(2, 0, "FOO", 1, 10,
                                    foreign_cache_guid(), "-2");
   SyncShareNudge();
   // Delete the legal one. The new update has a null name.
-  mock_server_->AddUpdateDirectory(
-      2, 0, std::string(), 2, 20, foreign_cache_guid(), "-2");
+  mock_server_->AddUpdateDirectory(2, 0, "", 2, 20,
+                                   foreign_cache_guid(), "-2");
   mock_server_->SetLastUpdateDeleted();
   SyncShareNudge();
 }
@@ -4044,11 +4044,9 @@ TEST_F(SyncerTest, UniqueServerTagUpdates) {
   }
 
   // Now download some tagged items as updates.
-  mock_server_->AddUpdateDirectory(
-      1, 0, "update1", 1, 10, std::string(), std::string());
+  mock_server_->AddUpdateDirectory(1, 0, "update1", 1, 10, "", "");
   mock_server_->SetLastUpdateServerTag("alpha");
-  mock_server_->AddUpdateDirectory(
-      2, 0, "update2", 2, 20, std::string(), std::string());
+  mock_server_->AddUpdateDirectory(2, 0, "update2", 2, 20, "", "");
   mock_server_->SetLastUpdateServerTag("bob");
   SyncShareNudge();
 
@@ -4254,7 +4252,7 @@ TEST_F(SyncerTest, GetKeyEmpty) {
     EXPECT_TRUE(directory()->GetNigoriHandler()->NeedKeystoreKey(&rtrans));
   }
 
-  mock_server_->SetKeystoreKey(std::string());
+  mock_server_->SetKeystoreKey("");
   SyncShareConfigure();
 
   EXPECT_NE(session_->status_controller().last_get_key_result(), SYNCER_OK);
diff --git a/sync/engine/syncer_util.cc b/sync/engine/syncer_util.cc
index d1bde98..c571b10 100644
--- a/sync/engine/syncer_util.cc
+++ b/sync/engine/syncer_util.cc
@@ -633,7 +633,7 @@ VerifyResult VerifyUndelete(syncable::WriteTransaction* trans,
     DCHECK(target->Get(UNIQUE_CLIENT_TAG).empty())
         << "Doing move-aside undeletion on client-tagged item.";
     target->Put(ID, trans->directory()->NextId());
-    target->Put(UNIQUE_CLIENT_TAG, std::string());
+    target->Put(UNIQUE_CLIENT_TAG, "");
     target->Put(BASE_VERSION, CHANGES_VERSION);
     target->Put(SERVER_VERSION, 0);
     return VERIFY_SUCCESS;
diff --git a/sync/internal_api/public/base/model_type_invalidation_map_unittest.cc b/sync/internal_api/public/base/model_type_invalidation_map_unittest.cc
index 772ee7e..f051479 100644
--- a/sync/internal_api/public/base/model_type_invalidation_map_unittest.cc
+++ b/sync/internal_api/public/base/model_type_invalidation_map_unittest.cc
@@ -35,7 +35,7 @@ TEST_F(ModelTypeInvalidationMapTest, TypeInvalidationMapToValue) {
   scoped_ptr<DictionaryValue> value(ModelTypeInvalidationMapToValue(states));
   EXPECT_EQ(2u, value->size());
   ExpectDictStringValue(states[BOOKMARKS].payload, *value, "Bookmarks");
-  ExpectDictStringValue(std::string(), *value, "Apps");
+  ExpectDictStringValue("", *value, "Apps");
   EXPECT_FALSE(value->HasKey("Preferences"));
 }
 
diff --git a/sync/internal_api/public/base/ordinal_unittest.cc b/sync/internal_api/public/base/ordinal_unittest.cc
index 8c77d6d..20a6d19 100644
--- a/sync/internal_api/public/base/ordinal_unittest.cc
+++ b/sync/internal_api/public/base/ordinal_unittest.cc
@@ -87,7 +87,7 @@ COMPILE_ASSERT(LargeOrdinal::kRadix == 256,
 // IsValid() should return false for all of them.
 TEST(Ordinal, Invalid) {
   // Length criterion.
-  EXPECT_FALSE(TestOrdinal(std::string()).IsValid());
+  EXPECT_FALSE(TestOrdinal("").IsValid());
   EXPECT_FALSE(LongOrdinal("0001").IsValid());
 
   const char kBeforeZero[] = { '0' - 1, '\0' };
diff --git a/sync/internal_api/public/base/unique_position.cc b/sync/internal_api/public/base/unique_position.cc
index b6c18ef..a47d42b 100644
--- a/sync/internal_api/public/base/unique_position.cc
+++ b/sync/internal_api/public/base/unique_position.cc
@@ -61,7 +61,7 @@ UniquePosition UniquePosition::FromInt64(
 UniquePosition UniquePosition::InitialPosition(
     const std::string& suffix) {
   DCHECK(IsValidSuffix(suffix));
-  return UniquePosition(std::string(), suffix);
+  return UniquePosition("", suffix);
 }
 
 // static.
@@ -175,7 +175,7 @@ std::string UniquePosition::FindSmallerWithSuffix(
 
   if (suffix_zeroes > ref_zeroes) {
     // Implies suffix < ref.
-    return std::string();
+    return "";
   }
 
   if (suffix.substr(suffix_zeroes) < reference.substr(ref_zeroes)) {
@@ -210,7 +210,7 @@ std::string UniquePosition::FindGreaterWithSuffix(
 
   if (suffix_FFs > ref_FFs) {
     // Implies suffix > reference.
-    return std::string();
+    return "";
   }
 
   if (suffix.substr(suffix_FFs) > reference.substr(ref_FFs)) {
@@ -244,7 +244,7 @@ std::string UniquePosition::FindBetweenWithSuffix(
 
   // Sometimes our suffix puts us where we want to be.
   if (before < suffix && suffix < after) {
-    return std::string();
+    return "";
   }
 
   size_t i = 0;
diff --git a/sync/internal_api/sync_encryption_handler_impl.cc b/sync/internal_api/sync_encryption_handler_impl.cc
index 655feb2..1a645bf 100644
--- a/sync/internal_api/sync_encryption_handler_impl.cc
+++ b/sync/internal_api/sync_encryption_handler_impl.cc
@@ -136,7 +136,7 @@ std::string PackKeystoreBootstrapToken(
     const std::string& current_keystore_key,
     Encryptor* encryptor) {
   if (current_keystore_key.empty())
-    return std::string();
+    return "";
 
   base::ListValue keystore_key_values;
   for (size_t i = 0; i < old_keystore_keys.size(); ++i)
@@ -1112,7 +1112,7 @@ void SyncEncryptionHandlerImpl::SetCustomPassphrase(
   if (passphrase_type_ != KEYSTORE_PASSPHRASE) {
     DVLOG(1) << "Failing to set a custom passphrase because one has already "
              << "been set.";
-    FinishSetPassphrase(false, std::string(), trans, nigori_node);
+    FinishSetPassphrase(false, "", trans, nigori_node);
     return;
   }
 
@@ -1125,7 +1125,7 @@ void SyncEncryptionHandlerImpl::SetCustomPassphrase(
     // if statement above. For the sake of safety though, we check for it in
     // case a client is misbehaving.
     LOG(ERROR) << "Failing to set custom passphrase because of pending keys.";
-    FinishSetPassphrase(false, std::string(), trans, nigori_node);
+    FinishSetPassphrase(false, "", trans, nigori_node);
     return;
   }
 
diff --git a/sync/internal_api/sync_encryption_handler_impl_unittest.cc b/sync/internal_api/sync_encryption_handler_impl_unittest.cc
index 919a65d..8abbd7e 100644
--- a/sync/internal_api/sync_encryption_handler_impl_unittest.cc
+++ b/sync/internal_api/sync_encryption_handler_impl_unittest.cc
@@ -91,8 +91,7 @@ class SyncEncryptionHandlerImplTest : public ::testing::Test {
     encryption_handler_.reset(
         new SyncEncryptionHandlerImpl(user_share(),
                                       &encryptor_,
-                                      std::string(),
-                                      std::string() /* bootstrap tokens */));
+                                      "", ""  /* bootstrap tokens */));
     encryption_handler_->AddObserver(&observer_);
   }
 
@@ -348,8 +347,7 @@ TEST_F(SyncEncryptionHandlerImplTest, NigoriEncryptionTypes) {
   StrictMock<SyncEncryptionHandlerObserverMock> observer2;
   SyncEncryptionHandlerImpl handler2(user_share(),
                                      &encryptor_,
-                                     std::string(),
-                                     std::string() /* bootstrap tokens */);
+                                     "", ""  /* bootstrap tokens */);
   handler2.AddObserver(&observer2);
 
   // Just set the sensitive types (shouldn't trigger any notifications).
@@ -613,8 +611,9 @@ TEST_F(SyncEncryptionHandlerImplTest, SetKeystoreMigratesAndUpdatesBootstrap) {
     WriteTransaction trans(FROM_HERE, user_share());
     EXPECT_FALSE(GetCryptographer()->is_initialized());
     EXPECT_TRUE(encryption_handler()->NeedKeystoreKey(trans.GetWrappedTrans()));
-    EXPECT_FALSE(encryption_handler()->SetKeystoreKeys(
-        BuildEncryptionKeyProto(std::string()), trans.GetWrappedTrans()));
+    EXPECT_FALSE(
+        encryption_handler()->SetKeystoreKeys(BuildEncryptionKeyProto(""),
+                                              trans.GetWrappedTrans()));
     EXPECT_TRUE(encryption_handler()->NeedKeystoreKey(trans.GetWrappedTrans()));
   }
   Mock::VerifyAndClearExpectations(observer());
@@ -680,7 +679,7 @@ TEST_F(SyncEncryptionHandlerImplTest, SetKeystoreMigratesAndUpdatesBootstrap) {
   // token.
   SyncEncryptionHandlerImpl handler2(user_share(),
                                      &encryptor_,
-                                     std::string(),  // Cryptographer bootstrap.
+                                     "",  // Cryptographer bootstrap.
                                      keystore_bootstrap);
 
   {
diff --git a/sync/internal_api/sync_manager_impl.cc b/sync/internal_api/sync_manager_impl.cc
index 7413b71..97d03ba 100644
--- a/sync/internal_api/sync_manager_impl.cc
+++ b/sync/internal_api/sync_manager_impl.cc
@@ -1289,7 +1289,7 @@ void SyncManagerImpl::OnIncomingInvalidation(
 void SyncManagerImpl::RefreshTypes(ModelTypeSet types) {
   DCHECK(thread_checker_.CalledOnValidThread());
   const ModelTypeInvalidationMap& type_invalidation_map =
-      ModelTypeSetToInvalidationMap(types, std::string());
+      ModelTypeSetToInvalidationMap(types, "");
   if (type_invalidation_map.empty()) {
     LOG(WARNING) << "Sync received refresh request with no types specified.";
   } else {
diff --git a/sync/internal_api/sync_manager_impl_unittest.cc b/sync/internal_api/sync_manager_impl_unittest.cc
index 7f96f49..9a6ddee 100644
--- a/sync/internal_api/sync_manager_impl_unittest.cc
+++ b/sync/internal_api/sync_manager_impl_unittest.cc
@@ -723,7 +723,7 @@ class TestHttpPostProviderInterface : public HttpPostProviderInterface {
   }
   virtual const std::string GetResponseHeaderValue(
       const std::string& name) const OVERRIDE {
-    return std::string();
+    return "";
   }
   virtual void Abort() OVERRIDE {}
 };
@@ -820,25 +820,20 @@ class SyncManagerTest : public testing::Test,
     GetModelSafeRoutingInfo(&routing_info);
 
     // Takes ownership of |fake_invalidator_|.
-    sync_manager_.Init(
-        temp_dir_.path(),
-        WeakHandle<JsEventHandler>(),
-        "bogus",
-        0,
-        false,
-        scoped_ptr<HttpPostProviderFactory>(new TestHttpPostProviderFactory()),
-        workers,
-        &extensions_activity_monitor_,
-        this,
-        credentials,
-        scoped_ptr<Invalidator>(fake_invalidator_),
-        "fake_invalidator_client_id",
-        std::string(),
-        std::string(),  // bootstrap tokens
-        scoped_ptr<InternalComponentsFactory>(GetFactory()),
-        &encryptor_,
-        &handler_,
-        NULL);
+    sync_manager_.Init(temp_dir_.path(),
+                       WeakHandle<JsEventHandler>(),
+                       "bogus", 0, false,
+                       scoped_ptr<HttpPostProviderFactory>(
+                           new TestHttpPostProviderFactory()),
+                       workers, &extensions_activity_monitor_, this,
+                       credentials,
+                       scoped_ptr<Invalidator>(fake_invalidator_),
+                       "fake_invalidator_client_id",
+                       "", "",  // bootstrap tokens
+                       scoped_ptr<InternalComponentsFactory>(GetFactory()),
+                       &encryptor_,
+                       &handler_,
+                       NULL);
 
     sync_manager_.GetEncryptionHandler()->AddObserver(&encryption_observer_);
 
@@ -1186,9 +1181,9 @@ class SyncManagerGetNodesByIdTest : public SyncManagerTest {
       base::ListValue args;
       base::ListValue* ids = new base::ListValue();
       args.Append(ids);
-      ids->Append(new base::StringValue(std::string()));
-      SendJsMessage(
-          message_name, JsArgList(&args), reply_handler.AsWeakHandle());
+      ids->Append(new base::StringValue(""));
+      SendJsMessage(message_name,
+                    JsArgList(&args), reply_handler.AsWeakHandle());
     }
 
     {
@@ -1278,9 +1273,9 @@ TEST_F(SyncManagerTest, GetChildNodeIdsFailure) {
 
   {
     base::ListValue args;
-    args.Append(new base::StringValue(std::string()));
-    SendJsMessage(
-        "getChildNodeIds", JsArgList(&args), reply_handler.AsWeakHandle());
+    args.Append(new base::StringValue(""));
+    SendJsMessage("getChildNodeIds",
+                  JsArgList(&args), reply_handler.AsWeakHandle());
   }
 
   {
diff --git a/sync/internal_api/syncapi_server_connection_manager_unittest.cc b/sync/internal_api/syncapi_server_connection_manager_unittest.cc
index a0fe420..f90c5e8 100644
--- a/sync/internal_api/syncapi_server_connection_manager_unittest.cc
+++ b/sync/internal_api/syncapi_server_connection_manager_unittest.cc
@@ -45,7 +45,7 @@ class BlockingHttpPost : public HttpPostProviderInterface {
   }
   virtual const std::string GetResponseHeaderValue(
       const std::string& name) const OVERRIDE {
-    return std::string();
+    return "";
   }
   virtual void Abort() OVERRIDE {
     wait_for_abort_.Signal();
diff --git a/sync/notifier/p2p_invalidator.cc b/sync/notifier/p2p_invalidator.cc
index 7825757..dd9a34d 100644
--- a/sync/notifier/p2p_invalidator.cc
+++ b/sync/notifier/p2p_invalidator.cc
@@ -40,7 +40,7 @@ std::string P2PNotificationTargetToString(P2PNotificationTarget target) {
       return kNotifyAll;
     default:
       NOTREACHED();
-      return std::string();
+      return "";
   }
 }
 
@@ -171,9 +171,8 @@ void P2PInvalidator::UpdateRegisteredIds(InvalidationHandler* handler,
                       ObjectIdLessThan());
   registrar_.UpdateRegisteredIds(handler, ids);
   const P2PNotificationData notification_data(
-      invalidator_client_id_,
-      NOTIFY_SELF,
-      ObjectIdSetToInvalidationMap(new_ids, std::string()));
+      invalidator_client_id_, NOTIFY_SELF,
+      ObjectIdSetToInvalidationMap(new_ids, ""));
   SendNotificationData(notification_data);
 }
 
@@ -225,10 +224,8 @@ void P2PInvalidator::OnNotificationsEnabled() {
   registrar_.UpdateInvalidatorState(INVALIDATIONS_ENABLED);
   if (just_turned_on) {
     const P2PNotificationData notification_data(
-        invalidator_client_id_,
-        NOTIFY_SELF,
-        ObjectIdSetToInvalidationMap(registrar_.GetAllRegisteredIds(),
-                                     std::string()));
+        invalidator_client_id_, NOTIFY_SELF,
+        ObjectIdSetToInvalidationMap(registrar_.GetAllRegisteredIds(), ""));
     SendNotificationData(notification_data);
   }
 }
@@ -259,11 +256,10 @@ void P2PInvalidator::OnIncomingNotification(
   if (!notification_data.ResetFromString(notification.data)) {
     LOG(WARNING) << "Could not parse notification data from "
                  << notification.data;
-    notification_data = P2PNotificationData(
-        invalidator_client_id_,
-        NOTIFY_ALL,
-        ObjectIdSetToInvalidationMap(registrar_.GetAllRegisteredIds(),
-                                     std::string()));
+    notification_data =
+        P2PNotificationData(
+            invalidator_client_id_, NOTIFY_ALL,
+            ObjectIdSetToInvalidationMap(registrar_.GetAllRegisteredIds(), ""));
   }
   if (!notification_data.IsTargeted(invalidator_client_id_)) {
     DVLOG(1) << "Not a target of the notification -- "
diff --git a/sync/notifier/p2p_invalidator_unittest.cc b/sync/notifier/p2p_invalidator_unittest.cc
index 6acc3d1..1b7aad4 100644
--- a/sync/notifier/p2p_invalidator_unittest.cc
+++ b/sync/notifier/p2p_invalidator_unittest.cc
@@ -69,7 +69,7 @@ class P2PInvalidatorTestDelegate {
   void TriggerOnIncomingInvalidation(
       const ObjectIdInvalidationMap& invalidation_map) {
     const P2PNotificationData notification_data(
-        std::string(), NOTIFY_ALL, invalidation_map);
+        "", NOTIFY_ALL, invalidation_map);
     notifier::Notification notification;
     notification.channel = kSyncP2PNotificationChannel;
     notification.data = notification_data.ToString();
@@ -160,7 +160,7 @@ TEST_F(P2PInvalidatorTest, P2PNotificationDataIsTargeted) {
 // default-constructed P2PNotificationData.
 TEST_F(P2PInvalidatorTest, P2PNotificationDataDefault) {
   const P2PNotificationData notification_data;
-  EXPECT_TRUE(notification_data.IsTargeted(std::string()));
+  EXPECT_TRUE(notification_data.IsTargeted(""));
   EXPECT_FALSE(notification_data.IsTargeted("other1"));
   EXPECT_FALSE(notification_data.IsTargeted("other2"));
   EXPECT_TRUE(notification_data.GetIdInvalidationMap().empty());
@@ -179,8 +179,7 @@ TEST_F(P2PInvalidatorTest, P2PNotificationDataDefault) {
 TEST_F(P2PInvalidatorTest, P2PNotificationDataNonDefault) {
   const ObjectIdInvalidationMap& invalidation_map =
       ObjectIdSetToInvalidationMap(
-          ModelTypeSetToObjectIdSet(ModelTypeSet(BOOKMARKS, THEMES)),
-          std::string());
+          ModelTypeSetToObjectIdSet(ModelTypeSet(BOOKMARKS, THEMES)), "");
   const P2PNotificationData notification_data(
       "sender", NOTIFY_ALL, invalidation_map);
   EXPECT_TRUE(notification_data.IsTargeted("sender"));
@@ -248,8 +247,7 @@ TEST_F(P2PInvalidatorTest, NotificationsBasic) {
   {
     const ObjectIdInvalidationMap& invalidation_map =
         ObjectIdSetToInvalidationMap(
-            ModelTypeSetToObjectIdSet(ModelTypeSet(THEMES, APPS)),
-            std::string());
+            ModelTypeSetToObjectIdSet(ModelTypeSet(THEMES, APPS)), "");
     invalidator->SendInvalidation(invalidation_map);
   }
 
@@ -266,8 +264,8 @@ TEST_F(P2PInvalidatorTest, SendNotificationData) {
   const ModelTypeSet expected_types(THEMES);
 
   const ObjectIdInvalidationMap& invalidation_map =
-      ObjectIdSetToInvalidationMap(ModelTypeSetToObjectIdSet(changed_types),
-                                   std::string());
+      ObjectIdSetToInvalidationMap(
+          ModelTypeSetToObjectIdSet(changed_types), "");
 
   P2PInvalidator* const invalidator = delegate_.GetInvalidator();
   notifier::FakePushClient* const push_client = delegate_.GetPushClient();
diff --git a/sync/notifier/push_client_channel_unittest.cc b/sync/notifier/push_client_channel_unittest.cc
index d017e1b..ffe90e7 100644
--- a/sync/notifier/push_client_channel_unittest.cc
+++ b/sync/notifier/push_client_channel_unittest.cc
@@ -73,7 +73,7 @@ TEST_F(PushClientChannelTest, EncodeDecode) {
 TEST_F(PushClientChannelTest, EncodeDecodeNoContext) {
   const notifier::Notification& notification =
       PushClientChannel::EncodeMessageForTest(
-          kMessage, std::string(), kSchedulingHash);
+          kMessage, "", kSchedulingHash);
   std::string message;
   std::string service_context = kServiceContext;
   int64 scheduling_hash = kSchedulingHash + 1;
diff --git a/sync/notifier/sync_invalidation_listener_unittest.cc b/sync/notifier/sync_invalidation_listener_unittest.cc
index dba4728..8177327 100644
--- a/sync/notifier/sync_invalidation_listener_unittest.cc
+++ b/sync/notifier/sync_invalidation_listener_unittest.cc
@@ -148,7 +148,7 @@ class FakeDelegate : public SyncInvalidationListener::Delegate {
 
   std::string GetPayload(const ObjectId& id) const {
     ObjectIdInvalidationMap::const_iterator it = invalidations_.find(id);
-    return (it == invalidations_.end()) ? std::string() : it->second.payload;
+    return (it == invalidations_.end()) ? "" : it->second.payload;
   }
 
   InvalidatorState GetInvalidatorState() const {
diff --git a/sync/notifier/sync_system_resources.cc b/sync/notifier/sync_system_resources.cc
index 3fc31fc..5328657 100644
--- a/sync/notifier/sync_system_resources.cc
+++ b/sync/notifier/sync_system_resources.cc
@@ -181,15 +181,14 @@ void SyncStorage::SetSystemResources(
 
 void SyncStorage::RunAndDeleteWriteKeyCallback(
     invalidation::WriteKeyCallback* callback) {
-  callback->Run(
-      invalidation::Status(invalidation::Status::SUCCESS, std::string()));
+  callback->Run(invalidation::Status(invalidation::Status::SUCCESS, ""));
   delete callback;
 }
 
 void SyncStorage::RunAndDeleteReadKeyCallback(
     invalidation::ReadKeyCallback* callback, const std::string& value) {
   callback->Run(std::make_pair(
-      invalidation::Status(invalidation::Status::SUCCESS, std::string()),
+      invalidation::Status(invalidation::Status::SUCCESS, ""),
       value));
   delete callback;
 }
diff --git a/sync/notifier/sync_system_resources_unittest.cc b/sync/notifier/sync_system_resources_unittest.cc
index cb406da..77423b3 100644
--- a/sync/notifier/sync_system_resources_unittest.cc
+++ b/sync/notifier/sync_system_resources_unittest.cc
@@ -168,10 +168,9 @@ TEST_F(SyncSystemResourcesTest, WriteState) {
   EXPECT_CALL(mock_storage_callback, Run(_))
       .WillOnce(SaveArg<0>(&results));
   sync_system_resources_.storage()->WriteKey(
-      std::string(), "state", mock_storage_callback.CreateCallback());
+      "", "state", mock_storage_callback.CreateCallback());
   message_loop_.RunUntilIdle();
-  EXPECT_EQ(invalidation::Status(invalidation::Status::SUCCESS, std::string()),
-            results);
+  EXPECT_EQ(invalidation::Status(invalidation::Status::SUCCESS, ""), results);
 }
 
 }  // namespace
diff --git a/sync/syncable/directory_backing_store.cc b/sync/syncable/directory_backing_store.cc
index 6d11e7f..f0b87be 100644
--- a/sync/syncable/directory_backing_store.cc
+++ b/sync/syncable/directory_backing_store.cc
@@ -1269,7 +1269,7 @@ bool DirectoryBackingStore::CreateTables() {
             "?);"));  // bag_of_chips
     s.BindString(0, dir_name_);                   // id
     s.BindString(1, dir_name_);                   // name
-    s.BindString(2, std::string());               // store_birthday
+    s.BindString(2, "");                          // store_birthday
     // TODO(akalin): Remove this unused db_create_version field. (Or
     // actually use it for something.) http://crbug.com/118356
     s.BindString(3, "Unknown");                   // db_create_version
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index eb28f37..2657ebc 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -523,7 +523,7 @@ base::StringValue* ModelTypeToValue(ModelType model_type) {
     return new base::StringValue("Unspecified");
   }
   NOTREACHED();
-  return new base::StringValue(std::string());
+  return new base::StringValue("");
 }
 
 ModelType ModelTypeFromValue(const base::Value& value) {
diff --git a/sync/syncable/syncable_unittest.cc b/sync/syncable/syncable_unittest.cc
index affaeb4..f99ad23 100644
--- a/sync/syncable/syncable_unittest.cc
+++ b/sync/syncable/syncable_unittest.cc
@@ -2253,7 +2253,7 @@ TEST_F(SyncableClientTagTest, TestClientTagClear) {
     WriteTransaction trans(FROM_HERE, UNITTEST, dir_.get());
     MutableEntry me(&trans, GET_BY_CLIENT_TAG, test_tag_);
     EXPECT_TRUE(me.good());
-    me.Put(UNIQUE_CLIENT_TAG, std::string());
+    me.Put(UNIQUE_CLIENT_TAG, "");
   }
   {
     ReadTransaction trans(FROM_HERE, dir_.get());
diff --git a/sync/syncable/syncable_write_transaction.cc b/sync/syncable/syncable_write_transaction.cc
index 5b884e7..788d922 100644
--- a/sync/syncable/syncable_write_transaction.cc
+++ b/sync/syncable/syncable_write_transaction.cc
@@ -175,7 +175,7 @@ std::string WriterTagToString(WriterTag writer_tag) {
     ENUM_CASE(SYNCAPI);
   };
   NOTREACHED();
-  return std::string();
+  return "";
 }
 
 #undef ENUM_CASE
diff --git a/sync/test/engine/mock_connection_manager.cc b/sync/test/engine/mock_connection_manager.cc
index 6ddd866..e5fd452 100644
--- a/sync/test/engine/mock_connection_manager.cc
+++ b/sync/test/engine/mock_connection_manager.cc
@@ -43,6 +43,7 @@ MockConnectionManager::MockConnectionManager(syncable::Directory* directory)
       store_birthday_("Store BDay!"),
       store_birthday_sent_(false),
       client_stuck_(false),
+      commit_time_rename_prepended_string_(""),
       countdown_to_postbuffer_fail_(0),
       directory_(directory),
       mid_commit_observer_(NULL),
diff --git a/sync/util/cryptographer.cc b/sync/util/cryptographer.cc
index 0fed51e..61b5e63 100644
--- a/sync/util/cryptographer.cc
+++ b/sync/util/cryptographer.cc
@@ -110,12 +110,12 @@ std::string Cryptographer::DecryptToString(
   NigoriMap::const_iterator it = nigoris_.find(encrypted.key_name());
   if (nigoris_.end() == it) {
     NOTREACHED() << "Cannot decrypt message";
-    return std::string();  // Caller should have called CanDecrypt(encrypt).
+    return std::string("");  // Caller should have called CanDecrypt(encrypt).
   }
 
   std::string plaintext;
   if (!it->second->Decrypt(encrypted.blob(), &plaintext)) {
-    return std::string();
+    return std::string("");
   }
 
   return plaintext;
@@ -271,18 +271,18 @@ bool Cryptographer::GetBootstrapToken(std::string* token) const {
 std::string Cryptographer::UnpackBootstrapToken(
     const std::string& token) const {
   if (token.empty())
-    return std::string();
+    return "";
 
   std::string encrypted_data;
   if (!base::Base64Decode(token, &encrypted_data)) {
     DLOG(WARNING) << "Could not decode token.";
-    return std::string();
+    return "";
   }
 
   std::string unencrypted_token;
   if (!encryptor_->DecryptString(encrypted_data, &unencrypted_token)) {
     DLOG(WARNING) << "Decryption of bootstrap token failed.";
-    return std::string();
+    return "";
   }
   return unencrypted_token;
 }
@@ -328,15 +328,15 @@ bool Cryptographer::KeybagIsStale(
 
 std::string Cryptographer::GetDefaultNigoriKey() const {
   if (!is_initialized())
-    return std::string();
+    return "";
   NigoriMap::const_iterator iter = nigoris_.find(default_nigori_name_);
   if (iter == nigoris_.end())
-    return std::string();
+    return "";
   sync_pb::NigoriKey key;
   if (!iter->second->ExportKeys(key.mutable_user_key(),
                                 key.mutable_encryption_key(),
                                 key.mutable_mac_key()))
-    return std::string();
+    return "";
   return key.SerializeAsString();
 }
 
diff --git a/ui/base/gtk/menu_label_accelerator_util.cc b/ui/base/gtk/menu_label_accelerator_util.cc
index 507bf99..f8192c5 100644
--- a/ui/base/gtk/menu_label_accelerator_util.cc
+++ b/ui/base/gtk/menu_label_accelerator_util.cc
@@ -46,7 +46,7 @@ std::string ConvertAcceleratorsFromWindowsStyle(const std::string& label) {
 }
 
 std::string RemoveWindowsStyleAccelerators(const std::string& label) {
-  return ConvertAmpersandsTo(label, std::string());
+  return ConvertAmpersandsTo(label, "");
 }
 
 // Replaces all ampersands in |label| with two ampersands. This effectively
diff --git a/ui/base/l10n/l10n_util_unittest.cc b/ui/base/l10n/l10n_util_unittest.cc
index 1fce2e2..085f2d6 100644
--- a/ui/base/l10n/l10n_util_unittest.cc
+++ b/ui/base/l10n/l10n_util_unittest.cc
@@ -124,59 +124,59 @@ TEST_F(L10nUtilTest, GetAppLocale) {
   // Test the support of LANGUAGE environment variable.
   base::i18n::SetICUDefaultLocale("en-US");
   env->SetVar("LANGUAGE", "xx:fr_CA");
-  EXPECT_EQ("fr", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("fr", l10n_util::GetApplicationLocale(""));
 
   env->SetVar("LANGUAGE", "xx:yy:en_gb.utf-8@quot");
-  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(""));
 
   env->SetVar("LANGUAGE", "xx:zh-hk");
-  EXPECT_EQ("zh-TW", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("zh-TW", l10n_util::GetApplicationLocale(""));
 
   // We emulate gettext's behavior here, which ignores LANG/LC_MESSAGES/LC_ALL
   // when LANGUAGE is specified. If no language specified in LANGUAGE is valid,
   // then just fallback to the default language, which is en-US for us.
   base::i18n::SetICUDefaultLocale("fr-FR");
   env->SetVar("LANGUAGE", "xx:yy");
-  EXPECT_EQ("en-US", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-US", l10n_util::GetApplicationLocale(""));
 
   env->SetVar("LANGUAGE", "/fr:zh_CN");
-  EXPECT_EQ("zh-CN", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("zh-CN", l10n_util::GetApplicationLocale(""));
 
   // Test prioritization of the different environment variables.
   env->SetVar("LANGUAGE", "fr");
   env->SetVar("LC_ALL", "es");
   env->SetVar("LC_MESSAGES", "he");
   env->SetVar("LANG", "nb");
-  EXPECT_EQ("fr", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("fr", l10n_util::GetApplicationLocale(""));
   env->UnSetVar("LANGUAGE");
-  EXPECT_EQ("es", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("es", l10n_util::GetApplicationLocale(""));
   env->UnSetVar("LC_ALL");
-  EXPECT_EQ("he", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("he", l10n_util::GetApplicationLocale(""));
   env->UnSetVar("LC_MESSAGES");
-  EXPECT_EQ("nb", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("nb", l10n_util::GetApplicationLocale(""));
   env->UnSetVar("LANG");
 
   SetDefaultLocaleForTest("ca", env.get());
-  EXPECT_EQ("ca", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("ca", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("ca-ES", env.get());
-  EXPECT_EQ("ca", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("ca", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("ca@valencia", env.get());
-  EXPECT_EQ("ca@valencia", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("ca@valencia", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("ca_ES@valencia", env.get());
-  EXPECT_EQ("ca@valencia", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("ca@valencia", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("ca_ES.UTF8@valencia", env.get());
-  EXPECT_EQ("ca@valencia", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("ca@valencia", l10n_util::GetApplicationLocale(""));
 #endif  // defined(OS_POSIX) && !defined(OS_CHROMEOS)
 
   SetDefaultLocaleForTest("en-US", env.get());
-  EXPECT_EQ("en-US", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-US", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("xx", env.get());
-  EXPECT_EQ("en-US", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-US", l10n_util::GetApplicationLocale(""));
 
 #if defined(OS_CHROMEOS)
   // ChromeOS honors preferred locale first in GetApplicationLocale(),
@@ -200,43 +200,43 @@ TEST_F(L10nUtilTest, GetAppLocale) {
   EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale("en-ZA"));
 #else  // !defined(OS_CHROMEOS)
   SetDefaultLocaleForTest("en-GB", env.get());
-  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("fr-CA", env.get());
-  EXPECT_EQ("fr", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("fr", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("es-MX", env.get());
-  EXPECT_EQ("es-419", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("es-419", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("es-AR", env.get());
-  EXPECT_EQ("es-419", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("es-419", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("es-ES", env.get());
-  EXPECT_EQ("es", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("es", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("es", env.get());
-  EXPECT_EQ("es", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("es", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("zh-HK", env.get());
-  EXPECT_EQ("zh-TW", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("zh-TW", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("zh-MO", env.get());
-  EXPECT_EQ("zh-TW", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("zh-TW", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("zh-SG", env.get());
-  EXPECT_EQ("zh-CN", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("zh-CN", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("en-CA", env.get());
-  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("en-AU", env.get());
-  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("en-NZ", env.get());
-  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(""));
 
   SetDefaultLocaleForTest("en-ZA", env.get());
-  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(std::string()));
+  EXPECT_EQ("en-GB", l10n_util::GetApplicationLocale(""));
 #endif  // defined(OS_CHROMEOS)
 
 #if defined(OS_WIN)
@@ -437,7 +437,7 @@ TEST_F(L10nUtilTest, IsValidLocaleSyntax) {
       "sr_Latn_RS_REVISED@currency=USD"));
 
   // Test invalid locales.
-  EXPECT_FALSE(l10n_util::IsValidLocaleSyntax(std::string()));
+  EXPECT_FALSE(l10n_util::IsValidLocaleSyntax(""));
   EXPECT_FALSE(l10n_util::IsValidLocaleSyntax("x"));
   EXPECT_FALSE(l10n_util::IsValidLocaleSyntax("12"));
   EXPECT_FALSE(l10n_util::IsValidLocaleSyntax("456"));
diff --git a/ui/gl/gl_surface.cc b/ui/gl/gl_surface.cc
index 0feeb34..2e945ed 100644
--- a/ui/gl/gl_surface.cc
+++ b/ui/gl/gl_surface.cc
@@ -89,7 +89,7 @@ bool GLSurface::DeferDraws() {
 }
 
 std::string GLSurface::GetExtensions() {
-  return std::string();
+  return std::string("");
 }
 
 bool GLSurface::HasExtension(const char* name) {
diff --git a/webkit/appcache/appcache_update_job_unittest.cc b/webkit/appcache/appcache_update_job_unittest.cc
index b90e783..86b3df6 100644
--- a/webkit/appcache/appcache_update_job_unittest.cc
+++ b/webkit/appcache/appcache_update_job_unittest.cc
@@ -2649,7 +2649,7 @@ class AppCacheUpdateJobTest : public testing::Test,
 
     // First test against a cache attempt. Will start manifest fetch
     // synchronously.
-    HttpHeadersRequestTestJob::Initialize(std::string(), std::string());
+    HttpHeadersRequestTestJob::Initialize("", "");
     MockFrontend mock_frontend;
     AppCacheHost host(1, &mock_frontend, service_.get());
     update->StartUpdate(&host, GURL());
@@ -2666,7 +2666,7 @@ class AppCacheUpdateJobTest : public testing::Test,
     net::HttpResponseInfo* response_info = new net::HttpResponseInfo();
     response_info->headers = headers;  // adds ref to headers
 
-    HttpHeadersRequestTestJob::Initialize(std::string(), std::string());
+    HttpHeadersRequestTestJob::Initialize("", "");
     update = new AppCacheUpdateJob(service_.get(), group_);
     group_->update_job_ = update;
     group_->update_status_ = AppCacheGroup::DOWNLOADING;
@@ -2687,8 +2687,7 @@ class AppCacheUpdateJobTest : public testing::Test,
     response_info = new net::HttpResponseInfo();
     response_info->headers = headers2;
 
-    HttpHeadersRequestTestJob::Initialize("Sat, 29 Oct 1994 19:43:31 GMT",
-                                          std::string());
+    HttpHeadersRequestTestJob::Initialize("Sat, 29 Oct 1994 19:43:31 GMT", "");
     update = new AppCacheUpdateJob(service_.get(), group_);
     group_->update_job_ = update;
     group_->update_status_ = AppCacheGroup::DOWNLOADING;
@@ -2704,8 +2703,7 @@ class AppCacheUpdateJobTest : public testing::Test,
   void IfModifiedSinceUpgradeTest() {
     ASSERT_EQ(MessageLoop::TYPE_IO, MessageLoop::current()->type());
 
-    HttpHeadersRequestTestJob::Initialize("Sat, 29 Oct 1994 19:43:31 GMT",
-                                          std::string());
+    HttpHeadersRequestTestJob::Initialize("Sat, 29 Oct 1994 19:43:31 GMT", "");
     net::URLRequestJobFactoryImpl* new_factory(
         new net::URLRequestJobFactoryImpl);
     new_factory->SetProtocolHandler("http", new IfModifiedSinceJobFactory);
@@ -2767,7 +2765,7 @@ class AppCacheUpdateJobTest : public testing::Test,
   void IfNoneMatchUpgradeTest() {
     ASSERT_EQ(MessageLoop::TYPE_IO, MessageLoop::current()->type());
 
-    HttpHeadersRequestTestJob::Initialize(std::string(), "\"LadeDade\"");
+    HttpHeadersRequestTestJob::Initialize("", "\"LadeDade\"");
     net::URLRequestJobFactoryImpl* new_factory(
         new net::URLRequestJobFactoryImpl);
     new_factory->SetProtocolHandler("http", new IfModifiedSinceJobFactory);
@@ -2829,7 +2827,7 @@ class AppCacheUpdateJobTest : public testing::Test,
   void IfNoneMatchRefetchTest() {
     ASSERT_EQ(MessageLoop::TYPE_IO, MessageLoop::current()->type());
 
-    HttpHeadersRequestTestJob::Initialize(std::string(), "\"LadeDade\"");
+    HttpHeadersRequestTestJob::Initialize("", "\"LadeDade\"");
     net::URLRequestJobFactoryImpl* new_factory(
         new net::URLRequestJobFactoryImpl);
     new_factory->SetProtocolHandler("http", new IfModifiedSinceJobFactory);
diff --git a/webkit/fileapi/copy_or_move_file_validator_unittest.cc b/webkit/fileapi/copy_or_move_file_validator_unittest.cc
index 6aafa88..7abc628 100644
--- a/webkit/fileapi/copy_or_move_file_validator_unittest.cc
+++ b/webkit/fileapi/copy_or_move_file_validator_unittest.cc
@@ -58,7 +58,8 @@ class CopyOrMoveFileValidatorTestHelper {
       FileSystemMountPointProvider* mount_point_provider =
           file_system_context_->GetMountPointProvider(src_type_);
       mount_point_provider->GetFileSystemRootPathOnFileThread(
-          SourceURL(std::string()), true /* create */);
+          SourceURL(""),
+          true /* create */);
     }
     DCHECK_EQ(kFileSystemTypeNativeMedia, dest_type_);
     base::FilePath dest_path = base_dir.Append(FILE_PATH_LITERAL("dest_media"));
diff --git a/webkit/fileapi/external_mount_points_unittest.cc b/webkit/fileapi/external_mount_points_unittest.cc
index 8c012fa..4b2ce6cb 100644
--- a/webkit/fileapi/external_mount_points_unittest.cc
+++ b/webkit/fileapi/external_mount_points_unittest.cc
@@ -154,7 +154,7 @@ TEST(ExternalMountPointsTest, GetVirtualPath) {
   // A mount point with an empty path.
   mount_points->RegisterFileSystem("empty_path",
                                    fileapi::kFileSystemTypeNativeLocal,
-                                   base::FilePath(FPL(std::string())));
+                                   base::FilePath(FPL("")));
 
   struct TestCase {
     const base::FilePath::CharType* const local_path;
@@ -271,7 +271,7 @@ TEST(ExternalMountPointsTest, CreateCrackedFileSystemURL) {
                                    base::FilePath(DRIVE FPL("/a/b/c(1)")));
   mount_points->RegisterFileSystem("empty_path",
                                    fileapi::kFileSystemTypeSyncable,
-                                   base::FilePath(FPL(std::string())));
+                                   base::FilePath(FPL("")));
   mount_points->RegisterFileSystem("mount",
                                    fileapi::kFileSystemTypeDrive,
                                    base::FilePath(DRIVE FPL("/root")));
@@ -382,7 +382,7 @@ TEST(ExternalMountPointsTest, CrackVirtualPath) {
                                    base::FilePath(DRIVE FPL("/a/b/c(1)")));
   mount_points->RegisterFileSystem("empty_path",
                                    fileapi::kFileSystemTypeSyncable,
-                                   base::FilePath(FPL(std::string())));
+                                   base::FilePath(FPL("")));
   mount_points->RegisterFileSystem("mount",
                                    fileapi::kFileSystemTypeDrive,
                                    base::FilePath(DRIVE FPL("/root")));
diff --git a/webkit/fileapi/file_system_directory_database_unittest.cc b/webkit/fileapi/file_system_directory_database_unittest.cc
index 5a4b889..b612669 100644
--- a/webkit/fileapi/file_system_directory_database_unittest.cc
+++ b/webkit/fileapi/file_system_directory_database_unittest.cc
@@ -569,7 +569,7 @@ TEST_F(FileSystemDirectoryDatabaseTest, TestConsistencyCheck_OrphanFile) {
 
 TEST_F(FileSystemDirectoryDatabaseTest, TestConsistencyCheck_RootLoop) {
   EXPECT_TRUE(db()->IsFileSystemConsistent());
-  MakeHierarchyLink(0, 0, FPL(std::string()));
+  MakeHierarchyLink(0, 0, FPL(""));
   EXPECT_FALSE(db()->IsFileSystemConsistent());
 }
 
diff --git a/webkit/fileapi/file_system_origin_database.cc b/webkit/fileapi/file_system_origin_database.cc
index a7405d9..1026418 100644
--- a/webkit/fileapi/file_system_origin_database.cc
+++ b/webkit/fileapi/file_system_origin_database.cc
@@ -265,7 +265,7 @@ bool FileSystemOriginDatabase::ListAllOrigins(
     return false;
   DCHECK(origins);
   scoped_ptr<leveldb::Iterator> iter(db_->NewIterator(leveldb::ReadOptions()));
-  std::string origin_key_prefix = OriginToOriginKey(std::string());
+  std::string origin_key_prefix = OriginToOriginKey("");
   iter->Seek(origin_key_prefix);
   origins->clear();
   while (iter->Valid() &&
diff --git a/webkit/fileapi/file_system_util_unittest.cc b/webkit/fileapi/file_system_util_unittest.cc
index 1c129bd..7c946cc 100644
--- a/webkit/fileapi/file_system_util_unittest.cc
+++ b/webkit/fileapi/file_system_util_unittest.cc
@@ -115,7 +115,7 @@ TEST_F(FileSystemUtilTest, GetNormalizedFilePath) {
 TEST_F(FileSystemUtilTest, IsAbsolutePath) {
   EXPECT_TRUE(VirtualPath::IsAbsolute(FILE_PATH_LITERAL("/")));
   EXPECT_TRUE(VirtualPath::IsAbsolute(FILE_PATH_LITERAL("/foo/bar")));
-  EXPECT_FALSE(VirtualPath::IsAbsolute(base::FilePath::StringType()));
+  EXPECT_FALSE(VirtualPath::IsAbsolute(FILE_PATH_LITERAL("")));
   EXPECT_FALSE(VirtualPath::IsAbsolute(FILE_PATH_LITERAL("foo/bar")));
 }
 
diff --git a/webkit/fileapi/local_file_stream_writer_unittest.cc b/webkit/fileapi/local_file_stream_writer_unittest.cc
index 41c547e..d67a7da 100644
--- a/webkit/fileapi/local_file_stream_writer_unittest.cc
+++ b/webkit/fileapi/local_file_stream_writer_unittest.cc
@@ -77,7 +77,7 @@ void NeverCalled(int unused) {
 }  // namespace
 
 TEST_F(LocalFileStreamWriterTest, Write) {
-  base::FilePath path = CreateFileWithContent("file_a", std::string());
+  base::FilePath path = CreateFileWithContent("file_a", "");
   scoped_ptr<LocalFileStreamWriter> writer(new LocalFileStreamWriter(path, 0));
   EXPECT_EQ(net::OK, WriteStringToWriter(writer.get(), "foo"));
   EXPECT_EQ(net::OK, WriteStringToWriter(writer.get(), "bar"));
@@ -126,7 +126,7 @@ TEST_F(LocalFileStreamWriterTest, CancelBeforeOperation) {
 }
 
 TEST_F(LocalFileStreamWriterTest, CancelAfterFinishedOperation) {
-  base::FilePath path = CreateFileWithContent("file_a", std::string());
+  base::FilePath path = CreateFileWithContent("file_a", "");
   scoped_ptr<LocalFileStreamWriter> writer(new LocalFileStreamWriter(path, 0));
   EXPECT_EQ(net::OK, WriteStringToWriter(writer.get(), "foo"));
 
diff --git a/webkit/fileapi/local_file_system_cross_operation_unittest.cc b/webkit/fileapi/local_file_system_cross_operation_unittest.cc
index 5466069..2929b93 100644
--- a/webkit/fileapi/local_file_system_cross_operation_unittest.cc
+++ b/webkit/fileapi/local_file_system_cross_operation_unittest.cc
@@ -71,11 +71,13 @@ class CrossOperationTestHelper {
     FileSystemMountPointProvider* mount_point_provider =
         file_system_context_->GetMountPointProvider(src_type_);
     mount_point_provider->GetFileSystemRootPathOnFileThread(
-        SourceURL(std::string()), true /* create */);
+        SourceURL(""),
+        true /* create */);
     mount_point_provider =
         file_system_context_->GetMountPointProvider(dest_type_);
     mount_point_provider->GetFileSystemRootPathOnFileThread(
-        DestURL(std::string()), true /* create */);
+        DestURL(""),
+        true /* create */);
 
     // Grant relatively big quota initially.
     quota_manager_->SetQuota(origin_,
diff --git a/webkit/fileapi/obfuscated_file_util_unittest.cc b/webkit/fileapi/obfuscated_file_util_unittest.cc
index 6a6d4a6..387f28e 100644
--- a/webkit/fileapi/obfuscated_file_util_unittest.cc
+++ b/webkit/fileapi/obfuscated_file_util_unittest.cc
@@ -941,7 +941,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND,
       ofu()->DeleteDirectory(context.get(), url));
 
-  FileSystemURL root = CreateURLFromUTF8(std::string());
+  FileSystemURL root = CreateURLFromUTF8("");
   EXPECT_FALSE(DirectoryExists(url));
   EXPECT_FALSE(PathExists(url));
   context.reset(NewContext(NULL));
@@ -1081,7 +1081,7 @@ TEST_F(ObfuscatedFileUtilTest, TestReadDirectory) {
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestReadRootWithSlash) {
-  TestReadDirectoryHelper(CreateURLFromUTF8(std::string()));
+  TestReadDirectoryHelper(CreateURLFromUTF8(""));
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestReadRootWithEmptyString) {
diff --git a/webkit/fileapi/syncable/canned_syncable_file_system.cc b/webkit/fileapi/syncable/canned_syncable_file_system.cc
index f323a1a..954d6a5 100644
--- a/webkit/fileapi/syncable/canned_syncable_file_system.cc
+++ b/webkit/fileapi/syncable/canned_syncable_file_system.cc
@@ -445,8 +445,7 @@ void CannedSyncableFileSystem::ClearChangeForURLInTracker(
 }
 
 FileSystemOperation* CannedSyncableFileSystem::NewOperation() {
-  return file_system_context_->CreateFileSystemOperation(URL(std::string()),
-                                                         NULL);
+  return file_system_context_->CreateFileSystemOperation(URL(""), NULL);
 }
 
 void CannedSyncableFileSystem::OnSyncEnabled(const FileSystemURL& url) {
diff --git a/webkit/glue/webclipboard_impl.cc b/webkit/glue/webclipboard_impl.cc
index 302c81e..3cbe45c 100644
--- a/webkit/glue/webclipboard_impl.cc
+++ b/webkit/glue/webclipboard_impl.cc
@@ -201,7 +201,7 @@ void WebClipboardImpl::writeURL(const WebURL& url, const WebString& title) {
   ScopedClipboardWriterGlue scw(client_);
 
   scw.WriteBookmark(title, url.spec());
-  scw.WriteHTML(UTF8ToUTF16(URLToMarkup(url, title)), std::string());
+  scw.WriteHTML(UTF8ToUTF16(URLToMarkup(url, title)), "");
   scw.WriteText(UTF8ToUTF16(std::string(url.spec())));
 }
 
@@ -225,7 +225,7 @@ void WebClipboardImpl::writeImage(
     // We also don't want to write HTML on a Mac, since Mail.app prefers to use
     // the image markup over attaching the actual image. See
     // http://crbug.com/33016 for details.
-    scw.WriteHTML(UTF8ToUTF16(URLToImageMarkup(url, title)), std::string());
+    scw.WriteHTML(UTF8ToUTF16(URLToImageMarkup(url, title)), "");
 #endif
   }
 }
@@ -238,7 +238,7 @@ void WebClipboardImpl::writeDataObject(const WebDragData& data) {
   if (!data_object.text.is_null())
     scw.WriteText(data_object.text.string());
   if (!data_object.html.is_null())
-    scw.WriteHTML(data_object.html.string(), std::string());
+    scw.WriteHTML(data_object.html.string(), "");
   // If there is no custom data, avoid calling WritePickledData. This ensures
   // that ScopedClipboardWriterGlue's dtor remains a no-op if the page didn't
   // modify the DataTransfer object, which is important to avoid stomping on
diff --git a/webkit/media/crypto/key_systems.cc b/webkit/media/crypto/key_systems.cc
index 0ffe951..b9c79d0 100644
--- a/webkit/media/crypto/key_systems.cc
+++ b/webkit/media/crypto/key_systems.cc
@@ -66,7 +66,7 @@ KeySystems::KeySystems() {
     for (size_t j = 0; j < mime_type_codecs.size(); ++j)
       codecs.insert(mime_type_codecs[j]);
     // Support the MIME type string alone, without codec(s) specified.
-    codecs.insert(std::string());
+    codecs.insert("");
 
     // Key systems can be repeated, so there may already be an entry.
     KeySystemMappings::iterator key_system_iter =
@@ -113,8 +113,7 @@ bool KeySystems::IsSupportedKeySystemWithMediaMimeType(
     const std::vector<std::string>& codecs,
     const std::string& key_system) {
   if (codecs.empty())
-    return IsSupportedKeySystemWithContainerAndCodec(
-        mime_type, std::string(), key_system);
+    return IsSupportedKeySystemWithContainerAndCodec(mime_type, "", key_system);
 
   for (size_t i = 0; i < codecs.size(); ++i) {
     if (!IsSupportedKeySystemWithContainerAndCodec(
diff --git a/webkit/media/crypto/key_systems_unittest.cc b/webkit/media/crypto/key_systems_unittest.cc
index 4b28ec9..0c25196 100644
--- a/webkit/media/crypto/key_systems_unittest.cc
+++ b/webkit/media/crypto/key_systems_unittest.cc
@@ -233,14 +233,14 @@ TEST_F(KeySystemsTest, ClearKey_IsSupportedKeySystem_InvalidVariants) {
 TEST_F(KeySystemsTest, IsSupportedKeySystemWithMediaMimeType_ClearKey_NoType) {
   // These two should be true. See http://crbug.com/164303.
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), kClearKey));
+      "", no_codecs(), kClearKey));
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "webkit-org.w3"));
+      "", no_codecs(), "webkit-org.w3"));
 
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "webkit-org.w3.foo"));
+      "", no_codecs(), "webkit-org.w3.foo"));
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "webkit-org.w3.clearkey.foo"));
+      "", no_codecs(), "webkit-org.w3.clearkey.foo"));
 }
 
 TEST_F(KeySystemsTest, IsSupportedKeySystemWithMediaMimeType_ClearKey_WebM) {
@@ -419,14 +419,14 @@ TEST_F(KeySystemsTest,
        IsSupportedKeySystemWithMediaMimeType_ExternalClearKey_NoType) {
   // These two should be true. See http://crbug.com/164303.
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), kExternalClearKey));
+      "", no_codecs(), kExternalClearKey));
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "org.chromium"));
+      "", no_codecs(), "org.chromium"));
 
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "org.chromium.foo"));
+      "", no_codecs(), "org.chromium.foo"));
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "org.chromium.externalclearkey.foo"));
+      "", no_codecs(), "org.chromium.externalclearkey.foo"));
 }
 
 TEST_F(KeySystemsTest,
@@ -606,14 +606,14 @@ TEST_F(KeySystemsTest, Widevine_IsSupportedKeySystem_InvalidVariants) {
 TEST_F(KeySystemsTest, IsSupportedKeySystemWithMediaMimeType_Widevine_NoType) {
   // These two should be true. See http://crbug.com/164303.
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), kWidevineAlpha));
+      "", no_codecs(), kWidevineAlpha));
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), kWidevine));
+      "", no_codecs(), kWidevine));
 
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "com.widevine.foo"));
+      "", no_codecs(), "com.widevine.foo"));
   EXPECT_FALSE(IsSupportedKeySystemWithMediaMimeType(
-      std::string(), no_codecs(), "com.widevine.alpha.foo"));
+      "", no_codecs(), "com.widevine.alpha.foo"));
 }
 
 TEST_F(KeySystemsTest, IsSupportedKeySystemWithMediaMimeType_Widevine_WebM) {
diff --git a/webkit/media/crypto/ppapi/cdm_wrapper.cc b/webkit/media/crypto/ppapi/cdm_wrapper.cc
index cd5b917..25eadb0 100644
--- a/webkit/media/crypto/ppapi/cdm_wrapper.cc
+++ b/webkit/media/crypto/ppapi/cdm_wrapper.cc
@@ -652,7 +652,7 @@ void CdmWrapper::GenerateKeyRequest(const std::string& key_system,
 
   if (!cdm_) {
     if (!CreateCdmInstance(key_system)) {
-      SendUnknownKeyError(key_system, std::string());
+      SendUnknownKeyError(key_system, "");
       return;
     }
   }
diff --git a/webkit/media/crypto/ppapi/clear_key_cdm.cc b/webkit/media/crypto/ppapi/clear_key_cdm.cc
index faa6635..4c0e2d5 100644
--- a/webkit/media/crypto/ppapi/clear_key_cdm.cc
+++ b/webkit/media/crypto/ppapi/clear_key_cdm.cc
@@ -249,11 +249,7 @@ cdm::Status ClearKeyCdm::AddKey(const char* session_id,
   DVLOG(1) << "AddKey()";
   base::AutoLock auto_lock(client_lock_);
   ScopedResetter<Client> auto_resetter(&client_);
-  decryptor_.AddKey(std::string(),
-                    key,
-                    key_size,
-                    key_id,
-                    key_id_size,
+  decryptor_.AddKey("", key, key_size, key_id, key_id_size,
                     std::string(session_id, session_id_size));
 
   if (client_.status() != Client::kKeyAdded)
@@ -272,8 +268,7 @@ cdm::Status ClearKeyCdm::CancelKeyRequest(const char* session_id,
   DVLOG(1) << "CancelKeyRequest()";
   base::AutoLock auto_lock(client_lock_);
   ScopedResetter<Client> auto_resetter(&client_);
-  decryptor_.CancelKeyRequest(std::string(),
-                              std::string(session_id, session_id_size));
+  decryptor_.CancelKeyRequest("", std::string(session_id, session_id_size));
   return cdm::kSuccess;
 }
 
diff --git a/webkit/media/crypto/ppapi_decryptor.cc b/webkit/media/crypto/ppapi_decryptor.cc
index 7b9c334..580c5a3 100644
--- a/webkit/media/crypto/ppapi_decryptor.cc
+++ b/webkit/media/crypto/ppapi_decryptor.cc
@@ -68,7 +68,7 @@ bool PpapiDecryptor::GenerateKeyRequest(const std::string& key_system,
 
   if (!plugin_cdm_delegate_->GenerateKeyRequest(
       key_system, type, init_data, init_data_length)) {
-    ReportFailureToCallPlugin(key_system, std::string());
+    ReportFailureToCallPlugin(key_system, "");
     return false;
   }
 
diff --git a/webkit/media/crypto/proxy_decryptor.cc b/webkit/media/crypto/proxy_decryptor.cc
index dafc955..bd0328a 100644
--- a/webkit/media/crypto/proxy_decryptor.cc
+++ b/webkit/media/crypto/proxy_decryptor.cc
@@ -117,8 +117,7 @@ bool ProxyDecryptor::GenerateKeyRequest(const std::string& key_system,
   if (!decryptor_) {
     decryptor_ = CreateDecryptor(key_system);
     if (!decryptor_) {
-      key_error_cb_.Run(
-          key_system, std::string(), media::Decryptor::kClientError, 0);
+      key_error_cb_.Run(key_system, "", media::Decryptor::kClientError, 0);
       return false;
     }
   }
diff --git a/webkit/plugins/ppapi/content_decryptor_delegate.cc b/webkit/plugins/ppapi/content_decryptor_delegate.cc
index 5e3a649..8515531 100644
--- a/webkit/plugins/ppapi/content_decryptor_delegate.cc
+++ b/webkit/plugins/ppapi/content_decryptor_delegate.cc
@@ -627,8 +627,7 @@ void ContentDecryptorDelegate::KeyAdded(PP_Var key_system_var,
   StringVar* key_system_string = StringVar::FromPPVar(key_system_var);
   StringVar* session_id_string = StringVar::FromPPVar(session_id_var);
   if (!key_system_string || !session_id_string) {
-    key_error_cb_.Run(
-        std::string(), std::string(), media::Decryptor::kUnknownError, 0);
+    key_error_cb_.Run("", "", media::Decryptor::kUnknownError, 0);
     return;
   }
 
@@ -657,8 +656,7 @@ void ContentDecryptorDelegate::KeyMessage(PP_Var key_system_var,
   StringVar* default_url_string = StringVar::FromPPVar(default_url_var);
 
   if (!key_system_string || !session_id_string || !default_url_string) {
-    key_error_cb_.Run(
-        std::string(), std::string(), media::Decryptor::kUnknownError, 0);
+    key_error_cb_.Run("", "", media::Decryptor::kUnknownError, 0);
     return;
   }
 
@@ -678,8 +676,7 @@ void ContentDecryptorDelegate::KeyError(PP_Var key_system_var,
   StringVar* key_system_string = StringVar::FromPPVar(key_system_var);
   StringVar* session_id_string = StringVar::FromPPVar(session_id_var);
   if (!key_system_string || !session_id_string) {
-    key_error_cb_.Run(
-        std::string(), std::string(), media::Decryptor::kUnknownError, 0);
+    key_error_cb_.Run("", "", media::Decryptor::kUnknownError, 0);
     return;
   }
 
diff --git a/webkit/quota/quota_manager_unittest.cc b/webkit/quota/quota_manager_unittest.cc
index c814dbc..ccbc826 100644
--- a/webkit/quota/quota_manager_unittest.cc
+++ b/webkit/quota/quota_manager_unittest.cc
@@ -1368,7 +1368,7 @@ TEST_F(QuotaManagerTest, DeleteHostDataSimple) {
   MessageLoop::current()->RunUntilIdle();
   int64 predelete_host_pers = usage();
 
-  DeleteHostData(std::string(), kTemp, kAllClients);
+  DeleteHostData("", kTemp, kAllClients);
   MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(kQuotaStatusOk, status());
 
diff --git a/webkit/tools/test_shell/test_shell.h b/webkit/tools/test_shell/test_shell.h
index 2640224..5b85305 100644
--- a/webkit/tools/test_shell/test_shell.h
+++ b/webkit/tools/test_shell/test_shell.h
@@ -243,8 +243,7 @@ public:
 
     // Get the JavaScript flags for a specific load
     static std::string GetJSFlagsForLoad(size_t load) {
-      if (load >= js_flags_.size())
-        return std::string();
+      if (load >= js_flags_.size()) return "";
       return js_flags_[load];
     }