chrome: Use base::MessageLoop. (Part 3)

This CL updates chrome/browser/* other than chrome/browser/ui which is in
another CL.

BUG=236029
TBR=brettw

Review URL: https://chromiumcodereview.appspot.com/14113053

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202664 0039d316-1c4b-4281-b951-d872f2087c98

571 files changed, 1863 insertions, 1809 deletions

diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index 26ea4fb..2012af5 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -835,7 +835,7 @@ void RecordLastRunAppBundlePath() {
   // nested message loop and commands dispatched during this operation cause
   // havoc.
   if (SessionRestore::IsRestoring(lastProfile) &&
-      MessageLoop::current()->IsNested())
+      base::MessageLoop::current()->IsNested())
     return;
 
   NSInteger tag = [sender tag];
diff --git a/chrome/browser/autocomplete/autocomplete_provider_unittest.cc b/chrome/browser/autocomplete/autocomplete_provider_unittest.cc
index d16ac4d..25318a2 100644
--- a/chrome/browser/autocomplete/autocomplete_provider_unittest.cc
+++ b/chrome/browser/autocomplete/autocomplete_provider_unittest.cc
@@ -96,8 +96,8 @@ void TestProvider::Start(const AutocompleteInput& input,
 
   if (input.matches_requested() == AutocompleteInput::ALL_MATCHES) {
     done_ = false;
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(&TestProvider::Run,
-                                                           this));
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(&TestProvider::Run, this));
   }
 }
 
@@ -194,7 +194,7 @@ class AutocompleteProviderTest : public testing::Test,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::NotificationRegistrar registrar_;
   TestingProfile profile_;
 };
@@ -393,7 +393,7 @@ void AutocompleteProviderTest::RunQuery(const string16 query) {
   if (!controller_->done())
     // The message loop will terminate when all autocomplete input has been
     // collected.
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 }
 
 void AutocompleteProviderTest::RunExactKeymatchTest(
@@ -422,7 +422,7 @@ void AutocompleteProviderTest::Observe(
     const content::NotificationDetails& details) {
   if (controller_->done()) {
     result_.CopyFrom(controller_->result());
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 }
 
diff --git a/chrome/browser/autocomplete/contact_provider_chromeos_unittest.cc b/chrome/browser/autocomplete/contact_provider_chromeos_unittest.cc
index 0add80b..99e215c 100644
--- a/chrome/browser/autocomplete/contact_provider_chromeos_unittest.cc
+++ b/chrome/browser/autocomplete/contact_provider_chromeos_unittest.cc
@@ -123,7 +123,7 @@ class ContactProviderTest : public testing::Test {
     return result;
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   scoped_ptr<TestingProfileManager> profile_manager_;
diff --git a/chrome/browser/autocomplete/extension_app_provider_unittest.cc b/chrome/browser/autocomplete/extension_app_provider_unittest.cc
index 29cf3ba..02e674e 100644
--- a/chrome/browser/autocomplete/extension_app_provider_unittest.cc
+++ b/chrome/browser/autocomplete/extension_app_provider_unittest.cc
@@ -33,7 +33,7 @@ class ExtensionAppProviderTest : public testing::Test {
                int num_cases);
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<ExtensionAppProvider> app_provider_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/autocomplete/history_contents_provider_unittest.cc b/chrome/browser/autocomplete/history_contents_provider_unittest.cc
index da15d1c..0701a14 100644
--- a/chrome/browser/autocomplete/history_contents_provider_unittest.cc
+++ b/chrome/browser/autocomplete/history_contents_provider_unittest.cc
@@ -56,7 +56,7 @@ class HistoryContentsProviderTest : public testing::Test,
     // When we're waiting for asynchronous messages, we have to spin the message
     // loop. This will be exited in the OnProviderUpdate function when complete.
     if (input.matches_requested() == AutocompleteInput::ALL_MATCHES)
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
   }
 
   const ACMatches& matches() const { return provider_->matches(); }
@@ -116,10 +116,11 @@ class HistoryContentsProviderTest : public testing::Test,
     // We must quit the message loop (if running) to return control to the test.
     // Note, calling Quit() directly will checkfail if the loop isn't running,
     // so we post a task, which is safe for either case.
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/autocomplete/history_quick_provider_unittest.cc b/chrome/browser/autocomplete/history_quick_provider_unittest.cc
index 4ac113c..28c9821 100644
--- a/chrome/browser/autocomplete/history_quick_provider_unittest.cc
+++ b/chrome/browser/autocomplete/history_quick_provider_unittest.cc
@@ -135,7 +135,7 @@ class HistoryQuickProviderTest : public testing::Test,
   // Pass-through functions to simplify our friendship with URLIndexPrivateData.
   bool UpdateURL(const history::URLRow& row);
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
@@ -228,7 +228,7 @@ void HistoryQuickProviderTest::RunTest(const string16 text,
                                        bool can_inline_top_result,
                                        string16 expected_fill_into_edit) {
   SCOPED_TRACE(text);  // Minimal hint to query being run.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   AutocompleteInput input(text, string16::npos, string16(), GURL(),false, false,
                           true, AutocompleteInput::ALL_MATCHES);
   provider_->Start(input, false);
diff --git a/chrome/browser/autocomplete/history_url_provider.cc b/chrome/browser/autocomplete/history_url_provider.cc
index 1bc460f..416d3d1 100644
--- a/chrome/browser/autocomplete/history_url_provider.cc
+++ b/chrome/browser/autocomplete/history_url_provider.cc
@@ -295,7 +295,7 @@ HistoryURLProviderParams::HistoryURLProviderParams(
     const std::string& languages,
     TemplateURL* default_search_provider,
     const SearchTermsData& search_terms_data)
-    : message_loop(MessageLoop::current()),
+    : message_loop(base::MessageLoop::current()),
       input(input),
       prevent_inline_autocomplete(input.prevent_inline_autocomplete()),
       trim_http(trim_http),
diff --git a/chrome/browser/autocomplete/history_url_provider_unittest.cc b/chrome/browser/autocomplete/history_url_provider_unittest.cc
index a4e49f40..a7feb11 100644
--- a/chrome/browser/autocomplete/history_url_provider_unittest.cc
+++ b/chrome/browser/autocomplete/history_url_provider_unittest.cc
@@ -187,7 +187,7 @@ class HistoryURLProviderTest : public testing::Test,
 
   void RunAdjustOffsetTest(const string16 text, size_t expected_offset);
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   ACMatches matches_;
@@ -207,7 +207,7 @@ class HistoryURLProviderTestNoDB : public HistoryURLProviderTest {
 
 void HistoryURLProviderTest::OnProviderUpdate(bool updated_matches) {
   if (autocomplete_->done())
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void HistoryURLProviderTest::SetUpImpl(bool no_db) {
@@ -266,7 +266,7 @@ void HistoryURLProviderTest::RunTest(
   *identified_input_type = input.type();
   autocomplete_->Start(input, false);
   if (!autocomplete_->done())
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
   matches_ = autocomplete_->matches();
   if (sort_matches_) {
@@ -292,7 +292,7 @@ void HistoryURLProviderTest::RunAdjustOffsetTest(const string16 text,
                           false, true, AutocompleteInput::ALL_MATCHES);
   autocomplete_->Start(input, false);
   if (!autocomplete_->done())
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
   matches_ = autocomplete_->matches();
   ASSERT_GE(matches_.size(), 1U) << "Input text: " << text;
@@ -547,7 +547,7 @@ TEST_F(HistoryURLProviderTest, EmptyVisits) {
   int pandora_relevance = matches_[0].relevance;
 
   // Run the message loop. When |autocomplete_| finishes the loop is quit.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(autocomplete_->done());
   matches_ = autocomplete_->matches();
   ASSERT_GT(matches_.size(), 0u);
@@ -575,7 +575,7 @@ TEST_F(HistoryURLProviderTest, DontAutocompleteOnTrailingWhitespace) {
                           AutocompleteInput::ALL_MATCHES);
   autocomplete_->Start(input, false);
   if (!autocomplete_->done())
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
   // None of the matches should attempt to autocomplete.
   matches_ = autocomplete_->matches();
@@ -743,7 +743,7 @@ TEST_F(HistoryURLProviderTest, CrashDueToFixup) {
                             AutocompleteInput::ALL_MATCHES);
     autocomplete_->Start(input, false);
     if (!autocomplete_->done())
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
   }
 }
 
diff --git a/chrome/browser/autocomplete/search_provider_unittest.cc b/chrome/browser/autocomplete/search_provider_unittest.cc
index 188ce0a..b1db4b1 100644
--- a/chrome/browser/autocomplete/search_provider_unittest.cc
+++ b/chrome/browser/autocomplete/search_provider_unittest.cc
@@ -145,7 +145,7 @@ class SearchProviderTest : public testing::Test,
   const string16 keyword_term_;
   GURL keyword_url_;
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
diff --git a/chrome/browser/autocomplete/shortcuts_provider_unittest.cc b/chrome/browser/autocomplete/shortcuts_provider_unittest.cc
index bc7d6f3..0685fd3 100644
--- a/chrome/browser/autocomplete/shortcuts_provider_unittest.cc
+++ b/chrome/browser/autocomplete/shortcuts_provider_unittest.cc
@@ -155,7 +155,7 @@ class ShortcutsProviderTest : public testing::Test,
                std::vector<std::string> expected_urls,
                std::string expected_top_result);
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
@@ -225,7 +225,7 @@ void ShortcutsProviderTest::RunTest(const string16 text,
                                    std::string expected_top_result) {
   std::sort(expected_urls.begin(), expected_urls.end());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   AutocompleteInput input(text, string16::npos, string16(), GURL(), false,
                           false, true, AutocompleteInput::ALL_MATCHES);
   provider_->Start(input, false);
diff --git a/chrome/browser/autofill/autofill_browsertest.cc b/chrome/browser/autofill/autofill_browsertest.cc
index 9a45a70..aee4806 100644
--- a/chrome/browser/autofill/autofill_browsertest.cc
+++ b/chrome/browser/autofill/autofill_browsertest.cc
@@ -153,7 +153,7 @@ class WindowedPersonalDataManagerObserver
   // PersonalDataManagerObserver:
   virtual void OnPersonalDataChanged() OVERRIDE {
     if (has_run_message_loop_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       has_run_message_loop_ = false;
     }
     alerted_ = true;
diff --git a/chrome/browser/autofill/autofill_interactive_uitest.cc b/chrome/browser/autofill/autofill_interactive_uitest.cc
index b4f8208..96ffae1 100644
--- a/chrome/browser/autofill/autofill_interactive_uitest.cc
+++ b/chrome/browser/autofill/autofill_interactive_uitest.cc
@@ -130,7 +130,7 @@ class WindowedPersonalDataManagerObserver
   // PersonalDataManagerObserver:
   virtual void OnPersonalDataChanged() OVERRIDE {
     if (has_run_message_loop_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       has_run_message_loop_ = false;
     }
     alerted_ = true;
diff --git a/chrome/browser/autofill/risk/fingerprint_browsertest.cc b/chrome/browser/autofill/risk/fingerprint_browsertest.cc
index f74bced..6d7b4e4 100644
--- a/chrome/browser/autofill/risk/fingerprint_browsertest.cc
+++ b/chrome/browser/autofill/risk/fingerprint_browsertest.cc
@@ -40,7 +40,7 @@ class AutofillRiskFingerprintTest : public InProcessBrowserTest {
         kScreenBounds(0, 0, 101, 71),
         kAvailableScreenBounds(0, 11, 101, 60),
         kUnavailableScreenBounds(0, 0, 101, 11),
-        message_loop_(MessageLoop::TYPE_UI) {}
+        message_loop_(base::MessageLoop::TYPE_UI) {}
 
   void GetFingerprintTestCallback(scoped_ptr<Fingerprint> fingerprint) {
     // Verify that all fields Chrome can fill have been filled.
@@ -138,7 +138,7 @@ class AutofillRiskFingerprintTest : public InProcessBrowserTest {
   const gfx::Rect kScreenBounds;
   const gfx::Rect kAvailableScreenBounds;
   const gfx::Rect kUnavailableScreenBounds;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 };
 
 // This test is flaky on Windows. See http://crbug.com/178356.
diff --git a/chrome/browser/automation/chrome_frame_automation_provider_win_unittest.cc b/chrome/browser/automation/chrome_frame_automation_provider_win_unittest.cc
index 1b9b9f0..3f9e9e4 100644
--- a/chrome/browser/automation/chrome_frame_automation_provider_win_unittest.cc
+++ b/chrome/browser/automation/chrome_frame_automation_provider_win_unittest.cc
@@ -25,7 +25,7 @@ class MockChromeFrameAutomationProvider
 typedef testing::Test AutomationProviderTest;
 
 TEST_F(AutomationProviderTest, TestInvalidChromeFrameMessage) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
 
   IPC::Message bad_msg(1, -1, IPC::Message::PRIORITY_NORMAL);
diff --git a/chrome/browser/automation/testing_automation_provider.cc b/chrome/browser/automation/testing_automation_provider.cc
index 9ae23bd..6f71e26 100644
--- a/chrome/browser/automation/testing_automation_provider.cc
+++ b/chrome/browser/automation/testing_automation_provider.cc
@@ -295,7 +295,7 @@ void TestingAutomationProvider::OnBrowserRemoved(Browser* browser) {
           switches::kKeepAliveForTest)) {
     // If you change this, update Observer for chrome::SESSION_END
     // below.
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&TestingAutomationProvider::OnRemoveProvider, this));
   }
diff --git a/chrome/browser/automation/url_request_automation_job.cc b/chrome/browser/automation/url_request_automation_job.cc
index 8ccd5f0..8591261d 100644
--- a/chrome/browser/automation/url_request_automation_job.cc
+++ b/chrome/browser/automation/url_request_automation_job.cc
@@ -173,7 +173,7 @@ void URLRequestAutomationJob::Start() {
   if (!is_pending()) {
     // Start reading asynchronously so that all error reporting and data
     // callbacks happen as they would for network requests.
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&URLRequestAutomationJob::StartAsync,
                    weak_factory_.GetWeakPtr()));
@@ -212,7 +212,7 @@ bool URLRequestAutomationJob::ReadRawData(
     message_filter_->Send(new AutomationMsg_RequestRead(tab_, id_, buf_size));
     SetStatus(net::URLRequestStatus(net::URLRequestStatus::IO_PENDING, 0));
   } else {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&URLRequestAutomationJob::NotifyJobCompletionTask,
                    weak_factory_.GetWeakPtr()));
diff --git a/chrome/browser/background/background_contents_service.cc b/chrome/browser/background/background_contents_service.cc
index 9b693d4..8bf6bca 100644
--- a/chrome/browser/background/background_contents_service.cc
+++ b/chrome/browser/background/background_contents_service.cc
@@ -60,9 +60,9 @@ void CloseBalloon(const std::string id) {
 }
 
 void ScheduleCloseBalloon(const std::string& extension_id) {
-  if (!MessageLoop::current())  // For unit_tests
+  if (!base::MessageLoop::current())  // For unit_tests
     return;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&CloseBalloon, kNotificationPrefix + extension_id));
 }
 
@@ -374,7 +374,7 @@ void BackgroundContentsService::Observe(
       // notifications for this extension to be cancelled by
       // DesktopNotificationService. For this reason, instead of showing the
       // balloon right now, we schedule it to show a little later.
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE, base::Bind(&ShowBalloon, extension, profile));
       break;
     }
diff --git a/chrome/browser/background/background_mode_manager.cc b/chrome/browser/background/background_mode_manager.cc
index 52298ad..881b775 100644
--- a/chrome/browser/background/background_mode_manager.cc
+++ b/chrome/browser/background/background_mode_manager.cc
@@ -530,8 +530,8 @@ void BackgroundModeManager::EndKeepAliveForStartup() {
     // We call this via the message queue to make sure we don't try to end
     // keep-alive (which can shutdown Chrome) before the message loop has
     // started.
-    MessageLoop::current()->PostTask(FROM_HERE,
-                                     base::Bind(&chrome::EndKeepAlive));
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(&chrome::EndKeepAlive));
   }
 }
 
diff --git a/chrome/browser/bookmarks/bookmark_expanded_state_tracker_unittest.cc b/chrome/browser/bookmarks/bookmark_expanded_state_tracker_unittest.cc
index 17e85d5..ba54755 100644
--- a/chrome/browser/bookmarks/bookmark_expanded_state_tracker_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_expanded_state_tracker_unittest.cc
@@ -26,7 +26,7 @@ class BookmarkExpandedStateTrackerTest : public testing::Test {
 
  private:
   scoped_ptr<TestingProfile> profile_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/bookmarks/bookmark_html_writer.cc b/chrome/browser/bookmarks/bookmark_html_writer.cc
index 6ddd35b..620628a 100644
--- a/chrome/browser/bookmarks/bookmark_html_writer.cc
+++ b/chrome/browser/bookmarks/bookmark_html_writer.cc
@@ -417,7 +417,7 @@ void BookmarkFaviconFetcher::Observe(
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   if (chrome::NOTIFICATION_PROFILE_DESTROYED == type && fetcher != NULL) {
-    MessageLoop::current()->DeleteSoon(FROM_HERE, fetcher);
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, fetcher);
     fetcher = NULL;
   }
 }
@@ -445,7 +445,7 @@ void BookmarkFaviconFetcher::ExecuteWriter() {
                                 profile_)),
                             path_, favicons_map_.release(), observer_)));
   if (fetcher != NULL) {
-    MessageLoop::current()->DeleteSoon(FROM_HERE, fetcher);
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, fetcher);
     fetcher = NULL;
   }
 }
diff --git a/chrome/browser/bookmarks/bookmark_html_writer_unittest.cc b/chrome/browser/bookmarks/bookmark_html_writer_unittest.cc
index 66cfc3d..6ee04ee 100644
--- a/chrome/browser/bookmarks/bookmark_html_writer_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_html_writer_unittest.cc
@@ -128,7 +128,7 @@ class BookmarkHTMLWriterTest : public testing::Test {
 // Class that will notify message loop when file is written.
 class BookmarksObserver : public BookmarksExportObserver {
  public:
-  explicit BookmarksObserver(MessageLoop* loop) : loop_(loop) {
+  explicit BookmarksObserver(base::MessageLoop* loop) : loop_(loop) {
     DCHECK(loop);
   }
 
@@ -137,14 +137,14 @@ class BookmarksObserver : public BookmarksExportObserver {
   }
 
  private:
-  MessageLoop* loop_;
+  base::MessageLoop* loop_;
   DISALLOW_COPY_AND_ASSIGN(BookmarksObserver);
 };
 
 // Tests bookmark_html_writer by populating a BookmarkModel, writing it out by
 // way of bookmark_html_writer, then using the importer to read it back in.
 TEST_F(BookmarkHTMLWriterTest, Test) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread fake_ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread fake_file_thread(BrowserThread::FILE,
                                               &message_loop);
diff --git a/chrome/browser/bookmarks/bookmark_index_unittest.cc b/chrome/browser/bookmarks/bookmark_index_unittest.cc
index f970aa9..d6eb132 100644
--- a/chrome/browser/bookmarks/bookmark_index_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_index_unittest.cc
@@ -234,7 +234,7 @@ TEST_F(BookmarkIndexTest, EmptyMatchOnMultiwideLowercaseString) {
 TEST_F(BookmarkIndexTest, GetResultsSortedByTypedCount) {
   // This ensures MessageLoop::current() will exist, which is needed by
   // TestingProfile::BlockUntilHistoryProcessesPendingRequests().
-  MessageLoop loop(MessageLoop::TYPE_DEFAULT);
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
   content::TestBrowserThread ui_thread(BrowserThread::UI, &loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE, &loop);
 
diff --git a/chrome/browser/bookmarks/bookmark_model_unittest.cc b/chrome/browser/bookmarks/bookmark_model_unittest.cc
index 5789977..ab57d44 100644
--- a/chrome/browser/bookmarks/bookmark_model_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_model_unittest.cc
@@ -890,7 +890,7 @@ class BookmarkModelTestWithProfile : public testing::Test {
   BookmarkModel* bb_model_;
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 };
diff --git a/chrome/browser/bookmarks/bookmark_node_data_unittest.cc b/chrome/browser/bookmarks/bookmark_node_data_unittest.cc
index 0750497..8ee4cd8 100644
--- a/chrome/browser/bookmarks/bookmark_node_data_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_node_data_unittest.cc
@@ -27,7 +27,7 @@ class BookmarkNodeDataTest : public testing::Test {
   }
 
  private:
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 };
diff --git a/chrome/browser/bookmarks/bookmark_utils_unittest.cc b/chrome/browser/bookmarks/bookmark_utils_unittest.cc
index a5f253d..45bdc58 100644
--- a/chrome/browser/bookmarks/bookmark_utils_unittest.cc
+++ b/chrome/browser/bookmarks/bookmark_utils_unittest.cc
@@ -25,7 +25,7 @@ class BookmarkUtilsTest : public ::testing::Test {
 
  private:
   // Clipboard requires a message loop.
-  MessageLoopForUI loop;
+  base::MessageLoopForUI loop;
 };
 
 TEST_F(BookmarkUtilsTest, GetBookmarksContainingText) {
diff --git a/chrome/browser/browser_about_handler_unittest.cc b/chrome/browser/browser_about_handler_unittest.cc
index de105be..c21f2e4 100644
--- a/chrome/browser/browser_about_handler_unittest.cc
+++ b/chrome/browser/browser_about_handler_unittest.cc
@@ -60,7 +60,7 @@ TEST_F(BrowserAboutHandlerTest, WillHandleBrowserAboutURL) {
         GURL(chrome_prefix + "host/path?query#ref"),
       }
   };
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   TestingProfile profile;
 
diff --git a/chrome/browser/browser_keyevents_browsertest.cc b/chrome/browser/browser_keyevents_browsertest.cc
index d765b55..a50d3fd 100644
--- a/chrome/browser/browser_keyevents_browsertest.cc
+++ b/chrome/browser/browser_keyevents_browsertest.cc
@@ -122,7 +122,7 @@ class TestFinishObserver : public content::NotificationObserver {
     if (dom_op_details->json == "\"FINISHED\"") {
       finished_ = true;
       if (waiting_)
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index f63c5a0..0d1214d 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -292,9 +292,9 @@ void BrowserProcessImpl::PostDestroyThreads() {
 // our (other) recent requests (to save preferences).
 // Change the boolean so that the receiving thread will know that we did indeed
 // send the QuitTask that terminated the message loop.
-static void PostQuit(MessageLoop* message_loop) {
+static void PostQuit(base::MessageLoop* message_loop) {
   g_end_session_file_thread_has_completed = true;
-  message_loop->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+  message_loop->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
 }
 #elif defined(USE_X11)
 static void Signal(base::WaitableEvent* event) {
@@ -334,14 +334,14 @@ unsigned int BrowserProcessImpl::ReleaseModule() {
     print_job_manager_.reset();
 #endif
 
-    CHECK(MessageLoop::current()->is_running());
+    CHECK(base::MessageLoop::current()->is_running());
 
 #if defined(OS_MACOSX)
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(ChromeBrowserMainPartsMac::DidEndMainMessageLoop));
 #endif
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
   return module_ref_count_;
 }
@@ -383,15 +383,17 @@ void BrowserProcessImpl::EndSession() {
 
 #elif defined(OS_WIN)
   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
-      base::Bind(PostQuit, MessageLoop::current()));
+      base::Bind(PostQuit, base::MessageLoop::current()));
   int quits_received = 0;
   do {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     ++quits_received;
   } while (!g_end_session_file_thread_has_completed);
   // If we did get extra quits, then we should re-post them to the message loop.
-  while (--quits_received > 0)
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+  while (--quits_received > 0) {
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+  }
 #else
   NOTIMPLEMENTED();
 #endif
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..a54b9bd 100644
--- a/chrome/browser/browsing_data/browsing_data_cookie_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_cookie_helper_unittest.cc
@@ -94,7 +94,7 @@ class BrowsingDataCookieHelperTest : public testing::Test {
     EXPECT_EQ("B", it->Name());
 
     ASSERT_TRUE(++it == cookies.end());
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void DomainCookieCallback(const net::CookieList& cookies) {
@@ -114,7 +114,7 @@ class BrowsingDataCookieHelperTest : public testing::Test {
     EXPECT_EQ("2", it->Value());
 
     ASSERT_TRUE(++it == cookies.end());
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void DeleteCallback(const net::CookieList& cookies) {
@@ -126,7 +126,7 @@ class BrowsingDataCookieHelperTest : public testing::Test {
     EXPECT_EQ("B", it->Name());
 
     ASSERT_TRUE(++it == cookies.end());
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void CannedUniqueCallback(const net::CookieList& cookies) {
@@ -209,7 +209,7 @@ class BrowsingDataCookieHelperTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
   scoped_ptr<content::TestBrowserThread> io_thread_;
   scoped_ptr<TestingProfile> testing_profile_;
@@ -227,7 +227,7 @@ TEST_F(BrowsingDataCookieHelperTest, FetchData) {
                  base::Unretained(this)));
 
   // Blocks until BrowsingDataCookieHelperTest::FetchCallback is notified.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 TEST_F(BrowsingDataCookieHelperTest, DomainCookie) {
@@ -240,7 +240,7 @@ TEST_F(BrowsingDataCookieHelperTest, DomainCookie) {
                  base::Unretained(this)));
 
   // Blocks until BrowsingDataCookieHelperTest::FetchCallback is notified.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 TEST_F(BrowsingDataCookieHelperTest, DeleteCookie) {
@@ -253,7 +253,7 @@ TEST_F(BrowsingDataCookieHelperTest, DeleteCookie) {
                  base::Unretained(this)));
 
   // Blocks until BrowsingDataCookieHelperTest::FetchCallback is notified.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   net::CanonicalCookie cookie = cookie_list_[0];
   cookie_helper->DeleteCookie(cookie);
@@ -261,7 +261,7 @@ TEST_F(BrowsingDataCookieHelperTest, DeleteCookie) {
   cookie_helper->StartFetching(
       base::Bind(&BrowsingDataCookieHelperTest::DeleteCallback,
                  base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 TEST_F(BrowsingDataCookieHelperTest, CannedDomainCookie) {
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..ab1d7c3 100644
--- a/chrome/browser/browsing_data/browsing_data_database_helper_browsertest.cc
+++ b/chrome/browser/browsing_data/browsing_data_database_helper_browsertest.cc
@@ -73,7 +73,7 @@ class StopTestOnCallback {
     ASSERT_EQ(1UL, database_info_list.size());
     EXPECT_EQ(std::string(kTestIdentifier1),
               database_info_list.begin()->origin_identifier);
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
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 5d30ec0..2f96b36 100644
--- a/chrome/browser/browsing_data/browsing_data_database_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_database_helper_unittest.cc
@@ -20,7 +20,7 @@ class CannedBrowsingDataDatabaseHelperTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/browsing_data/browsing_data_file_system_helper_unittest.cc b/chrome/browser/browsing_data/browsing_data_file_system_helper_unittest.cc
index 922a169..d2f2ef3 100644
--- a/chrome/browser/browsing_data/browsing_data_file_system_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_file_system_helper_unittest.cc
@@ -90,13 +90,13 @@ class BrowsingDataFileSystemHelperTest : public testing::Test {
 
   // Blocks on the current MessageLoop until Notify() is called.
   void BlockUntilNotified() {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   // Unblocks the current MessageLoop. Should be called in response to some sort
   // of async activity in a callback method.
   void Notify() {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Callback that should be executed in response to
@@ -197,7 +197,7 @@ class BrowsingDataFileSystemHelperTest : public testing::Test {
   // message_loop_, as well as all the threads associated with it must be
   // defined before profile_ to prevent explosions. The threads also must be
   // defined in the order they're listed here. Oh how I love C++.
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread webkit_thread_;
diff --git a/chrome/browser/browsing_data/browsing_data_helper_browsertest.h b/chrome/browser/browsing_data/browsing_data_helper_browsertest.h
index 1f953e3..f60e36a 100644
--- a/chrome/browser/browsing_data/browsing_data_helper_browsertest.h
+++ b/chrome/browser/browsing_data/browsing_data_helper_browsertest.h
@@ -24,7 +24,7 @@ class BrowsingDataHelperCallback {
   }
 
   const std::list<T>& result() {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     DCHECK(has_result_);
     return result_;
   }
@@ -32,7 +32,7 @@ class BrowsingDataHelperCallback {
   void callback(const std::list<T>& info) {
     result_ = info;
     has_result_ = true;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
diff --git a/chrome/browser/browsing_data/browsing_data_local_storage_helper.cc b/chrome/browser/browsing_data/browsing_data_local_storage_helper.cc
index 40e2036..906ba0a 100644
--- a/chrome/browser/browsing_data/browsing_data_local_storage_helper.cc
+++ b/chrome/browser/browsing_data/browsing_data_local_storage_helper.cc
@@ -128,10 +128,10 @@ void CannedBrowsingDataLocalStorageHelper::StartFetching(
   completion_callback_ = callback;
 
   // We post a task to emulate async fetching behavior.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
-      base::Bind(&CannedBrowsingDataLocalStorageHelper::
-          ConvertPendingInfo, this));
+      base::Bind(&CannedBrowsingDataLocalStorageHelper::ConvertPendingInfo,
+                 this));
 }
 
 CannedBrowsingDataLocalStorageHelper::~CannedBrowsingDataLocalStorageHelper() {}
@@ -144,7 +144,7 @@ void CannedBrowsingDataLocalStorageHelper::ConvertPendingInfo() {
     local_storage_info_.push_back(
         LocalStorageInfo(*iter, 0,  base::Time()));
   }
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&CannedBrowsingDataLocalStorageHelper::CallCompletionCallback,
                  this));
diff --git a/chrome/browser/browsing_data/browsing_data_local_storage_helper_browsertest.cc b/chrome/browser/browsing_data/browsing_data_local_storage_helper_browsertest.cc
index b123b89..269c647 100644
--- a/chrome/browser/browsing_data/browsing_data_local_storage_helper_browsertest.cc
+++ b/chrome/browser/browsing_data/browsing_data_local_storage_helper_browsertest.cc
@@ -102,7 +102,7 @@ class StopTestOnCallback {
     for (size_t i = 0; i < arraysize(kTestHosts); ++i) {
       ASSERT_TRUE(test_hosts_found[i]) << kTestHosts[i];
     }
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
diff --git a/chrome/browser/browsing_data/browsing_data_quota_helper_unittest.cc b/chrome/browser/browsing_data/browsing_data_quota_helper_unittest.cc
index cafd2b6..017570c 100644
--- a/chrome/browser/browsing_data/browsing_data_quota_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_quota_helper_unittest.cc
@@ -49,7 +49,7 @@ class BrowsingDataQuotaHelperTest : public testing::Test {
     helper_ = NULL;
     quota_manager_ = NULL;
     quota_info_.clear();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
  protected:
@@ -113,7 +113,7 @@ class BrowsingDataQuotaHelperTest : public testing::Test {
     fetching_completed_ = true;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread io_thread_;
@@ -132,7 +132,7 @@ class BrowsingDataQuotaHelperTest : public testing::Test {
 
 TEST_F(BrowsingDataQuotaHelperTest, Empty) {
   StartFetching();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(fetching_completed());
   EXPECT_TRUE(quota_info().empty());
 }
@@ -148,7 +148,7 @@ TEST_F(BrowsingDataQuotaHelperTest, FetchData) {
 
   RegisterClient(kOrigins, arraysize(kOrigins));
   StartFetching();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(fetching_completed());
 
   std::set<QuotaInfo> expected, actual;
@@ -177,7 +177,7 @@ TEST_F(BrowsingDataQuotaHelperTest, IgnoreExtensionsAndDevTools) {
 
   RegisterClient(kOrigins, arraysize(kOrigins));
   StartFetching();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(fetching_completed());
 
   std::set<QuotaInfo> expected, actual;
@@ -193,16 +193,16 @@ TEST_F(BrowsingDataQuotaHelperTest, RevokeHostQuota) {
 
   SetPersistentHostQuota(kHost1, 1);
   SetPersistentHostQuota(kHost2, 10);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   RevokeHostQuota(kHost1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   GetPersistentHostQuota(kHost1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(0, quota());
 
   GetPersistentHostQuota(kHost2);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(10, quota());
 }
diff --git a/chrome/browser/browsing_data/browsing_data_remover.cc b/chrome/browser/browsing_data/browsing_data_remover.cc
index fd49924..1c5935b 100644
--- a/chrome/browser/browsing_data/browsing_data_remover.cc
+++ b/chrome/browser/browsing_data/browsing_data_remover.cc
@@ -653,7 +653,7 @@ void BrowsingDataRemover::NotifyAndDeleteIfDone() {
 
   // History requests aren't happy if you delete yourself from the callback.
   // As such, we do a delete later.
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 void BrowsingDataRemover::OnClearedHostnameResolutionCache() {
diff --git a/chrome/browser/browsing_data/browsing_data_remover_unittest.cc b/chrome/browser/browsing_data/browsing_data_remover_unittest.cc
index 257e649..b976555 100644
--- a/chrome/browser/browsing_data/browsing_data_remover_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_remover_unittest.cc
@@ -133,7 +133,7 @@ class AwaitCompletionHelper : public BrowsingDataRemover::Observer {
     if (!already_quit_) {
       DCHECK(!start_);
       start_ = true;
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
     } else {
       DCHECK(!start_);
       already_quit_ = false;
@@ -143,7 +143,7 @@ class AwaitCompletionHelper : public BrowsingDataRemover::Observer {
   void Notify() {
     if (start_) {
       DCHECK(!already_quit_);
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
       start_ = false;
     } else {
       DCHECK(!already_quit_);
@@ -240,7 +240,7 @@ class RemoveSafeBrowsingCookieTester : public RemoveCookieTester {
         SafeBrowsingService::CreateSafeBrowsingService();
     browser_process_->SetSafeBrowsingService(sb_service);
     sb_service->Initialize();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     // Create a cookiemonster that does not have persistant storage, and replace
     // the SafeBrowsingService created one with it.
@@ -252,7 +252,7 @@ class RemoveSafeBrowsingCookieTester : public RemoveCookieTester {
 
   virtual ~RemoveSafeBrowsingCookieTester() {
     browser_process_->safe_browsing_service()->ShutDown();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     browser_process_->SetSafeBrowsingService(NULL);
   }
 
@@ -443,7 +443,7 @@ class RemoveAutofillTester : public autofill::PersonalDataManagerObserver {
     profiles.push_back(profile);
 
     personal_data_manager_->SetProfiles(&profiles);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     std::vector<autofill::CreditCard> cards;
     autofill::CreditCard card;
@@ -458,12 +458,12 @@ class RemoveAutofillTester : public autofill::PersonalDataManagerObserver {
     cards.push_back(card);
 
     personal_data_manager_->SetCreditCards(&cards);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
  private:
   virtual void OnPersonalDataChanged() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   autofill::PersonalDataManager* personal_data_manager_;
@@ -655,7 +655,7 @@ class BrowsingDataRemoverTest : public testing::Test,
 
   // message_loop_, as well as all the threads associated with it must be
   // defined before profile_ to prevent explosions. Oh how I love C++.
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread webkit_thread_;
diff --git a/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper.cc b/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper.cc
index e18f5ec..77068b3 100644
--- a/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper.cc
+++ b/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper.cc
@@ -198,7 +198,7 @@ void CannedBrowsingDataServerBoundCertHelper::StartFetching(
     return;
   // We post a task to emulate async fetching behavior.
   completion_callback_ = callback;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&CannedBrowsingDataServerBoundCertHelper::FinishFetching,
                  this));
diff --git a/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper_unittest.cc b/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper_unittest.cc
index 1443f54..58f397a 100644
--- a/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_server_bound_cert_helper_unittest.cc
@@ -57,7 +57,7 @@ class BrowsingDataServerBoundCertHelperTest
       const net::ServerBoundCertStore::ServerBoundCertList& certs) {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     server_bound_cert_list_ = certs;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // net::SSLConfigService::Observer implementation:
@@ -66,7 +66,7 @@ class BrowsingDataServerBoundCertHelperTest
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
   scoped_ptr<content::TestBrowserThread> io_thread_;
   scoped_ptr<TestingProfile> testing_profile_;
@@ -87,7 +87,7 @@ TEST_F(BrowsingDataServerBoundCertHelperTest, FetchData) {
 
   // Blocks until BrowsingDataServerBoundCertHelperTest::FetchCallback is
   // notified.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_EQ(2UL, server_bound_cert_list_.size());
   net::ServerBoundCertStore::ServerBoundCertList::const_iterator it =
@@ -116,7 +116,7 @@ TEST_F(BrowsingDataServerBoundCertHelperTest, DeleteCert) {
   helper->StartFetching(
       base::Bind(&BrowsingDataServerBoundCertHelperTest::FetchCallback,
                  base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(1, ssl_config_changed_count_);
   ASSERT_EQ(1UL, server_bound_cert_list_.size());
@@ -133,7 +133,7 @@ TEST_F(BrowsingDataServerBoundCertHelperTest, DeleteCert) {
   helper->StartFetching(
       base::Bind(&BrowsingDataServerBoundCertHelperTest::FetchCallback,
                  base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_EQ(2, ssl_config_changed_count_);
   ASSERT_EQ(0UL, server_bound_cert_list_.size());
 }
@@ -155,7 +155,7 @@ TEST_F(BrowsingDataServerBoundCertHelperTest, CannedUnique) {
   helper->StartFetching(
       base::Bind(&BrowsingDataServerBoundCertHelperTest::FetchCallback,
                  base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_EQ(1UL, server_bound_cert_list_.size());
   net::ServerBoundCertStore::ServerBoundCert& cert =
diff --git a/chrome/browser/browsing_data/cookies_tree_model_unittest.cc b/chrome/browser/browsing_data/cookies_tree_model_unittest.cc
index 936856f..5452af6 100644
--- a/chrome/browser/browsing_data/cookies_tree_model_unittest.cc
+++ b/chrome/browser/browsing_data/cookies_tree_model_unittest.cc
@@ -341,7 +341,7 @@ class CookiesTreeModelTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_user_blocking_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/captive_portal/captive_portal_browsertest.cc b/chrome/browser/captive_portal/captive_portal_browsertest.cc
index df3c769..7f97e9b 100644
--- a/chrome/browser/captive_portal/captive_portal_browsertest.cc
+++ b/chrome/browser/captive_portal/captive_portal_browsertest.cc
@@ -290,7 +290,7 @@ void URLRequestTimeoutOnDemandJob::MaybeStopWaitingForJobsOnIOThread() {
     last_num_jobs_to_wait_for_ = num_jobs_to_wait_for_;
     num_jobs_to_wait_for_ = 0;
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                            MessageLoop::QuitClosure());
+                            base::MessageLoop::QuitClosure());
   }
 }
 
@@ -579,7 +579,7 @@ void MultiNavigationObserver::Observe(
   if (waiting_for_navigation_ &&
       num_navigations_to_wait_for_ == num_navigations_) {
     waiting_for_navigation_ = false;
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 }
 
@@ -668,7 +668,7 @@ void FailLoadsAfterLoginObserver::Observe(
       tabs_needing_navigation_.size() ==
           tabs_navigated_to_final_destination_.size()) {
     waiting_for_navigation_ = false;
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 }
 
@@ -762,7 +762,7 @@ void CaptivePortalObserver::Observe(
   if (waiting_for_result_ &&
       num_results_to_wait_for_ == num_results_received_) {
     waiting_for_result_ = false;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 }
 
diff --git a/chrome/browser/captive_portal/captive_portal_detector_unittest.cc b/chrome/browser/captive_portal/captive_portal_detector_unittest.cc
index 568af8b..c0c1806 100644
--- a/chrome/browser/captive_portal/captive_portal_detector_unittest.cc
+++ b/chrome/browser/captive_portal/captive_portal_detector_unittest.cc
@@ -72,7 +72,7 @@ class CaptivePortalDetectorTest : public testing::Test,
                    base::Unretained(&client)));
 
     ASSERT_TRUE(FetchingURL());
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     CompleteURLFetch(net_error, status_code, response_headers);
 
@@ -96,7 +96,7 @@ class CaptivePortalDetectorTest : public testing::Test,
                    base::Unretained(&client)));
 
     ASSERT_TRUE(FetchingURL());
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     detector()->Cancel();
 
@@ -105,7 +105,7 @@ class CaptivePortalDetectorTest : public testing::Test,
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   // Definition order does matter.
   TestingProfile profile_;
diff --git a/chrome/browser/captive_portal/captive_portal_service_unittest.cc b/chrome/browser/captive_portal/captive_portal_service_unittest.cc
index cc0a4ff..3055703 100644
--- a/chrome/browser/captive_portal/captive_portal_service_unittest.cc
+++ b/chrome/browser/captive_portal/captive_portal_service_unittest.cc
@@ -167,7 +167,7 @@ class CaptivePortalServiceTest : public testing::Test,
     EXPECT_FALSE(FetchingURL());
     ASSERT_TRUE(TimerRunning());
 
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     EXPECT_EQ(CaptivePortalService::STATE_CHECKING_FOR_PORTAL,
               service()->state());
     ASSERT_TRUE(FetchingURL());
@@ -199,7 +199,7 @@ class CaptivePortalServiceTest : public testing::Test,
     EXPECT_FALSE(FetchingURL());
     ASSERT_TRUE(TimerRunning());
 
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     EXPECT_FALSE(FetchingURL());
     EXPECT_FALSE(TimerRunning());
     EXPECT_EQ(1, observer.num_results_received());
@@ -274,7 +274,7 @@ class CaptivePortalServiceTest : public testing::Test,
   // after the test.
   const CaptivePortalService::TestingState old_captive_portal_testing_state_;
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   // Note that the construction order of these matters.
   scoped_ptr<TestingProfile> profile_;
@@ -372,7 +372,7 @@ TEST_F(CaptivePortalServiceTest, CaptivePortalPrefDisabledWhileRunning) {
   // Needed to create the URLFetcher, even if it never returns any results.
   service()->DetectCaptivePortal();
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(FetchingURL());
   EXPECT_FALSE(TimerRunning());
 
@@ -381,7 +381,7 @@ TEST_F(CaptivePortalServiceTest, CaptivePortalPrefDisabledWhileRunning) {
   EXPECT_TRUE(TimerRunning());
   EXPECT_EQ(0, observer.num_results_received());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_FALSE(FetchingURL());
   EXPECT_FALSE(TimerRunning());
@@ -406,7 +406,7 @@ TEST_F(CaptivePortalServiceTest, CaptivePortalPrefDisabledWhilePending) {
   EXPECT_TRUE(TimerRunning());
   EXPECT_EQ(0, observer.num_results_received());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_FALSE(FetchingURL());
   EXPECT_FALSE(TimerRunning());
@@ -432,7 +432,7 @@ TEST_F(CaptivePortalServiceTest, CaptivePortalPrefEnabledWhilePending) {
   EXPECT_FALSE(FetchingURL());
   EXPECT_TRUE(TimerRunning());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   ASSERT_TRUE(FetchingURL());
   EXPECT_FALSE(TimerRunning());
 
diff --git a/chrome/browser/captive_portal/captive_portal_tab_reloader.cc b/chrome/browser/captive_portal/captive_portal_tab_reloader.cc
index dbf1a53..eb5c3ad 100644
--- a/chrome/browser/captive_portal/captive_portal_tab_reloader.cc
+++ b/chrome/browser/captive_portal/captive_portal_tab_reloader.cc
@@ -100,7 +100,7 @@ void CaptivePortalTabReloader::OnLoadCommitted(int net_error) {
   // If the tab needs to reload, do so asynchronously, to avoid reentrancy
   // issues.
   if (state_ == STATE_NEEDS_RELOAD) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&CaptivePortalTabReloader::ReloadTabIfNeeded,
                    weak_factory_.GetWeakPtr()));
diff --git a/chrome/browser/captive_portal/captive_portal_tab_reloader_unittest.cc b/chrome/browser/captive_portal/captive_portal_tab_reloader_unittest.cc
index 2856826..e09242d 100644
--- a/chrome/browser/captive_portal/captive_portal_tab_reloader_unittest.cc
+++ b/chrome/browser/captive_portal/captive_portal_tab_reloader_unittest.cc
@@ -135,7 +135,7 @@ TEST_F(CaptivePortalTabReloaderTest, InternetConnected) {
   EXPECT_TRUE(tab_reloader().TimerRunning());
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -183,7 +183,7 @@ TEST_F(CaptivePortalTabReloaderTest, NoResponse) {
   EXPECT_TRUE(tab_reloader().TimerRunning());
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -224,7 +224,7 @@ TEST_F(CaptivePortalTabReloaderTest, Login) {
   tab_reloader().OnLoadStart(true);
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -250,7 +250,7 @@ TEST_F(CaptivePortalTabReloaderTest, Login) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -260,7 +260,7 @@ TEST_F(CaptivePortalTabReloaderTest, LoginLate) {
   tab_reloader().OnLoadStart(true);
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -376,7 +376,7 @@ TEST_F(CaptivePortalTabReloaderTest, SSLProtocolErrorAlreadyLoggedIn) {
   // The error page commits, which should trigger a reload.
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
   tab_reloader().OnLoadCommitted(net::ERR_SSL_PROTOCOL_ERROR);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -387,7 +387,7 @@ TEST_F(CaptivePortalTabReloaderTest, AlreadyLoggedIn) {
   tab_reloader().OnLoadStart(true);
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -405,7 +405,7 @@ TEST_F(CaptivePortalTabReloaderTest, AlreadyLoggedIn) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -429,7 +429,7 @@ TEST_F(CaptivePortalTabReloaderTest, AlreadyLoggedInBeforeTimerTriggers) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -453,7 +453,7 @@ TEST_F(CaptivePortalTabReloaderTest, LoginWhileTimerRunning) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -475,7 +475,7 @@ TEST_F(CaptivePortalTabReloaderTest, BehindPortalResultWhileTimerRunning) {
 
   // The rest proceeds as normal.
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
 
@@ -500,7 +500,7 @@ TEST_F(CaptivePortalTabReloaderTest, BehindPortalResultWhileTimerRunning) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -559,7 +559,7 @@ TEST_F(CaptivePortalTabReloaderTest, SSLCertErrorLogin) {
 TEST_F(CaptivePortalTabReloaderTest, HttpToHttpsRedirectInternetConnected) {
   tab_reloader().OnLoadStart(false);
   // There should be no captive portal check pending.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // HTTP to HTTPS redirect.
   tab_reloader().OnRedirect(true);
@@ -568,7 +568,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpToHttpsRedirectInternetConnected) {
   EXPECT_TRUE(tab_reloader().TimerRunning());
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -588,7 +588,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpToHttpsRedirectInternetConnected) {
 TEST_F(CaptivePortalTabReloaderTest, HttpToHttpsRedirectLogin) {
   tab_reloader().OnLoadStart(false);
   // There should be no captive portal check pending.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // HTTP to HTTPS redirect.
   tab_reloader().OnRedirect(true);
@@ -596,7 +596,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpToHttpsRedirectLogin) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), CheckForCaptivePortal()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(tab_reloader().TimerRunning());
   EXPECT_EQ(CaptivePortalTabReloader::STATE_MAYBE_BROKEN_BY_PORTAL,
             tab_reloader().state());
@@ -622,7 +622,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpToHttpsRedirectLogin) {
             tab_reloader().state());
 
   EXPECT_CALL(tab_reloader(), ReloadTab()).Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(CaptivePortalTabReloader::STATE_NONE, tab_reloader().state());
 }
 
@@ -638,7 +638,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpsToHttpRedirect) {
   EXPECT_FALSE(tab_reloader().TimerRunning());
 
   // There should be no captive portal check pending after the redirect.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Logging in shouldn't do anything.
   tab_reloader().OnCaptivePortalResults(RESULT_BEHIND_CAPTIVE_PORTAL,
@@ -657,7 +657,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpsToHttpsRedirect) {
             tab_reloader().state());
   EXPECT_FALSE(tab_reloader().TimerRunning());
   // Nothing should happen.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 // Check that an HTTPS to HTTP to HTTPS redirect results in no timer running.
@@ -675,7 +675,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpsToHttpToHttpsRedirect) {
             tab_reloader().state());
   EXPECT_FALSE(tab_reloader().TimerRunning());
   // Nothing should happen.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 // Check that an HTTP to HTTP redirect results in the timer not running.
@@ -688,7 +688,7 @@ TEST_F(CaptivePortalTabReloaderTest, HttpToHttpRedirect) {
   EXPECT_FALSE(tab_reloader().TimerRunning());
 
   // There should be no captive portal check pending after the redirect.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Logging in shouldn't do anything.
   tab_reloader().OnCaptivePortalResults(RESULT_BEHIND_CAPTIVE_PORTAL,
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index e341805..cfb1378 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -1625,7 +1625,7 @@ bool ChromeBrowserMainParts::MainMessageLoopRun(int* result_code) {
   startup_timer_->SignalStartupComplete(
       performance_monitor::StartupTimer::STARTUP_NORMAL);
 
-  DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
 #if !defined(USE_AURA) && defined(TOOLKIT_VIEWS)
   views::AcceleratorHandler accelerator_handler;
   base::RunLoop run_loop(&accelerator_handler);
diff --git a/chrome/browser/chrome_browser_main_android.cc b/chrome/browser/chrome_browser_main_android.cc
index ea68eb3..f08ce27 100644
--- a/chrome/browser/chrome_browser_main_android.cc
+++ b/chrome/browser/chrome_browser_main_android.cc
@@ -69,13 +69,13 @@ void ChromeBrowserMainPartsAndroid::PreEarlyInitialization() {
   {
     TRACE_EVENT0("startup",
       "ChromeBrowserMainPartsAndroid::PreEarlyInitialization:CreateUiMsgLoop");
-    main_message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+    main_message_loop_.reset(new base::MessageLoop(base::MessageLoop::TYPE_UI));
   }
 
   {
     TRACE_EVENT0("startup",
       "ChromeBrowserMainPartsAndroid::PreEarlyInitialization:StartUiMsgLoop");
-    MessageLoopForUI::current()->Start();
+    base::MessageLoopForUI::current()->Start();
   }
 
   CommandLine::ForCurrentProcess()->AppendSwitch(
diff --git a/chrome/browser/chrome_browser_main_android.h b/chrome/browser/chrome_browser_main_android.h
index e07fbd8..1439ac2 100644
--- a/chrome/browser/chrome_browser_main_android.h
+++ b/chrome/browser/chrome_browser_main_android.h
@@ -24,7 +24,7 @@ class ChromeBrowserMainPartsAndroid : public ChromeBrowserMainParts {
   virtual void ShowMissingLocaleMessageBox() OVERRIDE;
 
  private:
-  scoped_ptr<MessageLoop> main_message_loop_;
+  scoped_ptr<base::MessageLoop> main_message_loop_;
   scoped_ptr<CrashDumpManager> crash_dump_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainPartsAndroid);
diff --git a/chrome/browser/chrome_browser_main_x11.cc b/chrome/browser/chrome_browser_main_x11.cc
index fadf018..a8b833a 100644
--- a/chrome/browser/chrome_browser_main_x11.cc
+++ b/chrome/browser/chrome_browser_main_x11.cc
@@ -32,7 +32,7 @@ const int kWaitForUIThreadSeconds = 10;
 
 int BrowserX11ErrorHandler(Display* d, XErrorEvent* error) {
   if (!g_in_x11_io_error_handler)
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&ui::LogErrorEventDescription, d, *error));
   return 0;
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_launcher.cc b/chrome/browser/chromeos/app_mode/kiosk_app_launcher.cc
index fce4145..f90c254 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_launcher.cc
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_launcher.cc
@@ -64,7 +64,7 @@ class KioskAppLauncher::CryptohomedChecker
       }
 
       const int retry_delay_in_milliseconds = 500 * (1 << retry_count_);
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           base::Bind(&CryptohomedChecker::StartCheck, AsWeakPtr()),
           base::TimeDelta::FromMilliseconds(retry_delay_in_milliseconds));
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc b/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
index a61dba7..0b66a91 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_manager_browsertest.cc
@@ -76,7 +76,7 @@ class AppDataLoadWaiter : public KioskAppManagerObserver {
   }
 
   void Wait() {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   bool loaded() const { return loaded_; }
@@ -85,11 +85,11 @@ class AppDataLoadWaiter : public KioskAppManagerObserver {
   // KioskAppManagerObserver overrides:
   virtual void OnKioskAppDataChanged(const std::string& app_id) OVERRIDE {
     loaded_ = true;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
   virtual void OnKioskAppDataLoadFailure(const std::string& app_id) OVERRIDE {
     loaded_ = false;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   KioskAppManager* manager_;
diff --git a/chrome/browser/chromeos/attestation/attestation_ca_client_unittest.cc b/chrome/browser/chromeos/attestation/attestation_ca_client_unittest.cc
index d3f54e2..4891c97 100644
--- a/chrome/browser/chromeos/attestation/attestation_ca_client_unittest.cc
+++ b/chrome/browser/chromeos/attestation/attestation_ca_client_unittest.cc
@@ -49,7 +49,7 @@ class AttestationCAClientTest : public ::testing::Test {
     fetcher->delegate()->OnURLFetchComplete(fetcher);
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread io_thread_;
   net::TestURLFetcherFactory url_fetcher_factory_;
 
diff --git a/chrome/browser/chromeos/attestation/attestation_policy_observer_unittest.cc b/chrome/browser/chromeos/attestation/attestation_policy_observer_unittest.cc
index 34d7317..19ef480 100644
--- a/chrome/browser/chromeos/attestation/attestation_policy_observer_unittest.cc
+++ b/chrome/browser/chromeos/attestation/attestation_policy_observer_unittest.cc
@@ -66,23 +66,23 @@ const uint8 kTestKeyData[] = {
 };
 
 void DBusCallbackFalse(const BoolDBusMethodCallback& callback) {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, DBUS_METHOD_CALL_SUCCESS, false));
 }
 
 void DBusCallbackTrue(const BoolDBusMethodCallback& callback) {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, DBUS_METHOD_CALL_SUCCESS, true));
 }
 
 void CertCallbackSuccess(const AttestationFlow::CertificateCallback& callback) {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, true, "fake_cert"));
 }
 
 void StatusCallbackSuccess(
     const policy::CloudPolicyClient::StatusCallback& callback) {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, true));
 }
 
@@ -91,7 +91,7 @@ class FakeDBusData {
   explicit FakeDBusData(const std::string& data) : data_(data) {}
 
   void operator() (const CryptohomeClient::DataMethodCallback& callback) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, DBUS_METHOD_CALL_SUCCESS, true, data_));
   }
@@ -105,7 +105,7 @@ class FakeDBusData {
 class AttestationPolicyObserverTest : public ::testing::Test {
  public:
   AttestationPolicyObserverTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &message_loop_) {
     // Remove the real DeviceSettingsProvider and replace it with a stub.
     CrosSettings* cros_settings = CrosSettings::Get();
@@ -235,7 +235,7 @@ class AttestationPolicyObserverTest : public ::testing::Test {
     return result;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   ScopedTestDeviceSettingsService test_device_settings_service_;
   ScopedTestCrosSettings test_cros_settings_;
diff --git a/chrome/browser/chromeos/audio/audio_mixer_alsa.cc b/chrome/browser/chromeos/audio/audio_mixer_alsa.cc
index 6720880..e83b0dc 100644
--- a/chrome/browser/chromeos/audio/audio_mixer_alsa.cc
+++ b/chrome/browser/chromeos/audio/audio_mixer_alsa.cc
@@ -87,7 +87,7 @@ AudioMixerAlsa::AudioMixerAlsa()
 AudioMixerAlsa::~AudioMixerAlsa() {
   if (!thread_.get())
     return;
-  DCHECK(MessageLoop::current() != thread_->message_loop());
+  DCHECK(base::MessageLoop::current() != thread_->message_loop());
 
   thread_->message_loop()->PostTask(
       FROM_HERE, base::Bind(&AudioMixerAlsa::Disconnect,
@@ -190,7 +190,7 @@ void AudioMixerAlsa::SetCaptureMuteLocked(bool locked) {
 }
 
 void AudioMixerAlsa::Connect() {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   DCHECK(!alsa_mixer_);
 
   if (disconnected_event_.IsSignaled())
@@ -208,7 +208,7 @@ void AudioMixerAlsa::Connect() {
 }
 
 bool AudioMixerAlsa::ConnectInternal() {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   num_connection_attempts_++;
   int err;
   snd_mixer_t* handle = NULL;
@@ -329,7 +329,7 @@ bool AudioMixerAlsa::ConnectInternal() {
 }
 
 void AudioMixerAlsa::Disconnect() {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   if (alsa_mixer_) {
     snd_mixer_close(alsa_mixer_);
     alsa_mixer_ = NULL;
@@ -338,7 +338,7 @@ void AudioMixerAlsa::Disconnect() {
 }
 
 void AudioMixerAlsa::ApplyState() {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   if (!alsa_mixer_)
     return;
 
@@ -377,7 +377,7 @@ void AudioMixerAlsa::ApplyState() {
 
 snd_mixer_elem_t* AudioMixerAlsa::FindElementWithName(
     snd_mixer_t* handle, const string& element_name) const {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   snd_mixer_selem_id_t* sid = NULL;
 
   // Using id_malloc/id_free API instead of id_alloca since the latter gives the
@@ -397,7 +397,7 @@ snd_mixer_elem_t* AudioMixerAlsa::FindElementWithName(
 
 bool AudioMixerAlsa::GetElementVolume(snd_mixer_elem_t* element,
                                       double* current_volume_db) {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   alsa_long_t long_volume = 0;
   int alsa_result = snd_mixer_selem_get_playback_dB(
       element, static_cast<snd_mixer_selem_channel_id_t>(0), &long_volume);
@@ -413,7 +413,7 @@ bool AudioMixerAlsa::GetElementVolume(snd_mixer_elem_t* element,
 bool AudioMixerAlsa::SetElementVolume(snd_mixer_elem_t* element,
                                       double new_volume_db,
                                       double rounding_bias) {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   alsa_long_t volume_low = 0;
   alsa_long_t volume_high = 0;
   int alsa_result = snd_mixer_selem_get_playback_volume_range(
@@ -463,7 +463,7 @@ bool AudioMixerAlsa::SetElementVolume(snd_mixer_elem_t* element,
 }
 
 void AudioMixerAlsa::SetElementMuted(snd_mixer_elem_t* element, bool mute) {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   int alsa_result = snd_mixer_selem_set_playback_switch_all(element, !mute);
   if (alsa_result != 0) {
     LOG(WARNING) << "snd_mixer_selem_set_playback_switch_all() failed: "
diff --git a/chrome/browser/chromeos/audio/audio_mixer_cras.cc b/chrome/browser/chromeos/audio/audio_mixer_cras.cc
index 89de431..5e49dd8 100644
--- a/chrome/browser/chromeos/audio/audio_mixer_cras.cc
+++ b/chrome/browser/chromeos/audio/audio_mixer_cras.cc
@@ -44,7 +44,7 @@ AudioMixerCras::AudioMixerCras()
 AudioMixerCras::~AudioMixerCras() {
   if (!thread_.get())
     return;
-  DCHECK(MessageLoop::current() != thread_->message_loop());
+  DCHECK(base::MessageLoop::current() != thread_->message_loop());
 
   base::ThreadRestrictions::ScopedAllowIO allow_io_for_thread_join;
   thread_->Stop();
@@ -139,7 +139,7 @@ void AudioMixerCras::SetCaptureMuteLocked(bool locked) {
 }
 
 void AudioMixerCras::Connect() {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
 
   // Create the client structure.
   if (client_ == NULL && cras_client_create(&client_) < 0) {
@@ -159,7 +159,7 @@ void AudioMixerCras::Connect() {
 }
 
 void AudioMixerCras::ApplyState() {
-  DCHECK(MessageLoop::current() == thread_->message_loop());
+  DCHECK(base::MessageLoop::current() == thread_->message_loop());
   if (!client_connected_)
     return;
 
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index cf3b0d3..eabdea2 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -131,7 +131,7 @@ void ChromeOSVersionCallback(const std::string& version) {
 
 #endif
 
-class MessageLoopObserver : public MessageLoopForUI::Observer {
+class MessageLoopObserver : public base::MessageLoopForUI::Observer {
   virtual base::EventStatus WillProcessEvent(
       const base::NativeEvent& event) OVERRIDE {
     return base::EVENT_CONTINUE;
@@ -448,7 +448,7 @@ void ChromeBrowserMainPartsChromeos::PreMainMessageLoopStart() {
 }
 
 void ChromeBrowserMainPartsChromeos::PostMainMessageLoopStart() {
-  MessageLoopForUI* message_loop = MessageLoopForUI::current();
+  base::MessageLoopForUI* message_loop = base::MessageLoopForUI::current();
   message_loop->AddObserver(g_message_loop_observer.Pointer());
 
   dbus_services_.reset(new internal::DBusServices(parameters()));
diff --git a/chrome/browser/chromeos/contacts/contact_database_unittest.cc b/chrome/browser/chromeos/contacts/contact_database_unittest.cc
index c32cad0..f45addd 100644
--- a/chrome/browser/chromeos/contacts/contact_database_unittest.cc
+++ b/chrome/browser/chromeos/contacts/contact_database_unittest.cc
@@ -129,7 +129,7 @@ class ContactDatabaseTest : public testing::Test {
     message_loop_.Quit();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   // Temporary directory where the database is saved.
diff --git a/chrome/browser/chromeos/contacts/contact_manager_unittest.cc b/chrome/browser/chromeos/contacts/contact_manager_unittest.cc
index 82984d8..237ae7a 100644
--- a/chrome/browser/chromeos/contacts/contact_manager_unittest.cc
+++ b/chrome/browser/chromeos/contacts/contact_manager_unittest.cc
@@ -80,7 +80,7 @@ class ContactManagerTest : public testing::Test {
     contact_manager_->Init();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   scoped_ptr<TestingProfileManager> profile_manager_;
diff --git a/chrome/browser/chromeos/contacts/gdata_contacts_service_unittest.cc b/chrome/browser/chromeos/contacts/gdata_contacts_service_unittest.cc
index fbf8809..1be34fd 100644
--- a/chrome/browser/chromeos/contacts/gdata_contacts_service_unittest.cc
+++ b/chrome/browser/chromeos/contacts/gdata_contacts_service_unittest.cc
@@ -150,7 +150,7 @@ class GDataContactsServiceTest : public testing::Test {
     CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     download_was_successful_ = true;
     downloaded_contacts_.swap(contacts);
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Handles failure for Download().
@@ -158,7 +158,7 @@ class GDataContactsServiceTest : public testing::Test {
     CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     download_was_successful_ = false;
     downloaded_contacts_.reset(new ScopedVector<contacts::Contact>());
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Handles a request for downloading a file. Reads a requested file and
@@ -174,7 +174,7 @@ class GDataContactsServiceTest : public testing::Test {
     return result.PassAs<net::test_server::HttpResponse>();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/chromeos/contacts/google_contact_store_unittest.cc b/chrome/browser/chromeos/contacts/google_contact_store_unittest.cc
index 90f5e62..377ce35 100644
--- a/chrome/browser/chromeos/contacts/google_contact_store_unittest.cc
+++ b/chrome/browser/chromeos/contacts/google_contact_store_unittest.cc
@@ -76,7 +76,7 @@ class GoogleContactStoreTest : public testing::Test {
     test_api_->SetGDataService(gdata_service_);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   TestContactStoreObserver observer_;
diff --git a/chrome/browser/chromeos/dbus/service_provider_test_helper.h b/chrome/browser/chromeos/dbus/service_provider_test_helper.h
index 17f6f8a..656e489 100644
--- a/chrome/browser/chromeos/dbus/service_provider_test_helper.h
+++ b/chrome/browser/chromeos/dbus/service_provider_test_helper.h
@@ -88,7 +88,7 @@ class ServiceProviderTestHelper {
   scoped_refptr<dbus::MockObjectProxy> mock_object_proxy_;
   dbus::ExportedObject::MethodCallCallback method_callback_;
   dbus::ObjectProxy::SignalCallback on_signal_callback_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   bool response_received_;
   scoped_ptr<dbus::Response> response_;
 };
diff --git a/chrome/browser/chromeos/drive/download_handler_unittest.cc b/chrome/browser/chromeos/drive/download_handler_unittest.cc
index 3a0db7f0..5cba3ec 100644
--- a/chrome/browser/chromeos/drive/download_handler_unittest.cc
+++ b/chrome/browser/chromeos/drive/download_handler_unittest.cc
@@ -68,7 +68,7 @@ class DownloadHandlerTest : public testing::Test {
 
  protected:
   base::ScopedTempDir temp_dir_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<content::MockDownloadManager> download_manager_;
   MockFileSystem file_system_;
diff --git a/chrome/browser/chromeos/drive/drive_app_registry_unittest.cc b/chrome/browser/chromeos/drive/drive_app_registry_unittest.cc
index 2d9dff7..5363193 100644
--- a/chrome/browser/chromeos/drive/drive_app_registry_unittest.cc
+++ b/chrome/browser/chromeos/drive/drive_app_registry_unittest.cc
@@ -86,7 +86,7 @@ class DriveAppRegistryTest : public testing::Test {
               is_primary);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc b/chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc
index 303dd3e..f266d21 100644
--- a/chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc
+++ b/chrome/browser/chromeos/drive/drive_file_stream_reader_unittest.cc
@@ -59,7 +59,7 @@ class LocalReaderProxyTest : public ::testing::Test {
     worker_thread_.reset();
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread io_thread_;
 
   base::ScopedTempDir temp_dir_;
@@ -112,7 +112,7 @@ class NetworkReaderProxyTest : public ::testing::Test {
   NetworkReaderProxyTest() : io_thread_(BrowserThread::IO, &message_loop_) {
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread io_thread_;
 };
 
@@ -348,7 +348,7 @@ class DriveFileStreamReaderTest : public ::testing::Test {
                       base::Unretained(this));
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
diff --git a/chrome/browser/chromeos/drive/drive_integration_service_unittest.cc b/chrome/browser/chromeos/drive/drive_integration_service_unittest.cc
index e84bedb..826f09f 100644
--- a/chrome/browser/chromeos/drive/drive_integration_service_unittest.cc
+++ b/chrome/browser/chromeos/drive/drive_integration_service_unittest.cc
@@ -36,7 +36,7 @@ class DriveIntegrationServiceTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<DriveIntegrationService> integration_service_;
diff --git a/chrome/browser/chromeos/drive/drive_url_request_job_unittest.cc b/chrome/browser/chromeos/drive/drive_url_request_job_unittest.cc
index 5274ce4..c5ca7df 100644
--- a/chrome/browser/chromeos/drive/drive_url_request_job_unittest.cc
+++ b/chrome/browser/chromeos/drive/drive_url_request_job_unittest.cc
@@ -202,7 +202,7 @@ class DriveURLRequestJobTest : public testing::Test {
     return true;
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
@@ -222,7 +222,7 @@ TEST_F(DriveURLRequestJobTest, NonGetMethod) {
   request.set_method("POST");  // Set non "GET" method.
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
   EXPECT_EQ(net::ERR_METHOD_NOT_SUPPORTED, request.status().error());
@@ -239,7 +239,7 @@ TEST_F(DriveURLRequestJobTest, RegularFile) {
         url_request_context_.get(), test_network_delegate_.get());
     request.Start();
 
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     EXPECT_EQ(net::URLRequestStatus::SUCCESS, request.status().status());
     // It looks weird, but the mime type for the "File 1.txt" is "audio/mpeg"
@@ -264,7 +264,7 @@ TEST_F(DriveURLRequestJobTest, RegularFile) {
         url_request_context_.get(), test_network_delegate_.get());
     request.Start();
 
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     EXPECT_EQ(net::URLRequestStatus::SUCCESS, request.status().status());
     std::string mime_type;
@@ -286,7 +286,7 @@ TEST_F(DriveURLRequestJobTest, HostedDocument) {
       url_request_context_.get(), test_network_delegate_.get());
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::SUCCESS, request.status().status());
   // Make sure that a hosted document triggers redirection.
@@ -301,7 +301,7 @@ TEST_F(DriveURLRequestJobTest, RootDirectory) {
       url_request_context_.get(), test_network_delegate_.get());
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
   EXPECT_EQ(net::ERR_FAILED, request.status().error());
@@ -313,7 +313,7 @@ TEST_F(DriveURLRequestJobTest, Directory) {
       url_request_context_.get(), test_network_delegate_.get());
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
   EXPECT_EQ(net::ERR_FAILED, request.status().error());
@@ -325,7 +325,7 @@ TEST_F(DriveURLRequestJobTest, NonExistingFile) {
       url_request_context_.get(), test_network_delegate_.get());
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
   EXPECT_EQ(net::ERR_FILE_NOT_FOUND, request.status().error());
@@ -337,7 +337,7 @@ TEST_F(DriveURLRequestJobTest, WrongFormat) {
       url_request_context_.get(), test_network_delegate_.get());
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
   EXPECT_EQ(net::ERR_INVALID_URL, request.status().error());
@@ -352,7 +352,7 @@ TEST_F(DriveURLRequestJobTest, Cancel) {
   request.Start();
   request.Cancel();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::CANCELED, request.status().status());
 }
@@ -370,7 +370,7 @@ TEST_F(DriveURLRequestJobTest, RangeHeader) {
       "Range", "bytes=3-5", false /* overwrite */);
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::SUCCESS, request.status().status());
 
@@ -393,7 +393,7 @@ TEST_F(DriveURLRequestJobTest, WrongRangeHeader) {
       "Range", "Wrong Range Header Value", false /* overwrite */);
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
   EXPECT_EQ(net::ERR_REQUEST_RANGE_NOT_SATISFIABLE, request.status().error());
diff --git a/chrome/browser/chromeos/drive/fake_file_system_unittest.cc b/chrome/browser/chromeos/drive/fake_file_system_unittest.cc
index d00bd76..3d3384a 100644
--- a/chrome/browser/chromeos/drive/fake_file_system_unittest.cc
+++ b/chrome/browser/chromeos/drive/fake_file_system_unittest.cc
@@ -36,7 +36,7 @@ class FakeFileSystemTest : public ::testing::Test {
     ASSERT_TRUE(fake_file_system_->InitializeForTesting());
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   scoped_ptr<google_apis::FakeDriveService> fake_drive_service_;
diff --git a/chrome/browser/chromeos/drive/file_cache_unittest.cc b/chrome/browser/chromeos/drive/file_cache_unittest.cc
index 5a63b0d..151bdb2 100644
--- a/chrome/browser/chromeos/drive/file_cache_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_cache_unittest.cc
@@ -522,7 +522,7 @@ class FileCacheTest : public testing::Test {
     return num_files_found;
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
   base::ScopedTempDir temp_dir_;
@@ -1264,7 +1264,7 @@ TEST_F(FileCacheTest, StoreToCacheNoSpace) {
 
 // Don't use TEST_F, as we don't want SetUp() and TearDown() for this test.
 TEST(FileCacheExtraTest, InitializationFailure) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(content::BrowserThread::UI,
                                        &message_loop);
 
diff --git a/chrome/browser/chromeos/drive/file_system/operation_test_base.h b/chrome/browser/chromeos/drive/file_system/operation_test_base.h
index fb1b6c2..7d320c5 100644
--- a/chrome/browser/chromeos/drive/file_system/operation_test_base.h
+++ b/chrome/browser/chromeos/drive/file_system/operation_test_base.h
@@ -89,7 +89,7 @@ class OperationTestBase : public testing::Test {
   internal::FileCache* cache() { return cache_.get(); }
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/chromeos/drive/file_system_unittest.cc b/chrome/browser/chromeos/drive/file_system_unittest.cc
index caadf8c..b2e09c2 100644
--- a/chrome/browser/chromeos/drive/file_system_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_system_unittest.cc
@@ -47,7 +47,7 @@ const int64 kLotsOfSpace = internal::kMinFreeSpace * 10;
 // Counts the number of invocation, and if it increased up to |expected_counter|
 // quits the current message loop.
 void AsyncInitializationCallback(
-    int* counter, int expected_counter, MessageLoop* message_loop,
+    int* counter, int expected_counter, base::MessageLoop* message_loop,
     FileError error, scoped_ptr<ResourceEntry> entry) {
   if (error != FILE_ERROR_OK || !entry) {
     // If we hit an error case, quit the message loop immediately.
@@ -367,7 +367,7 @@ class FileSystemTest : public testing::Test {
     EXPECT_EQ(entry.resource_id(), resource_id);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/chromeos/drive/file_system_util_unittest.cc b/chrome/browser/chromeos/drive/file_system_util_unittest.cc
index 4639bb2..93a8720 100644
--- a/chrome/browser/chromeos/drive/file_system_util_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_system_util_unittest.cc
@@ -92,7 +92,7 @@ TEST(FileSystemUtilTest, ExtractDrivePathFromFileSystemUrl) {
   base::ScopedTempDir temp_dir_;
   ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
 
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   scoped_refptr<fileapi::ExternalMountPoints> mount_points =
       fileapi::ExternalMountPoints::CreateRefCounted();
   scoped_refptr<fileapi::FileSystemContext> context(
diff --git a/chrome/browser/chromeos/drive/file_write_helper_unittest.cc b/chrome/browser/chromeos/drive/file_write_helper_unittest.cc
index bb68996..4a80cec 100644
--- a/chrome/browser/chromeos/drive/file_write_helper_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_write_helper_unittest.cc
@@ -77,7 +77,7 @@ class FileWriteHelperTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<TestFileSystem> test_file_system_;
 };
diff --git a/chrome/browser/chromeos/drive/job_scheduler_unittest.cc b/chrome/browser/chromeos/drive/job_scheduler_unittest.cc
index d455fd8b..0cf8546 100644
--- a/chrome/browser/chromeos/drive/job_scheduler_unittest.cc
+++ b/chrome/browser/chromeos/drive/job_scheduler_unittest.cc
@@ -161,7 +161,7 @@ class JobSchedulerTest : public testing::Test {
     ChangeConnectionType(net::NetworkChangeNotifier::CONNECTION_NONE);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<JobScheduler> scheduler_;
diff --git a/chrome/browser/chromeos/drive/local_file_reader_unittest.cc b/chrome/browser/chromeos/drive/local_file_reader_unittest.cc
index 43b6ce5..dd8acf4 100644
--- a/chrome/browser/chromeos/drive/local_file_reader_unittest.cc
+++ b/chrome/browser/chromeos/drive/local_file_reader_unittest.cc
@@ -60,7 +60,7 @@ class LocalFileReaderTest : public ::testing::Test {
     worker_thread_.reset();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   base::ScopedTempDir temp_dir_;
   scoped_ptr<base::Thread> worker_thread_;
   scoped_ptr<LocalFileReader> file_reader_;
diff --git a/chrome/browser/chromeos/drive/remove_stale_cache_files_unittest.cc b/chrome/browser/chromeos/drive/remove_stale_cache_files_unittest.cc
index 1d3d51e..6c46169 100644
--- a/chrome/browser/chromeos/drive/remove_stale_cache_files_unittest.cc
+++ b/chrome/browser/chromeos/drive/remove_stale_cache_files_unittest.cc
@@ -54,7 +54,7 @@ class RemoveStaleCacheFilesTest : public testing::Test {
     ASSERT_EQ(FILE_ERROR_OK, error);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   base::ScopedTempDir temp_dir_;
 
diff --git a/chrome/browser/chromeos/drive/resource_metadata_unittest.cc b/chrome/browser/chromeos/drive/resource_metadata_unittest.cc
index dc5a945..71ac23a 100644
--- a/chrome/browser/chromeos/drive/resource_metadata_unittest.cc
+++ b/chrome/browser/chromeos/drive/resource_metadata_unittest.cc
@@ -216,7 +216,7 @@ class ResourceMetadataTestOnUIThread : public testing::Test {
       resource_metadata_;
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
@@ -1198,7 +1198,7 @@ class ResourceMetadataTest : public testing::Test {
   }
 
   base::ScopedTempDir temp_dir_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<ResourceMetadata, test_util::DestroyHelperForTests>
       resource_metadata_;
diff --git a/chrome/browser/chromeos/drive/search_metadata_unittest.cc b/chrome/browser/chromeos/drive/search_metadata_unittest.cc
index ec892ff..0362d6e 100644
--- a/chrome/browser/chromeos/drive/search_metadata_unittest.cc
+++ b/chrome/browser/chromeos/drive/search_metadata_unittest.cc
@@ -215,7 +215,7 @@ class SearchMetadataTest : public testing::Test {
     EXPECT_EQ(FILE_ERROR_OK, error);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   base::ScopedTempDir temp_dir_;
   scoped_ptr<FakeFreeDiskSpaceGetter> fake_free_disk_space_getter_;
diff --git a/chrome/browser/chromeos/drive/sync_client_unittest.cc b/chrome/browser/chromeos/drive/sync_client_unittest.cc
index d88d687..e41bf43 100644
--- a/chrome/browser/chromeos/drive/sync_client_unittest.cc
+++ b/chrome/browser/chromeos/drive/sync_client_unittest.cc
@@ -215,7 +215,7 @@ class SyncClientTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   base::ScopedTempDir temp_dir_;
   scoped_ptr<StrictMock<MockFileSystem> > mock_file_system_;
diff --git a/chrome/browser/chromeos/drive/webkit_file_stream_reader_impl_unittest.cc b/chrome/browser/chromeos/drive/webkit_file_stream_reader_impl_unittest.cc
index 8064fc2..687bd52 100644
--- a/chrome/browser/chromeos/drive/webkit_file_stream_reader_impl_unittest.cc
+++ b/chrome/browser/chromeos/drive/webkit_file_stream_reader_impl_unittest.cc
@@ -96,7 +96,7 @@ class WebkitFileStreamReaderImplTest : public ::testing::Test {
                       base::Unretained(this));
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
diff --git a/chrome/browser/chromeos/extensions/file_manager/file_manager_browsertest.cc b/chrome/browser/chromeos/extensions/file_manager/file_manager_browsertest.cc
index 081e350..1e0bd76 100644
--- a/chrome/browser/chromeos/extensions/file_manager/file_manager_browsertest.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/file_manager_browsertest.cc
@@ -217,7 +217,7 @@ class DriveTestVolume : public TestVolume {
         name,
         google_apis::test_util::CreateCopyResultCallback(&error,
                                                          &resource_entry));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ASSERT_TRUE(error == google_apis::HTTP_CREATED);
     ASSERT_TRUE(resource_entry);
 
@@ -228,7 +228,7 @@ class DriveTestVolume : public TestVolume {
         time,
         google_apis::test_util::CreateCopyResultCallback(&error,
                                                          &resource_entry));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ASSERT_TRUE(error == google_apis::HTTP_SUCCESS);
     ASSERT_TRUE(resource_entry);
     CheckForUpdates();
@@ -264,7 +264,7 @@ class DriveTestVolume : public TestVolume {
         shared_with_me,
         google_apis::test_util::CreateCopyResultCallback(&error,
                                                          &resource_entry));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ASSERT_EQ(google_apis::HTTP_CREATED, error);
     ASSERT_TRUE(resource_entry);
 
@@ -275,7 +275,7 @@ class DriveTestVolume : public TestVolume {
         time,
         google_apis::test_util::CreateCopyResultCallback(&error,
                                                          &resource_entry));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ASSERT_EQ(google_apis::HTTP_SUCCESS, error);
     ASSERT_TRUE(resource_entry);
 
diff --git a/chrome/browser/chromeos/extensions/file_manager/file_manager_notifications.cc b/chrome/browser/chromeos/extensions/file_manager/file_manager_notifications.cc
index 8331d82..166b8d1 100644
--- a/chrome/browser/chromeos/extensions/file_manager/file_manager_notifications.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/file_manager_notifications.cc
@@ -319,7 +319,7 @@ void FileManagerNotifications::ShowNotificationDelayed(
     base::TimeDelta delay) {
   std::string notification_id = GetNotificationId(type, path);
   hidden_notifications_.erase(notification_id);
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&FileManagerNotifications::ShowNotificationById, AsWeakPtr(),
                  type, notification_id, GetMessage(type)),
@@ -334,7 +334,7 @@ void FileManagerNotifications::HideNotification(NotificationType type,
 
 void FileManagerNotifications::HideNotificationDelayed(
     NotificationType type, const std::string& path, base::TimeDelta delay) {
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&FileManagerNotifications::HideNotification, AsWeakPtr(),
                  type, path),
diff --git a/chrome/browser/chromeos/input_method/candidate_window_view.cc b/chrome/browser/chromeos/input_method/candidate_window_view.cc
index b9b9abc..7c482db 100644
--- a/chrome/browser/chromeos/input_method/candidate_window_view.cc
+++ b/chrome/browser/chromeos/input_method/candidate_window_view.cc
@@ -789,7 +789,7 @@ void CandidateWindowView::MaybeInitializeCandidateViews(
   for (size_t i = 0; i < candidate_views_.size(); ++i) {
     candidate_area_contents->RemoveChildView(candidate_views_[i]);
     // Delete the view after getting out the current message loop iteration.
-    MessageLoop::current()->DeleteSoon(FROM_HERE, candidate_views_[i]);
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, candidate_views_[i]);
   }
   candidate_views_.clear();
   selected_candidate_index_in_page_ = -1;  // Invalidates the index.
diff --git a/chrome/browser/chromeos/input_method/input_method_engine_ibus_browserttests.cc b/chrome/browser/chromeos/input_method/input_method_engine_ibus_browserttests.cc
index 3877887..4a92aa7 100644
--- a/chrome/browser/chromeos/input_method/input_method_engine_ibus_browserttests.cc
+++ b/chrome/browser/chromeos/input_method/input_method_engine_ibus_browserttests.cc
@@ -135,7 +135,7 @@ class KeyEventDoneCallback {
 
   void Run(bool consumed) {
     if (consumed == expected_argument_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
       is_called_ = true;
     }
   }
diff --git a/chrome/browser/chromeos/input_method/input_method_manager_impl_unittest.cc b/chrome/browser/chromeos/input_method/input_method_manager_impl_unittest.cc
index ee64734..a1b75d2 100644
--- a/chrome/browser/chromeos/input_method/input_method_manager_impl_unittest.cc
+++ b/chrome/browser/chromeos/input_method/input_method_manager_impl_unittest.cc
@@ -155,7 +155,7 @@ class InputMethodManagerImplTest :  public testing::Test {
   MockIBusClient* mock_ibus_client_;
   MockDBusThreadManagerWithoutGMock* mock_dbus_thread_manager_;
   MockXKeyboard* xkeyboard_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   MockComponentExtIMEManagerDelegate* mock_delegate_;
   std::vector<ComponentExtensionIME> ime_list_;
 
diff --git a/chrome/browser/chromeos/input_method/textinput_test_helper.cc b/chrome/browser/chromeos/input_method/textinput_test_helper.cc
index 2bf5712..5132724 100644
--- a/chrome/browser/chromeos/input_method/textinput_test_helper.cc
+++ b/chrome/browser/chromeos/input_method/textinput_test_helper.cc
@@ -75,7 +75,7 @@ void TextInputTestHelper::OnTextInputTypeChanged(
     const ui::TextInputClient* client) {
   latest_text_input_type_ = client->GetTextInputType();
   if (waiting_type_ == WAIT_ON_TEXT_INPUT_TYPE_CHANGED)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void TextInputTestHelper::OnInputMethodDestroyed(
@@ -85,13 +85,13 @@ void TextInputTestHelper::OnInputMethodDestroyed(
 void TextInputTestHelper::OnFocus() {
   focus_state_ = true;
   if (waiting_type_ == WAIT_ON_FOCUS)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void TextInputTestHelper::OnBlur() {
   focus_state_ = false;
   if (waiting_type_ == WAIT_ON_BLUR)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void TextInputTestHelper::OnCaretBoundsChanged(
@@ -102,7 +102,7 @@ void TextInputTestHelper::OnCaretBoundsChanged(
       !GetTextInputClient()->GetSelectionRange(&selection_range_))
       return;
   if (waiting_type_ == WAIT_ON_CARET_BOUNDS_CHANGED)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void TextInputTestHelper::OnTextInputStateChanged(
diff --git a/chrome/browser/chromeos/kiosk_mode/kiosk_mode_settings_unittest.cc b/chrome/browser/chromeos/kiosk_mode/kiosk_mode_settings_unittest.cc
index 2ebf51b..bad84df 100644
--- a/chrome/browser/chromeos/kiosk_mode/kiosk_mode_settings_unittest.cc
+++ b/chrome/browser/chromeos/kiosk_mode/kiosk_mode_settings_unittest.cc
@@ -26,7 +26,7 @@ namespace chromeos {
 class KioskModeSettingsTest : public testing::Test {
  protected:
   KioskModeSettingsTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &message_loop_),
         file_thread_(content::BrowserThread::FILE, &message_loop_) {
     CrosSettings* cros_settings = CrosSettings::Get();
@@ -70,7 +70,7 @@ class KioskModeSettingsTest : public testing::Test {
     KioskModeSettings::Get()->set_initialized(false);
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/chromeos/login/existing_user_controller_auto_login_unittest.cc b/chrome/browser/chromeos/login/existing_user_controller_auto_login_unittest.cc
index 3a7cadf..36831d0 100644
--- a/chrome/browser/chromeos/login/existing_user_controller_auto_login_unittest.cc
+++ b/chrome/browser/chromeos/login/existing_user_controller_auto_login_unittest.cc
@@ -46,7 +46,7 @@ class ExistingUserControllerAutoLoginTest : public ::testing::Test {
       : auto_login_user_id_(policy::GenerateDeviceLocalAccountUserId(
             kAutoLoginAccountId,
             policy::DeviceLocalAccount::TYPE_PUBLIC_SESSION)),
-        message_loop_(MessageLoop::TYPE_UI),
+        message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &message_loop_),
         local_state_(TestingBrowserProcess::GetGlobal()),
         mock_user_manager_(new MockUserManager()),
@@ -153,7 +153,7 @@ class ExistingUserControllerAutoLoginTest : public ::testing::Test {
   MockLoginDisplay* mock_login_display_;
 
   scoped_ptr<MockLoginDisplayHost> mock_login_display_host_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   ScopedTestingLocalState local_state_;
 
diff --git a/chrome/browser/chromeos/login/login_browsertest.cc b/chrome/browser/chromeos/login/login_browsertest.cc
index 74c2f2af..9dc8ded 100644
--- a/chrome/browser/chromeos/login/login_browsertest.cc
+++ b/chrome/browser/chromeos/login/login_browsertest.cc
@@ -209,7 +209,7 @@ IN_PROC_BROWSER_TEST_F(LoginCursorTest, CursorHidden) {
   EXPECT_TRUE(ui_test_utils::SendMouseMoveSync(gfx::Point()));
   EXPECT_TRUE(ash::Shell::GetInstance()->cursor_manager()->IsCursorVisible());
 
-  MessageLoop::current()->DeleteSoon(
+  base::MessageLoop::current()->DeleteSoon(
       FROM_HERE, chromeos::LoginDisplayHostImpl::default_host());
 }
 
diff --git a/chrome/browser/chromeos/login/login_display_host_impl.cc b/chrome/browser/chromeos/login/login_display_host_impl.cc
index 0953c6b..1a9cb25 100644
--- a/chrome/browser/chromeos/login/login_display_host_impl.cc
+++ b/chrome/browser/chromeos/login/login_display_host_impl.cc
@@ -584,9 +584,9 @@ void LoginDisplayHostImpl::ShutdownDisplayHost(bool post_quit_task) {
 
   shutting_down_ = true;
   registrar_.RemoveAll();
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
   if (post_quit_task)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void LoginDisplayHostImpl::StartAnimation() {
diff --git a/chrome/browser/chromeos/login/login_performer.cc b/chrome/browser/chromeos/login/login_performer.cc
index 2c24f7b..ab0a66e 100644
--- a/chrome/browser/chromeos/login/login_performer.cc
+++ b/chrome/browser/chromeos/login/login_performer.cc
@@ -109,7 +109,7 @@ void LoginPerformer::OnLoginFailure(const LoginFailure& failure) {
     VLOG(1) << "Online login timed out. "
             << "Granting user access based on offline auth only.";
     // ScreenLock is not active, it's ok to delete itself.
-    MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
   } else {
     // COULD_NOT_MOUNT_CRYPTOHOME, COULD_NOT_MOUNT_TMPFS:
     // happens during offline auth only.
@@ -150,7 +150,7 @@ void LoginPerformer::OnLoginSuccess(
   // 1. ScreenLock active (pending correct new password input)
   // 2. Pending online auth request.
   if (!pending_requests)
-    MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
   else
     initial_online_auth_pending_ = true;
 
@@ -375,7 +375,7 @@ void LoginPerformer::ResolveInitialNetworkAuthFailure() {
               << "Online login failed with "
               << last_login_failure_.error().state();
       // Resolving initial online auth failure, no ScreenLock is active.
-      MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+      base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
       return;
     case GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS:
       // Offline auth OK, so it might be the case of changed password.
@@ -473,7 +473,7 @@ void LoginPerformer::ResolveScreenUnlocked() {
   DVLOG(1) << "Screen unlocked";
   registrar_.RemoveAll();
   // If screen was unlocked that was for a reason, should delete itself now.
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 void LoginPerformer::StartLoginCompletion() {
diff --git a/chrome/browser/chromeos/login/login_utils_browsertest.cc b/chrome/browser/chromeos/login/login_utils_browsertest.cc
index d29059a..cbcc7eb 100644
--- a/chrome/browser/chromeos/login/login_utils_browsertest.cc
+++ b/chrome/browser/chromeos/login/login_utils_browsertest.cc
@@ -134,7 +134,7 @@ void BlockLoop(base::WaitableEvent* completion, base::Callback<bool()> work) {
   do {
     completion->Wait();
   } while (work.Run());
-  MessageLoop::current()->QuitNow();
+  base::MessageLoop::current()->QuitNow();
 }
 
 void CopyLockResult(base::RunLoop* loop,
@@ -159,7 +159,7 @@ class LoginUtilsTest : public testing::Test,
   LoginUtilsTest()
       : fake_io_thread_completion_(false, false),
         fake_io_thread_("fake_io_thread"),
-        loop_(MessageLoop::TYPE_IO),
+        loop_(base::MessageLoop::TYPE_IO),
         browser_process_(TestingBrowserProcess::GetGlobal()),
         local_state_(browser_process_),
         ui_thread_(BrowserThread::UI, &loop_),
@@ -185,8 +185,8 @@ class LoginUtilsTest : public testing::Test,
     // A thread is needed to create a new MessageLoop, since there can be only
     // one loop per thread.
     fake_io_thread_.StartWithOptions(
-        base::Thread::Options(MessageLoop::TYPE_IO, 0));
-    MessageLoop* fake_io_loop = fake_io_thread_.message_loop();
+        base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
+    base::MessageLoop* fake_io_loop = fake_io_thread_.message_loop();
     // Make this loop enter the single task, BlockLoop(). Pass in the completion
     // event and the work callback.
     fake_io_thread_.StopSoon();
@@ -363,7 +363,7 @@ class LoginUtilsTest : public testing::Test,
     fake_io_thread_work_.Reset();
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
-        MessageLoop::QuitWhenIdleClosure());
+        base::MessageLoop::QuitWhenIdleClosure());
     // If there was work then keep waiting for more work.
     // If there was no work then quit the fake IO loop.
     return has_work;
@@ -504,7 +504,7 @@ class LoginUtilsTest : public testing::Test,
   base::WaitableEvent fake_io_thread_completion_;
   base::Thread fake_io_thread_;
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   TestingBrowserProcess* browser_process_;
   ScopedTestingLocalState local_state_;
 
diff --git a/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc b/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc
index 8eef9c0..be5778d 100644
--- a/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc
+++ b/chrome/browser/chromeos/login/merge_session_load_page_unittest.cc
@@ -50,10 +50,10 @@ class TestMergeSessionLoadPage :  public MergeSessionLoadPage {
 class MergeSessionLoadPageTest : public ChromeRenderViewHostTestHarness {
  public:
   MergeSessionLoadPageTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
         file_user_blocking_thread_(
-            BrowserThread::FILE_USER_BLOCKING, MessageLoop::current()),
-        io_thread_(BrowserThread::IO, MessageLoop::current()) {
+            BrowserThread::FILE_USER_BLOCKING, base::MessageLoop::current()),
+        io_thread_(BrowserThread::IO, base::MessageLoop::current()) {
   }
 
   void Navigate(const char* url, int page_id) {
@@ -114,12 +114,12 @@ TEST_F(MergeSessionLoadPageTest, MergeSessionPageShown) {
   ShowInterstitial(kURL2);
   InterstitialPage* interstitial = GetMergeSessionLoadPage();
   ASSERT_TRUE(interstitial);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Simulate merge session completion.
   UserManager::Get()->SetMergeSessionState(
       UserManager::MERGE_STATUS_DONE);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // The URL remains to be URL2.
   EXPECT_EQ(kURL2, web_contents()->GetURL().spec());
diff --git a/chrome/browser/chromeos/login/mock_login_status_consumer.cc b/chrome/browser/chromeos/login/mock_login_status_consumer.cc
index 161bb05..a826ac6 100644
--- a/chrome/browser/chromeos/login/mock_login_status_consumer.cc
+++ b/chrome/browser/chromeos/login/mock_login_status_consumer.cc
@@ -17,25 +17,25 @@ MockConsumer::~MockConsumer() {}
 
 // static
 void MockConsumer::OnRetailModeSuccessQuit(const UserContext& user_context) {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnRetailModeSuccessQuitAndFail(
     const UserContext& user_context) {
   ADD_FAILURE() << "Retail mode login should have failed!";
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnGuestSuccessQuit() {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnGuestSuccessQuitAndFail() {
   ADD_FAILURE() << "Guest login should have failed!";
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
@@ -43,7 +43,7 @@ void MockConsumer::OnSuccessQuit(
     const UserContext& user_context,
     bool pending_requests,
     bool using_oauth) {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
@@ -52,29 +52,29 @@ void MockConsumer::OnSuccessQuitAndFail(
     bool pending_requests,
     bool using_oauth) {
   ADD_FAILURE() << "Login should NOT have succeeded!";
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnFailQuit(const LoginFailure& error) {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnFailQuitAndFail(const LoginFailure& error) {
   ADD_FAILURE() << "Login should not have failed!";
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnMigrateQuit() {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // static
 void MockConsumer::OnMigrateQuitAndFail() {
   ADD_FAILURE() << "Should not have detected a PW change!";
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/login/mock_url_fetchers.cc b/chrome/browser/chromeos/login/mock_url_fetchers.cc
index 8582ad6..8a45c12 100644
--- a/chrome/browser/chromeos/login/mock_url_fetchers.cc
+++ b/chrome/browser/chromeos/login/mock_url_fetchers.cc
@@ -32,7 +32,7 @@ ExpectCanceledFetcher::~ExpectCanceledFetcher() {
 }
 
 void ExpectCanceledFetcher::Start() {
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ExpectCanceledFetcher::CompleteFetch,
                  weak_factory_.GetWeakPtr()),
@@ -41,7 +41,7 @@ void ExpectCanceledFetcher::Start() {
 
 void ExpectCanceledFetcher::CompleteFetch() {
   ADD_FAILURE() << "Fetch completed in ExpectCanceledFetcher!";
-  MessageLoop::current()->Quit();  // Allow exiting even if we mess up.
+  base::MessageLoop::current()->Quit();  // Allow exiting even if we mess up.
 }
 
 GotCanceledFetcher::GotCanceledFetcher(
diff --git a/chrome/browser/chromeos/login/online_attempt_unittest.cc b/chrome/browser/chromeos/login/online_attempt_unittest.cc
index ac1a8de..34c089f 100644
--- a/chrome/browser/chromeos/login/online_attempt_unittest.cc
+++ b/chrome/browser/chromeos/login/online_attempt_unittest.cc
@@ -33,7 +33,7 @@ namespace chromeos {
 class OnlineAttemptTest : public testing::Test {
  public:
   OnlineAttemptTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(BrowserThread::UI, &message_loop_),
         state_(UserContext(), "", "", "", User::USER_TYPE_REGULAR, false),
         resolver_(new MockAuthAttemptStateResolver) {
@@ -72,14 +72,14 @@ class OnlineAttemptTest : public testing::Test {
 
   static void Quit() {
     BrowserThread::PostTask(
-        BrowserThread::UI, FROM_HERE, MessageLoop::QuitClosure());
+        BrowserThread::UI, FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
   static void RunThreadTest() {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   TestAttemptState state_;
   scoped_ptr<MockAuthAttemptStateResolver> resolver_;
@@ -121,7 +121,7 @@ TEST_F(OnlineAttemptTest, LoginCancelRetry) {
       BrowserThread::UI, FROM_HERE,
       base::Bind(&OnlineAttemptTest::RunThreadTest));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_TRUE(error == state_.online_outcome().error());
   EXPECT_EQ(LoginFailure::NETWORK_AUTH_FAILED,
@@ -149,7 +149,7 @@ TEST_F(OnlineAttemptTest, LoginTimeout) {
   // Post a task to cancel the login attempt.
   CancelLogin(attempt_.get());
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(LoginFailure::LOGIN_TIMED_OUT, state_.online_outcome().reason());
 }
@@ -176,7 +176,7 @@ TEST_F(OnlineAttemptTest, HostedLoginRejected) {
       BrowserThread::UI, FROM_HERE,
       base::Bind(&OnlineAttemptTest::RunThreadTest));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(error, local_state.online_outcome());
   EXPECT_EQ(LoginFailure::NETWORK_AUTH_FAILED,
@@ -201,7 +201,7 @@ TEST_F(OnlineAttemptTest, FullLogin) {
       BrowserThread::UI, FROM_HERE,
       base::Bind(&OnlineAttemptTest::RunThreadTest));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(LoginFailure::LoginFailureNone(), local_state.online_outcome());
 }
diff --git a/chrome/browser/chromeos/login/parallel_authenticator_unittest.cc b/chrome/browser/chromeos/login/parallel_authenticator_unittest.cc
index f491c19..64fb292 100644
--- a/chrome/browser/chromeos/login/parallel_authenticator_unittest.cc
+++ b/chrome/browser/chromeos/login/parallel_authenticator_unittest.cc
@@ -57,7 +57,7 @@ class TestOnlineAttempt : public OnlineAttempt {
 class ParallelAuthenticatorTest : public testing::Test {
  public:
   ParallelAuthenticatorTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(BrowserThread::UI, &message_loop_),
         file_thread_(BrowserThread::FILE, &message_loop_),
         io_thread_(BrowserThread::IO),
@@ -199,7 +199,7 @@ class ParallelAuthenticatorTest : public testing::Test {
     auth_->set_online_attempt(new TestOnlineAttempt(state_.get(), auth_.get()));
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/chromeos/login/screen_locker.cc b/chrome/browser/chromeos/login/screen_locker.cc
index 853d6215..3abd60b 100644
--- a/chrome/browser/chromeos/login/screen_locker.cc
+++ b/chrome/browser/chromeos/login/screen_locker.cc
@@ -222,7 +222,7 @@ void ScreenLocker::OnLoginSuccess(
   } else {
     // Add guard for case when something get broken in call chain to unlock
     // for sure.
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&ScreenLocker::UnlockOnLoginSuccess,
             weak_factory_.GetWeakPtr()),
@@ -232,7 +232,7 @@ void ScreenLocker::OnLoginSuccess(
 }
 
 void ScreenLocker::UnlockOnLoginSuccess() {
-  DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
+  DCHECK(base::MessageLoop::current()->type() == base::MessageLoop::TYPE_UI);
   if (!authentication_capture_.get()) {
     LOG(WARNING) << "Call to UnlockOnLoginSuccess without previous " <<
       "authentication success.";
@@ -312,7 +312,7 @@ void ScreenLocker::SetLoginStatusConsumer(
 // static
 void ScreenLocker::Show() {
   content::RecordAction(UserMetricsAction("ScreenLocker_Show"));
-  DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
+  DCHECK(base::MessageLoop::current()->type() == base::MessageLoop::TYPE_UI);
 
   // Check whether the currently logged in user is a guest account and if so,
   // refuse to lock the screen (crosbug.com/23764).
@@ -349,7 +349,7 @@ void ScreenLocker::Show() {
 
 // static
 void ScreenLocker::Hide() {
-  DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
+  DCHECK(base::MessageLoop::current()->type() == base::MessageLoop::TYPE_UI);
   // For a guest/demo user, screen_locker_ would have never been initialized.
   if (UserManager::Get()->IsLoggedInAsGuest() ||
       UserManager::Get()->IsLoggedInAsDemoUser()) {
@@ -371,7 +371,7 @@ void ScreenLocker::ScheduleDeletion() {
   VLOG(1) << "Posting task to delete ScreenLocker " << screen_locker_;
   ScreenLocker* screen_locker = screen_locker_;
   screen_locker_ = NULL;
-  MessageLoopForUI::current()->DeleteSoon(FROM_HERE, screen_locker);
+  base::MessageLoopForUI::current()->DeleteSoon(FROM_HERE, screen_locker);
 }
 
 // static
@@ -384,7 +384,7 @@ void ScreenLocker::InitClass() {
 
 ScreenLocker::~ScreenLocker() {
   VLOG(1) << "Destroying ScreenLocker " << this;
-  DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
+  DCHECK(base::MessageLoop::current()->type() == base::MessageLoop::TYPE_UI);
 
   if (authenticator_)
     authenticator_->SetConsumer(NULL);
diff --git a/chrome/browser/chromeos/login/screen_locker_browsertest.cc b/chrome/browser/chromeos/login/screen_locker_browsertest.cc
index 31b8f901..72f3e86 100644
--- a/chrome/browser/chromeos/login/screen_locker_browsertest.cc
+++ b/chrome/browser/chromeos/login/screen_locker_browsertest.cc
@@ -58,7 +58,7 @@ class Waiter : public content::NotificationObserver {
     DCHECK(type == chrome::NOTIFICATION_SCREEN_LOCK_STATE_CHANGED ||
            type == chrome::NOTIFICATION_FULLSCREEN_CHANGED);
     if (running_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   }
 
   // Wait until the two conditions are met.
diff --git a/chrome/browser/chromeos/login/screen_locker_tester.cc b/chrome/browser/chromeos/login/screen_locker_tester.cc
index 8e644cc..75a71ea 100644
--- a/chrome/browser/chromeos/login/screen_locker_tester.cc
+++ b/chrome/browser/chromeos/login/screen_locker_tester.cc
@@ -81,7 +81,7 @@ void LoginAttemptObserver::WaitForAttempt() {
 void LoginAttemptObserver::LoginAttempted() {
   login_attempted_ = true;
   if (waiting_)
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
 }
 
 }
diff --git a/chrome/browser/chromeos/login/screens/update_screen_browsertest.cc b/chrome/browser/chromeos/login/screens/update_screen_browsertest.cc
index 81c21de..bb11ddd 100644
--- a/chrome/browser/chromeos/login/screens/update_screen_browsertest.cc
+++ b/chrome/browser/chromeos/login/screens/update_screen_browsertest.cc
@@ -353,7 +353,7 @@ IN_PROC_BROWSER_TEST_F(UpdateScreenTest, TestVoidNetwork) {
       .Times(1);
   EXPECT_CALL(*mock_screen_observer_, ShowErrorScreen())
       .Times(1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   NotifyPortalDetectionCompleted();
 }
 
diff --git a/chrome/browser/chromeos/login/simple_web_view_dialog.cc b/chrome/browser/chromeos/login/simple_web_view_dialog.cc
index 996f682..29f6494 100644
--- a/chrome/browser/chromeos/login/simple_web_view_dialog.cc
+++ b/chrome/browser/chromeos/login/simple_web_view_dialog.cc
@@ -138,7 +138,7 @@ SimpleWebViewDialog::~SimpleWebViewDialog() {
   if (web_view_container_.get()) {
     // WebView can't be deleted immediately, because it could be on the stack.
     web_view_->web_contents()->SetDelegate(NULL);
-    MessageLoop::current()->DeleteSoon(
+    base::MessageLoop::current()->DeleteSoon(
         FROM_HERE, web_view_container_.release());
   }
 }
diff --git a/chrome/browser/chromeos/login/tpm_password_fetcher.cc b/chrome/browser/chromeos/login/tpm_password_fetcher.cc
index face9b1..e1e116e 100644
--- a/chrome/browser/chromeos/login/tpm_password_fetcher.cc
+++ b/chrome/browser/chromeos/login/tpm_password_fetcher.cc
@@ -66,7 +66,7 @@ void TpmPasswordFetcher::OnTpmGetPassword(DBusMethodCallStatus call_status,
 }
 
 void TpmPasswordFetcher::RescheduleFetch() {
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&TpmPasswordFetcher::Fetch, weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kTpmCheckIntervalMs));
diff --git a/chrome/browser/chromeos/login/user_flow.cc b/chrome/browser/chromeos/login/user_flow.cc
index a4da1a3..d7302e8 100644
--- a/chrome/browser/chromeos/login/user_flow.cc
+++ b/chrome/browser/chromeos/login/user_flow.cc
@@ -56,7 +56,7 @@ ExtendedUserFlow::~ExtendedUserFlow() {
 
 void ExtendedUserFlow::UnregisterFlowSoon() {
   std::string id_copy(user_id());
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&UnregisterFlow,
                  id_copy));
 }
diff --git a/chrome/browser/chromeos/login/user_image_loader.cc b/chrome/browser/chromeos/login/user_image_loader.cc
index 301d712..c67b5a4 100644
--- a/chrome/browser/chromeos/login/user_image_loader.cc
+++ b/chrome/browser/chromeos/login/user_image_loader.cc
@@ -51,7 +51,7 @@ void UserImageLoader::Start(const std::string& filepath,
                             int size,
                             const SequenceToken& token,
                             const LoadedCallback& loaded_cb) {
-  target_message_loop_ = MessageLoop::current();
+  target_message_loop_ = base::MessageLoop::current();
 
   ImageInfo image_info(size, loaded_cb);
   base::SequencedWorkerPool* pool = BrowserThread::GetBlockingPool();
diff --git a/chrome/browser/chromeos/login/user_image_manager_browsertest.cc b/chrome/browser/chromeos/login/user_image_manager_browsertest.cc
index 4dff6da..4e967e8 100644
--- a/chrome/browser/chromeos/login/user_image_manager_browsertest.cc
+++ b/chrome/browser/chromeos/login/user_image_manager_browsertest.cc
@@ -62,12 +62,12 @@ class UserImageManagerTest : public CrosInProcessBrowserTest,
     DCHECK(type == chrome::NOTIFICATION_LOGIN_USER_IMAGE_CHANGED);
     registrar_.Remove(this, chrome::NOTIFICATION_LOGIN_USER_IMAGE_CHANGED,
                       content::NotificationService::AllSources());
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   // UserManager::Observer overrides:
   virtual void LocalStateChanged(UserManager* user_manager) OVERRIDE {
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   // Adds given user to Local State, if not there.
diff --git a/chrome/browser/chromeos/login/user_manager_unittest.cc b/chrome/browser/chromeos/login/user_manager_unittest.cc
index 1e65fe0..b0fe8d8 100644
--- a/chrome/browser/chromeos/login/user_manager_unittest.cc
+++ b/chrome/browser/chromeos/login/user_manager_unittest.cc
@@ -30,7 +30,7 @@ namespace chromeos {
 class UserManagerTest : public testing::Test {
  public:
   UserManagerTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &message_loop_),
         file_thread_(content::BrowserThread::FILE, &message_loop_) {
   }
@@ -122,7 +122,7 @@ class UserManagerTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc b/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
index 1304215..0bb93e6 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
+++ b/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
@@ -85,11 +85,11 @@ class WallpaperManagerBrowserTest : public CrosInProcessBrowserTest,
   }
 
   void WaitAsyncWallpaperLoad() {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   virtual void OnWallpaperDataChanged() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  protected:
diff --git a/chrome/browser/chromeos/login/wizard_controller_browsertest.cc b/chrome/browser/chromeos/login/wizard_controller_browsertest.cc
index 373b142..361523c 100644
--- a/chrome/browser/chromeos/login/wizard_controller_browsertest.cc
+++ b/chrome/browser/chromeos/login/wizard_controller_browsertest.cc
@@ -307,7 +307,7 @@ IN_PROC_BROWSER_TEST_F(WizardControllerFlowTest,
   ExistingUserController::current_controller()->CompleteLogin(
       UserContext(kUsername, kPassword, ""));
   // Run the tasks posted to complete the login:
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EnrollmentScreen* screen =
       WizardController::default_controller()->GetEnrollmentScreen();
@@ -318,7 +318,7 @@ IN_PROC_BROWSER_TEST_F(WizardControllerFlowTest,
   // Prevent browser launch when the profile is prepared:
   browser_shutdown::SetTryingToQuit(true);
   // Run the tasks posted to complete the login:
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 IN_PROC_BROWSER_TEST_F(WizardControllerFlowTest, ControlFlowResetScreen) {
diff --git a/chrome/browser/chromeos/login/wizard_in_process_browser_test.cc b/chrome/browser/chromeos/login/wizard_in_process_browser_test.cc
index 1284143..56e5364 100644
--- a/chrome/browser/chromeos/login/wizard_in_process_browser_test.cc
+++ b/chrome/browser/chromeos/login/wizard_in_process_browser_test.cc
@@ -43,9 +43,9 @@ void WizardInProcessBrowserTest::SetUpOnMainThread() {
 
 void WizardInProcessBrowserTest::CleanUpOnMainThread() {
   // LoginDisplayHost owns controllers and all windows.
-  MessageLoopForUI::current()->DeleteSoon(FROM_HERE, host_);
+  base::MessageLoopForUI::current()->DeleteSoon(FROM_HERE, host_);
 
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
 }
 
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/net/network_portal_detector_impl.cc b/chrome/browser/chromeos/net/network_portal_detector_impl.cc
index 1ccf039..7f8d85e 100644
--- a/chrome/browser/chromeos/net/network_portal_detector_impl.cc
+++ b/chrome/browser/chromeos/net/network_portal_detector_impl.cc
@@ -286,9 +286,8 @@ void NetworkPortalDetectorImpl::DetectCaptivePortal(
   detection_task_.Reset(
       base::Bind(&NetworkPortalDetectorImpl::DetectCaptivePortalTask,
                  weak_ptr_factory_.GetWeakPtr()));
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-                                          detection_task_.callback(),
-                                          next_attempt_delay_);
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE, detection_task_.callback(), next_attempt_delay_);
 }
 
 void NetworkPortalDetectorImpl::DetectCaptivePortalTask() {
@@ -322,9 +321,8 @@ void NetworkPortalDetectorImpl::DetectCaptivePortalTask() {
     request_timeout = request_timeout_for_testing_;
   else
     request_timeout = base::TimeDelta::FromSeconds(GetRequestTimeoutSec());
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-                                          detection_timeout_.callback(),
-                                          request_timeout);
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE, detection_timeout_.callback(), request_timeout);
 }
 
 void NetworkPortalDetectorImpl::PortalDetectionTimeout() {
diff --git a/chrome/browser/chromeos/net/network_portal_detector_impl_unittest.cc b/chrome/browser/chromeos/net/network_portal_detector_impl_unittest.cc
index 74807a7..6b497dd 100644
--- a/chrome/browser/chromeos/net/network_portal_detector_impl_unittest.cc
+++ b/chrome/browser/chromeos/net/network_portal_detector_impl_unittest.cc
@@ -167,13 +167,13 @@ class NetworkPortalDetectorImplTest
         dbus::ObjectPath(service_path),
         flimflam::kStateProperty, base::StringValue(flimflam::kStatePortal),
         base::Bind(&base::DoNothing), base::Bind(&ErrorCallbackFunction));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   void SetNetworkDeviceEnabled(const std::string& type, bool enabled) {
     NetworkHandler::Get()->network_state_handler()->SetTechnologyEnabled(
         type, enabled, network_handler::ErrorCallback());
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   void SetConnected(const std::string& service_path) {
@@ -181,12 +181,12 @@ class NetworkPortalDetectorImplTest
         dbus::ObjectPath(service_path),
         flimflam::kStateProperty, base::StringValue(flimflam::kStateOnline),
         base::Bind(&base::DoNothing), base::Bind(&ErrorCallbackFunction));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
  private:
   void SetupDefaultShillState() {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ShillServiceClient::TestInterface* service_test =
         DBusThreadManager::Get()->GetShillServiceClient()->GetTestInterface();
     service_test->ClearServices();
@@ -214,7 +214,7 @@ class NetworkPortalDetectorImplTest
     NetworkHandler::Initialize();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<NetworkPortalDetectorImpl> network_portal_detector_;
 };
@@ -377,7 +377,7 @@ TEST_F(NetworkPortalDetectorImplTest, PortalDetectionTimeout) {
   ASSERT_EQ(0, attempt_count());
 
   SetConnected(kStubWireless1);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // First portal detection timeouts, next portal detection is
   // scheduled.
@@ -440,7 +440,7 @@ TEST_F(NetworkPortalDetectorImplTest, FirstAttemptFailed) {
   ASSERT_EQ(base::TimeDelta::FromSeconds(0), next_attempt_delay());
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 204, NULL);
   ASSERT_TRUE(is_state_idle());
@@ -466,7 +466,7 @@ TEST_F(NetworkPortalDetectorImplTest, AllAttemptsFailed) {
   ASSERT_EQ(base::TimeDelta::FromSeconds(0), next_attempt_delay());
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 503, retry_after);
   ASSERT_TRUE(is_state_portal_detection_pending());
@@ -474,7 +474,7 @@ TEST_F(NetworkPortalDetectorImplTest, AllAttemptsFailed) {
   ASSERT_EQ(base::TimeDelta::FromSeconds(0), next_attempt_delay());
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 503, retry_after);
   ASSERT_TRUE(is_state_idle());
@@ -495,7 +495,7 @@ TEST_F(NetworkPortalDetectorImplTest, ProxyAuthRequired) {
                    kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 407, NULL);
   ASSERT_EQ(2, attempt_count());
@@ -504,7 +504,7 @@ TEST_F(NetworkPortalDetectorImplTest, ProxyAuthRequired) {
                    kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 407, NULL);
   ASSERT_EQ(3, attempt_count());
@@ -528,7 +528,7 @@ TEST_F(NetworkPortalDetectorImplTest, NoResponseButBehindPortal) {
   ASSERT_TRUE(is_state_portal_detection_pending());
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::ERR_CONNECTION_CLOSED,
                    net::URLFetcher::RESPONSE_CODE_INVALID,
@@ -537,7 +537,7 @@ TEST_F(NetworkPortalDetectorImplTest, NoResponseButBehindPortal) {
   ASSERT_TRUE(is_state_portal_detection_pending());
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::ERR_CONNECTION_CLOSED,
                    net::URLFetcher::RESPONSE_CODE_INVALID,
@@ -566,7 +566,7 @@ TEST_F(NetworkPortalDetectorImplTest, LazyDetectionForOnlineNetwork) {
       kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 204, NULL);
 
@@ -577,7 +577,7 @@ TEST_F(NetworkPortalDetectorImplTest, LazyDetectionForOnlineNetwork) {
       kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   disable_lazy_detection();
 
@@ -608,7 +608,7 @@ TEST_F(NetworkPortalDetectorImplTest, LazyDetectionForPortalNetwork) {
                    kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::ERR_CONNECTION_CLOSED,
                    net::URLFetcher::RESPONSE_CODE_INVALID,
@@ -619,7 +619,7 @@ TEST_F(NetworkPortalDetectorImplTest, LazyDetectionForPortalNetwork) {
                    kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   CompleteURLFetch(net::OK, 200, NULL);
   ASSERT_EQ(3, attempt_count());
@@ -628,7 +628,7 @@ TEST_F(NetworkPortalDetectorImplTest, LazyDetectionForPortalNetwork) {
                    kStubWireless1);
 
   // To run CaptivePortalDetector::DetectCaptivePortal().
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   disable_lazy_detection();
 
@@ -678,7 +678,7 @@ TEST_F(NetworkPortalDetectorImplTest, TestDetectionRestart) {
   ASSERT_TRUE(is_state_portal_detection_pending());
   ASSERT_FALSE(start_detection_if_idle());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   ASSERT_TRUE(is_state_checking_for_portal());
   CompleteURLFetch(net::OK, 200, NULL);
 
@@ -701,13 +701,13 @@ TEST_F(NetworkPortalDetectorImplTest, RequestTimeouts) {
 
   // Second portal detection attempt for cellular1 uses 10sec timeout.
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   CheckRequestTimeoutAndCompleteAttempt(2, 10, net::ERR_CONNECTION_CLOSED,
                                         net::URLFetcher::RESPONSE_CODE_INVALID);
 
   // Third portal detection attempt for cellular1 uses 15sec timeout.
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   CheckRequestTimeoutAndCompleteAttempt(3, 15, net::ERR_CONNECTION_CLOSED,
                                         net::URLFetcher::RESPONSE_CODE_INVALID);
 
@@ -716,7 +716,7 @@ TEST_F(NetworkPortalDetectorImplTest, RequestTimeouts) {
   // Check that in lazy detection for cellular1 15sec timeout is used.
   enable_lazy_detection();
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   disable_lazy_detection();
   CheckRequestTimeoutAndCompleteAttempt(3, 15, net::ERR_CONNECTION_CLOSED,
                                         net::URLFetcher::RESPONSE_CODE_INVALID);
@@ -731,14 +731,14 @@ TEST_F(NetworkPortalDetectorImplTest, RequestTimeouts) {
 
   // Second portal detection attempt for wifi1 also uses 5sec timeout.
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   CheckRequestTimeoutAndCompleteAttempt(2, 10, net::OK, 204);
   ASSERT_TRUE(is_state_idle());
 
   // Check that in lazy detection for wifi1 5sec timeout is used.
   enable_lazy_detection();
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   disable_lazy_detection();
   CheckRequestTimeoutAndCompleteAttempt(3, 15, net::OK, 204);
   ASSERT_TRUE(is_state_idle());
@@ -753,13 +753,13 @@ TEST_F(NetworkPortalDetectorImplTest, StartDetectionIfIdle) {
   CheckRequestTimeoutAndCompleteAttempt(1, 5, net::ERR_CONNECTION_CLOSED,
                                         net::URLFetcher::RESPONSE_CODE_INVALID);
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Second portal detection attempt for wifi1 uses 10sec timeout.
   CheckRequestTimeoutAndCompleteAttempt(2, 10, net::ERR_CONNECTION_CLOSED,
                                         net::URLFetcher::RESPONSE_CODE_INVALID);
   ASSERT_TRUE(is_state_portal_detection_pending());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Second portal detection attempt for wifi1 uses 15sec timeout.
   CheckRequestTimeoutAndCompleteAttempt(3, 15, net::ERR_CONNECTION_CLOSED,
@@ -770,7 +770,7 @@ TEST_F(NetworkPortalDetectorImplTest, StartDetectionIfIdle) {
   ASSERT_TRUE(is_state_portal_detection_pending());
 
   // First portal detection attempt for wifi1 uses 5sec timeout.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   CheckRequestTimeoutAndCompleteAttempt(1, 5, net::OK, 204);
   ASSERT_TRUE(is_state_idle());
 }
diff --git a/chrome/browser/chromeos/offline/offline_load_page_unittest.cc b/chrome/browser/chromeos/offline/offline_load_page_unittest.cc
index 19c8518..db56c59 100644
--- a/chrome/browser/chromeos/offline/offline_load_page_unittest.cc
+++ b/chrome/browser/chromeos/offline/offline_load_page_unittest.cc
@@ -53,10 +53,10 @@ class OfflineLoadPageTest : public ChromeRenderViewHostTestHarness {
   };
 
   OfflineLoadPageTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
         file_user_blocking_thread_(
-            BrowserThread::FILE_USER_BLOCKING, MessageLoop::current()),
-        io_thread_(BrowserThread::IO, MessageLoop::current()) {
+            BrowserThread::FILE_USER_BLOCKING, base::MessageLoop::current()),
+        io_thread_(BrowserThread::IO, base::MessageLoop::current()) {
   }
 
   virtual void SetUp() {
@@ -117,11 +117,11 @@ TEST_F(OfflineLoadPageTest, OfflinePageProceed) {
   ShowInterstitial(kURL2);
   InterstitialPage* interstitial = GetOfflineLoadPage();
   ASSERT_TRUE(interstitial);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Simulate the user clicking "proceed".
   interstitial->Proceed();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_EQ(OK, user_response());
 
@@ -144,7 +144,7 @@ TEST_F(OfflineLoadPageTest, OfflinePageDontProceed) {
   ShowInterstitial(kURL2);
   InterstitialPage* interstitial = GetOfflineLoadPage();
   ASSERT_TRUE(interstitial);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Simulate the user clicking "don't proceed".
   interstitial->DontProceed();
diff --git a/chrome/browser/chromeos/policy/device_local_account_browsertest.cc b/chrome/browser/chromeos/policy/device_local_account_browsertest.cc
index f6de0a4..74e3203 100644
--- a/chrome/browser/chromeos/policy/device_local_account_browsertest.cc
+++ b/chrome/browser/chromeos/policy/device_local_account_browsertest.cc
@@ -172,8 +172,8 @@ class DeviceLocalAccountTest : public InProcessBrowserTest {
 
   virtual void CleanUpOnMainThread() OVERRIDE {
     // This shuts down the login UI.
-    MessageLoop::current()->PostTask(FROM_HERE,
-                                     base::Bind(&chrome::AttemptExit));
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(&chrome::AttemptExit));
     base::RunLoop().RunUntilIdle();
   }
 
diff --git a/chrome/browser/chromeos/policy/device_status_collector_browsertest.cc b/chrome/browser/chromeos/policy/device_status_collector_browsertest.cc
index 7d23452..12af15e 100644
--- a/chrome/browser/chromeos/policy/device_status_collector_browsertest.cc
+++ b/chrome/browser/chromeos/policy/device_status_collector_browsertest.cc
@@ -140,7 +140,7 @@ namespace policy {
 class DeviceStatusCollectorTest : public testing::Test {
  public:
   DeviceStatusCollectorTest()
-    : message_loop_(MessageLoop::TYPE_UI),
+    : message_loop_(base::MessageLoop::TYPE_UI),
       ui_thread_(content::BrowserThread::UI, &message_loop_),
       file_thread_(content::BrowserThread::FILE, &message_loop_),
       io_thread_(content::BrowserThread::IO, &message_loop_) {
@@ -236,7 +236,7 @@ class DeviceStatusCollectorTest : public testing::Test {
     return policy::DeviceStatusCollector::kIdlePollIntervalSeconds * 1000;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc b/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
index b5c1dfc..9f74d3f 100644
--- a/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
+++ b/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
@@ -298,7 +298,7 @@ void EnrollmentHandlerChromeOS::HandleLockDeviceResult(
         // InstallAttributes not ready yet, retry later.
         LOG(WARNING) << "Install Attributes not ready yet will retry in "
                      << kLockRetryIntervalMs << "ms.";
-        MessageLoop::current()->PostDelayedTask(
+        base::MessageLoop::current()->PostDelayedTask(
             FROM_HERE,
             base::Bind(&EnrollmentHandlerChromeOS::StartLockDevice,
                        weak_factory_.GetWeakPtr(),
diff --git a/chrome/browser/chromeos/policy/enterprise_install_attributes_unittest.cc b/chrome/browser/chromeos/policy/enterprise_install_attributes_unittest.cc
index fbc3ec9..a239ef5 100644
--- a/chrome/browser/chromeos/policy/enterprise_install_attributes_unittest.cc
+++ b/chrome/browser/chromeos/policy/enterprise_install_attributes_unittest.cc
@@ -57,7 +57,7 @@ class EnterpriseInstallAttributesTest : public testing::Test {
     attribute->set_value(value);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   base::ScopedTempDir temp_dir_;
   scoped_ptr<chromeos::CryptohomeLibrary> cryptohome_;
   scoped_ptr<chromeos::CryptohomeClient> stub_cryptohome_client_;
diff --git a/chrome/browser/chromeos/policy/network_configuration_updater_impl_cros_unittest.cc b/chrome/browser/chromeos/policy/network_configuration_updater_impl_cros_unittest.cc
index ccde105..f2608c9 100644
--- a/chrome/browser/chromeos/policy/network_configuration_updater_impl_cros_unittest.cc
+++ b/chrome/browser/chromeos/policy/network_configuration_updater_impl_cros_unittest.cc
@@ -145,7 +145,7 @@ class NetworkConfigurationUpdaterTest : public testing::Test {
   StrictMock<chromeos::MockNetworkLibrary> network_library_;
   StrictMock<MockConfigurationPolicyProvider> provider_;
   scoped_ptr<PolicyServiceImpl> policy_service_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 };
diff --git a/chrome/browser/chromeos/policy/policy_cert_verifier_browsertest.cc b/chrome/browser/chromeos/policy/policy_cert_verifier_browsertest.cc
index c39c460..fd440cf 100644
--- a/chrome/browser/chromeos/policy/policy_cert_verifier_browsertest.cc
+++ b/chrome/browser/chromeos/policy/policy_cert_verifier_browsertest.cc
@@ -93,7 +93,7 @@ class PolicyCertVerifierTest : public testing::Test {
  protected:
   crypto::ScopedTestNSSDB test_nssdb_;
   net::NSSCertDatabase* cert_db_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   TestingProfileManager profile_manager_;
diff --git a/chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos_unittest.cc b/chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos_unittest.cc
index cde6337..5613959 100644
--- a/chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos_unittest.cc
+++ b/chrome/browser/chromeos/policy/user_cloud_policy_manager_chromeos_unittest.cc
@@ -261,7 +261,7 @@ class UserCloudPolicyManagerChromeOSTest : public testing::Test {
   }
 
   // Required by the refresh scheduler that's created by the manager.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   // Required to cleanup the URLRequestContextGetter of the |signin_profile_|.
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos_unittest.cc b/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos_unittest.cc
index 7dc25de..9cb2b9c 100644
--- a/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos_unittest.cc
+++ b/chrome/browser/chromeos/policy/user_cloud_policy_store_chromeos_unittest.cc
@@ -45,14 +45,14 @@ const char kSanitizedUsername[] = "0123456789ABCDEF0123456789ABCDEF012345678";
 const char kDefaultHomepage[] = "http://chromium.org";
 
 ACTION_P2(SendSanitizedUsername, call_status, sanitized_username) {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(arg1, call_status, sanitized_username));
 }
 
 class UserCloudPolicyStoreChromeOSTest : public testing::Test {
  protected:
   UserCloudPolicyStoreChromeOSTest()
-      : loop_(MessageLoop::TYPE_UI),
+      : loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &loop_),
         file_thread_(content::BrowserThread::FILE, &loop_) {}
 
@@ -222,7 +222,7 @@ class UserCloudPolicyStoreChromeOSTest : public testing::Test {
     return tmp_dir_.path().AppendASCII("policy");
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   chromeos::MockCryptohomeClient cryptohome_client_;
   chromeos::MockSessionManagerClient session_manager_client_;
   UserPolicyBuilder policy_;
diff --git a/chrome/browser/chromeos/power/suspend_observer.cc b/chrome/browser/chromeos/power/suspend_observer.cc
index fb6b85f..fd7eb21 100644
--- a/chrome/browser/chromeos/power/suspend_observer.cc
+++ b/chrome/browser/chromeos/power/suspend_observer.cc
@@ -57,7 +57,7 @@ void SuspendObserver::ScreenIsLocked() {
     // Run the callback asynchronously.  ScreenIsLocked() is currently
     // called asynchronously after RequestLockScreen(), but this guards
     // against it being made synchronous later.
-    MessageLoop::current()->PostTask(FROM_HERE, screen_lock_callback_);
+    base::MessageLoop::current()->PostTask(FROM_HERE, screen_lock_callback_);
     screen_lock_callback_.Reset();
   } else {
     LOG(WARNING) << "Locking screen without suspend.";
diff --git a/chrome/browser/chromeos/proxy_config_service_impl_unittest.cc b/chrome/browser/chromeos/proxy_config_service_impl_unittest.cc
index 614c8c7..660e195 100644
--- a/chrome/browser/chromeos/proxy_config_service_impl_unittest.cc
+++ b/chrome/browser/chromeos/proxy_config_service_impl_unittest.cc
@@ -323,7 +323,7 @@ class ProxyConfigServiceImplTestBase : public TESTBASE {
     return proxy_config_service_->GetLatestProxyConfig(config);
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   scoped_ptr<ChromeProxyConfigService> proxy_config_service_;
   scoped_ptr<ProxyConfigServiceImpl> config_service_impl_;
 
diff --git a/chrome/browser/chromeos/screensaver/screensaver_controller_browsertest.cc b/chrome/browser/chromeos/screensaver/screensaver_controller_browsertest.cc
index a763b34..c9e547a 100644
--- a/chrome/browser/chromeos/screensaver/screensaver_controller_browsertest.cc
+++ b/chrome/browser/chromeos/screensaver/screensaver_controller_browsertest.cc
@@ -56,7 +56,7 @@ IN_PROC_BROWSER_TEST_F(ScreensaverControllerTest, Basic) {
 
   scoped_ptr<ScreensaverController> controller_;
   controller_.reset(new ScreensaverController());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Trigger idle.
   controller_->IdleNotify(0);
@@ -74,7 +74,7 @@ IN_PROC_BROWSER_TEST_F(ScreensaverControllerTest, OutOfOrder) {
 
   scoped_ptr<ScreensaverController> controller_;
   controller_.reset(new ScreensaverController());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Trigger active.
   controller_->OnUserActivity();
diff --git a/chrome/browser/chromeos/settings/cros_settings_unittest.cc b/chrome/browser/chromeos/settings/cros_settings_unittest.cc
index b119c98..49430a8 100644
--- a/chrome/browser/chromeos/settings/cros_settings_unittest.cc
+++ b/chrome/browser/chromeos/settings/cros_settings_unittest.cc
@@ -30,7 +30,7 @@ namespace chromeos {
 class CrosSettingsTest : public testing::Test {
  protected:
   CrosSettingsTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &message_loop_),
         local_state_(TestingBrowserProcess::GetGlobal()),
         settings_(DeviceSettingsService::Get()),
@@ -89,7 +89,7 @@ class CrosSettingsTest : public testing::Test {
     response.set_policy_data_signature("false");
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 
   ScopedTestingLocalState local_state_;
diff --git a/chrome/browser/chromeos/settings/device_oauth2_token_service_unittest.cc b/chrome/browser/chromeos/settings/device_oauth2_token_service_unittest.cc
index c1b49da..6424ccb 100644
--- a/chrome/browser/chromeos/settings/device_oauth2_token_service_unittest.cc
+++ b/chrome/browser/chromeos/settings/device_oauth2_token_service_unittest.cc
@@ -37,7 +37,7 @@ class DeviceOAuth2TokenServiceTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   ScopedTestingLocalState scoped_testing_local_state_;
 };
diff --git a/chrome/browser/chromeos/settings/device_settings_service.cc b/chrome/browser/chromeos/settings/device_settings_service.cc
index 6058e08..814df79 100644
--- a/chrome/browser/chromeos/settings/device_settings_service.cc
+++ b/chrome/browser/chromeos/settings/device_settings_service.cc
@@ -150,7 +150,7 @@ void DeviceSettingsService::GetOwnershipStatusAsync(
     const OwnershipStatusCallback& callback) {
   if (owner_key_.get()) {
     // If there is a key, report status immediately.
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    owner_key_->public_key() ? OWNERSHIP_TAKEN : OWNERSHIP_NONE,
diff --git a/chrome/browser/chromeos/settings/device_settings_test_helper.cc b/chrome/browser/chromeos/settings/device_settings_test_helper.cc
index bcce8ce..508de87 100644
--- a/chrome/browser/chromeos/settings/device_settings_test_helper.cc
+++ b/chrome/browser/chromeos/settings/device_settings_test_helper.cc
@@ -23,10 +23,10 @@ void DeviceSettingsTestHelper::FlushLoops() {
   // between the message loop and the blocking pool. 2 iterations are currently
   // sufficient (key loading, signing).
   for (int i = 0; i < 2; ++i) {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     content::BrowserThread::GetBlockingPool()->FlushForTesting();
   }
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 void DeviceSettingsTestHelper::FlushStore() {
@@ -186,7 +186,7 @@ ScopedDeviceSettingsTestHelper::~ScopedDeviceSettingsTestHelper() {
 }
 
 DeviceSettingsTestBase::DeviceSettingsTestBase()
-    : loop_(MessageLoop::TYPE_UI),
+    : loop_(base::MessageLoop::TYPE_UI),
       ui_thread_(content::BrowserThread::UI, &loop_),
       file_thread_(content::BrowserThread::FILE, &loop_),
       owner_key_util_(new MockOwnerKeyUtil()) {}
diff --git a/chrome/browser/chromeos/settings/device_settings_test_helper.h b/chrome/browser/chromeos/settings/device_settings_test_helper.h
index 0878c21..b6e0ab1 100644
--- a/chrome/browser/chromeos/settings/device_settings_test_helper.h
+++ b/chrome/browser/chromeos/settings/device_settings_test_helper.h
@@ -164,7 +164,7 @@ class DeviceSettingsTestBase : public testing::Test {
   // |device_settings_service_| and flushes the resulting load operation.
   void ReloadDeviceSettings();
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/chromeos/settings/session_manager_operation_unittest.cc b/chrome/browser/chromeos/settings/session_manager_operation_unittest.cc
index fa580ff..e2f1a44 100644
--- a/chrome/browser/chromeos/settings/session_manager_operation_unittest.cc
+++ b/chrome/browser/chromeos/settings/session_manager_operation_unittest.cc
@@ -73,7 +73,7 @@ class SessionManagerOperationTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/chromeos/system_key_event_listener.cc b/chrome/browser/chromeos/system_key_event_listener.cc
index ebc81a6..685b0af 100644
--- a/chrome/browser/chromeos/system_key_event_listener.cc
+++ b/chrome/browser/chromeos/system_key_event_listener.cc
@@ -69,7 +69,7 @@ SystemKeyEventListener::SystemKeyEventListener()
     LOG(WARNING) << "Could not install Xkb Indicator observer";
   }
 
-  MessageLoopForUI::current()->AddObserver(this);
+  base::MessageLoopForUI::current()->AddObserver(this);
 }
 
 SystemKeyEventListener::~SystemKeyEventListener() {
@@ -79,7 +79,7 @@ SystemKeyEventListener::~SystemKeyEventListener() {
 void SystemKeyEventListener::Stop() {
   if (stopped_)
     return;
-  MessageLoopForUI::current()->RemoveObserver(this);
+  base::MessageLoopForUI::current()->RemoveObserver(this);
   stopped_ = true;
 }
 
diff --git a/chrome/browser/chromeos/system_key_event_listener.h b/chrome/browser/chromeos/system_key_event_listener.h
index 11654e1..0e811c9 100644
--- a/chrome/browser/chromeos/system_key_event_listener.h
+++ b/chrome/browser/chromeos/system_key_event_listener.h
@@ -12,7 +12,7 @@ typedef union _XEvent XEvent;
 
 namespace chromeos {
 
-class SystemKeyEventListener : public MessageLoopForUI::Observer {
+class SystemKeyEventListener : public base::MessageLoopForUI::Observer {
  public:
   // Observer for caps lock state changes.
   class CapsLockObserver {
diff --git a/chrome/browser/chromeos/web_socket_proxy.cc b/chrome/browser/chromeos/web_socket_proxy.cc
index 6131c73..bdfa418 100644
--- a/chrome/browser/chromeos/web_socket_proxy.cc
+++ b/chrome/browser/chromeos/web_socket_proxy.cc
@@ -437,7 +437,7 @@ class Conn {
   DISALLOW_COPY_AND_ASSIGN(Conn);
 };
 
-class SSLChan : public MessageLoopForIO::Watcher {
+class SSLChan : public base::MessageLoopForIO::Watcher {
  public:
   static void Start(const net::AddressList& address_list,
                     const net::HostPortPair& host_port_pair,
@@ -585,7 +585,7 @@ class SSLChan : public MessageLoopForIO::Watcher {
       };
       for (int i = arraysize(buf); i--;) {
         if (buf[i] && buf[i]->size() > 0) {
-          MessageLoop::current()->PostTask(
+          base::MessageLoop::current()->PostTask(
               FROM_HERE,
               base::Bind(&SSLChan::Proceed, weak_factory_.GetWeakPtr()));
           return;
@@ -596,7 +596,7 @@ class SSLChan : public MessageLoopForIO::Watcher {
         socket_->Disconnect();
         socket_.reset();
       }
-      MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+      base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
     }
   }
 
@@ -639,11 +639,11 @@ class SSLChan : public MessageLoopForIO::Watcher {
     is_socket_write_pending_ = false;
     is_read_pipe_blocked_ = false;
     is_write_pipe_blocked_ = false;
-    MessageLoopForIO::current()->WatchFileDescriptor(
-        read_pipe_, false, MessageLoopForIO::WATCH_READ,
+    base::MessageLoopForIO::current()->WatchFileDescriptor(
+        read_pipe_, false, base::MessageLoopForIO::WATCH_READ,
         &read_pipe_controller_, this);
-    MessageLoopForIO::current()->WatchFileDescriptor(
-        write_pipe_, false, MessageLoopForIO::WATCH_WRITE,
+    base::MessageLoopForIO::current()->WatchFileDescriptor(
+        write_pipe_, false, base::MessageLoopForIO::WATCH_WRITE,
         &write_pipe_controller_, this);
     phase_ = PHASE_RUNNING;
     Proceed();
@@ -707,8 +707,8 @@ class SSLChan : public MessageLoopForIO::Watcher {
             proceed = true;
           } else if (rv == -1 && errno == EAGAIN) {
             is_read_pipe_blocked_ = true;
-            MessageLoopForIO::current()->WatchFileDescriptor(
-                read_pipe_, false, MessageLoopForIO::WATCH_READ,
+            base::MessageLoopForIO::current()->WatchFileDescriptor(
+                read_pipe_, false, base::MessageLoopForIO::WATCH_READ,
                 &read_pipe_controller_, this);
           } else if (rv == 0) {
             Shut(0);
@@ -728,7 +728,7 @@ class SSLChan : public MessageLoopForIO::Watcher {
               base::Bind(&SSLChan::OnSocketRead, base::Unretained(this)));
           is_socket_read_pending_ = true;
           if (rv != net::ERR_IO_PENDING) {
-            MessageLoop::current()->PostTask(
+            base::MessageLoop::current()->PostTask(
                 FROM_HERE, base::Bind(&SSLChan::OnSocketRead,
                                       weak_factory_.GetWeakPtr(), rv));
           }
@@ -743,7 +743,7 @@ class SSLChan : public MessageLoopForIO::Watcher {
               base::Bind(&SSLChan::OnSocketWrite, base::Unretained(this)));
           is_socket_write_pending_ = true;
           if (rv != net::ERR_IO_PENDING) {
-            MessageLoop::current()->PostTask(
+            base::MessageLoop::current()->PostTask(
                 FROM_HERE, base::Bind(&SSLChan::OnSocketWrite,
                                       weak_factory_.GetWeakPtr(), rv));
           }
@@ -761,8 +761,8 @@ class SSLChan : public MessageLoopForIO::Watcher {
             proceed = true;
           } else if (rv == -1 && errno == EAGAIN) {
             is_write_pipe_blocked_ = true;
-            MessageLoopForIO::current()->WatchFileDescriptor(
-                write_pipe_, false, MessageLoopForIO::WATCH_WRITE,
+            base::MessageLoopForIO::current()->WatchFileDescriptor(
+                write_pipe_, false, base::MessageLoopForIO::WATCH_WRITE,
                 &write_pipe_controller_, this);
           } else {
             DCHECK_LE(rv, 0);
@@ -791,8 +791,8 @@ class SSLChan : public MessageLoopForIO::Watcher {
   bool is_read_pipe_blocked_;
   bool is_write_pipe_blocked_;
   base::WeakPtrFactory<SSLChan> weak_factory_;
-  MessageLoopForIO::FileDescriptorWatcher read_pipe_controller_;
-  MessageLoopForIO::FileDescriptorWatcher write_pipe_controller_;
+  base::MessageLoopForIO::FileDescriptorWatcher read_pipe_controller_;
+  base::MessageLoopForIO::FileDescriptorWatcher write_pipe_controller_;
 
   friend class base::DeleteHelper<SSLChan>;
   DISALLOW_COPY_AND_ASSIGN(SSLChan);
diff --git a/chrome/browser/chromeos/web_socket_proxy_controller.cc b/chrome/browser/chromeos/web_socket_proxy_controller.cc
index 4bcf211..4cc3c28 100644
--- a/chrome/browser/chromeos/web_socket_proxy_controller.cc
+++ b/chrome/browser/chromeos/web_socket_proxy_controller.cc
@@ -41,7 +41,7 @@ class ProxyLifetime
         shutdown_requested_(false),
         web_socket_proxy_thread_("Chrome_WebSocketproxyThread") {
     DLOG(INFO) << "WebSocketProxyController initiation";
-    base::Thread::Options options(MessageLoop::TYPE_IO, 0);
+    base::Thread::Options options(base::MessageLoop::TYPE_IO, 0);
     web_socket_proxy_thread_.StartWithOptions(options);
     web_socket_proxy_thread_.message_loop()->PostTask(
         FROM_HERE,
@@ -98,7 +98,7 @@ class ProxyLifetime
         if (delay_ms_ < 100 * 1000)
           (delay_ms_ *= 3) /= 2;
 
-        MessageLoop::current()->PostDelayedTask(
+        base::MessageLoop::current()->PostDelayedTask(
             FROM_HERE,
             base::Bind(&ProxyLifetime::ProxyCallback, base::Unretained(this)),
             base::TimeDelta::FromMilliseconds(delay_ms_));
diff --git a/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h b/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h
index 64b76db..99e9af4 100644
--- a/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h
+++ b/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h
@@ -18,7 +18,8 @@ namespace chromeos {
 // which is sent to Chrome when X detects a system or USB keyboard (or mouse),
 // then tells X to change the current XKB keyboard layout. Start by just calling
 // instance() to get it going.
-class XInputHierarchyChangedEventListener : public MessageLoopForUI::Observer {
+class XInputHierarchyChangedEventListener
+    : public base::MessageLoopForUI::Observer {
  public:
   static XInputHierarchyChangedEventListener* GetInstance();
 
diff --git a/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener_aura.cc b/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener_aura.cc
index 1641348..3d2c2da 100644
--- a/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener_aura.cc
+++ b/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener_aura.cc
@@ -7,11 +7,11 @@
 namespace chromeos {
 
 void XInputHierarchyChangedEventListener::Init() {
-  MessageLoopForUI::current()->AddObserver(this);
+  base::MessageLoopForUI::current()->AddObserver(this);
 }
 
 void XInputHierarchyChangedEventListener::StopImpl() {
-  MessageLoopForUI::current()->RemoveObserver(this);
+  base::MessageLoopForUI::current()->RemoveObserver(this);
 }
 
 base::EventStatus XInputHierarchyChangedEventListener::WillProcessEvent(
diff --git a/chrome/browser/common/cancelable_request.cc b/chrome/browser/common/cancelable_request.cc
index 39fb29a..dbcb314 100644
--- a/chrome/browser/common/cancelable_request.cc
+++ b/chrome/browser/common/cancelable_request.cc
@@ -93,7 +93,7 @@ CancelableRequestBase::CancelableRequestBase()
     : provider_(NULL),
       consumer_(NULL),
       handle_(0) {
-  callback_thread_ = MessageLoop::current();
+  callback_thread_ = base::MessageLoop::current();
 }
 
 CancelableRequestBase::~CancelableRequestBase() {
@@ -110,7 +110,7 @@ void CancelableRequestBase::Init(CancelableRequestProvider* provider,
 
 void CancelableRequestBase::DoForward(const base::Closure& forwarded_call,
                                       bool force_async) {
-  if (force_async || callback_thread_ != MessageLoop::current()) {
+  if (force_async || callback_thread_ != base::MessageLoop::current()) {
     callback_thread_->PostTask(
         FROM_HERE,
         base::Bind(&CancelableRequestBase::ExecuteCallback, this,
@@ -123,7 +123,7 @@ void CancelableRequestBase::DoForward(const base::Closure& forwarded_call,
 
 void CancelableRequestBase::ExecuteCallback(
     const base::Closure& forwarded_call) {
-  DCHECK_EQ(callback_thread_, MessageLoop::current());
+  DCHECK_EQ(callback_thread_, base::MessageLoop::current());
 
   if (!canceled_.IsSet()) {
     WillExecute();
diff --git a/chrome/browser/common/cancelable_request.h b/chrome/browser/common/cancelable_request.h
index a43e60b..f1c4c208 100644
--- a/chrome/browser/common/cancelable_request.h
+++ b/chrome/browser/common/cancelable_request.h
@@ -587,7 +587,7 @@ class CancelableRequestBase
 
   // The message loop that this request was created on. The callback will
   // happen on the same thread.
-  MessageLoop* callback_thread_;
+  base::MessageLoop* callback_thread_;
 
   // The provider for this request. When we execute, we will notify this that
   // request is complete to it can remove us from the requests it tracks.
@@ -670,7 +670,7 @@ class CancelableRequest : public CancelableRequestBase {
   void ForwardResult(const TupleType& param) {
     DCHECK(callback_.get());
     if (!canceled()) {
-      if (callback_thread_ == MessageLoop::current()) {
+      if (callback_thread_ == base::MessageLoop::current()) {
         // We can do synchronous callbacks when we're on the same thread.
         ExecuteCallback(param);
       } else {
diff --git a/chrome/browser/component_updater/test/component_installers_unittest.cc b/chrome/browser/component_updater/test/component_installers_unittest.cc
index c3abab10..91b59bb 100644
--- a/chrome/browser/component_updater/test/component_installers_unittest.cc
+++ b/chrome/browser/component_updater/test/component_installers_unittest.cc
@@ -52,7 +52,7 @@ const base::FilePath::CharType kDataPath[] =
 
 // TODO(viettrungluu): Separate out into two separate tests; use a test fixture.
 TEST(ComponentInstallerTest, MAYBE_PepperFlashCheck) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
 
   ppapi::PpapiGlobals::PerThreadForTest per_thread_for_test;
diff --git a/chrome/browser/component_updater/test/component_updater_service_unittest.cc b/chrome/browser/component_updater/test/component_updater_service_unittest.cc
index 2677c9c..a7359fb 100644
--- a/chrome/browser/component_updater/test/component_updater_service_unittest.cc
+++ b/chrome/browser/component_updater/test/component_updater_service_unittest.cc
@@ -49,7 +49,7 @@ class TestConfigurator : public ComponentUpdateService::Configurator {
     // time to break from the test messageloop Run() method so the test can
     // finish.
     if (--times_ <= 0) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
       return 0;
 
     }
@@ -271,7 +271,7 @@ TEST_F(ComponentUpdaterTest, VerifyFixture) {
 // start-shutdown situation. Failure of this test will be a crash. Also
 // if there is no work to do, there are no notifications generated.
 TEST_F(ComponentUpdaterTest, StartStop) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
 
   component_updater()->Start();
@@ -285,7 +285,7 @@ TEST_F(ComponentUpdaterTest, StartStop) {
 // the COMPONENT_UPDATER_STARTED and COMPONENT_UPDATER_SLEEPING notifications
 // are generated.
 TEST_F(ComponentUpdaterTest, CheckCrxSleep) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE);
   content::TestBrowserThread io_thread(BrowserThread::IO);
@@ -364,7 +364,7 @@ TEST_F(ComponentUpdaterTest, CheckCrxSleep) {
 // 2- download crx
 // 3- second manifest check.
 TEST_F(ComponentUpdaterTest, InstallCrx) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE);
   content::TestBrowserThread io_thread(BrowserThread::IO);
@@ -429,7 +429,7 @@ TEST_F(ComponentUpdaterTest, InstallCrx) {
 // has a different source. In this case there would be two manifest
 // checks to different urls, each only containing one component.
 TEST_F(ComponentUpdaterTest, InstallCrxTwoSources) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE);
   content::TestBrowserThread io_thread(BrowserThread::IO);
@@ -501,7 +501,7 @@ TEST_F(ComponentUpdaterTest, InstallCrxTwoSources) {
 // particular there should not be an install because the minimum product
 // version is much higher than of chrome.
 TEST_F(ComponentUpdaterTest, ProdVersionCheck) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE);
   content::TestBrowserThread io_thread(BrowserThread::IO);
@@ -541,7 +541,7 @@ TEST_F(ComponentUpdaterTest, ProdVersionCheck) {
 //  - We ping.
 //  - This triggers a second loop, which has a reply that triggers an install.
 TEST_F(ComponentUpdaterTest, CheckForUpdateSoon) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE);
   content::TestBrowserThread io_thread(BrowserThread::IO);
@@ -657,7 +657,7 @@ TEST_F(ComponentUpdaterTest, CheckForUpdateSoon) {
 // Verify that a previously registered component can get re-registered
 // with a different version.
 TEST_F(ComponentUpdaterTest, CheckReRegistration) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE);
   content::TestBrowserThread io_thread(BrowserThread::IO);
diff --git a/chrome/browser/content_settings/content_settings_default_provider_unittest.cc b/chrome/browser/content_settings/content_settings_default_provider_unittest.cc
index f5404be..cfd7448 100644
--- a/chrome/browser/content_settings/content_settings_default_provider_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_default_provider_unittest.cc
@@ -29,7 +29,7 @@ class DefaultProviderTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   TestingProfile profile_;
   content_settings::DefaultProvider provider_;
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..ca4ab11 100644
--- a/chrome/browser/content_settings/content_settings_policy_provider_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_policy_provider_unittest.cc
@@ -41,7 +41,7 @@ class PolicyProviderTest : public testing::Test {
   // from NonThreadSafe and to use native thread identifiers instead of
   // BrowserThread IDs. Then we could get rid of the message_loop and ui_thread
   // fields.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
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 656d517..6572f11 100644
--- a/chrome/browser/content_settings/content_settings_pref_provider_unittest.cc
+++ b/chrome/browser/content_settings/content_settings_pref_provider_unittest.cc
@@ -98,7 +98,7 @@ class PrefProviderTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/content_settings/cookie_settings_unittest.cc b/chrome/browser/content_settings/cookie_settings_unittest.cc
index a3a91ef..59d2d55 100644
--- a/chrome/browser/content_settings/cookie_settings_unittest.cc
+++ b/chrome/browser/content_settings/cookie_settings_unittest.cc
@@ -35,7 +35,7 @@ class CookieSettingsTest : public testing::Test {
 }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   TestingProfile profile_;
   CookieSettings* cookie_settings_;
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..ed4f55d 100644
--- a/chrome/browser/content_settings/host_content_settings_map_unittest.cc
+++ b/chrome/browser/content_settings/host_content_settings_map_unittest.cc
@@ -33,7 +33,7 @@ class HostContentSettingsMapTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/crash_handler_host_linux.cc b/chrome/browser/crash_handler_host_linux.cc
index 9298ebb..a2393bd 100644
--- a/chrome/browser/crash_handler_host_linux.cc
+++ b/chrome/browser/crash_handler_host_linux.cc
@@ -99,10 +99,10 @@ CrashHandlerHostLinux::~CrashHandlerHostLinux() {
 }
 
 void CrashHandlerHostLinux::Init() {
-  MessageLoopForIO* ml = MessageLoopForIO::current();
+  base::MessageLoopForIO* ml = base::MessageLoopForIO::current();
   CHECK(ml->WatchFileDescriptor(
       browser_socket_, true /* persistent */,
-      MessageLoopForIO::WATCH_READ,
+      base::MessageLoopForIO::WATCH_READ,
       &file_descriptor_watcher_, this));
   ml->AddDestructionObserver(this);
 }
diff --git a/chrome/browser/crash_handler_host_linux.h b/chrome/browser/crash_handler_host_linux.h
index f0db83e..bcd9dd7 100644
--- a/chrome/browser/crash_handler_host_linux.h
+++ b/chrome/browser/crash_handler_host_linux.h
@@ -34,8 +34,8 @@ template <typename T> struct DefaultSingletonTraits;
 // Processes signal that they need to be dumped by sending a datagram over a
 // UNIX domain socket. All processes of the same type share the client end of
 // this socket which is installed in their descriptor table before exec.
-class CrashHandlerHostLinux : public MessageLoopForIO::Watcher,
-                              public MessageLoop::DestructionObserver {
+class CrashHandlerHostLinux : public base::MessageLoopForIO::Watcher,
+                              public base::MessageLoop::DestructionObserver {
  public:
   // Get the file descriptor which processes should be given in order to signal
   // crashes to the browser.
@@ -87,7 +87,7 @@ class CrashHandlerHostLinux : public MessageLoopForIO::Watcher,
   int browser_socket_;
 
 #if defined(USE_LINUX_BREAKPAD)
-  MessageLoopForIO::FileDescriptorWatcher file_descriptor_watcher_;
+  base::MessageLoopForIO::FileDescriptorWatcher file_descriptor_watcher_;
   scoped_ptr<base::Thread> uploader_thread_;
   bool shutting_down_;
 #endif
diff --git a/chrome/browser/custom_handlers/protocol_handler_registry_unittest.cc b/chrome/browser/custom_handlers/protocol_handler_registry_unittest.cc
index db486c2..d29c0c0 100644
--- a/chrome/browser/custom_handlers/protocol_handler_registry_unittest.cc
+++ b/chrome/browser/custom_handlers/protocol_handler_registry_unittest.cc
@@ -51,7 +51,7 @@ void AssertIntercepted(
                           base::Bind(AssertInterceptedIO,
                                      url,
                                      base::Unretained(interceptor)));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 // FakeURLRequestJobFactory returns NULL for all job creation requests and false
@@ -100,7 +100,7 @@ void AssertWillHandle(
                                      scheme,
                                      expected,
                                      base::Unretained(interceptor)));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 class FakeDelegate : public ProtocolHandlerRegistry::Delegate {
@@ -178,7 +178,7 @@ class FakeClientObserver
       delegate_->FakeRegisterWithOS(worker_->protocol());
     }
     if (state != ShellIntegration::STATE_PROCESSING) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
@@ -280,19 +280,19 @@ class QueryProtocolHandlerOnChange
 // guarantee all messages are processed.) By overriding the IsType method
 // we basically ignore the supplied message loop type, and instead infer
 // our type based on the current thread. GO DEPENDENCY INJECTION!
-class TestMessageLoop : public MessageLoop {
+class TestMessageLoop : public base::MessageLoop {
  public:
-  TestMessageLoop() : MessageLoop(MessageLoop::TYPE_DEFAULT) {}
+  TestMessageLoop() : base::MessageLoop(base::MessageLoop::TYPE_DEFAULT) {}
   virtual ~TestMessageLoop() {}
-  virtual bool IsType(MessageLoop::Type type) const OVERRIDE {
+  virtual bool IsType(base::MessageLoop::Type type) const OVERRIDE {
     switch (type) {
-       case MessageLoop::TYPE_UI:
-         return BrowserThread::CurrentlyOn(BrowserThread::UI);
-       case MessageLoop::TYPE_IO:
-         return BrowserThread::CurrentlyOn(BrowserThread::IO);
-       case MessageLoop::TYPE_DEFAULT:
-         return !BrowserThread::CurrentlyOn(BrowserThread::UI) &&
-             !BrowserThread::CurrentlyOn(BrowserThread::IO);
+      case base::MessageLoop::TYPE_UI:
+        return BrowserThread::CurrentlyOn(BrowserThread::UI);
+      case base::MessageLoop::TYPE_IO:
+        return BrowserThread::CurrentlyOn(BrowserThread::IO);
+      case base::MessageLoop::TYPE_DEFAULT:
+        return !BrowserThread::CurrentlyOn(BrowserThread::UI) &&
+               !BrowserThread::CurrentlyOn(BrowserThread::IO);
     }
     return false;
   }
@@ -734,7 +734,7 @@ TEST_F(ProtocolHandlerRegistryTest, TestOSRegistration) {
 
   registry()->OnAcceptRegisterProtocolHandler(ph_do1);
   registry()->OnDenyRegisterProtocolHandler(ph_dont);
-  MessageLoop::current()->Run();  // FILE thread needs to run.
+  base::MessageLoop::current()->Run();  // FILE thread needs to run.
   ASSERT_TRUE(delegate()->IsFakeRegisteredWithOS("do"));
   ASSERT_FALSE(delegate()->IsFakeRegisteredWithOS("dont"));
 
@@ -764,10 +764,10 @@ TEST_F(ProtocolHandlerRegistryTest, MAYBE_TestOSRegistrationFailure) {
   ASSERT_FALSE(registry()->IsHandledProtocol("dont"));
 
   registry()->OnAcceptRegisterProtocolHandler(ph_do);
-  MessageLoop::current()->Run();  // FILE thread needs to run.
+  base::MessageLoop::current()->Run();  // FILE thread needs to run.
   delegate()->set_force_os_failure(true);
   registry()->OnAcceptRegisterProtocolHandler(ph_dont);
-  MessageLoop::current()->Run();  // FILE thread needs to run.
+  base::MessageLoop::current()->Run();  // FILE thread needs to run.
   ASSERT_TRUE(registry()->IsHandledProtocol("do"));
   ASSERT_EQ(static_cast<size_t>(1), registry()->GetHandlersFor("do").size());
   ASSERT_FALSE(registry()->IsHandledProtocol("dont"));
diff --git a/chrome/browser/devtools/devtools_adb_bridge.cc b/chrome/browser/devtools/devtools_adb_bridge.cc
index 4be00b3..fa5b881 100644
--- a/chrome/browser/devtools/devtools_adb_bridge.cc
+++ b/chrome/browser/devtools/devtools_adb_bridge.cc
@@ -578,7 +578,7 @@ DevToolsAdbBridge::RefCountedAdbThread::RefCountedAdbThread() {
   instance_ = this;
   thread_ = new base::Thread(kDevToolsAdbBridgeThreadName);
   base::Thread::Options options;
-  options.message_loop_type = MessageLoop::TYPE_IO;
+  options.message_loop_type = base::MessageLoop::TYPE_IO;
   if (!thread_->StartWithOptions(options)) {
     delete thread_;
     thread_ = NULL;
diff --git a/chrome/browser/devtools/devtools_sanity_browsertest.cc b/chrome/browser/devtools/devtools_sanity_browsertest.cc
index e143d81..d5b6889 100644
--- a/chrome/browser/devtools/devtools_sanity_browsertest.cc
+++ b/chrome/browser/devtools/devtools_sanity_browsertest.cc
@@ -70,7 +70,7 @@ class BrowserClosedObserver : public content::NotificationObserver {
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE {
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
  private:
@@ -171,7 +171,7 @@ class DevToolsSanityTest : public InProcessBrowserTest {
 
 void TimeoutCallback(const std::string& timeout_message) {
   FAIL() << timeout_message;
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // Base class for DevTools tests that test devtools functionality for
@@ -203,7 +203,7 @@ class DevToolsExtensionTest : public DevToolsSanityTest,
                     content::NotificationService::AllSources());
       base::CancelableClosure timeout(
           base::Bind(&TimeoutCallback, "Extension load timed out."));
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE, timeout.callback(), base::TimeDelta::FromSeconds(4));
       extensions::UnpackedInstaller::Create(service)->Load(path);
       content::RunMessageLoop();
@@ -226,7 +226,7 @@ class DevToolsExtensionTest : public DevToolsSanityTest,
                   content::NotificationService::AllSources());
     base::CancelableClosure timeout(
         base::Bind(&TimeoutCallback, "Extension host load timed out."));
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE, timeout.callback(), base::TimeDelta::FromSeconds(4));
 
     ExtensionProcessManager* manager =
@@ -252,7 +252,7 @@ class DevToolsExtensionTest : public DevToolsSanityTest,
     switch (type) {
       case chrome::NOTIFICATION_EXTENSION_LOADED:
       case chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING:
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
         break;
       default:
         NOTREACHED();
@@ -304,7 +304,7 @@ class WorkerDevToolsSanityTest : public InProcessBrowserTest {
       worker_data_->worker_route_id = route_id;
       WorkerService::GetInstance()->RemoveObserver(this);
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-          MessageLoop::QuitClosure());
+          base::MessageLoop::QuitClosure());
       delete this;
     }
     scoped_refptr<WorkerData> worker_data_;
@@ -324,7 +324,7 @@ class WorkerDevToolsSanityTest : public InProcessBrowserTest {
       ASSERT_EQ(worker_data_->worker_route_id, route_id);
       WorkerService::GetInstance()->RemoveObserver(this);
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-          MessageLoop::QuitClosure());
+          base::MessageLoop::QuitClosure());
       delete this;
     }
     scoped_refptr<WorkerData> worker_data_;
@@ -366,7 +366,7 @@ class WorkerDevToolsSanityTest : public InProcessBrowserTest {
       worker_data->worker_process_id = worker_info[0].process_id;
       worker_data->worker_route_id = worker_info[0].route_id;
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-          MessageLoop::QuitClosure());
+          base::MessageLoop::QuitClosure());
       return;
     }
 
diff --git a/chrome/browser/download/chrome_download_manager_delegate_unittest.cc b/chrome/browser/download/chrome_download_manager_delegate_unittest.cc
index abb3b98..0c58cd7 100644
--- a/chrome/browser/download/chrome_download_manager_delegate_unittest.cc
+++ b/chrome/browser/download/chrome_download_manager_delegate_unittest.cc
@@ -55,12 +55,12 @@ class MockWebContentsDelegate : public content::WebContentsDelegate {
 //   EXPECT_CALL(mock_fooclass_instance, Foo(callback))
 //     .WillOnce(ScheduleCallback(false));
 ACTION_P(ScheduleCallback, result) {
-  MessageLoop::current()->PostTask(FROM_HERE, base::Bind(arg0, result));
+  base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(arg0, result));
 }
 
 // Similar to ScheduleCallback, but binds 2 arguments.
 ACTION_P2(ScheduleCallback2, result0, result1) {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(arg0, result0, result1));
 }
 
@@ -101,8 +101,8 @@ class TestChromeDownloadManagerDelegate : public ChromeDownloadManagerDelegate {
       OVERRIDE {
     // Pretend the path reservation succeeded without any change to
     // |target_path|.
-    MessageLoop::current()->PostTask(FROM_HERE,
-                                     base::Bind(callback, virtual_path, true));
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(callback, virtual_path, true));
   }
 
   virtual void PromptUserForDownloadPath(
diff --git a/chrome/browser/download/download_browsertest.cc b/chrome/browser/download/download_browsertest.cc
index 42e36970..ba0f098 100644
--- a/chrome/browser/download/download_browsertest.cc
+++ b/chrome/browser/download/download_browsertest.cc
@@ -123,7 +123,7 @@ class CreatedObserver : public content::DownloadManager::Observer {
                                  content::DownloadItem* item) OVERRIDE {
     DCHECK_EQ(manager_, manager);
     if (waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   content::DownloadManager* manager_;
@@ -165,10 +165,10 @@ class PercentWaiter : public content::DownloadItem::Observer {
           (item_->PercentComplete() != 100)))) {
       error_ = true;
       if (waiting_)
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
     }
     if (item_->GetState() == DownloadItem::COMPLETE && waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   virtual void OnDownloadDestroyed(content::DownloadItem* item) OVERRIDE {
@@ -220,7 +220,7 @@ class DownloadsHistoryDataCollector {
       scoped_ptr<std::vector<history::DownloadRow> > entries) {
     result_valid_ = true;
     results_ = entries.Pass();
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   Profile* profile_;
@@ -246,7 +246,7 @@ class MockAbortExtensionInstallPrompt : public ExtensionInstallPrompt {
       const Extension* extension,
       const ShowDialogCallback& show_dialog_callback) OVERRIDE {
     delegate->InstallUIAbort(true);
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   virtual void OnInstallSuccess(const Extension* extension,
@@ -349,7 +349,7 @@ class HistoryObserver : public DownloadHistory::Observer {
 
     seen_stored_ = true;
     if (waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   virtual void OnDownloadHistoryDestroyed() OVERRIDE {
@@ -1007,7 +1007,7 @@ class DownloadTest : public InProcessBrowserTest {
     if (URLRequestSlowDownloadJob::NumberOutstandingRequests())
       *result = false;
     BrowserThread::PostTask(
-        BrowserThread::UI, FROM_HERE, MessageLoop::QuitClosure());
+        BrowserThread::UI, FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
   // Location of the test data.
@@ -1186,8 +1186,8 @@ IN_PROC_BROWSER_TEST_F(DownloadTest, DownloadResourceThrottleCancels) {
   ASSERT_TRUE(download_assempted);
   observer.WaitForObservation(
       base::Bind(&content::RunMessageLoop),
-      base::Bind(&MessageLoop::Quit,
-                 base::Unretained(MessageLoopForUI::current())));
+      base::Bind(&base::MessageLoop::Quit,
+                 base::Unretained(base::MessageLoopForUI::current())));
 
   // Check that we did not download the file.
   base::FilePath file(FILE_PATH_LITERAL("download-test1.lib"));
diff --git a/chrome/browser/download/download_history_unittest.cc b/chrome/browser/download/download_history_unittest.cc
index 63528cd..2c70a77 100644
--- a/chrome/browser/download/download_history_unittest.cc
+++ b/chrome/browser/download/download_history_unittest.cc
@@ -410,7 +410,7 @@ class DownloadHistoryTest : public testing::Test {
   }
 
  private:
-  MessageLoopForUI loop_;
+  base::MessageLoopForUI loop_;
   content::TestBrowserThread ui_thread_;
   std::vector<NiceMockDownloadItem*> items_;
   scoped_refptr<content::MockDownloadManager> manager_;
diff --git a/chrome/browser/download/download_path_reservation_tracker_unittest.cc b/chrome/browser/download/download_path_reservation_tracker_unittest.cc
index 0341cb0..5b11c8d 100644
--- a/chrome/browser/download/download_path_reservation_tracker_unittest.cc
+++ b/chrome/browser/download/download_path_reservation_tracker_unittest.cc
@@ -94,7 +94,7 @@ class DownloadPathReservationTrackerTest : public testing::Test {
  protected:
   base::ScopedTempDir test_download_dir_;
   base::FilePath default_download_path_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/download/download_shelf.cc b/chrome/browser/download/download_shelf.cc
index c1c3b7f9..e9a9b32 100644
--- a/chrome/browser/download/download_shelf.cc
+++ b/chrome/browser/download/download_shelf.cc
@@ -44,7 +44,7 @@ void DownloadShelf::AddDownload(DownloadItem* download) {
     // If we are going to remove the download from the shelf upon completion,
     // wait a few seconds to see if it completes quickly. If it's a small
     // download, then the user won't have time to interact with it.
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&DownloadShelf::ShowDownloadById,
                    weak_ptr_factory_.GetWeakPtr(),
diff --git a/chrome/browser/download/download_shelf_unittest.cc b/chrome/browser/download/download_shelf_unittest.cc
index 21ca398..ad78008 100644
--- a/chrome/browser/download/download_shelf_unittest.cc
+++ b/chrome/browser/download/download_shelf_unittest.cc
@@ -40,7 +40,7 @@ class DownloadShelfTest : public testing::Test {
  private:
   scoped_ptr<content::MockDownloadItem> GetInProgressMockDownload();
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<content::MockDownloadItem> download_item_;
   scoped_refptr<content::MockDownloadManager> download_manager_;
diff --git a/chrome/browser/download/download_status_updater_unittest.cc b/chrome/browser/download/download_status_updater_unittest.cc
index 367399b..dbe7c6d 100644
--- a/chrome/browser/download/download_status_updater_unittest.cc
+++ b/chrome/browser/download/download_status_updater_unittest.cc
@@ -188,7 +188,7 @@ class DownloadStatusUpdaterTest : public testing::Test {
   // object) can be deleted.
   // TODO(rdsmith): This can be removed when the DownloadManager
   // is no longer required to be deleted on the UI thread.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/download/download_target_determiner.cc b/chrome/browser/download/download_target_determiner.cc
index 98dfa31..6572846 100644
--- a/chrome/browser/download/download_target_determiner.cc
+++ b/chrome/browser/download/download_target_determiner.cc
@@ -460,7 +460,7 @@ void DownloadTargetDeterminer::ScheduleCallbackAndDeleteSelf() {
             << " Intermediate:" << intermediate_path_.AsUTF8Unsafe()
             << " Should prompt:" << should_prompt_
             << " Danger type:" << danger_type_;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(completion_callback_,
                  local_path_,
diff --git a/chrome/browser/download/download_test_file_activity_observer.cc b/chrome/browser/download/download_test_file_activity_observer.cc
index 0dca0d9..0a0835a 100644
--- a/chrome/browser/download/download_test_file_activity_observer.cc
+++ b/chrome/browser/download/download_test_file_activity_observer.cc
@@ -43,7 +43,7 @@ class DownloadTestFileActivityObserver::MockDownloadManagerDelegate
                                          const FileSelectedCallback&
                                              callback) OVERRIDE {
     file_chooser_displayed_ = true;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, (file_chooser_enabled_ ? suggested_path
                                          : base::FilePath())));
   }
diff --git a/chrome/browser/download/save_page_browsertest.cc b/chrome/browser/download/save_page_browsertest.cc
index 47f6cc5..eff3068 100644
--- a/chrome/browser/download/save_page_browsertest.cc
+++ b/chrome/browser/download/save_page_browsertest.cc
@@ -89,7 +89,7 @@ class DownloadPersistedObserver : public DownloadHistory::Observer {
                                 const history::DownloadRow& info) OVERRIDE {
     persisted_ = filter_.Run(item, info);
     if (persisted_ && waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
  private:
@@ -129,7 +129,7 @@ class DownloadRemovedObserver : public DownloadPersistedObserver {
   virtual void OnDownloadsRemoved(const DownloadHistory::IdSet& ids) OVERRIDE {
     removed_ = ids.find(download_id_) != ids.end();
     if (removed_ && waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
  private:
@@ -230,14 +230,14 @@ class DownloadItemCreatedObserver : public DownloadManager::Observer {
     items_seen_.push_back(item);
 
     if (waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   virtual void ManagerGoingDown(DownloadManager* manager) OVERRIDE {
     manager_->RemoveObserver(this);
     manager_ = NULL;
     if (waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   bool waiting_;
diff --git a/chrome/browser/errorpage_browsertest.cc b/chrome/browser/errorpage_browsertest.cc
index d87b5ac..5195a7e 100644
--- a/chrome/browser/errorpage_browsertest.cc
+++ b/chrome/browser/errorpage_browsertest.cc
@@ -109,8 +109,8 @@ class ErrorPageTest : public InProcessBrowserTest {
     }
     test_navigation_observer.WaitForObservation(
         base::Bind(&content::RunMessageLoop),
-        base::Bind(&MessageLoop::Quit,
-                   base::Unretained(MessageLoopForUI::current())));
+        base::Bind(&base::MessageLoop::Quit,
+                   base::Unretained(base::MessageLoopForUI::current())));
 
     EXPECT_EQ(title_watcher.WaitAndGetTitle(), ASCIIToUTF16(expected_title));
   }
diff --git a/chrome/browser/extensions/active_tab_unittest.cc b/chrome/browser/extensions/active_tab_unittest.cc
index 4a244b4..9ca1052 100644
--- a/chrome/browser/extensions/active_tab_unittest.cc
+++ b/chrome/browser/extensions/active_tab_unittest.cc
@@ -59,7 +59,7 @@ class ActiveTabTest : public ChromeRenderViewHostTestHarness {
       : extension(CreateTestExtension("deadbeef", true)),
         another_extension(CreateTestExtension("feedbeef", true)),
         extension_without_active_tab(CreateTestExtension("badbeef", false)),
-        ui_thread_(BrowserThread::UI, MessageLoop::current()) {}
+        ui_thread_(BrowserThread::UI, base::MessageLoop::current()) {}
 
  protected:
   virtual void SetUp() OVERRIDE {
diff --git a/chrome/browser/extensions/activity_log/activity_database_unittest.cc b/chrome/browser/extensions/activity_log/activity_database_unittest.cc
index 4006d6e..4e62c13 100644
--- a/chrome/browser/extensions/activity_log/activity_database_unittest.cc
+++ b/chrome/browser/extensions/activity_log/activity_database_unittest.cc
@@ -39,9 +39,9 @@ namespace extensions {
 class ActivityDatabaseTest : public ChromeRenderViewHostTestHarness {
  public:
   ActivityDatabaseTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        db_thread_(BrowserThread::DB, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()) {}
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        db_thread_(BrowserThread::DB, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()) {}
 
   virtual void SetUp() OVERRIDE {
     ChromeRenderViewHostTestHarness::SetUp();
@@ -56,8 +56,9 @@ class ActivityDatabaseTest : public ChromeRenderViewHostTestHarness {
   }
 
   virtual ~ActivityDatabaseTest() {
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
  protected:
@@ -371,7 +372,7 @@ TEST_F(ActivityDatabaseTest, BatchModeOn) {
 
   // Artificially trigger and then stop the timer.
   activity_db->SetTimerForTesting(0);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   scoped_ptr<std::vector<scoped_refptr<Action> > > actions_after =
         activity_db->GetActions("punky", 0);
diff --git a/chrome/browser/extensions/activity_log/activity_log_unittest.cc b/chrome/browser/extensions/activity_log/activity_log_unittest.cc
index 62ab52a..f8898f5 100644
--- a/chrome/browser/extensions/activity_log/activity_log_unittest.cc
+++ b/chrome/browser/extensions/activity_log/activity_log_unittest.cc
@@ -29,9 +29,9 @@ namespace extensions {
 class ActivityLogTest : public ChromeRenderViewHostTestHarness {
  public:
   ActivityLogTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        db_thread_(BrowserThread::DB, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()) {}
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        db_thread_(BrowserThread::DB, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()) {}
 
   virtual void SetUp() OVERRIDE {
     ChromeRenderViewHostTestHarness::SetUp();
@@ -49,8 +49,9 @@ class ActivityLogTest : public ChromeRenderViewHostTestHarness {
   }
 
   virtual ~ActivityLogTest() {
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
   static void RetrieveActions_LogAndFetchActions(
diff --git a/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc b/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc
index e90e3d3..fd8b7c6 100644
--- a/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc
+++ b/chrome/browser/extensions/api/alarms/alarms_api_unittest.cc
@@ -36,7 +36,7 @@ class AlarmDelegate : public AlarmManager::Delegate {
   virtual void OnAlarm(const std::string& extension_id,
                        const Alarm& alarm) OVERRIDE {
     alarms_seen.push_back(alarm.js_alarm->name);
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   std::vector<std::string> alarms_seen;
@@ -157,7 +157,7 @@ TEST_F(ExtensionAlarmsTest, Create) {
 
   // Now wait for the alarm to fire. Our test delegate will quit the
   // MessageLoop when that happens.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_EQ(1u, alarm_delegate_->alarms_seen.size());
   EXPECT_EQ("", alarm_delegate_->alarms_seen[0]);
@@ -187,12 +187,12 @@ TEST_F(ExtensionAlarmsTest, CreateRepeating) {
   test_clock_->Advance(base::TimeDelta::FromSeconds(1));
   // Now wait for the alarm to fire. Our test delegate will quit the
   // MessageLoop when that happens.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   test_clock_->Advance(base::TimeDelta::FromSeconds(1));
   // Wait again, and ensure the alarm fires again.
   alarm_manager_->ScheduleNextPoll();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_EQ(2u, alarm_delegate_->alarms_seen.size());
   EXPECT_EQ("", alarm_delegate_->alarms_seen[0]);
@@ -213,7 +213,7 @@ TEST_F(ExtensionAlarmsTest, CreateAbsolute) {
   test_clock_->SetNow(base::Time::FromDoubleT(10.1));
   // Now wait for the alarm to fire. Our test delegate will quit the
   // MessageLoop when that happens.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_FALSE(alarm_manager_->GetAlarm(extension_->id(), std::string()));
 
@@ -236,13 +236,13 @@ TEST_F(ExtensionAlarmsTest, CreateRepeatingWithQuickFirstCall) {
   test_clock_->SetNow(base::Time::FromDoubleT(10.1));
   // Now wait for the alarm to fire. Our test delegate will quit the
   // MessageLoop when that happens.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_TRUE(alarm_manager_->GetAlarm(extension_->id(), std::string()));
   EXPECT_THAT(alarm_delegate_->alarms_seen, testing::ElementsAre(""));
 
   test_clock_->SetNow(base::Time::FromDoubleT(10.7));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_TRUE(alarm_manager_->GetAlarm(extension_->id(), std::string()));
   EXPECT_THAT(alarm_delegate_->alarms_seen, testing::ElementsAre("", ""));
@@ -372,7 +372,7 @@ TEST_F(ExtensionAlarmsTest, Clear) {
   // Now wait for the alarms to fire, and ensure the cancelled alarms don't
   // fire.
   alarm_manager_->ScheduleNextPoll();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_EQ(1u, alarm_delegate_->alarms_seen.size());
   EXPECT_EQ("", alarm_delegate_->alarms_seen[0]);
@@ -457,7 +457,7 @@ TEST_F(ExtensionAlarmsSchedulingTest, PollScheduling) {
     alarm.js_alarm->scheduled_time = 3 * 60000;
     alarm.js_alarm->period_in_minutes.reset(new double(3));
     alarm_manager_->AddAlarmImpl(extension_->id(), alarm);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     EXPECT_EQ(alarm_manager_->last_poll_time_ + base::TimeDelta::FromMinutes(3),
               alarm_manager_->next_poll_time_);
     alarm_manager_->RemoveAllAlarms(extension_->id());
@@ -476,7 +476,7 @@ TEST_F(ExtensionAlarmsSchedulingTest, PollScheduling) {
     alarm3.js_alarm->scheduled_time = 25 * 60000;
     alarm3.js_alarm->period_in_minutes.reset(new double(25));
     alarm_manager_->AddAlarmImpl(extension_->id(), alarm3);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     EXPECT_EQ(alarm_manager_->last_poll_time_ + base::TimeDelta::FromMinutes(4),
               alarm_manager_->next_poll_time_);
     alarm_manager_->RemoveAllAlarms(extension_->id());
@@ -508,7 +508,7 @@ TEST_F(ExtensionAlarmsSchedulingTest, TimerRunning) {
   EXPECT_FALSE(alarm_manager_->timer_.IsRunning());
   CreateAlarm("[\"a\", {\"delayInMinutes\": 0.001}]");
   EXPECT_TRUE(alarm_manager_->timer_.IsRunning());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_FALSE(alarm_manager_->timer_.IsRunning());
   CreateAlarm("[\"bb\", {\"delayInMinutes\": 10}]");
   EXPECT_TRUE(alarm_manager_->timer_.IsRunning());
diff --git a/chrome/browser/extensions/api/bluetooth/bluetooth_event_router_unittest.cc b/chrome/browser/extensions/api/bluetooth/bluetooth_event_router_unittest.cc
index b5a3446..82e6ab2 100644
--- a/chrome/browser/extensions/api/bluetooth/bluetooth_event_router_unittest.cc
+++ b/chrome/browser/extensions/api/bluetooth/bluetooth_event_router_unittest.cc
@@ -104,7 +104,7 @@ class ExtensionBluetoothEventRouterTest : public testing::Test {
   testing::NiceMock<device::MockBluetoothProfile> mock_health_profile_;
   scoped_ptr<TestingProfile> test_profile_;
   ExtensionBluetoothEventRouter router_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/extensions/api/declarative/initializing_rules_registry_unittest.cc b/chrome/browser/extensions/api/declarative/initializing_rules_registry_unittest.cc
index 5d7e868..539cad9 100644
--- a/chrome/browser/extensions/api/declarative/initializing_rules_registry_unittest.cc
+++ b/chrome/browser/extensions/api/declarative/initializing_rules_registry_unittest.cc
@@ -19,7 +19,7 @@ const char kRuleId[] = "foo";
 namespace extensions {
 
 TEST(InitializingRulesRegistryTest, FillOptionalIdentifiers) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread thread(content::BrowserThread::UI, &message_loop);
 
   std::string error;
@@ -136,7 +136,7 @@ TEST(InitializingRulesRegistryTest, FillOptionalIdentifiers) {
 }
 
 TEST(InitializingRulesRegistryTest, FillOptionalPriority) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread thread(content::BrowserThread::UI, &message_loop);
 
   std::string error;
diff --git a/chrome/browser/extensions/api/declarative/rules_registry_service_unittest.cc b/chrome/browser/extensions/api/declarative/rules_registry_service_unittest.cc
index 8a998fd..2c7c646 100644
--- a/chrome/browser/extensions/api/declarative/rules_registry_service_unittest.cc
+++ b/chrome/browser/extensions/api/declarative/rules_registry_service_unittest.cc
@@ -47,7 +47,7 @@ class RulesRegistryServiceTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui;
   content::TestBrowserThread io;
 };
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 31b1354..cf02cef 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
@@ -73,7 +73,7 @@ class RulesRegistryWithCacheTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_refptr<TestRulesRegistry> registry_;
diff --git a/chrome/browser/extensions/api/declarative_webrequest/webrequest_action_unittest.cc b/chrome/browser/extensions/api/declarative_webrequest/webrequest_action_unittest.cc
index 79a46bf..b3e23fd 100644
--- a/chrome/browser/extensions/api/declarative_webrequest/webrequest_action_unittest.cc
+++ b/chrome/browser/extensions/api/declarative_webrequest/webrequest_action_unittest.cc
@@ -99,7 +99,7 @@ class WebRequestActionWithThreadsTest : public testing::Test {
   scoped_refptr<ExtensionInfoMap> extension_info_map_;
 
  private:
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread io_thread_;
 };
 
diff --git a/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_attribute_unittest.cc b/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_attribute_unittest.cc
index 99a62f1..fb11630 100644
--- a/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_attribute_unittest.cc
+++ b/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_attribute_unittest.cc
@@ -31,7 +31,7 @@ namespace keys = declarative_webrequest_constants;
 
 TEST(WebRequestConditionAttributeTest, CreateConditionAttribute) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   std::string error;
   scoped_refptr<const WebRequestConditionAttribute> result;
@@ -72,7 +72,7 @@ TEST(WebRequestConditionAttributeTest, CreateConditionAttribute) {
 
 TEST(WebRequestConditionAttributeTest, ResourceType) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   std::string error;
   ListValue resource_types;
@@ -105,7 +105,7 @@ TEST(WebRequestConditionAttributeTest, ResourceType) {
 
 TEST(WebRequestConditionAttributeTest, ContentType) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   std::string error;
   scoped_refptr<const WebRequestConditionAttribute> result;
@@ -122,7 +122,7 @@ TEST(WebRequestConditionAttributeTest, ContentType) {
   net::TestURLRequest url_request(
       test_server.GetURL("files/headers.html"), &delegate, &context, NULL);
   url_request.Start();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ListValue content_types;
   content_types.Append(Value::CreateStringValue("text/plain"));
@@ -174,7 +174,7 @@ TEST(WebRequestConditionAttributeTest, ContentType) {
 // Testing WebRequestConditionAttributeThirdParty.
 TEST(WebRequestConditionAttributeTest, ThirdParty) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   std::string error;
   const FundamentalValue value_true(true);
@@ -235,7 +235,7 @@ TEST(WebRequestConditionAttributeTest, ThirdParty) {
 // applicable in all stages.
 TEST(WebRequestConditionAttributeTest, Stages) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   typedef std::pair<RequestStage, const char*> StageNamePair;
   static const StageNamePair active_stages[] = {
@@ -411,7 +411,7 @@ void MatchAndCheck(const std::vector< std::vector<const std::string*> >& tests,
 // by both types of condition attributes, so it is enough to test it once.
 TEST(WebRequestConditionAttributeTest, RequestHeaders) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   net::TestURLRequestContext context;
   net::TestDelegate delegate;
@@ -420,7 +420,7 @@ TEST(WebRequestConditionAttributeTest, RequestHeaders) {
   url_request.SetExtraRequestHeaderByName(
       "Custom-header", "custom/value", true /* overwrite */);
   url_request.Start();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   std::vector<std::vector<const std::string*> > tests;
   bool result = false;
@@ -489,7 +489,7 @@ TEST(WebRequestConditionAttributeTest, RequestHeaders) {
 // 3. Negating the match in case of 'doesNotContainHeaders'.
 TEST(WebRequestConditionAttributeTest, ResponseHeaders) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
 
   net::SpawnedTestServer test_server(
       net::SpawnedTestServer::TYPE_HTTP,
@@ -503,7 +503,7 @@ TEST(WebRequestConditionAttributeTest, ResponseHeaders) {
   net::TestURLRequest url_request(test_server.GetURL("files/headers.html"),
                                   &delegate, &context, NULL);
   url_request.Start();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // In all the tests below we assume that the server includes the headers
   // Custom-Header: custom/value
diff --git a/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_unittest.cc b/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_unittest.cc
index 69c53f0..6cfbd15 100644
--- a/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_unittest.cc
+++ b/chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_unittest.cc
@@ -22,7 +22,7 @@ namespace keys2 = url_matcher_constants;
 
 TEST(WebRequestConditionTest, CreateCondition) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
   URLMatcher matcher;
 
   std::string error;
@@ -95,7 +95,7 @@ TEST(WebRequestConditionTest, CreateCondition) {
 
 TEST(WebRequestConditionTest, CreateConditionFirstPartyForCookies) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
   URLMatcher matcher;
 
   std::string error;
@@ -139,7 +139,7 @@ TEST(WebRequestConditionTest, CreateConditionFirstPartyForCookies) {
 //      always fulfilled.
 TEST(WebRequestConditionTest, NoUrlAttributes) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
   URLMatcher matcher;
   std::string error;
 
@@ -207,7 +207,7 @@ TEST(WebRequestConditionTest, NoUrlAttributes) {
 
 TEST(WebRequestConditionTest, CreateConditionSet) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
   URLMatcher matcher;
 
   WebRequestConditionSet::AnyVector conditions;
@@ -274,7 +274,7 @@ TEST(WebRequestConditionTest, CreateConditionSet) {
 
 TEST(WebRequestConditionTest, TestPortFilter) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
   URLMatcher matcher;
 
   WebRequestConditionSet::AnyVector conditions;
@@ -331,7 +331,7 @@ TEST(WebRequestConditionTest, TestPortFilter) {
 // impossible that both conditions are fulfilled at the same time.
 TEST(WebRequestConditionTest, ConditionsWithConflictingStages) {
   // Necessary for TestURLRequest.
-  MessageLoop message_loop(MessageLoop::TYPE_IO);
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_IO);
   URLMatcher matcher;
 
   std::string error;
diff --git a/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry_unittest.cc b/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry_unittest.cc
index cb404ba..c811841 100644
--- a/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry_unittest.cc
+++ b/chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry_unittest.cc
@@ -77,7 +77,7 @@ class TestWebRequestRulesRegistry : public WebRequestRulesRegistry {
 class WebRequestRulesRegistryTest : public testing::Test {
  public:
   WebRequestRulesRegistryTest()
-      : message_loop(MessageLoop::TYPE_IO),
+      : message_loop(base::MessageLoop::TYPE_IO),
         ui(content::BrowserThread::UI, &message_loop),
         io(content::BrowserThread::IO, &message_loop) {}
 
@@ -219,7 +219,7 @@ class WebRequestRulesRegistryTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui;
   content::TestBrowserThread io;
   // Two extensions with host permissions for all URLs and the DWR permission.
diff --git a/chrome/browser/extensions/api/dial/dial_registry_unittest.cc b/chrome/browser/extensions/api/dial/dial_registry_unittest.cc
index ba39270..0e3acfd 100644
--- a/chrome/browser/extensions/api/dial/dial_registry_unittest.cc
+++ b/chrome/browser/extensions/api/dial/dial_registry_unittest.cc
@@ -108,7 +108,7 @@ class DialRegistryTest : public testing::Test {
 
   // Must instantiate a MessageLoop for the thread, as the registry starts a
   // RepeatingTimer when there are listeners.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   void SetListenerExpectations() {
     EXPECT_CALL(registry_->mock_service(),
diff --git a/chrome/browser/extensions/api/dial/dial_service_unittest.cc b/chrome/browser/extensions/api/dial/dial_service_unittest.cc
index b378589..f8365b6 100644
--- a/chrome/browser/extensions/api/dial/dial_service_unittest.cc
+++ b/chrome/browser/extensions/api/dial/dial_service_unittest.cc
@@ -53,7 +53,7 @@ class DialServiceTest : public testing::Test {
 };
 
 TEST_F(DialServiceTest, TestSendMultipleRequests) {
-  MessageLoop loop(MessageLoop::TYPE_IO);
+  base::MessageLoop loop(base::MessageLoop::TYPE_IO);
   // Setting the finish delay to zero disables the timer that invokes
   // FinishDiscovery().
   dial_service_.finish_delay_ = TimeDelta::FromSeconds(0);
diff --git a/chrome/browser/extensions/api/downloads/downloads_api.cc b/chrome/browser/extensions/api/downloads/downloads_api.cc
index bcf7eba..ddb8303 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api.cc
@@ -681,7 +681,7 @@ class ExtensionDownloadsEventRouterData : public base::SupportsUserData::Data {
     // determiners_ doesn't keep hogging memory.
     weak_ptr_factory_.reset(
         new base::WeakPtrFactory<ExtensionDownloadsEventRouterData>(this));
-    MessageLoopForUI::current()->PostDelayedTask(
+    base::MessageLoopForUI::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&ExtensionDownloadsEventRouterData::ClearPendingDeterminers,
                    weak_ptr_factory_->GetWeakPtr()),
@@ -1138,7 +1138,8 @@ bool DownloadsDragFunction::RunImpl() {
   gfx::NativeView view = web_contents->GetView()->GetNativeView();
   {
     // Enable nested tasks during DnD, while |DragDownload()| blocks.
-    MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
+    base::MessageLoop::ScopedNestableTaskAllower allow(
+        base::MessageLoop::current());
     download_util::DragDownload(download_item, icon, view);
   }
   return true;
diff --git a/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc b/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
index bc93564..e84ceba 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
@@ -187,7 +187,7 @@ class DownloadsEventsListener : public content::NotificationObserver {
               waiting_for_.get() &&
               new_event->Satisfies(*waiting_for_)) {
             waiting_ = false;
-            MessageLoopForUI::current()->Quit();
+            base::MessageLoopForUI::current()->Quit();
           }
           break;
         }
diff --git a/chrome/browser/extensions/api/history/history_api.cc b/chrome/browser/extensions/api/history/history_api.cc
index d6c61f1..d5d8f92 100644
--- a/chrome/browser/extensions/api/history/history_api.cc
+++ b/chrome/browser/extensions/api/history/history_api.cc
@@ -280,7 +280,7 @@ bool HistoryFunctionWithCallback::RunImpl() {
 }
 
 void HistoryFunctionWithCallback::SendAsyncResponse() {
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&HistoryFunctionWithCallback::SendResponseToCallback, this));
 }
diff --git a/chrome/browser/extensions/api/identity/experimental_identity_apitest.cc b/chrome/browser/extensions/api/identity/experimental_identity_apitest.cc
index eb9553a..ee3ab02 100644
--- a/chrome/browser/extensions/api/identity/experimental_identity_apitest.cc
+++ b/chrome/browser/extensions/api/identity/experimental_identity_apitest.cc
@@ -68,7 +68,7 @@ class SendResponseDelegate :
     response_.reset(new bool);
     *response_ = success;
     if (should_post_quit_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/extensions/api/identity/experimental_web_auth_flow.cc b/chrome/browser/extensions/api/identity/experimental_web_auth_flow.cc
index 983f26d..e06a3b9 100644
--- a/chrome/browser/extensions/api/identity/experimental_web_auth_flow.cc
+++ b/chrome/browser/extensions/api/identity/experimental_web_auth_flow.cc
@@ -85,7 +85,7 @@ void ExperimentalWebAuthFlow::Start() {
 
 void ExperimentalWebAuthFlow::DetachDelegateAndDelete() {
   delegate_ = NULL;
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 WebContents* ExperimentalWebAuthFlow::CreateWebContents() {
diff --git a/chrome/browser/extensions/api/identity/gaia_web_auth_flow_unittest.cc b/chrome/browser/extensions/api/identity/gaia_web_auth_flow_unittest.cc
index c9bf6de..787351fd 100644
--- a/chrome/browser/extensions/api/identity/gaia_web_auth_flow_unittest.cc
+++ b/chrome/browser/extensions/api/identity/gaia_web_auth_flow_unittest.cc
@@ -102,7 +102,7 @@ class IdentityGaiaWebAuthFlowTest : public testing::Test {
  protected:
   testing::StrictMock<MockGaiaWebAuthFlowDelegate> delegate_;
   GoogleServiceAuthError::State ubertoken_error_state_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread fake_ui_thread_;
 };
 
diff --git a/chrome/browser/extensions/api/identity/identity_apitest.cc b/chrome/browser/extensions/api/identity/identity_apitest.cc
index b18c138..6514e1e 100644
--- a/chrome/browser/extensions/api/identity/identity_apitest.cc
+++ b/chrome/browser/extensions/api/identity/identity_apitest.cc
@@ -72,7 +72,7 @@ class SendResponseDelegate
     response_.reset(new bool);
     *response_ = success;
     if (should_post_quit_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/extensions/api/identity/web_auth_flow.cc b/chrome/browser/extensions/api/identity/web_auth_flow.cc
index 7a27f16..d4347d4 100644
--- a/chrome/browser/extensions/api/identity/web_auth_flow.cc
+++ b/chrome/browser/extensions/api/identity/web_auth_flow.cc
@@ -91,7 +91,7 @@ void WebAuthFlow::Start() {
 
 void WebAuthFlow::DetachDelegateAndDelete() {
   delegate_ = NULL;
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 WebContents* WebAuthFlow::CreateWebContents() {
diff --git a/chrome/browser/extensions/api/messaging/native_message_process_host.cc b/chrome/browser/extensions/api/messaging/native_message_process_host.cc
index 6e32df8..a856d2b 100644
--- a/chrome/browser/extensions/api/messaging/native_message_process_host.cc
+++ b/chrome/browser/extensions/api/messaging/native_message_process_host.cc
@@ -197,8 +197,8 @@ void NativeMessageProcessHost::WaitRead() {
   // would always be consuming one thread in the thread pool. On Windows
   // FileStream uses overlapped IO, so that optimization isn't necessary there.
 #if defined(OS_POSIX)
-  MessageLoopForIO::current()->WatchFileDescriptor(
-    read_file_, false /* persistent */, MessageLoopForIO::WATCH_READ,
+  base::MessageLoopForIO::current()->WatchFileDescriptor(
+    read_file_, false /* persistent */, base::MessageLoopForIO::WATCH_READ,
     &read_watcher_, this);
 #else  // defined(OS_POSIX)
   DoRead();
diff --git a/chrome/browser/extensions/api/messaging/native_message_process_host.h b/chrome/browser/extensions/api/messaging/native_message_process_host.h
index 1d2475b..987055f 100644
--- a/chrome/browser/extensions/api/messaging/native_message_process_host.h
+++ b/chrome/browser/extensions/api/messaging/native_message_process_host.h
@@ -34,7 +34,7 @@ namespace extensions {
 // thread.
 class NativeMessageProcessHost
 #if defined(OS_POSIX)
-    : public MessageLoopForIO::Watcher
+    : public base::MessageLoopForIO::Watcher
 #endif  // !defined(OS_POSIX)
 {
  public:
@@ -134,7 +134,7 @@ class NativeMessageProcessHost
   scoped_ptr<net::FileStream> read_stream_;
 
 #if defined(OS_POSIX)
-  MessageLoopForIO::FileDescriptorWatcher read_watcher_;
+  base::MessageLoopForIO::FileDescriptorWatcher read_watcher_;
 #endif  // !defined(OS_POSIX)
 
   // Write stream.
diff --git a/chrome/browser/extensions/api/messaging/native_message_process_host_unittest.cc b/chrome/browser/extensions/api/messaging/native_message_process_host_unittest.cc
index 36298f7..080be62 100644
--- a/chrome/browser/extensions/api/messaging/native_message_process_host_unittest.cc
+++ b/chrome/browser/extensions/api/messaging/native_message_process_host_unittest.cc
@@ -153,7 +153,7 @@ class NativeMessagingTest : public ::testing::Test,
   Feature::ScopedCurrentChannel current_channel_;
   scoped_ptr<NativeMessageProcessHost> native_message_process_host_;
   base::FilePath user_data_dir_;
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   scoped_ptr<base::RunLoop> read_message_run_loop_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
   scoped_ptr<content::TestBrowserThread> io_thread_;
diff --git a/chrome/browser/extensions/api/processes/processes_api.cc b/chrome/browser/extensions/api/processes/processes_api.cc
index 1d0d76c..404b968 100644
--- a/chrome/browser/extensions/api/processes/processes_api.cc
+++ b/chrome/browser/extensions/api/processes/processes_api.cc
@@ -552,7 +552,7 @@ bool GetProcessIdForTabFunction::RunImpl() {
   // the data gathering.
   if (ProcessesAPI::Get(profile_)->processes_event_router()->
       is_task_manager_listening()) {
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+    base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         &GetProcessIdForTabFunction::GetProcessIdForTab, this));
   } else {
     registrar_.Add(this,
@@ -615,7 +615,7 @@ bool TerminateFunction::RunImpl() {
   // the data gathering.
   if (ProcessesAPI::Get(profile_)->processes_event_router()->
       is_task_manager_listening()) {
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+    base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         &TerminateFunction::TerminateProcess, this));
   } else {
     registrar_.Add(this,
@@ -703,7 +703,7 @@ bool GetProcessInfoFunction::RunImpl() {
   // the data gathering.
   if (ProcessesAPI::Get(profile_)->processes_event_router()->
       is_task_manager_listening()) {
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+    base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         &GetProcessInfoFunction::GatherProcessInfo, this));
   } else {
     registrar_.Add(this,
diff --git a/chrome/browser/extensions/api/runtime/runtime_api.cc b/chrome/browser/extensions/api/runtime/runtime_api.cc
index 1bf7b7e..db940db 100644
--- a/chrome/browser/extensions/api/runtime/runtime_api.cc
+++ b/chrome/browser/extensions/api/runtime/runtime_api.cc
@@ -235,7 +235,7 @@ bool RuntimeReloadFunction::RunImpl() {
   // We can't call ReloadExtension directly, since when this method finishes
   // it tries to decrease the reference count for the extension, which fails
   // if the extension has already been reloaded; so instead we post a task.
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ExtensionService::ReloadExtension,
                  profile()->GetExtensionService()->AsWeakPtr(),
                  extension_id()));
diff --git a/chrome/browser/extensions/api/socket/udp_socket_unittest.cc b/chrome/browser/extensions/api/socket/udp_socket_unittest.cc
index 0730d64..6acddf3 100644
--- a/chrome/browser/extensions/api/socket/udp_socket_unittest.cc
+++ b/chrome/browser/extensions/api/socket/udp_socket_unittest.cc
@@ -39,7 +39,7 @@ static void OnSendCompleted(int result) {
 }
 
 TEST(UDPSocketUnitTest, TestUDPSocketRecvFrom) {
-  MessageLoopForIO io_loop;  // For RecvFrom to do its threaded work.
+  base::MessageLoopForIO io_loop;  // For RecvFrom to do its threaded work.
   UDPSocket socket("abcdefghijklmnopqrst");
 
   // Confirm that we can call two RecvFroms in quick succession without
@@ -81,7 +81,7 @@ TEST(UDPSocketUnitTest, TestUDPMulticastLoopbackMode) {
 }
 
 static void QuitMessageLoop() {
-  MessageLoopForIO::current()->QuitNow();
+  base::MessageLoopForIO::current()->QuitNow();
 }
 
 // Send a test multicast packet every second.
@@ -90,7 +90,7 @@ static void SendMulticastPacket(UDPSocket* src, int result) {
   if (result == 0) {
     scoped_refptr<net::IOBuffer> data = new net::WrappedIOBuffer(test_message);
     src->Write(data, test_message_length, base::Bind(&OnSendCompleted));
-    MessageLoopForIO::current()->PostDelayedTask(FROM_HERE,
+    base::MessageLoopForIO::current()->PostDelayedTask(FROM_HERE,
           base::Bind(&SendMulticastPacket, src, result),
           base::TimeDelta::FromSeconds(1));
   } else {
@@ -112,7 +112,7 @@ TEST(UDPSocketUnitTest, TestUDPMulticastRecv) {
   const int kPort = 9999;
   const char* const kGroup = "237.132.100.17";
   bool packet_received = false;
-  MessageLoopForIO io_loop;  // For Read to do its threaded work.
+  base::MessageLoopForIO io_loop;  // For Read to do its threaded work.
   UDPSocket dest("abcdefghijklmnopqrst");
   UDPSocket src("abcdefghijklmnopqrst");
 
diff --git a/chrome/browser/extensions/api/storage/policy_value_store_unittest.cc b/chrome/browser/extensions/api/storage/policy_value_store_unittest.cc
index 29783a9..dc3a183 100644
--- a/chrome/browser/extensions/api/storage/policy_value_store_unittest.cc
+++ b/chrome/browser/extensions/api/storage/policy_value_store_unittest.cc
@@ -108,7 +108,7 @@ class PolicyValueStoreTest : public testing::Test {
 
  protected:
   base::ScopedTempDir scoped_temp_dir_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread file_thread_;
   scoped_ptr<PolicyValueStore> store_;
   MockSettingsObserver observer_;
diff --git a/chrome/browser/extensions/api/storage/settings_apitest.cc b/chrome/browser/extensions/api/storage/settings_apitest.cc
index fd81c9d..30742f0 100644
--- a/chrome/browser/extensions/api/storage/settings_apitest.cc
+++ b/chrome/browser/extensions/api/storage/settings_apitest.cc
@@ -128,7 +128,7 @@ class ExtensionSettingsApiTest : public ExtensionApiTest {
   }
 
   void InitSync(syncer::SyncChangeProcessor* sync_processor) {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     InitSyncWithSyncableService(
         sync_processor,
         browser()->profile()->GetExtensionService()->settings_frontend()->
@@ -136,7 +136,7 @@ class ExtensionSettingsApiTest : public ExtensionApiTest {
   }
 
   void SendChanges(const syncer::SyncChangeList& change_list) {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     SendChangesToSyncableService(
         change_list,
         browser()->profile()->GetExtensionService()->settings_frontend()->
diff --git a/chrome/browser/extensions/api/storage/settings_frontend_unittest.cc b/chrome/browser/extensions/api/storage/settings_frontend_unittest.cc
index d53b2ea..06555b9 100644
--- a/chrome/browser/extensions/api/storage/settings_frontend_unittest.cc
+++ b/chrome/browser/extensions/api/storage/settings_frontend_unittest.cc
@@ -53,8 +53,8 @@ class ExtensionSettingsFrontendTest : public testing::Test {
  public:
   ExtensionSettingsFrontendTest()
       : storage_factory_(new util::ScopedSettingsStorageFactory()),
-        ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()) {}
+        ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()) {}
 
   virtual void SetUp() OVERRIDE {
     ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
@@ -82,7 +82,7 @@ class ExtensionSettingsFrontendTest : public testing::Test {
   scoped_refptr<util::ScopedSettingsStorageFactory> storage_factory_;
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 };
@@ -141,7 +141,7 @@ TEST_F(ExtensionSettingsFrontendTest, SettingsClearedOnUninstall) {
 
   // This would be triggered by extension uninstall via a DataDeleter.
   frontend_->DeleteStorageSoon(id);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // The storage area may no longer be valid post-uninstall, so re-request.
   storage = util::GetStorage(id, frontend_.get());
@@ -177,7 +177,7 @@ TEST_F(ExtensionSettingsFrontendTest, LeveldbDatabaseDeletedFromDiskOnClear) {
   }
 
   frontend_.reset();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   // TODO(kalman): Figure out why this fails, despite appearing to work.
   // Leaving this commented out rather than disabling the whole test so that the
   // deletion code paths are at least exercised.
@@ -282,7 +282,7 @@ TEST_F(ExtensionSettingsFrontendTest,
   frontend_->RunWithStorage(
       id, settings::LOCAL, base::Bind(&UnlimitedLocalStorageTestCallback));
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/storage/settings_sync_unittest.cc b/chrome/browser/extensions/api/storage/settings_sync_unittest.cc
index fcfcdc8..ae4a353 100644
--- a/chrome/browser/extensions/api/storage/settings_sync_unittest.cc
+++ b/chrome/browser/extensions/api/storage/settings_sync_unittest.cc
@@ -201,8 +201,8 @@ class TestingValueStoreFactory : public SettingsStorageFactory {
 class ExtensionSettingsSyncTest : public testing::Test {
  public:
   ExtensionSettingsSyncTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()),
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()),
         storage_factory_(new util::ScopedSettingsStorageFactory()),
         sync_processor_(new MockSyncChangeProcessor),
         sync_processor_delegate_(new SyncChangeProcessorDelegate(
@@ -237,7 +237,7 @@ class ExtensionSettingsSyncTest : public testing::Test {
 
   // Gets the syncer::SyncableService for the given sync type.
   syncer::SyncableService* GetSyncableService(syncer::ModelType model_type) {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     return frontend_->GetBackendForSync(model_type);
   }
 
@@ -257,7 +257,7 @@ class ExtensionSettingsSyncTest : public testing::Test {
   }
 
   // Need these so that the DCHECKs for running on FILE or UI threads pass.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/extensions/api/storage/settings_test_util.cc b/chrome/browser/extensions/api/storage/settings_test_util.cc
index f6e714a..30bf92b 100644
--- a/chrome/browser/extensions/api/storage/settings_test_util.cc
+++ b/chrome/browser/extensions/api/storage/settings_test_util.cc
@@ -27,7 +27,7 @@ ValueStore* GetStorage(
       extension_id,
       settings_namespace,
       base::Bind(&AssignStorage, &storage));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   return storage;
 }
 
diff --git a/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc b/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
index 36e06cc..9e4a683 100644
--- a/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
+++ b/chrome/browser/extensions/api/streams_private/streams_private_apitest.cc
@@ -210,7 +210,7 @@ IN_PROC_BROWSER_TEST_F(StreamsPrivateApiTest, Navigate) {
                                test_server_->GetURL("/doc_path.doc"));
 
   // Wait for the response from the test server.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // There should be no downloads started by the navigation.
   DownloadManager* download_manager = GetDownloadManager();
diff --git a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_unittest.cc b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_unittest.cc
index 8db85c1..18aa3da 100644
--- a/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_unittest.cc
+++ b/chrome/browser/extensions/api/system_info_cpu/cpu_info_provider_unittest.cc
@@ -145,7 +145,7 @@ class CpuInfoProviderTest : public testing::Test {
   void VerifyResult();
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_refptr<TestCpuInfoProvider> cpu_info_provider_;
@@ -158,7 +158,7 @@ class CpuInfoProviderTest : public testing::Test {
 };
 
 CpuInfoProviderTest::CpuInfoProviderTest()
-    : message_loop_(MessageLoop::TYPE_UI),
+    : message_loop_(base::MessageLoop::TYPE_UI),
       ui_thread_(BrowserThread::UI, &message_loop_),
       file_thread_(BrowserThread::FILE, &message_loop_) {
 }
@@ -173,7 +173,7 @@ void CpuInfoProviderTest::OnCheckCpuSamplingFinishedForTesting(
   // UI thread a chance to verify results.
   if (cpu_info_provider_->is_complete_sampling()) {
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                            MessageLoop::QuitClosure());
+                            base::MessageLoop::QuitClosure());
   }
 
   TestCpuUpdateInfo result;
diff --git a/chrome/browser/extensions/api/system_info_cpu/system_info_cpu_apitest.cc b/chrome/browser/extensions/api/system_info_cpu/system_info_cpu_apitest.cc
index 84911d4..6d8c35e 100644
--- a/chrome/browser/extensions/api/system_info_cpu/system_info_cpu_apitest.cc
+++ b/chrome/browser/extensions/api/system_info_cpu/system_info_cpu_apitest.cc
@@ -68,11 +68,11 @@ class SystemInfoCpuApiTest: public ExtensionApiTest {
 
   virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
-    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+    message_loop_.reset(new base::MessageLoop(base::MessageLoop::TYPE_UI));
   }
 
  private:
-  scoped_ptr<MessageLoop> message_loop_;
+  scoped_ptr<base::MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoCpuApiTest, Cpu) {
diff --git a/chrome/browser/extensions/api/system_info_display/system_info_display_apitest.cc b/chrome/browser/extensions/api/system_info_display/system_info_display_apitest.cc
index b719fe6..35107f7 100644
--- a/chrome/browser/extensions/api/system_info_display/system_info_display_apitest.cc
+++ b/chrome/browser/extensions/api/system_info_display/system_info_display_apitest.cc
@@ -55,11 +55,11 @@ class SystemInfoDisplayApiTest: public ExtensionApiTest {
 
   virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
-    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+    message_loop_.reset(new base::MessageLoop(base::MessageLoop::TYPE_UI));
   }
 
  private:
-  scoped_ptr<MessageLoop> message_loop_;
+  scoped_ptr<base::MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoDisplayApiTest, Display) {
diff --git a/chrome/browser/extensions/api/system_info_memory/system_info_memory_apitest.cc b/chrome/browser/extensions/api/system_info_memory/system_info_memory_apitest.cc
index bfaf312..8035b70 100644
--- a/chrome/browser/extensions/api/system_info_memory/system_info_memory_apitest.cc
+++ b/chrome/browser/extensions/api/system_info_memory/system_info_memory_apitest.cc
@@ -39,11 +39,11 @@ class SystemInfoMemoryApiTest: public ExtensionApiTest {
 
   virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
-    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+    message_loop_.reset(new base::MessageLoop(base::MessageLoop::TYPE_UI));
   }
 
  private:
-  scoped_ptr<MessageLoop> message_loop_;
+  scoped_ptr<base::MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoMemoryApiTest, Memory) {
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_unittest.cc b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_unittest.cc
index d80b14f..a225735 100644
--- a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_unittest.cc
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_unittest.cc
@@ -173,7 +173,7 @@ void TestStorageInfoProvider::OnCheckWatchedStoragesFinishedForTesting() {
   // Note the QuitClosure is actually bound to QuitCurrentWhenIdle, it means
   // that the UI thread wil continue to process pending messages util idle.
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-      MessageLoop::QuitClosure());
+      base::MessageLoop::QuitClosure());
 }
 
 class StorageInfoProviderTest : public testing::Test {
@@ -190,14 +190,14 @@ class StorageInfoProviderTest : public testing::Test {
   static void RunLoopAndFlushBlockingPool();
   static void RunAllPendingAndFlushBlockingPool();
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<TestStorageInfoProvider> storage_info_provider_;
   scoped_ptr<TestStorageMonitor> storage_test_notifications_;
 };
 
 StorageInfoProviderTest::StorageInfoProviderTest()
-    : message_loop_(MessageLoop::TYPE_UI),
+    : message_loop_(base::MessageLoop::TYPE_UI),
       ui_thread_(BrowserThread::UI, &message_loop_) {
 }
 
diff --git a/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc b/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
index 3fb84a2..b316a755 100644
--- a/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
+++ b/chrome/browser/extensions/api/system_info_storage/system_info_storage_apitest.cc
@@ -102,7 +102,7 @@ class SystemInfoStorageApiTest: public ExtensionApiTest {
 
   virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
-    message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
+    message_loop_.reset(new base::MessageLoop(base::MessageLoop::TYPE_UI));
   }
 
   void ProcessAttach(const std::string& device_id,
@@ -118,7 +118,7 @@ class SystemInfoStorageApiTest: public ExtensionApiTest {
   }
 
  private:
-  scoped_ptr<MessageLoop> message_loop_;
+  scoped_ptr<base::MessageLoop> message_loop_;
 };
 
 IN_PROC_BROWSER_TEST_F(SystemInfoStorageApiTest, Storage) {
diff --git a/chrome/browser/extensions/api/tabs/tabs_api.cc b/chrome/browser/extensions/api/tabs/tabs_api.cc
index 3f9f851..fcb587b 100644
--- a/chrome/browser/extensions/api/tabs/tabs_api.cc
+++ b/chrome/browser/extensions/api/tabs/tabs_api.cc
@@ -1917,7 +1917,7 @@ bool TabsDetectLanguageFunction::RunImpl() {
   if (!translate_tab_helper->language_state().original_language().empty()) {
     // Delay the callback invocation until after the current JS call has
     // returned.
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+    base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         &TabsDetectLanguageFunction::GotLanguage, this,
         translate_tab_helper->language_state().original_language()));
     return true;
diff --git a/chrome/browser/extensions/api/top_sites/top_sites_apitest.cc b/chrome/browser/extensions/api/top_sites/top_sites_apitest.cc
index 32c791b..7d8086c 100644
--- a/chrome/browser/extensions/api/top_sites/top_sites_apitest.cc
+++ b/chrome/browser/extensions/api/top_sites/top_sites_apitest.cc
@@ -33,7 +33,7 @@ class TopSitesExtensionTest : public InProcessBrowserTest {
 
     if (!top_sites_inited_) {
       waiting_ = true;
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
     }
 
     // By this point, we know topsites has loaded. We can run the tests now.
@@ -42,7 +42,7 @@ class TopSitesExtensionTest : public InProcessBrowserTest {
  private:
   void OnTopSitesAvailable(const history::MostVisitedURLList& data) {
     if (waiting_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
       waiting_ = false;
     }
     top_sites_inited_ = true;
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 52ad26e..4746018 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
@@ -159,7 +159,7 @@ class TestIPCSender : public IPC::Sender {
     EXPECT_EQ(ExtensionMsg_MessageInvoke::ID, message->type());
 
     EXPECT_FALSE(task_queue_.empty());
-    MessageLoop::current()->PostTask(FROM_HERE, task_queue_.front());
+    base::MessageLoop::current()->PostTask(FROM_HERE, task_queue_.front());
     task_queue_.pop();
 
     sent_messages_.push_back(linked_ptr<IPC::Message>(message));
@@ -200,7 +200,7 @@ class ExtensionWebRequestTest : public testing::Test {
                               const std::vector<char>& bytes_1,
                               const std::vector<char>& bytes_2);
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   TestingProfile profile_;
@@ -284,7 +284,7 @@ TEST_F(ExtensionWebRequestTest, BlockingEventPrecedenceRedirect) {
             request.identifier(), response));
 
     request.Start();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     EXPECT_TRUE(!request.is_pending());
     EXPECT_EQ(net::URLRequestStatus::SUCCESS, request.status().status());
@@ -334,7 +334,7 @@ TEST_F(ExtensionWebRequestTest, BlockingEventPrecedenceRedirect) {
             request2.identifier(), response));
 
     request2.Start();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     EXPECT_TRUE(!request2.is_pending());
     EXPECT_EQ(net::URLRequestStatus::SUCCESS, request2.status().status());
@@ -398,7 +398,7 @@ TEST_F(ExtensionWebRequestTest, BlockingEventPrecedenceCancel) {
 
   request.Start();
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_TRUE(!request.is_pending());
   EXPECT_EQ(net::URLRequestStatus::FAILED, request.status().status());
@@ -452,14 +452,14 @@ TEST_F(ExtensionWebRequestTest, SimulateChancelWhileBlocked) {
 
   // Extension response for OnErrorOccurred: Terminate the message loop.
   ipc_sender_.PushTask(
-      base::Bind(&MessageLoop::PostTask,
-                 base::Unretained(MessageLoop::current()),
-                 FROM_HERE, MessageLoop::QuitClosure()));
+      base::Bind(&base::MessageLoop::PostTask,
+                 base::Unretained(base::MessageLoop::current()),
+                 FROM_HERE, base::MessageLoop::QuitClosure()));
 
   request.Start();
   // request.Start() will have submitted OnBeforeRequest by the time we cancel.
   request.Cancel();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_TRUE(!request.is_pending());
   EXPECT_EQ(net::URLRequestStatus::CANCELED, request.status().status());
@@ -623,7 +623,7 @@ TEST_F(ExtensionWebRequestTest, AccessRequestBodyData) {
   FireURLRequestWithData(kMethodPost, kMultipart, form_1, form_2);
 
   // We inspect the result in the message list of |ipc_sender_| later.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   ExtensionWebRequestEventRouter::GetInstance()->RemoveEventListener(
       &profile_, extension_id, kEventName + "/1");
@@ -656,7 +656,7 @@ TEST_F(ExtensionWebRequestTest, AccessRequestBodyData) {
   // Now send a PUT request with the same body as above.
   FireURLRequestWithData(kMethodPut, NULL /*no header*/, plain_1, plain_2);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Clean-up.
   ExtensionWebRequestEventRouter::GetInstance()->RemoveEventListener(
@@ -717,7 +717,7 @@ TEST_F(ExtensionWebRequestTest, NoAccessRequestBodyData) {
   }
 
   // We inspect the result in the message list of |ipc_sender_| later.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   ExtensionWebRequestEventRouter::GetInstance()->RemoveEventListener(
       &profile_, extension_id, kEventName + "/1");
@@ -790,7 +790,7 @@ class ExtensionWebRequestHeaderModificationTest
     context_->Init();
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   TestingProfile profile_;
@@ -888,7 +888,7 @@ TEST_P(ExtensionWebRequestHeaderModificationTest, TestModifications) {
   // exists and are therefore not listed in the responses. This makes
   // them seem deleted.
   request.Start();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_TRUE(!request.is_pending());
   // This cannot succeed as we send the request to a server that does not exist.
diff --git a/chrome/browser/extensions/api/web_request/web_request_permissions_unittest.cc b/chrome/browser/extensions/api/web_request/web_request_permissions_unittest.cc
index 35bec82..01777f9 100644
--- a/chrome/browser/extensions/api/web_request/web_request_permissions_unittest.cc
+++ b/chrome/browser/extensions/api/web_request/web_request_permissions_unittest.cc
@@ -38,7 +38,7 @@ class ExtensionWebRequestHelpersTestWithThreadsTest : public testing::Test {
   scoped_refptr<ExtensionInfoMap> extension_info_map_;
 
  private:
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread io_thread_;
 };
 
@@ -70,7 +70,7 @@ void ExtensionWebRequestHelpersTestWithThreadsTest::SetUp() {
 }
 
 TEST(ExtensionWebRequestHelpersTest, TestHideRequestForURL) {
-  MessageLoopForIO message_loop;
+  base::MessageLoopForIO message_loop;
   net::TestURLRequestContext context;
   scoped_refptr<ExtensionInfoMap> extension_info_map(new ExtensionInfoMap);
   const char* sensitive_urls[] = {
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 feb7ba9..67ce366 100644
--- a/chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc
+++ b/chrome/browser/extensions/api/webstore_private/webstore_private_apitest.cc
@@ -50,7 +50,7 @@ class WebstoreInstallListener : public WebstoreInstaller::Delegate {
 
     if (waiting_) {
       waiting_ = false;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
@@ -64,7 +64,7 @@ class WebstoreInstallListener : public WebstoreInstaller::Delegate {
 
     if (waiting_) {
       waiting_ = false;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/extensions/app_process_apitest.cc b/chrome/browser/extensions/app_process_apitest.cc
index 811d94d..9bffa84 100644
--- a/chrome/browser/extensions/app_process_apitest.cc
+++ b/chrome/browser/extensions/app_process_apitest.cc
@@ -689,8 +689,8 @@ IN_PROC_BROWSER_TEST_F(AppApiTest, OpenAppFromExtension) {
   // Wait for app tab to be created and loaded.
   test_navigation_observer.WaitForObservation(
       base::Bind(&content::RunMessageLoop),
-      base::Bind(&MessageLoop::Quit,
-                 base::Unretained(MessageLoopForUI::current())));
+      base::Bind(&base::MessageLoop::Quit,
+                 base::Unretained(base::MessageLoopForUI::current())));
 
   // App has loaded, and chrome.app.isInstalled should be true.
   bool is_installed = false;
diff --git a/chrome/browser/extensions/blacklist_unittest.cc b/chrome/browser/extensions/blacklist_unittest.cc
index 31d20ba..dc8f58a 100644
--- a/chrome/browser/extensions/blacklist_unittest.cc
+++ b/chrome/browser/extensions/blacklist_unittest.cc
@@ -33,7 +33,7 @@ class BlacklistTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   TestExtensionPrefs prefs_;
 
diff --git a/chrome/browser/extensions/browser_permissions_policy_delegate_unittest.cc b/chrome/browser/extensions/browser_permissions_policy_delegate_unittest.cc
index a31970d..6fef348 100644
--- a/chrome/browser/extensions/browser_permissions_policy_delegate_unittest.cc
+++ b/chrome/browser/extensions/browser_permissions_policy_delegate_unittest.cc
@@ -20,10 +20,9 @@ namespace {
 
 class BrowserPermissionsPolicyDelegateTest : public testing::Test {
 public:
-  BrowserPermissionsPolicyDelegateTest()
-      : loop_(MessageLoop::TYPE_UI),
-        ui_thread_(content::BrowserThread::UI, &loop_) {
-  }
+ BrowserPermissionsPolicyDelegateTest()
+     : loop_(base::MessageLoop::TYPE_UI),
+       ui_thread_(content::BrowserThread::UI, &loop_) {}
   virtual void SetUp() {
     profile_manager_.reset(
         new TestingProfileManager(TestingBrowserProcess::GetGlobal()));
@@ -35,8 +34,8 @@ public:
     profile_manager_->DeleteTestingProfile("test");
     profile_manager_.reset();
   }
-protected:
-  MessageLoop loop_;
+ protected:
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<TestingProfileManager> profile_manager_;
   TestingProfile* profile_;
diff --git a/chrome/browser/extensions/convert_web_app_browsertest.cc b/chrome/browser/extensions/convert_web_app_browsertest.cc
index 42cebd2..95e1415 100644
--- a/chrome/browser/extensions/convert_web_app_browsertest.cc
+++ b/chrome/browser/extensions/convert_web_app_browsertest.cc
@@ -44,7 +44,7 @@ class ExtensionFromWebAppTest
           content::Details<const InstalledExtensionInfo>(details)->extension;
       if (extension->id() == expected_extension_id_) {
         installed_extension_ = extension;
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
       }
     }
   }
diff --git a/chrome/browser/extensions/crx_installer_browsertest.cc b/chrome/browser/extensions/crx_installer_browsertest.cc
index f297d20..49a0a2a 100644
--- a/chrome/browser/extensions/crx_installer_browsertest.cc
+++ b/chrome/browser/extensions/crx_installer_browsertest.cc
@@ -55,11 +55,11 @@ class MockInstallPrompt : public ExtensionInstallPrompt {
   virtual void OnInstallSuccess(const Extension* extension,
                                 SkBitmap* icon) OVERRIDE {
     extension_ = extension;
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
   virtual void OnInstallFailure(const CrxInstallerError& error) OVERRIDE {
     error_ = error.message();
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
  private:
diff --git a/chrome/browser/extensions/default_apps_unittest.cc b/chrome/browser/extensions/default_apps_unittest.cc
index cfff341..1104e7b 100644
--- a/chrome/browser/extensions/default_apps_unittest.cc
+++ b/chrome/browser/extensions/default_apps_unittest.cc
@@ -29,11 +29,11 @@ class MockExternalLoader : public ExternalLoader {
 
 class DefaultAppsTest : public testing::Test {
  public:
-  DefaultAppsTest() : loop_(MessageLoop::TYPE_IO),
+  DefaultAppsTest() : loop_(base::MessageLoop::TYPE_IO),
       ui_thread_(content::BrowserThread::UI, &loop_) {}
   virtual ~DefaultAppsTest() {}
  private:
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/extensions/event_router.cc b/chrome/browser/extensions/event_router.cc
index 9224a51..246f985 100644
--- a/chrome/browser/extensions/event_router.cc
+++ b/chrome/browser/extensions/event_router.cc
@@ -771,7 +771,7 @@ void EventRouter::Observe(int type,
         listeners_.LoadFilteredLazyListeners(extension->id(), *filtered_events);
 
       if (dispatch_chrome_updated_event_) {
-        MessageLoop::current()->PostTask(FROM_HERE,
+        base::MessageLoop::current()->PostTask(FROM_HERE,
             base::Bind(&DispatchOnInstalledEvent, profile_, extension->id(),
                        Version(), true));
       }
@@ -797,7 +797,7 @@ void EventRouter::Observe(int type,
       if (old)
         old_version = *old->version();
 
-      MessageLoop::current()->PostTask(FROM_HERE,
+      base::MessageLoop::current()->PostTask(FROM_HERE,
           base::Bind(&DispatchOnInstalledEvent, profile_, extension->id(),
                      old_version, false));
       break;
diff --git a/chrome/browser/extensions/event_router_forwarder_unittest.cc b/chrome/browser/extensions/event_router_forwarder_unittest.cc
index 975d986..e8172f7 100644
--- a/chrome/browser/extensions/event_router_forwarder_unittest.cc
+++ b/chrome/browser/extensions/event_router_forwarder_unittest.cc
@@ -114,7 +114,7 @@ class EventRouterForwarderTest : public testing::Test {
     return incognito;
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   TestingProfileManager profile_manager_;
@@ -172,7 +172,7 @@ TEST_F(EventRouterForwarderTest, BroadcastRendererIO) {
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)));
   ASSERT_TRUE(helper->Run());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 TEST_F(EventRouterForwarderTest, UnicastRendererUIRestricted) {
diff --git a/chrome/browser/extensions/extension_action.cc b/chrome/browser/extensions/extension_action.cc
index d8ec44f..f86760f 100644
--- a/chrome/browser/extensions/extension_action.cc
+++ b/chrome/browser/extensions/extension_action.cc
@@ -394,7 +394,7 @@ void ExtensionAction::RunIconAnimation(int tab_id) {
   // timer delays), destroy it. We use a delayed task so that the Animation is
   // deleted even if it hasn't finished by the time the MessageLoop is
   // destroyed.
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&DestroyIconAnimation, base::Passed(&icon_animation)),
       base::TimeDelta::FromMilliseconds(kIconFadeInDurationMs * 2));
diff --git a/chrome/browser/extensions/extension_action_icon_factory_unittest.cc b/chrome/browser/extensions/extension_action_icon_factory_unittest.cc
index 78e49e1..0e42893 100644
--- a/chrome/browser/extensions/extension_action_icon_factory_unittest.cc
+++ b/chrome/browser/extensions/extension_action_icon_factory_unittest.cc
@@ -95,7 +95,7 @@ class ExtensionActionIconFactoryTest
 
   void WaitForIconUpdate() {
     quit_in_icon_updated_ = true;
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     quit_in_icon_updated_ = false;
   }
 
@@ -150,7 +150,7 @@ class ExtensionActionIconFactoryTest
   // ExtensionActionIconFactory::Observer overrides:
   virtual void OnIconUpdated() OVERRIDE {
     if (quit_in_icon_updated_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   }
 
   gfx::ImageSkia GetFavicon() {
@@ -166,7 +166,7 @@ class ExtensionActionIconFactoryTest
 
  private:
   bool quit_in_icon_updated_;
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/extensions/extension_action_unittest.cc b/chrome/browser/extensions/extension_action_unittest.cc
index 6c2ca63..2aba574 100644
--- a/chrome/browser/extensions/extension_action_unittest.cc
+++ b/chrome/browser/extensions/extension_action_unittest.cc
@@ -59,7 +59,7 @@ TEST(ExtensionActionTest, Visibility) {
 
 TEST(ExtensionActionTest, ScriptBadgeAnimation) {
   // Supports the icon animation.
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
 
   ExtensionAction script_badge(
       std::string(), ActionInfo::TYPE_SCRIPT_BADGE, ActionInfo());
@@ -83,7 +83,7 @@ TEST(ExtensionActionTest, ScriptBadgeAnimation) {
 
 TEST(ExtensionActionTest, GetAttention) {
   // Supports the icon animation.
-  scoped_ptr<MessageLoop> message_loop(new MessageLoop);
+  scoped_ptr<base::MessageLoop> message_loop(new base::MessageLoop);
 
   ExtensionAction script_badge(
       std::string(), ActionInfo::TYPE_SCRIPT_BADGE, ActionInfo());
@@ -95,7 +95,7 @@ TEST(ExtensionActionTest, GetAttention) {
 
   // Simulate waiting long enough for the animation to end.
   message_loop.reset();  // Can't have 2 MessageLoops alive at once.
-  message_loop.reset(new MessageLoop);
+  message_loop.reset(new base::MessageLoop);
   EXPECT_FALSE(script_badge.GetIconAnimation(1));  // Sanity check.
 
   script_badge.SetAppearance(1, ExtensionAction::ACTIVE);
diff --git a/chrome/browser/extensions/extension_apitest.cc b/chrome/browser/extensions/extension_apitest.cc
index 09ed180f6..ae7030a 100644
--- a/chrome/browser/extensions/extension_apitest.cc
+++ b/chrome/browser/extensions/extension_apitest.cc
@@ -82,7 +82,7 @@ void ExtensionApiTest::ResultCatcher::Observe(
       results_.push_back(true);
       messages_.push_back(std::string());
       if (waiting_)
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_EXTENSION_TEST_FAILED:
@@ -90,7 +90,7 @@ void ExtensionApiTest::ResultCatcher::Observe(
       results_.push_back(false);
       messages_.push_back(*(content::Details<std::string>(details).ptr()));
       if (waiting_)
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
       break;
 
     default:
diff --git a/chrome/browser/extensions/extension_browsertest.cc b/chrome/browser/extensions/extension_browsertest.cc
index 49a9dc9..658decd 100644
--- a/chrome/browser/extensions/extension_browsertest.cc
+++ b/chrome/browser/extensions/extension_browsertest.cc
@@ -306,7 +306,7 @@ class MockAbortExtensionInstallPrompt : public ExtensionInstallPrompt {
       const Extension* extension,
       const ShowDialogCallback& show_dialog_callback) OVERRIDE {
     delegate->InstallUIAbort(true);
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   virtual void OnInstallSuccess(const Extension* extension,
@@ -663,7 +663,7 @@ void ExtensionBrowserTest::Observe(
       last_loaded_extension_id_ =
           content::Details<const Extension>(details).ptr()->id();
       VLOG(1) << "Got EXTENSION_LOADED notification.";
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_CRX_INSTALLER_DONE:
@@ -677,29 +677,29 @@ void ExtensionBrowserTest::Observe(
           last_loaded_extension_id_ = "";
       }
       ++crx_installers_done_observed_;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_EXTENSION_INSTALLED:
       VLOG(1) << "Got EXTENSION_INSTALLED notification.";
       ++extension_installs_observed_;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_EXTENSION_INSTALL_ERROR:
       VLOG(1) << "Got EXTENSION_INSTALL_ERROR notification.";
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_EXTENSION_PROCESS_TERMINATED:
       VLOG(1) << "Got EXTENSION_PROCESS_TERMINATED notification.";
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_EXTENSION_LOAD_ERROR:
       VLOG(1) << "Got EXTENSION_LOAD_ERROR notification.";
       ++extension_load_errors_observed_;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     case chrome::NOTIFICATION_EXTENSION_PAGE_ACTION_COUNT_CHANGED: {
@@ -710,7 +710,7 @@ void ExtensionBrowserTest::Observe(
       if (location_bar->PageActionCount() ==
           target_page_action_count_) {
         target_page_action_count_ = -1;
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
       }
       break;
     }
@@ -724,14 +724,14 @@ void ExtensionBrowserTest::Observe(
       if (location_bar->PageActionVisibleCount() ==
           target_visible_page_action_count_) {
         target_visible_page_action_count_ = -1;
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
       }
       break;
     }
 
     case content::NOTIFICATION_LOAD_STOP:
       VLOG(1) << "Got LOAD_STOP notification.";
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
       break;
 
     default:
diff --git a/chrome/browser/extensions/extension_crash_recovery_browsertest.cc b/chrome/browser/extensions/extension_crash_recovery_browsertest.cc
index be889eb..3eaf9a6 100644
--- a/chrome/browser/extensions/extension_crash_recovery_browsertest.cc
+++ b/chrome/browser/extensions/extension_crash_recovery_browsertest.cc
@@ -72,7 +72,7 @@ class ExtensionCrashRecoveryTestBase : public ExtensionBrowserTest {
                  GetBackgroundHostForExtension(extension_id));
 
     // Wait for extension crash balloon to appear.
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   void CheckExtensionConsistency(std::string extension_id) {
@@ -500,7 +500,7 @@ IN_PROC_BROWSER_TEST_F(MAYBE_ExtensionCrashRecoveryTest,
 
   ASSERT_EQ(1U, CountBalloons());
   UninstallExtension(first_extension_id_);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   SCOPED_TRACE("after uninstalling");
   ASSERT_EQ(size_before + 1, GetExtensionService()->extensions()->size());
diff --git a/chrome/browser/extensions/extension_disabled_ui.cc b/chrome/browser/extensions/extension_disabled_ui.cc
index a39a0b5..3f0da2c 100644
--- a/chrome/browser/extensions/extension_disabled_ui.cc
+++ b/chrome/browser/extensions/extension_disabled_ui.cc
@@ -262,7 +262,7 @@ void ExtensionDisabledGlobalError::OnBubbleViewDidClose(Browser* browser) {
 void ExtensionDisabledGlobalError::BubbleViewAcceptButtonPressed(
     Browser* browser) {
   // Delay extension reenabling so this bubble closes properly.
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ExtensionService::GrantPermissionsAndEnableExtension,
                  service_->AsWeakPtr(), extension_));
 }
@@ -274,7 +274,7 @@ void ExtensionDisabledGlobalError::BubbleViewCancelButtonPressed(
       ExtensionUninstallDialog::Create(service_->profile(), browser, this));
   // Delay showing the uninstall dialog, so that this function returns
   // immediately, to close the bubble properly. See crbug.com/121544.
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ExtensionUninstallDialog::ConfirmUninstall,
                  uninstall_dialog_->AsWeakPtr(), extension_));
 #endif  // !defined(OS_ANDROID)
diff --git a/chrome/browser/extensions/extension_error_reporter.cc b/chrome/browser/extensions/extension_error_reporter.cc
index e5abe83..9cbf944 100644
--- a/chrome/browser/extensions/extension_error_reporter.cc
+++ b/chrome/browser/extensions/extension_error_reporter.cc
@@ -29,7 +29,7 @@ ExtensionErrorReporter* ExtensionErrorReporter::GetInstance() {
 }
 
 ExtensionErrorReporter::ExtensionErrorReporter(bool enable_noisy_errors)
-    : ui_loop_(MessageLoop::current()),
+    : ui_loop_(base::MessageLoop::current()),
       enable_noisy_errors_(enable_noisy_errors) {
 }
 
@@ -38,7 +38,7 @@ ExtensionErrorReporter::~ExtensionErrorReporter() {}
 void ExtensionErrorReporter::ReportError(const string16& message,
                                          bool be_noisy) {
   // NOTE: There won't be a ui_loop_ in the unit test environment.
-  if (ui_loop_ && MessageLoop::current() != ui_loop_) {
+  if (ui_loop_ && base::MessageLoop::current() != ui_loop_) {
     // base::Unretained is okay since the ExtensionErrorReporter is a singleton
     // that lives until the end of the process.
     ui_loop_->PostTask(FROM_HERE,
diff --git a/chrome/browser/extensions/extension_function_test_utils.cc b/chrome/browser/extensions/extension_function_test_utils.cc
index d834aa00..3104222 100644
--- a/chrome/browser/extensions/extension_function_test_utils.cc
+++ b/chrome/browser/extensions/extension_function_test_utils.cc
@@ -229,7 +229,7 @@ class SendResponseDelegate
     response_.reset(new bool);
     *response_ = success;
     if (should_post_quit_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/extensions/extension_host.cc b/chrome/browser/extensions/extension_host.cc
index f980a82..6b97d397 100644
--- a/chrome/browser/extensions/extension_host.cc
+++ b/chrome/browser/extensions/extension_host.cc
@@ -96,7 +96,7 @@ class ExtensionHost::ProcessCreationQueue {
   // Queue up a delayed task to process the next ExtensionHost in the queue.
   void PostTask() {
     if (!pending_create_) {
-      MessageLoop::current()->PostTask(FROM_HERE,
+      base::MessageLoop::current()->PostTask(FROM_HERE,
           base::Bind(&ProcessCreationQueue::ProcessOneHost,
                      ptr_factory_.GetWeakPtr()));
       pending_create_ = true;
diff --git a/chrome/browser/extensions/extension_icon_image_unittest.cc b/chrome/browser/extensions/extension_icon_image_unittest.cc
index fcb5af9..f6bee7f 100644
--- a/chrome/browser/extensions/extension_icon_image_unittest.cc
+++ b/chrome/browser/extensions/extension_icon_image_unittest.cc
@@ -82,7 +82,7 @@ class TestImageLoader {
     image_ = image;
     image_loaded_ = true;
     if (waiting_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   }
 
   SkBitmap LoadBitmap(const std::string& path,
@@ -98,7 +98,7 @@ class TestImageLoader {
     // asynchronously), wait for it.
     if (!image_loaded_) {
       waiting_ = true;
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
       waiting_ = false;
     }
 
@@ -132,7 +132,7 @@ class ExtensionIconImageTest : public testing::Test,
 
   void WaitForImageLoad() {
     quit_in_image_loaded_ = true;
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     quit_in_image_loaded_ = false;
   }
 
@@ -179,7 +179,7 @@ class ExtensionIconImageTest : public testing::Test,
   virtual void OnExtensionIconImageChanged(IconImage* image) OVERRIDE {
     image_loaded_count_++;
     if (quit_in_image_loaded_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   }
 
   gfx::ImageSkia GetDefaultIcon() {
@@ -199,7 +199,7 @@ class ExtensionIconImageTest : public testing::Test,
  private:
   int image_loaded_count_;
   bool quit_in_image_loaded_;
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/extensions/extension_icon_manager_unittest.cc b/chrome/browser/extensions/extension_icon_manager_unittest.cc
index 98b5b13..d092c2d 100644
--- a/chrome/browser/extensions/extension_icon_manager_unittest.cc
+++ b/chrome/browser/extensions/extension_icon_manager_unittest.cc
@@ -35,14 +35,14 @@ class ExtensionIconManagerTest : public testing::Test {
   void ImageLoadObserved() {
     unwaited_image_loads_++;
     if (waiting_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
   void WaitForImageLoad() {
     if (unwaited_image_loads_ == 0) {
       waiting_ = true;
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
       waiting_ = false;
     }
     ASSERT_GT(unwaited_image_loads_, 0);
@@ -61,7 +61,7 @@ class ExtensionIconManagerTest : public testing::Test {
   // Whether we are currently waiting for an image load.
   bool waiting_;
 
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/extensions/extension_info_map_unittest.cc b/chrome/browser/extensions/extension_info_map_unittest.cc
index 561803a..932bd06 100644
--- a/chrome/browser/extensions/extension_info_map_unittest.cc
+++ b/chrome/browser/extensions/extension_info_map_unittest.cc
@@ -33,7 +33,7 @@ class ExtensionInfoMapTest : public testing::Test {
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 };
diff --git a/chrome/browser/extensions/extension_install_prompt.cc b/chrome/browser/extensions/extension_install_prompt.cc
index 73b893c..b78f4d3 100644
--- a/chrome/browser/extensions/extension_install_prompt.cc
+++ b/chrome/browser/extensions/extension_install_prompt.cc
@@ -151,7 +151,7 @@ bool AutoConfirmPrompt(ExtensionInstallPrompt::Delegate* delegate) {
   // the real implementations it's highly likely the message loop will be
   // pumping a few times before the user clicks accept or cancel.
   if (value == "accept") {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&ExtensionInstallPrompt::Delegate::InstallUIProceed,
                    base::Unretained(delegate)));
@@ -159,7 +159,7 @@ bool AutoConfirmPrompt(ExtensionInstallPrompt::Delegate* delegate) {
   }
 
   if (value == "cancel") {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&ExtensionInstallPrompt::Delegate::InstallUIAbort,
                    base::Unretained(delegate),
@@ -414,7 +414,7 @@ scoped_refptr<Extension>
 ExtensionInstallPrompt::ExtensionInstallPrompt(
     content::WebContents* contents)
     : record_oauth2_grant_(false),
-      ui_loop_(MessageLoop::current()),
+      ui_loop_(base::MessageLoop::current()),
       extension_(NULL),
       install_ui_(ExtensionInstallUI::Create(ProfileForWebContents(contents))),
       show_params_(contents),
@@ -428,7 +428,7 @@ ExtensionInstallPrompt::ExtensionInstallPrompt(
     gfx::NativeWindow native_window,
     content::PageNavigator* navigator)
     : record_oauth2_grant_(false),
-      ui_loop_(MessageLoop::current()),
+      ui_loop_(base::MessageLoop::current()),
       extension_(NULL),
       install_ui_(ExtensionInstallUI::Create(profile)),
       show_params_(native_window, navigator),
@@ -443,7 +443,7 @@ ExtensionInstallPrompt::~ExtensionInstallPrompt() {
 void ExtensionInstallPrompt::ConfirmBundleInstall(
     extensions::BundleInstaller* bundle,
     const PermissionSet* permissions) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   bundle_ = bundle;
   permissions_ = permissions;
   delegate_ = bundle;
@@ -457,7 +457,7 @@ void ExtensionInstallPrompt::ConfirmStandaloneInstall(
     const Extension* extension,
     SkBitmap* icon,
     const ExtensionInstallPrompt::Prompt& prompt) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   permissions_ = extension->GetActivePermissions();
   delegate_ = delegate;
@@ -483,7 +483,7 @@ void ExtensionInstallPrompt::ConfirmInstall(
     Delegate* delegate,
     const Extension* extension,
     const ShowDialogCallback& show_dialog_callback) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   permissions_ = extension->GetActivePermissions();
   delegate_ = delegate;
@@ -510,7 +510,7 @@ void ExtensionInstallPrompt::ConfirmInstall(
 
 void ExtensionInstallPrompt::ConfirmReEnable(Delegate* delegate,
                                              const Extension* extension) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   permissions_ = extension->GetActivePermissions();
   delegate_ = delegate;
@@ -523,7 +523,7 @@ void ExtensionInstallPrompt::ConfirmExternalInstall(
     Delegate* delegate,
     const Extension* extension,
     const ShowDialogCallback& show_dialog_callback) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   permissions_ = extension->GetActivePermissions();
   delegate_ = delegate;
@@ -537,7 +537,7 @@ void ExtensionInstallPrompt::ConfirmPermissions(
     Delegate* delegate,
     const Extension* extension,
     const PermissionSet* permissions) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   permissions_ = permissions;
   delegate_ = delegate;
@@ -550,7 +550,7 @@ void ExtensionInstallPrompt::ConfirmIssueAdvice(
     Delegate* delegate,
     const Extension* extension,
     const IssueAdviceInfo& issue_advice) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   delegate_ = delegate;
   prompt_.set_type(PERMISSIONS_PROMPT);
@@ -563,7 +563,7 @@ void ExtensionInstallPrompt::ConfirmIssueAdvice(
 
 void ExtensionInstallPrompt::ReviewPermissions(Delegate* delegate,
                                                const Extension* extension) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   permissions_ = extension->GetActivePermissions();
   delegate_ = delegate;
diff --git a/chrome/browser/extensions/extension_prefs_unittest.h b/chrome/browser/extensions/extension_prefs_unittest.h
index c28673d1..eb3cf6c 100644
--- a/chrome/browser/extensions/extension_prefs_unittest.h
+++ b/chrome/browser/extensions/extension_prefs_unittest.h
@@ -46,7 +46,7 @@ class ExtensionPrefsTest : public testing::Test {
  protected:
   ExtensionPrefs* prefs() { return prefs_.prefs(); }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 
   TestExtensionPrefs prefs_;
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index 6a6993c..8d67d77 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -431,7 +431,7 @@ int ExtensionProcessManager::DecrementLazyKeepaliveCount(
   int& count = background_page_data_[extension->id()].lazy_keepalive_count;
   DCHECK_GT(count, 0);
   if (--count == 0) {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&ExtensionProcessManager::OnLazyBackgroundPageIdle,
                    weak_ptr_factory_.GetWeakPtr(), extension->id(),
@@ -494,7 +494,7 @@ void ExtensionProcessManager::OnShouldSuspendAck(
 void ExtensionProcessManager::OnSuspendAck(const std::string& extension_id) {
   background_page_data_[extension_id].is_closing = true;
   int sequence_id = background_page_data_[extension_id].close_sequence_id;
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ExtensionProcessManager::CloseLazyBackgroundPageNow,
                  weak_ptr_factory_.GetWeakPtr(), extension_id, sequence_id),
diff --git a/chrome/browser/extensions/extension_protocols_unittest.cc b/chrome/browser/extensions/extension_protocols_unittest.cc
index 6b34e771..c9075a3 100644
--- a/chrome/browser/extensions/extension_protocols_unittest.cc
+++ b/chrome/browser/extensions/extension_protocols_unittest.cc
@@ -101,11 +101,11 @@ class ExtensionProtocolTest : public testing::Test {
                                                      -1,
                                                      -1);
     request->Start();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
  protected:
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index a1ad7e2..9037e6a 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -1970,7 +1970,7 @@ void ExtensionService::GarbageCollectExtensions() {
     // Don't garbage collect while there are pending installations, which may
     // be using the temporary installation directory. Try to garbage collect
     // again later.
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&ExtensionService::GarbageCollectExtensions, AsWeakPtr()),
         base::TimeDelta::FromSeconds(kGarbageCollectRetryDelay));
@@ -2647,7 +2647,7 @@ void ExtensionService::Observe(int type,
       // at all, but never half-crashed.  We do it in a PostTask so
       // that other handlers of this notification will still have
       // access to the Extension and ExtensionHost.
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(
               &ExtensionService::TrackTerminatedExtension,
@@ -2715,7 +2715,7 @@ void ExtensionService::Observe(int type,
       if (delayed_updates_for_idle_.Contains(extension_id)) {
         // We were waiting for this extension to become idle, it now might have,
         // so maybe finish installation.
-        MessageLoop::current()->PostDelayedTask(
+        base::MessageLoop::current()->PostDelayedTask(
             FROM_HERE,
             base::Bind(&ExtensionService::MaybeFinishDelayedInstallation,
                        AsWeakPtr(), extension_id),
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index 9df92a9..ac29e00 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -418,7 +418,7 @@ ExtensionServiceInitParams()
 
 // Our message loop may be used in tests which require it to be an IO loop.
 ExtensionServiceTestBase::ExtensionServiceTestBase()
-    : loop_(MessageLoop::TYPE_IO),
+    : loop_(base::MessageLoop::TYPE_IO),
       service_(NULL),
       management_policy_(NULL),
       expected_extensions_count_(0),
@@ -441,9 +441,9 @@ ExtensionServiceTestBase::~ExtensionServiceTestBase() {
   // can be destroyed while BrowserThreads and MessageLoop are still around
   // (they are used in the destruction process).
   service_ = NULL;
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   profile_.reset(NULL);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 void ExtensionServiceTestBase::InitializeExtensionService(
@@ -1126,7 +1126,7 @@ void PackExtensionTestClient::OnPackSuccess(
   // on with the rest of the test.
   // This call to |Quit()| matches the call to |Run()| in the
   // |PackPunctuatedExtension| test.
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
   EXPECT_EQ(expected_crx_path_.value(), crx_path.value());
   EXPECT_EQ(expected_private_key_path_.value(), private_key_path.value());
   ASSERT_TRUE(file_util::PathExists(private_key_path));
@@ -2027,7 +2027,7 @@ TEST_F(ExtensionServiceTest, PackPunctuatedExtension) {
     // block and catch the notification; otherwise, the process would exit.
     // This call to |Run()| is matched by a call to |Quit()| in the
     // |PackExtensionTestClient|'s notification handling code.
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     if (HasFatalFailure())
       return;
@@ -3812,22 +3812,22 @@ class ExtensionCookieCallback {
  public:
   ExtensionCookieCallback()
     : result_(false),
-      weak_factory_(MessageLoop::current()) {}
+      weak_factory_(base::MessageLoop::current()) {}
 
   void SetCookieCallback(bool result) {
-    MessageLoop::current()->PostTask(
-        FROM_HERE, base::Bind(&MessageLoop::Quit, weak_factory_.GetWeakPtr()));
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+        base::Bind(&base::MessageLoop::Quit, weak_factory_.GetWeakPtr()));
     result_ = result;
   }
 
   void GetAllCookiesCallback(const net::CookieList& list) {
-    MessageLoop::current()->PostTask(
-        FROM_HERE, base::Bind(&MessageLoop::Quit, weak_factory_.GetWeakPtr()));
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+        base::Bind(&base::MessageLoop::Quit, weak_factory_.GetWeakPtr()));
     list_ = list;
   }
   net::CookieList list_;
   bool result_;
-  base::WeakPtrFactory<MessageLoop> weak_factory_;
+  base::WeakPtrFactory<base::MessageLoop> weak_factory_;
 };
 
 // Verifies extension state is removed upon uninstall.
@@ -4643,7 +4643,7 @@ TEST(ExtensionServiceTestSimple, Enabledness) {
   ExtensionErrorReporter::Init(false);  // no noisy errors
   ExtensionsReadyRecorder recorder;
   scoped_ptr<TestingProfile> profile(new TestingProfile());
-  MessageLoop loop;
+  base::MessageLoop loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &loop);
   content::TestBrowserThread file_thread(BrowserThread::FILE, &loop);
 #if defined OS_CHROMEOS
diff --git a/chrome/browser/extensions/extension_service_unittest.h b/chrome/browser/extensions/extension_service_unittest.h
index 80d50c8..1c09479 100644
--- a/chrome/browser/extensions/extension_service_unittest.h
+++ b/chrome/browser/extensions/extension_service_unittest.h
@@ -69,7 +69,7 @@ class ExtensionServiceTestBase : public testing::Test {
   void InitializeExtensionServiceHelper(bool autoupdate_enabled,
                                         bool is_first_run);
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   base::ShadowingAtExitManager at_exit_manager_;
   base::ScopedTempDir temp_dir_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/extensions/extension_special_storage_policy_unittest.cc b/chrome/browser/extensions/extension_special_storage_policy_unittest.cc
index 33e1394..257b8ec 100644
--- a/chrome/browser/extensions/extension_special_storage_policy_unittest.cc
+++ b/chrome/browser/extensions/extension_special_storage_policy_unittest.cc
@@ -300,7 +300,7 @@ TEST_F(ExtensionSpecialStoragePolicyTest, OverlappingApps) {
 }
 
 TEST_F(ExtensionSpecialStoragePolicyTest, HasSessionOnlyOrigins) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
 
   TestingProfile profile;
@@ -335,7 +335,7 @@ TEST_F(ExtensionSpecialStoragePolicyTest, HasSessionOnlyOrigins) {
 }
 
 TEST_F(ExtensionSpecialStoragePolicyTest, NotificationTest) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   content::TestBrowserThread io_thread(BrowserThread::IO, &message_loop);
 
diff --git a/chrome/browser/extensions/extension_test_message_listener.cc b/chrome/browser/extensions/extension_test_message_listener.cc
index e892ba1..f548ac1 100644
--- a/chrome/browser/extensions/extension_test_message_listener.cc
+++ b/chrome/browser/extensions/extension_test_message_listener.cc
@@ -63,7 +63,7 @@ void ExtensionTestMessageListener::Observe(
     }
     if (waiting_) {
       waiting_ = false;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 }
diff --git a/chrome/browser/extensions/extension_ui_unittest.cc b/chrome/browser/extensions/extension_ui_unittest.cc
index 10b3ecc..b99aa93 100644
--- a/chrome/browser/extensions/extension_ui_unittest.cc
+++ b/chrome/browser/extensions/extension_ui_unittest.cc
@@ -118,7 +118,7 @@ class ExtensionUITest : public testing::Test {
     }
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/extensions/extension_uninstall_dialog.cc b/chrome/browser/extensions/extension_uninstall_dialog.cc
index 1bde628..f7881a5 100644
--- a/chrome/browser/extensions/extension_uninstall_dialog.cc
+++ b/chrome/browser/extensions/extension_uninstall_dialog.cc
@@ -56,7 +56,7 @@ ExtensionUninstallDialog::ExtensionUninstallDialog(
       delegate_(delegate),
       extension_(NULL),
       state_(kImageIsLoading),
-      ui_loop_(MessageLoop::current()) {
+      ui_loop_(base::MessageLoop::current()) {
   if (browser) {
     registrar_.Add(this,
                    chrome::NOTIFICATION_BROWSER_CLOSED,
@@ -69,7 +69,7 @@ ExtensionUninstallDialog::~ExtensionUninstallDialog() {
 
 void ExtensionUninstallDialog::ConfirmUninstall(
     const extensions::Extension* extension) {
-  DCHECK(ui_loop_ == MessageLoop::current());
+  DCHECK(ui_loop_ == base::MessageLoop::current());
   extension_ = extension;
   extensions::ExtensionResource image = extensions::IconsInfo::GetIconResource(
       extension_,
diff --git a/chrome/browser/extensions/extensions_quota_service.cc b/chrome/browser/extensions/extensions_quota_service.cc
index 6b267a5..bd34b1f 100644
--- a/chrome/browser/extensions/extensions_quota_service.cc
+++ b/chrome/browser/extensions/extensions_quota_service.cc
@@ -21,7 +21,7 @@ const char kOverQuotaError[] = "This request exceeds the * quota.";
 }  // namespace
 
 ExtensionsQuotaService::ExtensionsQuotaService() {
-  if (MessageLoop::current() != NULL) {  // Null in unit tests.
+  if (base::MessageLoop::current() != NULL) {  // Null in unit tests.
     purge_timer_.Start(FROM_HERE,
                        base::TimeDelta::FromDays(kPurgeIntervalInDays),
                        this, &ExtensionsQuotaService::Purge);
diff --git a/chrome/browser/extensions/extensions_quota_service_unittest.cc b/chrome/browser/extensions/extensions_quota_service_unittest.cc
index 2d02bfc..7a113bd 100644
--- a/chrome/browser/extensions/extensions_quota_service_unittest.cc
+++ b/chrome/browser/extensions/extensions_quota_service_unittest.cc
@@ -140,7 +140,7 @@ class ExtensionsQuotaServiceTest : public testing::Test {
   std::string extension_b_;
   std::string extension_c_;
   scoped_ptr<ExtensionsQuotaService> service_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/extensions/external_policy_loader_unittest.cc b/chrome/browser/extensions/external_policy_loader_unittest.cc
index 75bd788..28ce8aa 100644
--- a/chrome/browser/extensions/external_policy_loader_unittest.cc
+++ b/chrome/browser/extensions/external_policy_loader_unittest.cc
@@ -27,7 +27,7 @@ namespace extensions {
 class ExternalPolicyLoaderTest : public testing::Test {
  public:
   ExternalPolicyLoaderTest()
-      : loop_(MessageLoop::TYPE_IO),
+      : loop_(base::MessageLoop::TYPE_IO),
         ui_thread_(BrowserThread::UI, &loop_) {
   }
 
@@ -36,7 +36,7 @@ class ExternalPolicyLoaderTest : public testing::Test {
  private:
   // We need these to satisfy BrowserThread::CurrentlyOn(BrowserThread::UI)
   // checks in ExternalProviderImpl.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/extensions/image_loader_unittest.cc b/chrome/browser/extensions/image_loader_unittest.cc
index c34f128..04cf2c9 100644
--- a/chrome/browser/extensions/image_loader_unittest.cc
+++ b/chrome/browser/extensions/image_loader_unittest.cc
@@ -43,13 +43,13 @@ class ImageLoaderTest : public testing::Test {
   void OnImageLoaded(const gfx::Image& image) {
     image_loaded_count_++;
     if (quit_in_image_loaded_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     image_ = image;
   }
 
   void WaitForImageLoad() {
     quit_in_image_loaded_ = true;
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     quit_in_image_loaded_ = false;
   }
 
@@ -105,7 +105,7 @@ class ImageLoaderTest : public testing::Test {
 
   int image_loaded_count_;
   bool quit_in_image_loaded_;
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/extensions/installed_loader.cc b/chrome/browser/extensions/installed_loader.cc
index 20712d9..2a6d97b 100644
--- a/chrome/browser/extensions/installed_loader.cc
+++ b/chrome/browser/extensions/installed_loader.cc
@@ -173,7 +173,7 @@ void InstalledLoader::LoadAllExtensions() {
           old_version = Version(version_str);
         }
       }
-      MessageLoop::current()->PostTask(FROM_HERE,
+      base::MessageLoop::current()->PostTask(FROM_HERE,
           base::Bind(&DispatchOnInstalledEvent, extension_service_->profile(),
                      info->extension_id, old_version, false));
 
diff --git a/chrome/browser/extensions/menu_manager_unittest.cc b/chrome/browser/extensions/menu_manager_unittest.cc
index 27f0020..66430f2 100644
--- a/chrome/browser/extensions/menu_manager_unittest.cc
+++ b/chrome/browser/extensions/menu_manager_unittest.cc
@@ -84,7 +84,7 @@ class MenuManagerTest : public testing::Test {
 
  protected:
   TestingProfile profile_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/extensions/pack_extension_unittest.cc b/chrome/browser/extensions/pack_extension_unittest.cc
index f83a3f4..5198be2 100644
--- a/chrome/browser/extensions/pack_extension_unittest.cc
+++ b/chrome/browser/extensions/pack_extension_unittest.cc
@@ -38,7 +38,7 @@ class PackExtensionTest : public testing::Test {
     return startup_helper_.PackExtension(command_line);
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/extensions/page_action_controller_unittest.cc b/chrome/browser/extensions/page_action_controller_unittest.cc
index b18d9c8..5268a9a 100644
--- a/chrome/browser/extensions/page_action_controller_unittest.cc
+++ b/chrome/browser/extensions/page_action_controller_unittest.cc
@@ -36,8 +36,8 @@ namespace {
 class PageActionControllerTest : public ChromeRenderViewHostTestHarness {
  public:
   PageActionControllerTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()) {}
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()) {}
 
   virtual void SetUp() OVERRIDE {
     ChromeRenderViewHostTestHarness::SetUp();
diff --git a/chrome/browser/extensions/permissions_updater_unittest.cc b/chrome/browser/extensions/permissions_updater_unittest.cc
index 8552b61..14a52e8 100644
--- a/chrome/browser/extensions/permissions_updater_unittest.cc
+++ b/chrome/browser/extensions/permissions_updater_unittest.cc
@@ -75,7 +75,7 @@ class PermissionsUpdaterListener : public content::NotificationObserver {
 
     if (waiting_) {
       waiting_ = false;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/extensions/sandboxed_unpacker_unittest.cc b/chrome/browser/extensions/sandboxed_unpacker_unittest.cc
index ddb56c01..4a97f57 100644
--- a/chrome/browser/extensions/sandboxed_unpacker_unittest.cc
+++ b/chrome/browser/extensions/sandboxed_unpacker_unittest.cc
@@ -159,7 +159,7 @@ class SandboxedUnpackerTest : public testing::Test {
   MockSandboxedUnpackerClient* client_;
   scoped_ptr<Unpacker> unpacker_;
   scoped_refptr<SandboxedUnpacker> sandboxed_unpacker_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   scoped_ptr<content::TestBrowserThread> file_thread_;
 };
 
diff --git a/chrome/browser/extensions/script_badge_controller_unittest.cc b/chrome/browser/extensions/script_badge_controller_unittest.cc
index 9600018..ee17b94 100644
--- a/chrome/browser/extensions/script_badge_controller_unittest.cc
+++ b/chrome/browser/extensions/script_badge_controller_unittest.cc
@@ -46,8 +46,8 @@ class ScriptBadgeControllerTest : public ChromeRenderViewHostTestHarness {
  public:
   ScriptBadgeControllerTest()
       : feature_override_(FeatureSwitch::script_badges(), true),
-        ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()),
+        ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()),
         current_channel_(chrome::VersionInfo::CHANNEL_DEV) {}
 
   virtual void SetUp() OVERRIDE {
diff --git a/chrome/browser/extensions/script_bubble_controller_unittest.cc b/chrome/browser/extensions/script_bubble_controller_unittest.cc
index b339d0f..36fe5b9 100644
--- a/chrome/browser/extensions/script_bubble_controller_unittest.cc
+++ b/chrome/browser/extensions/script_bubble_controller_unittest.cc
@@ -39,8 +39,8 @@ namespace {
 class ScriptBubbleControllerTest : public ChromeRenderViewHostTestHarness {
  public:
   ScriptBubbleControllerTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()),
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()),
         enable_script_bubble_(FeatureSwitch::script_bubble(), true) {
   }
 
diff --git a/chrome/browser/extensions/standard_management_policy_provider_unittest.cc b/chrome/browser/extensions/standard_management_policy_provider_unittest.cc
index 52a396f..05a00a0 100644
--- a/chrome/browser/extensions/standard_management_policy_provider_unittest.cc
+++ b/chrome/browser/extensions/standard_management_policy_provider_unittest.cc
@@ -41,7 +41,7 @@ class StandardManagementPolicyProviderTest : public testing::Test {
     return extension;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/extensions/startup_helper.cc b/chrome/browser/extensions/startup_helper.cc
index 77dc2d2..80c2837 100644
--- a/chrome/browser/extensions/startup_helper.cc
+++ b/chrome/browser/extensions/startup_helper.cc
@@ -298,9 +298,9 @@ bool StartupHelper::InstallFromWebstore(const CommandLine& cmd_line,
   AppInstallHelper helper;
   helper.BeginInstall(profile, id,
                       !cmd_line.HasSwitch(switches::kForceAppMode),
-                      MessageLoop::QuitWhenIdleClosure());
+                      base::MessageLoop::QuitWhenIdleClosure());
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   if (!helper.success())
     LOG(ERROR) << "InstallFromWebstore failed with error: " << helper.error();
   return helper.success();
diff --git a/chrome/browser/extensions/state_store.cc b/chrome/browser/extensions/state_store.cc
index f46685b..f1d09bc 100644
--- a/chrome/browser/extensions/state_store.cc
+++ b/chrome/browser/extensions/state_store.cc
@@ -143,7 +143,7 @@ void StateStore::Observe(int type,
                         content::NotificationService::AllSources());
       registrar_.Remove(this, chrome::NOTIFICATION_SESSION_RESTORE_DONE,
                         content::NotificationService::AllSources());
-      MessageLoop::current()->PostDelayedTask(FROM_HERE,
+      base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
           base::Bind(&StateStore::Init, AsWeakPtr()),
           base::TimeDelta::FromSeconds(kInitDelaySeconds));
       break;
diff --git a/chrome/browser/extensions/test_extension_environment.h b/chrome/browser/extensions/test_extension_environment.h
index 825a571..a193345 100644
--- a/chrome/browser/extensions/test_extension_environment.h
+++ b/chrome/browser/extensions/test_extension_environment.h
@@ -57,7 +57,7 @@ class TestExtensionEnvironment {
   scoped_ptr<content::WebContents> MakeTab() const;
 
  private:
-  MessageLoopForUI loop_;
+  base::MessageLoopForUI loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread file_blocking_thread_;
diff --git a/chrome/browser/extensions/updater/extension_updater_unittest.cc b/chrome/browser/extensions/updater/extension_updater_unittest.cc
index 281cfad..edd4281 100644
--- a/chrome/browser/extensions/updater/extension_updater_unittest.cc
+++ b/chrome/browser/extensions/updater/extension_updater_unittest.cc
@@ -1468,7 +1468,7 @@ class ExtensionUpdaterTest : public testing::Test {
   scoped_ptr<TestExtensionPrefs> prefs_;
 
  private:
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/extensions/user_script_listener_unittest.cc b/chrome/browser/extensions/user_script_listener_unittest.cc
index ed379bb..18d899a 100644
--- a/chrome/browser/extensions/user_script_listener_unittest.cc
+++ b/chrome/browser/extensions/user_script_listener_unittest.cc
@@ -143,14 +143,14 @@ class UserScriptListenerTest : public ExtensionServiceTestBase {
 
     InitializeEmptyExtensionService();
     service_->Init();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     listener_ = new UserScriptListener();
   }
 
   virtual void TearDown() OVERRIDE {
     listener_ = NULL;
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ExtensionServiceTestBase::TearDown();
   }
 
@@ -203,7 +203,7 @@ namespace {
 
 TEST_F(UserScriptListenerTest, DelayAndUpdate) {
   LoadTestExtension();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   net::TestDelegate delegate;
   net::TestURLRequestContext context;
@@ -215,13 +215,13 @@ TEST_F(UserScriptListenerTest, DelayAndUpdate) {
       chrome::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(profile_.get()),
       content::NotificationService::NoDetails());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(kTestData, delegate.data_received());
 }
 
 TEST_F(UserScriptListenerTest, DelayAndUnload) {
   LoadTestExtension();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   net::TestDelegate delegate;
   net::TestURLRequestContext context;
@@ -230,7 +230,7 @@ TEST_F(UserScriptListenerTest, DelayAndUnload) {
   ASSERT_FALSE(request->is_pending());
 
   UnloadTestExtension();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // This is still not enough to start delayed requests. We have to notify the
   // listener that the user scripts have been updated.
@@ -240,7 +240,7 @@ TEST_F(UserScriptListenerTest, DelayAndUnload) {
       chrome::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(profile_.get()),
       content::NotificationService::NoDetails());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(kTestData, delegate.data_received());
 }
 
@@ -253,13 +253,13 @@ TEST_F(UserScriptListenerTest, NoDelayNoExtension) {
   // The request should be started immediately.
   ASSERT_TRUE(request->is_pending());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(kTestData, delegate.data_received());
 }
 
 TEST_F(UserScriptListenerTest, NoDelayNotMatching) {
   LoadTestExtension();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   net::TestDelegate delegate;
   net::TestURLRequestContext context;
@@ -270,13 +270,13 @@ TEST_F(UserScriptListenerTest, NoDelayNotMatching) {
   // The request should be started immediately.
   ASSERT_TRUE(request->is_pending());
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(kTestData, delegate.data_received());
 }
 
 TEST_F(UserScriptListenerTest, MultiProfile) {
   LoadTestExtension();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Fire up a second profile and have it load and extension with a content
   // script.
@@ -303,7 +303,7 @@ TEST_F(UserScriptListenerTest, MultiProfile) {
       chrome::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(profile_.get()),
       content::NotificationService::NoDetails());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   ASSERT_FALSE(request->is_pending());
   EXPECT_TRUE(delegate.data_received().empty());
 
@@ -312,7 +312,7 @@ TEST_F(UserScriptListenerTest, MultiProfile) {
       chrome::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(&profile2),
       content::NotificationService::NoDetails());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(kTestData, delegate.data_received());
 }
 
@@ -321,7 +321,7 @@ TEST_F(UserScriptListenerTest, MultiProfile) {
 // throttles.
 TEST_F(UserScriptListenerTest, ResumeBeforeStart) {
   LoadTestExtension();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   net::TestDelegate delegate;
   net::TestURLRequestContext context;
   GURL url(kMatchingUrl);
@@ -339,7 +339,7 @@ TEST_F(UserScriptListenerTest, ResumeBeforeStart) {
       chrome::NOTIFICATION_USER_SCRIPTS_UPDATED,
       content::Source<Profile>(profile_.get()),
       content::NotificationService::NoDetails());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   bool defer = false;
   throttle->WillStartRequest(&defer);
diff --git a/chrome/browser/extensions/user_script_master_unittest.cc b/chrome/browser/extensions/user_script_master_unittest.cc
index d71dd2a..a272ea1 100644
--- a/chrome/browser/extensions/user_script_master_unittest.cc
+++ b/chrome/browser/extensions/user_script_master_unittest.cc
@@ -40,7 +40,7 @@ class UserScriptMasterTest : public testing::Test,
                              public content::NotificationObserver {
  public:
   UserScriptMasterTest()
-      : message_loop_(MessageLoop::TYPE_UI),
+      : message_loop_(base::MessageLoop::TYPE_UI),
         shared_memory_(NULL) {
   }
 
@@ -54,9 +54,9 @@ class UserScriptMasterTest : public testing::Test,
     // UserScriptMaster posts tasks to the file thread so make the current
     // thread look like one.
     file_thread_.reset(new content::TestBrowserThread(
-        BrowserThread::FILE, MessageLoop::current()));
+        BrowserThread::FILE, base::MessageLoop::current()));
     ui_thread_.reset(new content::TestBrowserThread(
-        BrowserThread::UI, MessageLoop::current()));
+        BrowserThread::UI, base::MessageLoop::current()));
   }
 
   virtual void TearDown() {
@@ -70,8 +70,8 @@ class UserScriptMasterTest : public testing::Test,
     DCHECK(type == chrome::NOTIFICATION_USER_SCRIPTS_UPDATED);
 
     shared_memory_ = content::Details<base::SharedMemory>(details).ptr();
-    if (MessageLoop::current() == &message_loop_)
-      MessageLoop::current()->Quit();
+    if (base::MessageLoop::current() == &message_loop_)
+      base::MessageLoop::current()->Quit();
   }
 
   // Directory containing user scripts.
@@ -80,7 +80,7 @@ class UserScriptMasterTest : public testing::Test,
   content::NotificationRegistrar registrar_;
 
   // MessageLoop used in tests.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   scoped_ptr<content::TestBrowserThread> file_thread_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
@@ -94,7 +94,7 @@ TEST_F(UserScriptMasterTest, NoScripts) {
   TestingProfile profile;
   scoped_refptr<UserScriptMaster> master(new UserScriptMaster(&profile));
   master->StartLoad();
-  message_loop_.PostTask(FROM_HERE, MessageLoop::QuitClosure());
+  message_loop_.PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
   message_loop_.Run();
 
   ASSERT_TRUE(shared_memory_ != NULL);
diff --git a/chrome/browser/extensions/webstore_startup_installer_browsertest.cc b/chrome/browser/extensions/webstore_startup_installer_browsertest.cc
index 8a02c4c..d55ac8b 100644
--- a/chrome/browser/extensions/webstore_startup_installer_browsertest.cc
+++ b/chrome/browser/extensions/webstore_startup_installer_browsertest.cc
@@ -357,8 +357,8 @@ IN_PROC_BROWSER_TEST_F(CommandLineWebstoreInstall, LimitedAccept) {
   command_line->AppendSwitchASCII(
       switches::kLimitedInstallFromWebstore, "2");
   helper.LimitedInstallFromWebstore(*command_line, browser()->profile(),
-      MessageLoop::QuitWhenIdleClosure());
-  MessageLoop::current()->Run();
+      base::MessageLoop::QuitWhenIdleClosure());
+  base::MessageLoop::current()->Run();
 
   EXPECT_TRUE(saw_install());
   EXPECT_EQ(0, browser_open_count());
diff --git a/chrome/browser/external_protocol/external_protocol_handler.cc b/chrome/browser/external_protocol/external_protocol_handler.cc
index faaecc3..a1aac4d 100644
--- a/chrome/browser/external_protocol/external_protocol_handler.cc
+++ b/chrome/browser/external_protocol/external_protocol_handler.cc
@@ -96,7 +96,7 @@ class ExternalDefaultProtocolObserver
 
   virtual void SetDefaultWebClientUIState(
       ShellIntegration::DefaultWebClientUIState state) OVERRIDE {
-    DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
+    DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
 
     // If we are still working out if we're the default, or we've found
     // out we definately are the default, we end here.
@@ -247,7 +247,7 @@ void ExternalProtocolHandler::LaunchUrlWithDelegate(const GURL& url,
                                                     int render_process_host_id,
                                                     int tab_contents_id,
                                                     Delegate* delegate) {
-  DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
 
   // Escape the input scheme to be sure that the command does not
   // have parameters unexpected by the external program.
@@ -303,6 +303,6 @@ void ExternalProtocolHandler::RegisterPrefs(PrefRegistrySimple* registry) {
 
 // static
 void ExternalProtocolHandler::PermitLaunchUrl() {
-  DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
   g_accept_requests = true;
 }
diff --git a/chrome/browser/external_protocol/external_protocol_handler_unittest.cc b/chrome/browser/external_protocol/external_protocol_handler_unittest.cc
index faf5704..d8a3679 100644
--- a/chrome/browser/external_protocol/external_protocol_handler_unittest.cc
+++ b/chrome/browser/external_protocol/external_protocol_handler_unittest.cc
@@ -74,7 +74,7 @@ class FakeExternalProtocolHandlerDelegate
   }
 
   virtual void FinishedProcessingCheck() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void set_os_state(ShellIntegration::DefaultWebClientState value) {
@@ -100,7 +100,7 @@ class FakeExternalProtocolHandlerDelegate
 class ExternalProtocolHandlerTest : public testing::Test {
  protected:
   ExternalProtocolHandlerTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
         file_thread_(BrowserThread::FILE) {}
 
   virtual void SetUp() {
@@ -124,14 +124,14 @@ class ExternalProtocolHandlerTest : public testing::Test {
     delegate_.set_os_state(os_state);
     ExternalProtocolHandler::LaunchUrlWithDelegate(url, 0, 0, &delegate_);
     if (block_state != ExternalProtocolHandler::BLOCK)
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
 
     ASSERT_EQ(should_prompt, delegate_.has_prompted());
     ASSERT_EQ(should_launch, delegate_.has_launched());
     ASSERT_EQ(should_block, delegate_.has_blocked());
   }
 
-  MessageLoopForUI ui_message_loop_;
+  base::MessageLoopForUI ui_message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/feedback/feedback_util.cc b/chrome/browser/feedback/feedback_util.cc
index 4a3ee74..456d21f 100644
--- a/chrome/browser/feedback/feedback_util.cc
+++ b/chrome/browser/feedback/feedback_util.cc
@@ -176,7 +176,7 @@ void FeedbackUtil::DispatchFeedback(Profile* profile,
                                     int64 delay) {
   DCHECK(post_body);
 
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&FeedbackUtil::SendFeedback, profile, post_body, delay),
       base::TimeDelta::FromMilliseconds(delay));
diff --git a/chrome/browser/first_run/first_run.cc b/chrome/browser/first_run/first_run.cc
index 9ff9d5b..f5c40b3 100644
--- a/chrome/browser/first_run/first_run.cc
+++ b/chrome/browser/first_run/first_run.cc
@@ -88,7 +88,7 @@ class ImportEndedObserver : public importer::ImporterProgressObserver {
   virtual void ImportEnded() OVERRIDE {
     ended_ = true;
     if (should_quit_message_loop_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   }
 
   void set_should_quit_message_loop() {
@@ -244,7 +244,7 @@ void ImportFromSourceProfile(ImporterHost* importer_host,
   // If the import process has not errored out, block on it.
   if (!observer.ended()) {
     observer.set_should_quit_message_loop();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 }
 
diff --git a/chrome/browser/first_run/try_chrome_dialog_view.cc b/chrome/browser/first_run/try_chrome_dialog_view.cc
index dee183f..3678ed1 100644
--- a/chrome/browser/first_run/try_chrome_dialog_view.cc
+++ b/chrome/browser/first_run/try_chrome_dialog_view.cc
@@ -301,7 +301,7 @@ TryChromeDialogView::Result TryChromeDialogView::ShowModal(
   popup_->Show();
   if (!listener.is_null())
     listener.Run(popup_->GetNativeView());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   if (!listener.is_null())
     listener.Run(NULL);
   return result_;
@@ -374,7 +374,7 @@ void TryChromeDialogView::ButtonPressed(views::Button* sender,
   }
 
   popup_->Close();
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 void TryChromeDialogView::LinkClicked(views::Link* source, int event_flags) {
diff --git a/chrome/browser/geolocation/access_token_store_browsertest.cc b/chrome/browser/geolocation/access_token_store_browsertest.cc
index c964546..58fa159 100644
--- a/chrome/browser/geolocation/access_token_store_browsertest.cc
+++ b/chrome/browser/geolocation/access_token_store_browsertest.cc
@@ -100,7 +100,7 @@ void GeolocationAccessTokenStoreTest::OnAccessTokenStoresLoaded(
     store->SaveAccessToken(ref_url_, *token_to_set_);
   }
   BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE, MessageLoop::QuitClosure());
+      BrowserThread::UI, FROM_HERE, base::MessageLoop::QuitClosure());
 }
 
 IN_PROC_BROWSER_TEST_F(GeolocationAccessTokenStoreTest, SetAcrossInstances) {
diff --git a/chrome/browser/geolocation/chrome_geolocation_permission_context_unittest.cc b/chrome/browser/geolocation/chrome_geolocation_permission_context_unittest.cc
index 2e0de99..88c0f45 100644
--- a/chrome/browser/geolocation/chrome_geolocation_permission_context_unittest.cc
+++ b/chrome/browser/geolocation/chrome_geolocation_permission_context_unittest.cc
@@ -149,7 +149,7 @@ class GeolocationPermissionContextTests
 
 GeolocationPermissionContextTests::GeolocationPermissionContextTests()
     : ChromeRenderViewHostTestHarness(),
-      ui_thread_(content::BrowserThread::UI, MessageLoop::current()),
+      ui_thread_(content::BrowserThread::UI, base::MessageLoop::current()),
       db_thread_(content::BrowserThread::DB) {
 }
 
diff --git a/chrome/browser/geolocation/geolocation_browsertest.cc b/chrome/browser/geolocation/geolocation_browsertest.cc
index 8b715c7..797b401 100644
--- a/chrome/browser/geolocation/geolocation_browsertest.cc
+++ b/chrome/browser/geolocation/geolocation_browsertest.cc
@@ -116,7 +116,7 @@ void IFrameLoader::Observe(int type,
     javascript_completed_ = true;
   }
   if (javascript_completed_ && navigation_completed_)
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
 }
 
 
@@ -194,9 +194,9 @@ void GeolocationNotificationObserver::Observe(
   // We're either waiting for just the inforbar, or for both a javascript
   // prompt and response.
   if (wait_for_infobar_ && infobar_)
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   else if (navigation_completed_ && !javascript_response_.empty())
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
 }
 
 void GeolocationNotificationObserver::AddWatchAndWaitForNotification(
diff --git a/chrome/browser/geolocation/geolocation_infobar_queue_controller_unittest.cc b/chrome/browser/geolocation/geolocation_infobar_queue_controller_unittest.cc
index 1322684..30586cd 100644
--- a/chrome/browser/geolocation/geolocation_infobar_queue_controller_unittest.cc
+++ b/chrome/browser/geolocation/geolocation_infobar_queue_controller_unittest.cc
@@ -31,7 +31,7 @@ class GeolocationInfoBarQueueControllerTests
 };
 
 GeolocationInfoBarQueueControllerTests::GeolocationInfoBarQueueControllerTests()
-    : ui_thread_(content::BrowserThread::UI, MessageLoop::current()) {
+    : ui_thread_(content::BrowserThread::UI, base::MessageLoop::current()) {
 }
 
 GeolocationPermissionRequestID
diff --git a/chrome/browser/geolocation/geolocation_settings_state_unittest.cc b/chrome/browser/geolocation/geolocation_settings_state_unittest.cc
index fadcce6..b6b5f8f 100644
--- a/chrome/browser/geolocation/geolocation_settings_state_unittest.cc
+++ b/chrome/browser/geolocation/geolocation_settings_state_unittest.cc
@@ -25,7 +25,7 @@ class GeolocationSettingsStateTests : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/google/google_update_win.cc b/chrome/browser/google/google_update_win.cc
index cfa08c6..bd73a74 100644
--- a/chrome/browser/google/google_update_win.cc
+++ b/chrome/browser/google/google_update_win.cc
@@ -176,7 +176,7 @@ class GoogleUpdateJobObserver
 
     // No longer need to spin the message loop that started spinning in
     // InitiateGoogleUpdateCheck.
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
     return S_OK;
   }
   STDMETHOD(SetEventSink)(IProgressWndEvents* event_sink) {
@@ -238,7 +238,7 @@ void GoogleUpdate::CheckForUpdate(bool install_if_newer, HWND window) {
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       base::Bind(&GoogleUpdate::InitiateGoogleUpdateCheck, this,
-                 install_if_newer, window, MessageLoop::current()));
+                 install_if_newer, window, base::MessageLoop::current()));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -246,7 +246,7 @@ void GoogleUpdate::CheckForUpdate(bool install_if_newer, HWND window) {
 
 void GoogleUpdate::InitiateGoogleUpdateCheck(bool install_if_newer,
                                              HWND window,
-                                             MessageLoop* main_loop) {
+                                             base::MessageLoop* main_loop) {
   base::FilePath chrome_exe;
   if (!PathService::Get(base::DIR_EXE, &chrome_exe))
     NOTREACHED();
@@ -337,7 +337,7 @@ void GoogleUpdate::InitiateGoogleUpdateCheck(bool install_if_newer,
   // can report back to us through GoogleUpdateJobObserver. This message loop
   // will terminate once Google Update sends us the completion status
   // (success/error). See OnComplete().
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   GoogleUpdateUpgradeResult results;
   hr = job_observer->GetResult(&results);
@@ -395,7 +395,7 @@ void GoogleUpdate::ReportResults(GoogleUpdateUpgradeResult results,
 bool GoogleUpdate::ReportFailure(HRESULT hr,
                                  GoogleUpdateErrorCode error_code,
                                  const string16& error_message,
-                                 MessageLoop* main_loop) {
+                                 base::MessageLoop* main_loop) {
   NOTREACHED() << "Communication with Google Update failed: " << hr
                << " error: " << error_code
                << ", message: " << error_message.c_str();
diff --git a/chrome/browser/google/google_url_tracker.cc b/chrome/browser/google/google_url_tracker.cc
index 67926fa..521d48d 100644
--- a/chrome/browser/google/google_url_tracker.cc
+++ b/chrome/browser/google/google_url_tracker.cc
@@ -61,7 +61,7 @@ GoogleURLTracker::GoogleURLTracker(
   // "wakes up", we do nothing at all.
   if (mode == NORMAL_MODE) {
     static const int kStartFetchDelayMS = 5000;
-    MessageLoop::current()->PostDelayedTask(FROM_HERE,
+    base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
         base::Bind(&GoogleURLTracker::FinishSleep,
                    weak_ptr_factory_.GetWeakPtr()),
         base::TimeDelta::FromMilliseconds(kStartFetchDelayMS));
diff --git a/chrome/browser/google/google_url_tracker_unittest.cc b/chrome/browser/google/google_url_tracker_unittest.cc
index 91bb0a5..8f999a7 100644
--- a/chrome/browser/google/google_url_tracker_unittest.cc
+++ b/chrome/browser/google/google_url_tracker_unittest.cc
@@ -249,7 +249,7 @@ class GoogleURLTrackerTest : public testing::Test {
 
   // These are required by the TestURLFetchers GoogleURLTracker will create (see
   // test_url_fetcher_factory.h).
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread io_thread_;
   // Creating this allows us to call
   // net::NetworkChangeNotifier::NotifyObserversOfIPAddressChangeForTests().
@@ -283,7 +283,7 @@ void GoogleURLTrackerTest::OnInfoBarClosed(InfoBarDelegate* infobar,
 }
 
 GoogleURLTrackerTest::GoogleURLTrackerTest()
-    : message_loop_(MessageLoop::TYPE_IO),
+    : message_loop_(base::MessageLoop::TYPE_IO),
       io_thread_(content::BrowserThread::IO, &message_loop_) {
   GoogleURLTrackerFactory::GetInstance()->RegisterUserPrefsOnBrowserContext(
       &profile_);
@@ -351,7 +351,7 @@ void GoogleURLTrackerTest::NotifyIPAddressChanged() {
   net::NetworkChangeNotifier::NotifyObserversOfIPAddressChangeForTests();
   // For thread safety, the NCN queues tasks to do the actual notifications, so
   // we need to spin the message loop so the tracker will actually be notified.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 void GoogleURLTrackerTest::SetLastPromptedGoogleURL(const GURL& url) {
diff --git a/chrome/browser/google_apis/base_operations_server_unittest.cc b/chrome/browser/google_apis/base_operations_server_unittest.cc
index 2cb2488..29b50bb 100644
--- a/chrome/browser/google_apis/base_operations_server_unittest.cc
+++ b/chrome/browser/google_apis/base_operations_server_unittest.cc
@@ -73,7 +73,7 @@ class BaseOperationsServerTest : public testing::Test {
     return profile_->GetPath().Append(file_name);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
@@ -104,7 +104,7 @@ TEST_F(BaseOperationsServerTest, DownloadFileOperation_ValidFile) {
       GetTestCachedFilePath(
           base::FilePath::FromUTF8Unsafe("cached_testfile.txt")));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   std::string contents;
   file_util::ReadFileToString(temp_file, &contents);
@@ -139,7 +139,7 @@ TEST_F(BaseOperationsServerTest,
       GetTestCachedFilePath(
           base::FilePath::FromUTF8Unsafe("cache_no-such-file.txt")));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   std::string contents;
   file_util::ReadFileToString(temp_file, &contents);
diff --git a/chrome/browser/google_apis/base_operations_unittest.cc b/chrome/browser/google_apis/base_operations_unittest.cc
index 05a721b..81f2803 100644
--- a/chrome/browser/google_apis/base_operations_unittest.cc
+++ b/chrome/browser/google_apis/base_operations_unittest.cc
@@ -73,7 +73,7 @@ class BaseOperationsTest : public testing::Test {
     LOG(ERROR) << "Initialized.";
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<OperationRunner> runner_;
diff --git a/chrome/browser/google_apis/drive_api_operations_unittest.cc b/chrome/browser/google_apis/drive_api_operations_unittest.cc
index f845d2a..4107645 100644
--- a/chrome/browser/google_apis/drive_api_operations_unittest.cc
+++ b/chrome/browser/google_apis/drive_api_operations_unittest.cc
@@ -104,7 +104,7 @@ class DriveApiOperationsTest : public testing::Test {
     ResetExpectedResponse();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
@@ -332,7 +332,7 @@ TEST_F(DriveApiOperationsTest, GetAboutOperation_ValidJson) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&error, &about_resource)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -364,7 +364,7 @@ TEST_F(DriveApiOperationsTest, GetAboutOperation_InvalidJson) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&error, &about_resource)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // "parse error" should be returned, and the about resource should be NULL.
   EXPECT_EQ(GDATA_PARSE_ERROR, error);
@@ -389,7 +389,7 @@ TEST_F(DriveApiOperationsTest, GetApplistOperation) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&error, &result)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -416,7 +416,7 @@ TEST_F(DriveApiOperationsTest, GetChangelistOperation) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&error, &result)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -443,7 +443,7 @@ TEST_F(DriveApiOperationsTest, GetFilelistOperation) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&error, &result)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -469,7 +469,7 @@ TEST_F(DriveApiOperationsTest, ContinueGetFileListOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &result)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -497,7 +497,7 @@ TEST_F(DriveApiOperationsTest, CreateDirectoryOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &file_resource)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -539,7 +539,7 @@ TEST_F(DriveApiOperationsTest, RenameResourceOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_PATCH, http_request_.method);
@@ -574,7 +574,7 @@ TEST_F(DriveApiOperationsTest, TouchResourceOperation) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&error, &file_resource)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_PATCH, http_request_.method);
@@ -611,7 +611,7 @@ TEST_F(DriveApiOperationsTest, CopyResourceOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &file_resource)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -647,7 +647,7 @@ TEST_F(DriveApiOperationsTest, CopyResourceOperation_EmptyParentResourceId) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &file_resource)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -678,7 +678,7 @@ TEST_F(DriveApiOperationsTest, TrashResourceOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -707,7 +707,7 @@ TEST_F(DriveApiOperationsTest, InsertResourceOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -735,7 +735,7 @@ TEST_F(DriveApiOperationsTest, DeleteResourceOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_NO_CONTENT, error);
   EXPECT_EQ(net::test_server::METHOD_DELETE, http_request_.method);
@@ -773,7 +773,7 @@ TEST_F(DriveApiOperationsTest, UploadNewFileOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(kTestUploadNewFilePath, upload_url.path());
@@ -813,7 +813,7 @@ TEST_F(DriveApiOperationsTest, UploadNewFileOperation) {
               test_util::CreateCopyResultCallback(&response, &new_entry)),
           ProgressCallback());
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -863,7 +863,7 @@ TEST_F(DriveApiOperationsTest, UploadNewEmptyFileOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(kTestUploadNewFilePath, upload_url.path());
@@ -902,7 +902,7 @@ TEST_F(DriveApiOperationsTest, UploadNewEmptyFileOperation) {
               test_util::CreateCopyResultCallback(&response, &new_entry)),
           ProgressCallback());
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -953,7 +953,7 @@ TEST_F(DriveApiOperationsTest, UploadNewLargeFileOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(kTestUploadNewFilePath, upload_url.path());
@@ -992,7 +992,7 @@ TEST_F(DriveApiOperationsTest, UploadNewLargeFileOperation) {
                 base::Bind(&test_util::RunAndQuit),
                 test_util::CreateCopyResultCallback(&response, &new_entry)));
     operation_runner_->StartOperationWithRetry(get_upload_status_operation);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // METHOD_PUT should be used to upload data.
     EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1038,7 +1038,7 @@ TEST_F(DriveApiOperationsTest, UploadNewLargeFileOperation) {
                 test_util::CreateCopyResultCallback(&response, &new_entry)),
             ProgressCallback());
     operation_runner_->StartOperationWithRetry(resume_operation);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // METHOD_PUT should be used to upload data.
     EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1082,7 +1082,7 @@ TEST_F(DriveApiOperationsTest, UploadNewLargeFileOperation) {
                 base::Bind(&test_util::RunAndQuit),
                 test_util::CreateCopyResultCallback(&response, &new_entry)));
     operation_runner_->StartOperationWithRetry(get_upload_status_operation);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // METHOD_PUT should be used to upload data.
     EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1131,7 +1131,7 @@ TEST_F(DriveApiOperationsTest, UploadExistingFileOperation) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(kTestUploadExistingFilePath, upload_url.path());
@@ -1166,7 +1166,7 @@ TEST_F(DriveApiOperationsTest, UploadExistingFileOperation) {
               test_util::CreateCopyResultCallback(&response, &new_entry)),
           ProgressCallback());
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1216,7 +1216,7 @@ TEST_F(DriveApiOperationsTest, UploadExistingFileOperationWithETag) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, error);
   EXPECT_EQ(kTestUploadExistingFilePath, upload_url.path());
@@ -1251,7 +1251,7 @@ TEST_F(DriveApiOperationsTest, UploadExistingFileOperationWithETag) {
               test_util::CreateCopyResultCallback(&response, &new_entry)),
           ProgressCallback());
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1298,7 +1298,7 @@ TEST_F(DriveApiOperationsTest, UploadExistingFileOperationWithETagConflicting) {
               base::Bind(&test_util::RunAndQuit),
               test_util::CreateCopyResultCallback(&error, &upload_url)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_PRECONDITION, error);
   EXPECT_EQ(kTestContentType, http_request_.headers["X-Upload-Content-Type"]);
diff --git a/chrome/browser/google_apis/drive_uploader.cc b/chrome/browser/google_apis/drive_uploader.cc
index 5de1d56..012b32a 100644
--- a/chrome/browser/google_apis/drive_uploader.cc
+++ b/chrome/browser/google_apis/drive_uploader.cc
@@ -281,7 +281,7 @@ void DriveUploader::OnUploadLocationReceived(
   // PostTask is necessary because we have to finish
   // InitiateUpload's callback before calling ResumeUpload, due to the
   // implementation of OperationRegistry. (http://crbug.com/134814)
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&DriveUploader::UploadNextChunk,
                  weak_ptr_factory_.GetWeakPtr(),
@@ -386,7 +386,7 @@ void DriveUploader::OnUploadRangeResponseReceived(
   // PostTask is necessary because we have to finish previous ResumeUpload's
   // callback before calling ResumeUpload again, due to the implementation of
   // OperationRegistry. (http://crbug.com/134814)
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&DriveUploader::UploadNextChunk,
                  weak_ptr_factory_.GetWeakPtr(),
diff --git a/chrome/browser/google_apis/drive_uploader_unittest.cc b/chrome/browser/google_apis/drive_uploader_unittest.cc
index 34f96e2..3ed550b 100644
--- a/chrome/browser/google_apis/drive_uploader_unittest.cc
+++ b/chrome/browser/google_apis/drive_uploader_unittest.cc
@@ -74,7 +74,7 @@ class MockDriveServiceWithUploadExpectation : public DummyDriveService {
 
     // Calls back the upload URL for subsequent ResumeUpload operations.
     // InitiateUpload is an asynchronous function, so don't callback directly.
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, HTTP_SUCCESS, GURL(kTestUploadNewFileURL)));
   }
 
@@ -90,14 +90,14 @@ class MockDriveServiceWithUploadExpectation : public DummyDriveService {
     EXPECT_EQ(kTestInitiateUploadResourceId, resource_id);
 
     if (!etag.empty() && etag != kTestETag) {
-      MessageLoop::current()->PostTask(FROM_HERE,
+      base::MessageLoop::current()->PostTask(FROM_HERE,
           base::Bind(callback, HTTP_PRECONDITION, GURL()));
       return;
     }
 
     // Calls back the upload URL for subsequent ResumeUpload operations.
     // InitiateUpload is an asynchronous function, so don't callback directly.
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, HTTP_SUCCESS, GURL(kTestUploadExistingFileURL)));
   }
 
@@ -138,7 +138,7 @@ class MockDriveServiceWithUploadExpectation : public DummyDriveService {
       // For the testing purpose, it always notifies the progress at the end of
       // each chunk uploading.
       int64 chunk_size = end_position - start_position;
-      MessageLoop::current()->PostTask(FROM_HERE,
+      base::MessageLoop::current()->PostTask(FROM_HERE,
           base::Bind(progress_callback, chunk_size, chunk_size));
     }
 
@@ -178,7 +178,7 @@ class MockDriveServiceWithUploadExpectation : public DummyDriveService {
           HTTP_RESUME_INCOMPLETE, 0, received_bytes_);
     }
     // ResumeUpload is an asynchronous function, so don't callback directly.
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, response, base::Passed(&entry)));
   }
 
@@ -198,7 +198,7 @@ class MockDriveServiceNoConnectionAtInitiate : public DummyDriveService {
       const std::string& parent_resource_id,
       const std::string& title,
       const InitiateUploadCallback& callback) OVERRIDE {
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, GDATA_NO_CONNECTION, GURL()));
   }
 
@@ -209,7 +209,7 @@ class MockDriveServiceNoConnectionAtInitiate : public DummyDriveService {
       const std::string& resource_id,
       const std::string& etag,
       const InitiateUploadCallback& callback) OVERRIDE {
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, GDATA_NO_CONNECTION, GURL()));
   }
 
@@ -238,7 +238,7 @@ class MockDriveServiceNoConnectionAtResume : public DummyDriveService {
       const std::string& parent_resource_id,
       const std::string& title,
       const InitiateUploadCallback& callback) OVERRIDE {
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, HTTP_SUCCESS, GURL(kTestUploadNewFileURL)));
   }
 
@@ -249,7 +249,7 @@ class MockDriveServiceNoConnectionAtResume : public DummyDriveService {
       const std::string& resource_id,
       const std::string& etag,
       const InitiateUploadCallback& callback) OVERRIDE {
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback, HTTP_SUCCESS, GURL(kTestUploadExistingFileURL)));
   }
 
@@ -264,7 +264,7 @@ class MockDriveServiceNoConnectionAtResume : public DummyDriveService {
       const base::FilePath& local_file_path,
       const UploadRangeCallback& callback,
       const ProgressCallback& progress_callback) OVERRIDE {
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(callback,
                    UploadRangeResponse(GDATA_NO_CONNECTION, -1, -1),
                    base::Passed(scoped_ptr<ResourceEntry>())));
@@ -286,7 +286,7 @@ class DriveUploaderTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   base::ScopedTempDir temp_dir_;
 };
diff --git a/chrome/browser/google_apis/fake_drive_service.cc b/chrome/browser/google_apis/fake_drive_service.cc
index 3b224f9..20253a6 100644
--- a/chrome/browser/google_apis/fake_drive_service.cc
+++ b/chrome/browser/google_apis/fake_drive_service.cc
@@ -370,7 +370,7 @@ void FakeDriveService::GetResourceEntry(
 
   if (offline_) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -382,14 +382,14 @@ void FakeDriveService::GetResourceEntry(
   if (entry) {
     scoped_ptr<ResourceEntry> resource_entry =
         ResourceEntry::CreateFrom(*entry);
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_SUCCESS, base::Passed(&resource_entry)));
     return;
   }
 
   scoped_ptr<ResourceEntry> null;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_NOT_FOUND, base::Passed(&null)));
 }
@@ -404,7 +404,7 @@ void FakeDriveService::GetAboutResource(
 
   if (offline_) {
     scoped_ptr<AboutResource> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION, base::Passed(&null)));
@@ -418,7 +418,7 @@ void FakeDriveService::GetAboutResource(
           GetRootResourceId()));
   // Overwrite the change id.
   about_resource->set_largest_change_id(largest_changestamp_);
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback,
                  HTTP_SUCCESS, base::Passed(&about_resource)));
@@ -431,7 +431,7 @@ void FakeDriveService::GetAppList(const GetAppListCallback& callback) {
 
   if (offline_) {
     scoped_ptr<AppList> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -440,7 +440,7 @@ void FakeDriveService::GetAppList(const GetAppListCallback& callback) {
   }
 
   scoped_ptr<AppList> app_list(AppList::CreateFrom(*app_info_value_));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_SUCCESS, base::Passed(&app_list)));
 }
@@ -453,7 +453,7 @@ void FakeDriveService::DeleteResource(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, GDATA_NO_CONNECTION));
     return;
   }
@@ -470,7 +470,7 @@ void FakeDriveService::DeleteResource(
           entry->GetString("gd$resourceId.$t", &current_resource_id) &&
           resource_id == current_resource_id) {
         entries->Remove(i, NULL);
-        MessageLoop::current()->PostTask(
+        base::MessageLoop::current()->PostTask(
             FROM_HERE, base::Bind(callback, HTTP_SUCCESS));
         return;
       }
@@ -479,7 +479,7 @@ void FakeDriveService::DeleteResource(
 
   // TODO(satorux): Add support for returning "deleted" entries in
   // changelists from GetResourceList().
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, HTTP_NOT_FOUND));
 }
 
@@ -494,7 +494,7 @@ void FakeDriveService::DownloadFile(
   DCHECK(!download_action_callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(download_action_callback,
                    GDATA_NO_CONNECTION,
@@ -575,7 +575,7 @@ void FakeDriveService::CopyResource(
 
   if (offline_) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -625,7 +625,7 @@ void FakeDriveService::CopyResource(
         // Add it to the resource list.
         entries->Append(copied_entry.release());
 
-        MessageLoop::current()->PostTask(
+        base::MessageLoop::current()->PostTask(
             FROM_HERE,
             base::Bind(callback,
                        HTTP_SUCCESS,
@@ -636,7 +636,7 @@ void FakeDriveService::CopyResource(
   }
 
   scoped_ptr<ResourceEntry> null;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_NOT_FOUND, base::Passed(&null)));
 }
@@ -659,7 +659,7 @@ void FakeDriveService::RenameResource(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, GDATA_NO_CONNECTION));
     return;
   }
@@ -668,12 +668,12 @@ void FakeDriveService::RenameResource(
   if (entry) {
     entry->SetString("title.$t", new_name);
     AddNewChangestamp(entry);
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, HTTP_SUCCESS));
     return;
   }
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, HTTP_NOT_FOUND));
 }
 
@@ -688,7 +688,7 @@ void FakeDriveService::TouchResource(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, GDATA_NO_CONNECTION,
                    base::Passed(scoped_ptr<ResourceEntry>())));
@@ -697,7 +697,7 @@ void FakeDriveService::TouchResource(
 
   base::DictionaryValue* entry = FindEntryByResourceId(resource_id);
   if (!entry) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_NOT_FOUND,
                    base::Passed(scoped_ptr<ResourceEntry>())));
@@ -711,7 +711,7 @@ void FakeDriveService::TouchResource(
   AddNewChangestamp(entry);
 
   scoped_ptr<ResourceEntry> parsed_entry(ResourceEntry::CreateFrom(*entry));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_SUCCESS, base::Passed(&parsed_entry)));
 }
@@ -724,7 +724,7 @@ void FakeDriveService::AddResourceToDirectory(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, GDATA_NO_CONNECTION));
     return;
   }
@@ -748,12 +748,12 @@ void FakeDriveService::AddResourceToDirectory(
     links->Append(link);
 
     AddNewChangestamp(entry);
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, HTTP_SUCCESS));
     return;
   }
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, HTTP_NOT_FOUND));
 }
 
@@ -765,7 +765,7 @@ void FakeDriveService::RemoveResourceFromDirectory(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(callback, GDATA_NO_CONNECTION));
     return;
   }
@@ -786,7 +786,7 @@ void FakeDriveService::RemoveResourceFromDirectory(
             GURL(href) == parent_content_url) {
           links->Remove(i, NULL);
           AddNewChangestamp(entry);
-          MessageLoop::current()->PostTask(
+          base::MessageLoop::current()->PostTask(
               FROM_HERE, base::Bind(callback, HTTP_SUCCESS));
           return;
         }
@@ -794,7 +794,7 @@ void FakeDriveService::RemoveResourceFromDirectory(
     }
   }
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, HTTP_NOT_FOUND));
 }
 
@@ -807,7 +807,7 @@ void FakeDriveService::AddNewDirectory(
 
   if (offline_) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -824,14 +824,14 @@ void FakeDriveService::AddNewDirectory(
                                                        "folder");
   if (!new_entry) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_NOT_FOUND, base::Passed(&null)));
     return;
   }
 
   scoped_ptr<ResourceEntry> parsed_entry(ResourceEntry::CreateFrom(*new_entry));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_CREATED, base::Passed(&parsed_entry)));
 }
@@ -847,7 +847,7 @@ void FakeDriveService::InitiateUploadNewFile(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, GDATA_NO_CONNECTION, GURL()));
     return;
@@ -862,7 +862,7 @@ void FakeDriveService::InitiateUploadNewFile(
                                                        false,  // shared_with_me
                                                        "file");
   if (!new_entry) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_NOT_FOUND, GURL()));
     return;
@@ -870,7 +870,7 @@ void FakeDriveService::InitiateUploadNewFile(
   const GURL upload_url = GetUploadUrl(*new_entry);
   DCHECK(upload_url.is_valid());
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_SUCCESS,
                  net::AppendQueryParameter(upload_url, "mode", "newfile")));
@@ -888,7 +888,7 @@ void FakeDriveService::InitiateUploadExistingFile(
   DCHECK(!callback.is_null());
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, GDATA_NO_CONNECTION, GURL()));
     return;
@@ -896,7 +896,7 @@ void FakeDriveService::InitiateUploadExistingFile(
 
   DictionaryValue* entry = FindEntryByResourceId(resource_id);
   if (!entry) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_NOT_FOUND, GURL()));
     return;
@@ -905,7 +905,7 @@ void FakeDriveService::InitiateUploadExistingFile(
   std::string entry_etag;
   entry->GetString("gd$etag", &entry_etag);
   if (!etag.empty() && etag != entry_etag) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_PRECONDITION, GURL()));
     return;
@@ -915,7 +915,7 @@ void FakeDriveService::InitiateUploadExistingFile(
   const GURL upload_url = GetUploadUrl(*entry);
   DCHECK(upload_url.is_valid());
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_SUCCESS,
                  net::AppendQueryParameter(upload_url, "mode", "existing")));
@@ -946,7 +946,7 @@ void FakeDriveService::ResumeUpload(
   scoped_ptr<ResourceEntry> result_entry;
 
   if (offline_) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    UploadRangeResponse(GDATA_NO_CONNECTION,
@@ -959,7 +959,7 @@ void FakeDriveService::ResumeUpload(
   DictionaryValue* entry = NULL;
   entry = FindEntryByUploadUrl(RemoveQueryParameter(upload_url));
   if (!entry) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    UploadRangeResponse(HTTP_NOT_FOUND,
@@ -976,7 +976,7 @@ void FakeDriveService::ResumeUpload(
   if (!entry->GetString("docs$size.$t", &current_size_string) ||
       !base::StringToInt64(current_size_string, &current_size) ||
       current_size != start_position) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    UploadRangeResponse(HTTP_BAD_REQUEST,
@@ -996,14 +996,14 @@ void FakeDriveService::ResumeUpload(
     // crucial difference of the progress callback from others.
     // Note that progress is notified in the relative offset in each chunk.
     const int64 chunk_size = end_position - start_position;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(progress_callback, chunk_size / 2, chunk_size));
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(progress_callback, chunk_size, chunk_size));
   }
 
   if (content_length != end_position) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    UploadRangeResponse(HTTP_RESUME_INCOMPLETE,
@@ -1025,7 +1025,7 @@ void FakeDriveService::ResumeUpload(
   GDataErrorCode return_code =
       upload_mode == "newfile" ? HTTP_CREATED : HTTP_SUCCESS;
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback,
                  UploadRangeResponse(return_code,
@@ -1052,7 +1052,7 @@ void FakeDriveService::AddNewFile(const std::string& content_type,
 
   if (offline_) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -1075,7 +1075,7 @@ void FakeDriveService::AddNewFile(const std::string& content_type,
                                                        entry_kind);
   if (!new_entry) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_NOT_FOUND, base::Passed(&null)));
     return;
@@ -1083,7 +1083,7 @@ void FakeDriveService::AddNewFile(const std::string& content_type,
 
   scoped_ptr<ResourceEntry> parsed_entry(
       ResourceEntry::CreateFrom(*new_entry));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_CREATED, base::Passed(&parsed_entry)));
 }
@@ -1097,7 +1097,7 @@ void FakeDriveService::SetLastModifiedTime(
 
   if (offline_) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -1108,7 +1108,7 @@ void FakeDriveService::SetLastModifiedTime(
   base::DictionaryValue* entry = FindEntryByResourceId(resource_id);
   if (!entry) {
     scoped_ptr<ResourceEntry> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback, HTTP_NOT_FOUND, base::Passed(&null)));
     return;
@@ -1123,7 +1123,7 @@ void FakeDriveService::SetLastModifiedTime(
 
   scoped_ptr<ResourceEntry> parsed_entry(
       ResourceEntry::CreateFrom(*entry));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback, HTTP_SUCCESS, base::Passed(&parsed_entry)));
 }
@@ -1329,7 +1329,7 @@ void FakeDriveService::GetResourceListInternal(
     const GetResourceListCallback& callback) {
   if (offline_) {
     scoped_ptr<ResourceList> null;
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(callback,
                    GDATA_NO_CONNECTION,
@@ -1429,7 +1429,7 @@ void FakeDriveService::GetResourceListInternal(
 
   if (load_counter)
     *load_counter += 1;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(callback,
                  HTTP_SUCCESS,
diff --git a/chrome/browser/google_apis/fake_drive_service_unittest.cc b/chrome/browser/google_apis/fake_drive_service_unittest.cc
index bdd31c9..28406e8 100644
--- a/chrome/browser/google_apis/fake_drive_service_unittest.cc
+++ b/chrome/browser/google_apis/fake_drive_service_unittest.cc
@@ -86,7 +86,7 @@ class FakeDriveServiceTest : public testing::Test {
     return about_resource->largest_change_id();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   FakeDriveService fake_service_;
 };
diff --git a/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc b/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc
index d3ebf54..39a7a62 100644
--- a/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc
+++ b/chrome/browser/google_apis/gdata_wapi_operations_unittest.cc
@@ -315,7 +315,7 @@ class GDataWapiOperationsTest : public testing::Test {
     return response.PassAs<net::test_server::HttpResponse>();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
@@ -358,7 +358,7 @@ TEST_F(GDataWapiOperationsTest, GetResourceListOperation_DefaultFeed) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -390,7 +390,7 @@ TEST_F(GDataWapiOperationsTest, GetResourceListOperation_ValidFeed) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -423,7 +423,7 @@ TEST_F(GDataWapiOperationsTest, GetResourceListOperation_InvalidFeed) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(GDATA_PARSE_ERROR, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -447,7 +447,7 @@ TEST_F(GDataWapiOperationsTest, SearchByTitleOperation) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -471,7 +471,7 @@ TEST_F(GDataWapiOperationsTest, GetResourceEntryOperation_ValidResourceId) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -496,7 +496,7 @@ TEST_F(GDataWapiOperationsTest, GetResourceEntryOperation_InvalidResourceId) {
           base::Bind(&test_util::RunAndQuit),
           test_util::CreateCopyResultCallback(&result_code, &result_data)));
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_NOT_FOUND, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -519,7 +519,7 @@ TEST_F(GDataWapiOperationsTest, GetAccountMetadataOperation) {
           test_util::CreateCopyResultCallback(&result_code, &result_data)),
       true);  // Include installed apps.
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -558,7 +558,7 @@ TEST_F(GDataWapiOperationsTest,
           test_util::CreateCopyResultCallback(&result_code, &result_data)),
       false);  // Exclude installed apps.
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_GET, http_request_.method);
@@ -594,7 +594,7 @@ TEST_F(GDataWapiOperationsTest, DeleteResourceOperation) {
       std::string());
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_DELETE, http_request_.method);
@@ -619,7 +619,7 @@ TEST_F(GDataWapiOperationsTest, DeleteResourceOperationWithETag) {
       "etag");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_DELETE, http_request_.method);
@@ -646,7 +646,7 @@ TEST_F(GDataWapiOperationsTest, CreateDirectoryOperation) {
       "new directory");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -681,7 +681,7 @@ TEST_F(GDataWapiOperationsTest, CopyHostedDocumentOperation) {
       "New Document");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -713,7 +713,7 @@ TEST_F(GDataWapiOperationsTest, RenameResourceOperation) {
       "New File");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -748,7 +748,7 @@ TEST_F(GDataWapiOperationsTest, AuthorizeAppOperation_ValidFeed) {
       "the_app_id");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(GURL("https://entry1_open_with_link/"), result_data);
@@ -785,7 +785,7 @@ TEST_F(GDataWapiOperationsTest, AuthorizeAppOperation_NotFound) {
       "unauthorized_app_id");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(GDATA_OTHER_ERROR, result_code);
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -820,7 +820,7 @@ TEST_F(GDataWapiOperationsTest, AuthorizeAppOperation_InvalidFeed) {
       "APP_ID");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(GDATA_PARSE_ERROR, result_code);
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -855,7 +855,7 @@ TEST_F(GDataWapiOperationsTest, AddResourceToDirectoryOperation) {
           "file:2_file_resource_id");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(net::test_server::METHOD_POST, http_request_.method);
@@ -890,7 +890,7 @@ TEST_F(GDataWapiOperationsTest, RemoveResourceFromDirectoryOperation) {
           "file:2_file_resource_id");
 
   operation_runner_->StartOperationWithRetry(operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   // DELETE method should be used, without the body content.
@@ -929,7 +929,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewFile) {
           "New file");
 
   operation_runner_->StartOperationWithRetry(initiate_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(test_server_.GetURL("/upload_new_file"), upload_url);
@@ -972,7 +972,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewFile) {
       kTestFilePath);
 
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1031,7 +1031,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewLargeFile) {
           "New file");
 
   operation_runner_->StartOperationWithRetry(initiate_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(test_server_.GetURL("/upload_new_file"), upload_url);
@@ -1074,7 +1074,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewLargeFile) {
             upload_url,
             kUploadContent.size());
     operation_runner_->StartOperationWithRetry(get_upload_status_operation);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // METHOD_PUT should be used to upload data.
     EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1126,7 +1126,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewLargeFile) {
         kTestFilePath);
 
     operation_runner_->StartOperationWithRetry(resume_operation);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // METHOD_PUT should be used to upload data.
     EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1171,7 +1171,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewLargeFile) {
             upload_url,
             kUploadContent.size());
     operation_runner_->StartOperationWithRetry(get_upload_operation);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // METHOD_PUT should be used to upload data.
     EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1224,7 +1224,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewEmptyFile) {
           "New file");
 
   operation_runner_->StartOperationWithRetry(initiate_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(test_server_.GetURL("/upload_new_file"), upload_url);
@@ -1267,7 +1267,7 @@ TEST_F(GDataWapiOperationsTest, UploadNewEmptyFile) {
       kTestFilePath);
 
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1314,7 +1314,7 @@ TEST_F(GDataWapiOperationsTest, UploadExistingFile) {
           std::string() /* etag */);
 
   operation_runner_->StartOperationWithRetry(initiate_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(test_server_.GetURL("/upload_existing_file"), upload_url);
@@ -1356,7 +1356,7 @@ TEST_F(GDataWapiOperationsTest, UploadExistingFile) {
       kTestFilePath);
 
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1405,7 +1405,7 @@ TEST_F(GDataWapiOperationsTest, UploadExistingFileWithETag) {
           kTestETag);
 
   operation_runner_->StartOperationWithRetry(initiate_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_SUCCESS, result_code);
   EXPECT_EQ(test_server_.GetURL("/upload_existing_file"), upload_url);
@@ -1447,7 +1447,7 @@ TEST_F(GDataWapiOperationsTest, UploadExistingFileWithETag) {
       kTestFilePath);
 
   operation_runner_->StartOperationWithRetry(resume_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // METHOD_PUT should be used to upload data.
   EXPECT_EQ(net::test_server::METHOD_PUT, http_request_.method);
@@ -1492,7 +1492,7 @@ TEST_F(GDataWapiOperationsTest, UploadExistingFileWithETagConflict) {
           kWrongETag);
 
   operation_runner_->StartOperationWithRetry(initiate_operation);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(HTTP_PRECONDITION, result_code);
   // For updating an existing file, METHOD_PUT should be used.
diff --git a/chrome/browser/google_apis/operation_registry_unittest.cc b/chrome/browser/google_apis/operation_registry_unittest.cc
index 183d7ac..f2b3bfb 100644
--- a/chrome/browser/google_apis/operation_registry_unittest.cc
+++ b/chrome/browser/google_apis/operation_registry_unittest.cc
@@ -41,7 +41,7 @@ class OperationRegistryTest : public testing::Test {
   OperationRegistryTest()
       : ui_thread_(content::BrowserThread::UI, &message_loop_) {
   }
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/google_apis/test_util.cc b/chrome/browser/google_apis/test_util.cc
index ef91aec..42a8f86 100644
--- a/chrome/browser/google_apis/test_util.cc
+++ b/chrome/browser/google_apis/test_util.cc
@@ -28,7 +28,7 @@ namespace google_apis {
 namespace test_util {
 
 // This class is used to monitor if any task is posted to a message loop.
-class TaskObserver : public MessageLoop::TaskObserver {
+class TaskObserver : public base::MessageLoop::TaskObserver {
  public:
   TaskObserver() : posted_(false) {}
   virtual ~TaskObserver() {}
@@ -78,9 +78,9 @@ void RunBlockingPoolTask() {
     content::BrowserThread::GetBlockingPool()->FlushForTesting();
 
     TaskObserver task_observer;
-    MessageLoop::current()->AddTaskObserver(&task_observer);
-    MessageLoop::current()->RunUntilIdle();
-    MessageLoop::current()->RemoveTaskObserver(&task_observer);
+    base::MessageLoop::current()->AddTaskObserver(&task_observer);
+    base::MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RemoveTaskObserver(&task_observer);
     if (!task_observer.posted())
       break;
   }
@@ -88,7 +88,7 @@ void RunBlockingPoolTask() {
 
 void RunAndQuit(const base::Closure& closure) {
   closure.Run();
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 bool WriteStringToFile(const base::FilePath& file_path,
diff --git a/chrome/browser/history/android/android_history_provider_service_unittest.cc b/chrome/browser/history/android/android_history_provider_service_unittest.cc
index caa0ff8..faf1f4f 100644
--- a/chrome/browser/history/android/android_history_provider_service_unittest.cc
+++ b/chrome/browser/history/android/android_history_provider_service_unittest.cc
@@ -65,7 +65,7 @@ class AndroidHistoryProviderServiceTest : public testing::Test {
 
  protected:
   TestingProfileManager profile_manager_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_ptr<AndroidHistoryProviderService> service_;
@@ -105,7 +105,7 @@ class CallbackHelper : public base::RefCountedThreadSafe<CallbackHelper> {
                   bool success,
                   int64 id) {
     success_ = success;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnQueryResult(AndroidHistoryProviderService::Handle handle,
@@ -113,7 +113,7 @@ class CallbackHelper : public base::RefCountedThreadSafe<CallbackHelper> {
                      AndroidStatement* statement) {
     success_ = success;
     statement_ = statement;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnUpdated(AndroidHistoryProviderService::Handle handle,
@@ -121,7 +121,7 @@ class CallbackHelper : public base::RefCountedThreadSafe<CallbackHelper> {
                  int count) {
     success_ = success;
     count_ = count;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnDeleted(AndroidHistoryProviderService::Handle handle,
@@ -129,13 +129,13 @@ class CallbackHelper : public base::RefCountedThreadSafe<CallbackHelper> {
                  int count) {
     success_ = success;
     count_ = count;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnStatementMoved(AndroidHistoryProviderService::Handle handle,
                         int cursor_position) {
     cursor_position_ = cursor_position;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
@@ -162,7 +162,7 @@ TEST_F(AndroidHistoryProviderServiceTest, TestHistoryAndBookmark) {
   service_->InsertHistoryAndBookmark(row, &cancelable_consumer_,
       Bind(&CallbackHelper::OnInserted, callback.get()));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
 
   std::vector<HistoryAndBookmarkRow::ColumnID> projections;
@@ -172,7 +172,7 @@ TEST_F(AndroidHistoryProviderServiceTest, TestHistoryAndBookmark) {
   service_->QueryHistoryAndBookmarks(projections, std::string(),
       std::vector<string16>(), std::string(), &cancelable_consumer_,
       Bind(&CallbackHelper::OnQueryResult, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   ASSERT_TRUE(callback->success());
 
   // Move the cursor to the begining and verify whether we could get
@@ -180,7 +180,7 @@ TEST_F(AndroidHistoryProviderServiceTest, TestHistoryAndBookmark) {
   AndroidStatement* statement = callback->statement();
   service_->MoveStatement(statement, 0, -1, &cancelable_consumer_,
       Bind(&CallbackHelper::OnStatementMoved, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_EQ(-1, callback->cursor_position());
   EXPECT_TRUE(callback->statement()->statement()->Step());
   EXPECT_FALSE(callback->statement()->statement()->Step());
@@ -192,14 +192,14 @@ TEST_F(AndroidHistoryProviderServiceTest, TestHistoryAndBookmark) {
   service_->UpdateHistoryAndBookmarks(update_row, std::string(),
       std::vector<string16>(), &cancelable_consumer_,
       Bind(&CallbackHelper::OnUpdated, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
   EXPECT_EQ(1, callback->count());
 
   // Delete the row.
   service_->DeleteHistoryAndBookmarks(std::string(), std::vector<string16>(),
       &cancelable_consumer_, Bind(&CallbackHelper::OnDeleted, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
   EXPECT_EQ(1, callback->count());
 }
@@ -217,7 +217,7 @@ TEST_F(AndroidHistoryProviderServiceTest, TestSearchTerm) {
   service_->InsertSearchTerm(search_row, &cancelable_consumer_,
       Bind(&CallbackHelper::OnInserted, callback.get()));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
 
   std::vector<SearchRow::ColumnID> projections;
@@ -227,7 +227,7 @@ TEST_F(AndroidHistoryProviderServiceTest, TestSearchTerm) {
   service_->QuerySearchTerms(projections, std::string(),
       std::vector<string16>(), std::string(), &cancelable_consumer_,
       Bind(&CallbackHelper::OnQueryResult, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   ASSERT_TRUE(callback->success());
 
   // Move the cursor to the begining and verify whether we could get
@@ -235,7 +235,7 @@ TEST_F(AndroidHistoryProviderServiceTest, TestSearchTerm) {
   AndroidStatement* statement = callback->statement();
   service_->MoveStatement(statement, 0, -1, &cancelable_consumer_,
       Bind(&CallbackHelper::OnStatementMoved, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_EQ(-1, callback->cursor_position());
   EXPECT_TRUE(callback->statement()->statement()->Step());
   EXPECT_FALSE(callback->statement()->statement()->Step());
@@ -247,14 +247,14 @@ TEST_F(AndroidHistoryProviderServiceTest, TestSearchTerm) {
   service_->UpdateSearchTerms(update_row, std::string(),
       std::vector<string16>(), &cancelable_consumer_,
       Bind(&CallbackHelper::OnUpdated, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
   EXPECT_EQ(1, callback->count());
 
   // Delete the row.
   service_->DeleteSearchTerms(std::string(), std::vector<string16>(),
       &cancelable_consumer_, Bind(&CallbackHelper::OnDeleted, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
   EXPECT_EQ(1, callback->count());
 }
diff --git a/chrome/browser/history/android/android_provider_backend_unittest.cc b/chrome/browser/history/android/android_provider_backend_unittest.cc
index 04b50d0..5c8f8c7 100644
--- a/chrome/browser/history/android/android_provider_backend_unittest.cc
+++ b/chrome/browser/history/android/android_provider_backend_unittest.cc
@@ -196,7 +196,7 @@ class AndroidProviderBackendTest : public testing::Test {
 
   TestingProfileManager profile_manager_;
   BookmarkModel* bookmark_model_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/history/android/bookmark_model_sql_handler_unittest.cc b/chrome/browser/history/android/bookmark_model_sql_handler_unittest.cc
index 9f83555..1fd0737 100644
--- a/chrome/browser/history/android/bookmark_model_sql_handler_unittest.cc
+++ b/chrome/browser/history/android/bookmark_model_sql_handler_unittest.cc
@@ -68,7 +68,7 @@ class BookmarkModelSQLHandlerTest : public testing::Test {
 
   TestingProfileManager profile_manager_;
   BookmarkModel* bookmark_model_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   base::ScopedTempDir temp_dir_;
diff --git a/chrome/browser/history/android/sqlite_cursor_unittest.cc b/chrome/browser/history/android/sqlite_cursor_unittest.cc
index 421db9f..47cade3 100644
--- a/chrome/browser/history/android/sqlite_cursor_unittest.cc
+++ b/chrome/browser/history/android/sqlite_cursor_unittest.cc
@@ -77,24 +77,24 @@ class SQLiteCursorTest : public testing::Test,
 
   // Override SQLiteCursor::TestObserver.
   virtual void OnPostMoveToTask() OVERRIDE {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   virtual void OnGetMoveToResult() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   virtual void OnPostGetFaviconTask() OVERRIDE {
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   virtual void OnGetFaviconResult() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  protected:
   TestingProfileManager profile_manager_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_ptr<AndroidHistoryProviderService> service_;
@@ -126,7 +126,7 @@ class CallbackHelper : public base::RefCountedThreadSafe<CallbackHelper> {
                   bool success,
                   int64 id) {
     success_ = success;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnQueryResult(AndroidHistoryProviderService::Handle handle,
@@ -134,7 +134,7 @@ class CallbackHelper : public base::RefCountedThreadSafe<CallbackHelper> {
                      AndroidStatement* statement) {
     success_ = success;
     statement_ = statement;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
@@ -168,7 +168,7 @@ TEST_F(SQLiteCursorTest, Run) {
   service_->InsertHistoryAndBookmark(row, &cancelable_consumer_,
       Bind(&CallbackHelper::OnInserted, callback.get()));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(callback->success());
 
   std::vector<HistoryAndBookmarkRow::ColumnID> projections;
@@ -181,7 +181,7 @@ TEST_F(SQLiteCursorTest, Run) {
   service_->QueryHistoryAndBookmarks(projections, std::string(),
       std::vector<string16>(), std::string(), &cancelable_consumer_,
       Bind(&CallbackHelper::OnQueryResult, callback.get()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   ASSERT_TRUE(callback->success());
 
   AndroidStatement* statement = callback->statement();
diff --git a/chrome/browser/history/expire_history_backend.cc b/chrome/browser/history/expire_history_backend.cc
index c5798a9..797cb93 100644
--- a/chrome/browser/history/expire_history_backend.cc
+++ b/chrome/browser/history/expire_history_backend.cc
@@ -635,7 +635,7 @@ void ExpireHistoryBackend::ScheduleArchive() {
     delay = TimeDelta::FromSeconds(kExpirationDelaySec);
   }
 
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ExpireHistoryBackend::DoArchiveIteration,
                  weak_factory_.GetWeakPtr()),
@@ -731,7 +731,7 @@ void ExpireHistoryBackend::ScheduleExpireHistoryIndexFiles() {
   }
 
   TimeDelta delay = TimeDelta::FromMinutes(kIndexExpirationDelayMin);
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ExpireHistoryBackend::DoExpireHistoryIndexFiles,
                  weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/history/expire_history_backend_unittest.cc b/chrome/browser/history/expire_history_backend_unittest.cc
index 98cf02c..5ee0640 100644
--- a/chrome/browser/history/expire_history_backend_unittest.cc
+++ b/chrome/browser/history/expire_history_backend_unittest.cc
@@ -105,7 +105,7 @@ class ExpireHistoryTest : public testing::Test,
 
   BookmarkModel bookmark_model_;
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
 
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index ef46ea9..cad3877a 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -231,7 +231,7 @@ class KillHistoryDatabaseErrorDelegate : public sql::ErrorDelegate {
 
       // Don't just do the close/delete here, as we are being called by |db| and
       // that seems dangerous.
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&HistoryBackend::KillHistoryDatabase, backend_));
     }
@@ -302,7 +302,7 @@ void HistoryBackend::Init(const std::string& languages, bool force_fail) {
   typed_url_syncable_service_.reset(new TypedUrlSyncableService(this));
 }
 
-void HistoryBackend::SetOnBackendDestroyTask(MessageLoop* message_loop,
+void HistoryBackend::SetOnBackendDestroyTask(base::MessageLoop* message_loop,
                                              const base::Closure& task) {
   if (!backend_destroy_task_.is_null())
     DLOG(WARNING) << "Setting more than one destroy task, overriding";
@@ -1218,7 +1218,7 @@ void HistoryBackend::QuerySegmentUsage(
     // entries.
     if (!segment_queried_) {
       segment_queried_ = true;
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&HistoryBackend::DeleteOldSegmentData, this));
     }
@@ -2651,7 +2651,7 @@ void HistoryBackend::ScheduleCommit() {
   if (scheduled_commit_)
     return;
   scheduled_commit_ = new CommitLaterTask(this);
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&CommitLaterTask::RunCommit, scheduled_commit_.get()),
       base::TimeDelta::FromSeconds(kCommitIntervalSeconds));
@@ -2691,7 +2691,7 @@ void HistoryBackend::ProcessDBTaskImpl() {
     // Tasks wants to run some more. Schedule it at the end of current tasks.
     db_task_requests_.push_back(request);
     // And process it after an invoke later.
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(&HistoryBackend::ProcessDBTaskImpl, this));
   }
 }
diff --git a/chrome/browser/history/history_backend.h b/chrome/browser/history/history_backend.h
index ff75904..2aff659 100644
--- a/chrome/browser/history/history_backend.h
+++ b/chrome/browser/history/history_backend.h
@@ -479,7 +479,7 @@ class HistoryBackend : public base::RefCountedThreadSafe<HistoryBackend>,
   // Sets the task to run and the message loop to run it on when this object
   // is destroyed. See HistoryService::SetOnBackendDestroyTask for a more
   // complete description.
-  void SetOnBackendDestroyTask(MessageLoop* message_loop,
+  void SetOnBackendDestroyTask(base::MessageLoop* message_loop,
                                const base::Closure& task);
 
   // Adds the given rows to the database if it doesn't exist. A visit will be
@@ -876,7 +876,7 @@ class HistoryBackend : public base::RefCountedThreadSafe<HistoryBackend>,
   base::Time first_recorded_time_;
 
   // When set, this is the task that should be invoked on destruction.
-  MessageLoop* backend_destroy_message_loop_;
+  base::MessageLoop* backend_destroy_message_loop_;
   base::Closure backend_destroy_task_;
 
   // Tracks page transition types.
diff --git a/chrome/browser/history/history_backend_unittest.cc b/chrome/browser/history/history_backend_unittest.cc
index 6cf44ef..a27edb4 100644
--- a/chrome/browser/history/history_backend_unittest.cc
+++ b/chrome/browser/history/history_backend_unittest.cc
@@ -413,7 +413,7 @@ class HistoryBackendTest : public testing::Test {
   // The number of notifications which were broadcasted.
   int num_broadcasted_notifications_;
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   base::FilePath test_dir_;
   history::MostVisitedURLList most_visited_list_;
   history::FilteredURLList filtered_list_;
diff --git a/chrome/browser/history/history_browsertest.cc b/chrome/browser/history/history_browsertest.cc
index 4a40313..d84de7f 100644
--- a/chrome/browser/history/history_browsertest.cc
+++ b/chrome/browser/history/history_browsertest.cc
@@ -49,7 +49,7 @@ class WaitForHistoryTask : public history::HistoryDBTask {
   }
 
   virtual void DoneRunOnMainThread() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
diff --git a/chrome/browser/history/history_querying_unittest.cc b/chrome/browser/history/history_querying_unittest.cc
index 6e1d12b0..0b6781a 100644
--- a/chrome/browser/history/history_querying_unittest.cc
+++ b/chrome/browser/history/history_querying_unittest.cc
@@ -85,7 +85,8 @@ class HistoryQueryTest : public testing::Test {
         UTF8ToUTF16(text_query), options, &consumer_,
         base::Bind(&HistoryQueryTest::QueryHistoryComplete,
                    base::Unretained(this)));
-    MessageLoop::current()->Run();  // Will go until ...Complete calls Quit.
+    // Will go until ...Complete calls Quit.
+    base::MessageLoop::current()->Run();
     results->Swap(&last_query_results_);
   }
 
@@ -182,21 +183,21 @@ class HistoryQueryTest : public testing::Test {
 
   virtual void TearDown() {
     if (history_) {
-      history_->SetOnBackendDestroyTask(MessageLoop::QuitClosure());
+      history_->SetOnBackendDestroyTask(base::MessageLoop::QuitClosure());
       history_->Cleanup();
       history_.reset();
-      MessageLoop::current()->Run();  // Wait for the other thread.
+      base::MessageLoop::current()->Run();  // Wait for the other thread.
     }
   }
 
   void QueryHistoryComplete(HistoryService::Handle, QueryResults* results) {
     results->Swap(&last_query_results_);
-    MessageLoop::current()->Quit();  // Will return out to QueryHistory.
+    base::MessageLoop::current()->Quit();  // Will return out to QueryHistory.
   }
 
   base::ScopedTempDir temp_dir_;
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   base::FilePath history_dir_;
 
diff --git a/chrome/browser/history/history_service.cc b/chrome/browser/history/history_service.cc
index ccb0b99..61b7858 100644
--- a/chrome/browser/history/history_service.cc
+++ b/chrome/browser/history/history_service.cc
@@ -464,7 +464,7 @@ HistoryService::Handle HistoryService::QuerySegmentDurationSince(
 void HistoryService::SetOnBackendDestroyTask(const base::Closure& task) {
   DCHECK(thread_checker_.CalledOnValidThread());
   ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::SetOnBackendDestroyTask,
-                    MessageLoop::current(), task);
+                    base::MessageLoop::current(), task);
 }
 
 void HistoryService::AddPage(const GURL& url,
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index 083905a..423b38f 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -156,8 +156,9 @@ class HistoryBackendDBTest : public HistoryUnitTestBase {
 
     // Make sure we don't have any event pending that could disrupt the next
     // test.
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
   int64 AddDownload(DownloadItem::DownloadState state, const Time& time) {
@@ -182,7 +183,7 @@ class HistoryBackendDBTest : public HistoryUnitTestBase {
 
   base::ScopedTempDir temp_dir_;
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
 
   // names of the database files
   base::FilePath history_dir_;
@@ -551,7 +552,7 @@ TEST_F(HistoryBackendDBTest, ConfirmDownloadInProgressCleanup) {
 
   // Allow the update to propagate, shut down the DB, and confirm that
   // the query updated the on disk database as well.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   DeleteBackend();
   {
     sql::Connection db;
@@ -683,17 +684,17 @@ class HistoryTest : public testing::Test {
   void OnSegmentUsageAvailable(CancelableRequestProvider::Handle handle,
                                std::vector<PageUsageData*>* data) {
     page_usage_data_.swap(*data);
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnDeleteURLsDone(CancelableRequestProvider::Handle handle) {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnMostVisitedURLsAvailable(CancelableRequestProvider::Handle handle,
                                   MostVisitedURLList url_list) {
     most_visited_urls_.swap(url_list);
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  protected:
@@ -717,15 +718,16 @@ class HistoryTest : public testing::Test {
 
     // Make sure we don't have any event pending that could disrupt the next
     // test.
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
   void CleanupHistoryService() {
     DCHECK(history_service_);
 
     history_service_->NotifyRenderProcessHostDestruction(0);
-    history_service_->SetOnBackendDestroyTask(MessageLoop::QuitClosure());
+    history_service_->SetOnBackendDestroyTask(base::MessageLoop::QuitClosure());
     history_service_->Cleanup();
     history_service_.reset();
 
@@ -733,7 +735,7 @@ class HistoryTest : public testing::Test {
     // moving to the next test. Note: if this never terminates, somebody is
     // probably leaking a reference to the history backend, so it never calls
     // our destroy task.
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   // Fills the query_url_row_ and query_url_visits_ structures with the
@@ -743,7 +745,7 @@ class HistoryTest : public testing::Test {
     history_service_->QueryURL(url, true, &consumer_,
                                base::Bind(&HistoryTest::SaveURLAndQuit,
                                           base::Unretained(this)));
-    MessageLoop::current()->Run();  // Will be exited in SaveURLAndQuit.
+    base::MessageLoop::current()->Run();  // Will be exited in SaveURLAndQuit.
     return query_url_success_;
   }
 
@@ -760,7 +762,7 @@ class HistoryTest : public testing::Test {
       query_url_row_ = URLRow();
       query_url_visits_.clear();
     }
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Fills in saved_redirects_ with the redirect information for the given URL,
@@ -770,7 +772,7 @@ class HistoryTest : public testing::Test {
         url, &consumer_,
         base::Bind(&HistoryTest::OnRedirectQueryComplete,
                    base::Unretained(this)));
-    MessageLoop::current()->Run();  // Will be exited in *QueryComplete.
+    base::MessageLoop::current()->Run();  // Will be exited in *QueryComplete.
     return redirect_query_success_;
   }
 
@@ -784,12 +786,12 @@ class HistoryTest : public testing::Test {
       saved_redirects_.swap(*redirects);
     else
       saved_redirects_.clear();
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   base::ScopedTempDir temp_dir_;
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
 
   // PageUsageData vector to test segments.
   ScopedVector<PageUsageData> page_usage_data_;
@@ -1104,7 +1106,7 @@ TEST_F(HistoryTest, DISABLED_Segments) {
                  base::Unretained(this)));
 
   // Wait for processing.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   ASSERT_EQ(1U, page_usage_data_.size());
   EXPECT_TRUE(page_usage_data_[0]->GetURL() == existing_url);
@@ -1124,7 +1126,7 @@ TEST_F(HistoryTest, DISABLED_Segments) {
                  base::Unretained(this)));
 
   // Wait for processing.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // Make sure we still have one segment.
   ASSERT_EQ(1U, page_usage_data_.size());
@@ -1144,7 +1146,7 @@ TEST_F(HistoryTest, DISABLED_Segments) {
                  base::Unretained(this)));
 
   // Wait for processing.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // Make sure we still have one segment.
   ASSERT_EQ(1U, page_usage_data_.size());
@@ -1179,7 +1181,7 @@ TEST_F(HistoryTest, MostVisitedURLs) {
       base::Bind(
           &HistoryTest::OnMostVisitedURLsAvailable,
           base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(2U, most_visited_urls_.size());
   EXPECT_EQ(url0, most_visited_urls_[0].url);
@@ -1195,7 +1197,7 @@ TEST_F(HistoryTest, MostVisitedURLs) {
       base::Bind(
           &HistoryTest::OnMostVisitedURLsAvailable,
           base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(3U, most_visited_urls_.size());
   EXPECT_EQ(url0, most_visited_urls_[0].url);
@@ -1212,7 +1214,7 @@ TEST_F(HistoryTest, MostVisitedURLs) {
       base::Bind(
           &HistoryTest::OnMostVisitedURLsAvailable,
           base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(3U, most_visited_urls_.size());
   EXPECT_EQ(url2, most_visited_urls_[0].url);
@@ -1229,7 +1231,7 @@ TEST_F(HistoryTest, MostVisitedURLs) {
       base::Bind(
           &HistoryTest::OnMostVisitedURLsAvailable,
           base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(3U, most_visited_urls_.size());
   EXPECT_EQ(url1, most_visited_urls_[0].url);
@@ -1251,7 +1253,7 @@ TEST_F(HistoryTest, MostVisitedURLs) {
       base::Bind(
           &HistoryTest::OnMostVisitedURLsAvailable,
           base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_EQ(4U, most_visited_urls_.size());
   EXPECT_EQ(url1, most_visited_urls_[0].url);
@@ -1281,7 +1283,7 @@ class HistoryDBTaskImpl : public HistoryDBTask {
 
   virtual void DoneRunOnMainThread() OVERRIDE {
     done_invoked = true;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   int invoke_count;
@@ -1306,7 +1308,7 @@ TEST_F(HistoryTest, HistoryDBTask) {
   // Run the message loop. When HistoryDBTaskImpl::DoneRunOnMainThread runs,
   // it will stop the message loop. If the test hangs here, it means
   // DoneRunOnMainThread isn't being invoked correctly.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   CleanupHistoryService();
   // WARNING: history has now been deleted.
   history_service_.reset();
@@ -1438,7 +1440,7 @@ void CheckDirectiveProcessingResult(
   }
 
   base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&CheckDirectiveProcessingResult, timeout,
                  change_processor, num_changes));
@@ -1497,12 +1499,12 @@ TEST_F(HistoryTest, ProcessGlobalIdDeleteDirective) {
 
   // Inject a task to check status and keep message loop filled before directive
   // processing finishes.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&CheckDirectiveProcessingResult,
                  base::Time::Now() + base::TimeDelta::FromSeconds(10),
                  &change_processor, 2));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(QueryURL(history_service_.get(), test_url));
   ASSERT_EQ(5, query_url_row_.visit_count());
   EXPECT_EQ(base::Time::UnixEpoch() + base::TimeDelta::FromMicroseconds(1),
@@ -1569,12 +1571,12 @@ TEST_F(HistoryTest, ProcessTimeRangeDeleteDirective) {
 
   // Inject a task to check status and keep message loop filled before
   // directive processing finishes.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&CheckDirectiveProcessingResult,
                  base::Time::Now() + base::TimeDelta::FromSeconds(10),
                  &change_processor, 2));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(QueryURL(history_service_.get(), test_url));
   ASSERT_EQ(3, query_url_row_.visit_count());
   EXPECT_EQ(base::Time::UnixEpoch() + base::TimeDelta::FromMicroseconds(1),
diff --git a/chrome/browser/history/in_memory_url_index_unittest.cc b/chrome/browser/history/in_memory_url_index_unittest.cc
index 7de8e8c..2e0b258 100644
--- a/chrome/browser/history/in_memory_url_index_unittest.cc
+++ b/chrome/browser/history/in_memory_url_index_unittest.cc
@@ -54,15 +54,15 @@ namespace history {
 // Observer class so the unit tests can wait while the cache is being saved.
 class CacheFileSaverObserver : public InMemoryURLIndex::SaveCacheObserver {
  public:
-  explicit CacheFileSaverObserver(MessageLoop* loop);
+  explicit CacheFileSaverObserver(base::MessageLoop* loop);
   virtual void OnCacheSaveFinished(bool succeeded) OVERRIDE;
 
-  MessageLoop* loop_;
+  base::MessageLoop* loop_;
   bool succeeded_;
   DISALLOW_COPY_AND_ASSIGN(CacheFileSaverObserver);
 };
 
-CacheFileSaverObserver::CacheFileSaverObserver(MessageLoop* loop)
+CacheFileSaverObserver::CacheFileSaverObserver(base::MessageLoop* loop)
     : loop_(loop),
       succeeded_(false) {
   DCHECK(loop);
@@ -118,7 +118,7 @@ class InMemoryURLIndexTest : public testing::Test {
   void ExpectPrivateDataEqual(const URLIndexPrivateData& expected,
                               const URLIndexPrivateData& actual);
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   TestingProfile profile_;
@@ -1038,7 +1038,7 @@ TEST_F(InMemoryURLIndexTest, CacheSaveRestore) {
   EXPECT_TRUE(private_data.word_starts_map_.empty());
 
   HistoryIndexRestoreObserver restore_observer(
-      base::Bind(&MessageLoop::Quit, base::Unretained(&message_loop_)));
+      base::Bind(&base::MessageLoop::Quit, base::Unretained(&message_loop_)));
   url_index_->set_restore_cache_observer(&restore_observer);
   PostRestoreFromCacheFileTask();
   message_loop_.Run();
diff --git a/chrome/browser/history/redirect_browsertest.cc b/chrome/browser/history/redirect_browsertest.cc
index 000444f..0948696 100644
--- a/chrome/browser/history/redirect_browsertest.cc
+++ b/chrome/browser/history/redirect_browsertest.cc
@@ -62,7 +62,8 @@ class RedirectTest : public InProcessBrowserTest {
       history::RedirectList* redirects) {
     for (size_t i = 0; i < redirects->size(); ++i)
       rv->push_back(redirects->at(i));
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
   }
 
   // Consumer for asynchronous history queries.
diff --git a/chrome/browser/history/shortcuts_backend_unittest.cc b/chrome/browser/history/shortcuts_backend_unittest.cc
index 2324385..0a7ffda 100644
--- a/chrome/browser/history/shortcuts_backend_unittest.cc
+++ b/chrome/browser/history/shortcuts_backend_unittest.cc
@@ -42,7 +42,7 @@ class ShortcutsBackendTest : public testing::Test,
 
   TestingProfile profile_;
   scoped_refptr<ShortcutsBackend> backend_;
-  MessageLoopForUI ui_message_loop_;
+  base::MessageLoopForUI ui_message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
 
@@ -66,7 +66,7 @@ void ShortcutsBackendTest::TearDown() {
 
 void ShortcutsBackendTest::OnShortcutsLoaded() {
   load_notified_ = true;
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 void ShortcutsBackendTest::OnShortcutsChanged() {
@@ -78,7 +78,7 @@ void ShortcutsBackendTest::InitBackend() {
   ASSERT_TRUE(backend);
   ASSERT_FALSE(load_notified_);
   ASSERT_FALSE(backend_->initialized());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(load_notified_);
   EXPECT_TRUE(backend_->initialized());
 }
diff --git a/chrome/browser/history/text_database_manager.cc b/chrome/browser/history/text_database_manager.cc
index 97f6555..f6ca82e 100644
--- a/chrome/browser/history/text_database_manager.cc
+++ b/chrome/browser/history/text_database_manager.cc
@@ -559,7 +559,7 @@ TextDatabase* TextDatabaseManager::GetDBForTime(Time time,
 
 void TextDatabaseManager::ScheduleFlushOldChanges() {
   weak_factory_.InvalidateWeakPtrs();
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&TextDatabaseManager::FlushOldChanges,
                  weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/history/text_database_manager_unittest.cc b/chrome/browser/history/text_database_manager_unittest.cc
index 8185773..0ec6753 100644
--- a/chrome/browser/history/text_database_manager_unittest.cc
+++ b/chrome/browser/history/text_database_manager_unittest.cc
@@ -164,7 +164,7 @@ class TextDatabaseManagerTest : public testing::Test {
     file_util::Delete(dir_, true);
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   // Directory containing the databases.
   base::FilePath dir_;
diff --git a/chrome/browser/history/top_sites_impl_unittest.cc b/chrome/browser/history/top_sites_impl_unittest.cc
index 98c2eef..d9bbb80 100644
--- a/chrome/browser/history/top_sites_impl_unittest.cc
+++ b/chrome/browser/history/top_sites_impl_unittest.cc
@@ -59,7 +59,7 @@ class WaitForHistoryTask : public HistoryDBTask {
   }
 
   virtual void DoneRunOnMainThread() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
@@ -87,7 +87,7 @@ class TopSitesQuerier {
                    weak_ptr_factory_.GetWeakPtr()));
     if (wait && start_number_of_callbacks == number_of_callbacks_) {
       waiting_ = true;
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
     }
   }
 
@@ -106,7 +106,7 @@ class TopSitesQuerier {
     urls_ = data;
     number_of_callbacks_++;
     if (waiting_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
       waiting_ = false;
     }
   }
@@ -193,7 +193,7 @@ class TopSitesImplTest : public HistoryUnitTestBase {
   // need to wait until you know history has processed a task.
   void WaitForHistory() {
     history_service()->ScheduleDBTask(new WaitForHistoryTask(), &consumer_);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   // Waits for top sites to finish processing a task. This is useful if you need
@@ -202,7 +202,7 @@ class TopSitesImplTest : public HistoryUnitTestBase {
     top_sites()->backend_->DoEmptyRequest(
         base::Bind(&TopSitesImplTest::QuitCallback, base::Unretained(this)),
         &cancelable_task_tracker_);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   TopSitesImpl* top_sites() {
@@ -239,7 +239,7 @@ class TopSitesImplTest : public HistoryUnitTestBase {
   // Quit the current message loop when invoked. Useful when running a nested
   // message loop.
   void QuitCallback() {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Adds a page to history.
@@ -327,7 +327,7 @@ class TopSitesImplTest : public HistoryUnitTestBase {
   }
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/history/top_sites_likely_impl_unittest.cc b/chrome/browser/history/top_sites_likely_impl_unittest.cc
index 684c51b..1901b7e 100644
--- a/chrome/browser/history/top_sites_likely_impl_unittest.cc
+++ b/chrome/browser/history/top_sites_likely_impl_unittest.cc
@@ -59,7 +59,7 @@ class WaitForHistoryTask : public HistoryDBTask {
   }
 
   virtual void DoneRunOnMainThread() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
@@ -87,7 +87,7 @@ class TopSitesQuerier {
                    weak_ptr_factory_.GetWeakPtr()));
     if (wait && start_number_of_callbacks == number_of_callbacks_) {
       waiting_ = true;
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
     }
   }
 
@@ -106,7 +106,7 @@ class TopSitesQuerier {
     urls_ = data;
     number_of_callbacks_++;
     if (waiting_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
       waiting_ = false;
     }
   }
@@ -193,7 +193,7 @@ class TopSitesLikelyImplTest : public HistoryUnitTestBase {
   // need to wait until you know history has processed a task.
   void WaitForHistory() {
     history_service()->ScheduleDBTask(new WaitForHistoryTask(), &consumer_);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   // Waits for top sites to finish processing a task. This is useful if you need
@@ -203,7 +203,7 @@ class TopSitesLikelyImplTest : public HistoryUnitTestBase {
         base::Bind(&TopSitesLikelyImplTest::QuitCallback,
                    base::Unretained(this)),
         &cancelable_task_tracker_);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   TopSitesLikelyImpl* top_sites() {
@@ -240,7 +240,7 @@ class TopSitesLikelyImplTest : public HistoryUnitTestBase {
   // Quit the current message loop when invoked. Useful when running a nested
   // message loop.
   void QuitCallback() {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Adds a page to history.
@@ -328,7 +328,7 @@ class TopSitesLikelyImplTest : public HistoryUnitTestBase {
   }
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/history/typed_url_syncable_service.cc b/chrome/browser/history/typed_url_syncable_service.cc
index c410937..92240d2 100644
--- a/chrome/browser/history/typed_url_syncable_service.cc
+++ b/chrome/browser/history/typed_url_syncable_service.cc
@@ -64,13 +64,13 @@ TypedUrlSyncableService::TypedUrlSyncableService(
     HistoryBackend* history_backend)
     : history_backend_(history_backend),
       processing_syncer_changes_(false),
-      expected_loop_(MessageLoop::current()) {
+      expected_loop_(base::MessageLoop::current()) {
   DCHECK(history_backend_);
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 }
 
 TypedUrlSyncableService::~TypedUrlSyncableService() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 }
 
 syncer::SyncMergeResult TypedUrlSyncableService::MergeDataAndStartSyncing(
@@ -78,7 +78,7 @@ syncer::SyncMergeResult TypedUrlSyncableService::MergeDataAndStartSyncing(
     const syncer::SyncDataList& initial_sync_data,
     scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
     scoped_ptr<syncer::SyncErrorFactory> error_handler) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK(!sync_processor_.get());
   DCHECK(sync_processor.get());
   DCHECK(error_handler.get());
@@ -94,7 +94,7 @@ syncer::SyncMergeResult TypedUrlSyncableService::MergeDataAndStartSyncing(
 }
 
 void TypedUrlSyncableService::StopSyncing(syncer::ModelType type) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK_EQ(type, syncer::TYPED_URLS);
 
   sync_processor_.reset();
@@ -103,7 +103,7 @@ void TypedUrlSyncableService::StopSyncing(syncer::ModelType type) {
 
 syncer::SyncDataList TypedUrlSyncableService::GetAllSyncData(
     syncer::ModelType type) const {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   syncer::SyncDataList list;
 
   // TODO(mgist): Add implementation
@@ -114,7 +114,7 @@ syncer::SyncDataList TypedUrlSyncableService::GetAllSyncData(
 syncer::SyncError TypedUrlSyncableService::ProcessSyncChanges(
     const tracked_objects::Location& from_here,
     const syncer::SyncChangeList& change_list) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   // TODO(mgist): Add implementation
 
@@ -124,7 +124,7 @@ syncer::SyncError TypedUrlSyncableService::ProcessSyncChanges(
 }
 
 void TypedUrlSyncableService::OnUrlsModified(URLRows* changed_urls) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK(changed_urls);
 
   if (processing_syncer_changes_)
@@ -152,7 +152,7 @@ void TypedUrlSyncableService::OnUrlsModified(URLRows* changed_urls) {
 
 void TypedUrlSyncableService::OnUrlVisited(content::PageTransition transition,
                                            URLRow* row) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK(row);
 
   if (processing_syncer_changes_)
@@ -175,7 +175,7 @@ void TypedUrlSyncableService::OnUrlVisited(content::PageTransition transition,
 void TypedUrlSyncableService::OnUrlsDeleted(bool all_history,
                                             bool archived,
                                             URLRows* rows) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   if (processing_syncer_changes_)
     return;  // These are changes originating from us, ignore.
diff --git a/chrome/browser/importer/firefox_importer_browsertest.cc b/chrome/browser/importer/firefox_importer_browsertest.cc
index fc87222..d8fe3e3 100644
--- a/chrome/browser/importer/firefox_importer_browsertest.cc
+++ b/chrome/browser/importer/firefox_importer_browsertest.cc
@@ -117,7 +117,7 @@ class Firefox3Observer : public ProfileWriter,
   virtual void ImportItemStarted(importer::ImportItem item) OVERRIDE {}
   virtual void ImportItemEnded(importer::ImportItem item) OVERRIDE {}
   virtual void ImportEnded() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
     EXPECT_EQ(arraysize(kFirefox3Bookmarks), bookmark_count_);
     EXPECT_EQ(1U, history_count_);
     EXPECT_EQ(arraysize(kFirefox3Passwords), password_count_);
@@ -278,7 +278,7 @@ class FirefoxProfileImporterBrowserTest : public InProcessBrowserTest {
     host->SetObserver(observer);
     host->StartImportSettings(source_profile, browser()->profile(),
                               items, make_scoped_refptr(writer));
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   base::ScopedTempDir temp_dir_;
diff --git a/chrome/browser/importer/firefox_importer_unittest_utils_mac.cc b/chrome/browser/importer/firefox_importer_unittest_utils_mac.cc
index 638f860..33c877a 100644
--- a/chrome/browser/importer/firefox_importer_unittest_utils_mac.cc
+++ b/chrome/browser/importer/firefox_importer_unittest_utils_mac.cc
@@ -85,14 +85,14 @@ class FFDecryptorServerChannelListener : public IPC::Listener {
     DCHECK(!got_result);
     result_bool = result;
     got_result = true;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnDecryptedTextResonse(const string16& decrypted_text) {
     DCHECK(!got_result);
     result_string = decrypted_text;
     got_result = true;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void QuitClient() {
@@ -113,7 +113,7 @@ class FFDecryptorServerChannelListener : public IPC::Listener {
   // If an error occured, just kill the message Loop.
   virtual void OnChannelError() OVERRIDE {
     got_result = false;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   // Results of IPC calls.
@@ -132,7 +132,7 @@ FFUnitTestDecryptorProxy::FFUnitTestDecryptorProxy()
 
 bool FFUnitTestDecryptorProxy::Setup(const base::FilePath& nss_path) {
   // Create a new message loop and spawn the child process.
-  message_loop_.reset(new MessageLoopForIO());
+  message_loop_.reset(new base::MessageLoopForIO());
 
   listener_.reset(new FFDecryptorServerChannelListener());
   channel_.reset(new IPC::Channel(kTestChannelID,
@@ -165,7 +165,7 @@ class CancellableQuitMsgLoop : public base::RefCounted<CancellableQuitMsgLoop> {
   CancellableQuitMsgLoop() : cancelled_(false) {}
   void QuitNow() {
     if (!cancelled_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   }
   bool cancelled_;
 
@@ -185,7 +185,7 @@ bool FFUnitTestDecryptorProxy::WaitForClientResponse() {
   // a message comes in.
   scoped_refptr<CancellableQuitMsgLoop> quit_task(
       new CancellableQuitMsgLoop());
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&CancellableQuitMsgLoop::QuitNow, quit_task.get()),
       TestTimeouts::action_max_timeout());
@@ -241,7 +241,7 @@ class FFDecryptorClientChannelListener : public IPC::Listener {
   }
 
   void OnQuitRequest() {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE {
@@ -256,7 +256,7 @@ class FFDecryptorClientChannelListener : public IPC::Listener {
   }
 
   virtual void OnChannelError() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  private:
@@ -266,7 +266,7 @@ class FFDecryptorClientChannelListener : public IPC::Listener {
 
 // Entry function in child process.
 MULTIPROCESS_IPC_TEST_MAIN(NSSDecrypterChildProcess) {
-  MessageLoopForIO main_message_loop;
+  base::MessageLoopForIO main_message_loop;
   FFDecryptorClientChannelListener listener;
 
   IPC::Channel channel(kTestChannelID, IPC::Channel::MODE_CLIENT, &listener);
@@ -274,7 +274,7 @@ MULTIPROCESS_IPC_TEST_MAIN(NSSDecrypterChildProcess) {
   listener.SetSender(&channel);
 
   // run message loop
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   return 0;
 }
diff --git a/chrome/browser/importer/ie_importer_browsertest_win.cc b/chrome/browser/importer/ie_importer_browsertest_win.cc
index ac04365..b97892b 100644
--- a/chrome/browser/importer/ie_importer_browsertest_win.cc
+++ b/chrome/browser/importer/ie_importer_browsertest_win.cc
@@ -268,7 +268,7 @@ class TestObserver : public ProfileWriter,
   virtual void ImportItemStarted(importer::ImportItem item) OVERRIDE {}
   virtual void ImportItemEnded(importer::ImportItem item) OVERRIDE {}
   virtual void ImportEnded() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
     EXPECT_EQ(arraysize(kIEBookmarks), bookmark_count_);
     EXPECT_EQ(1, history_count_);
     EXPECT_EQ(arraysize(kIEFaviconGroup), favicon_count_);
@@ -374,7 +374,7 @@ class MalformedFavoritesRegistryTestObserver
   virtual void ImportItemStarted(importer::ImportItem item) OVERRIDE {}
   virtual void ImportItemEnded(importer::ImportItem item) OVERRIDE {}
   virtual void ImportEnded() OVERRIDE {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
     EXPECT_EQ(arraysize(kIESortedBookmarks), bookmark_count_);
   }
 
@@ -498,7 +498,7 @@ IN_PROC_BROWSER_TEST_F(IEImporterBrowserTest, IEImporter) {
       browser()->profile(),
       importer::HISTORY | importer::PASSWORDS | importer::FAVORITES,
       observer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // Cleans up.
   url_history_stg2->DeleteUrl(kIEIdentifyUrl, 0);
@@ -575,6 +575,6 @@ IN_PROC_BROWSER_TEST_F(IEImporterBrowserTest,
         browser()->profile(),
         importer::FAVORITES,
         observer);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 }
diff --git a/chrome/browser/importer/importer_host.cc b/chrome/browser/importer/importer_host.cc
index 13da1ae..0f89d0c 100644
--- a/chrome/browser/importer/importer_host.cc
+++ b/chrome/browser/importer/importer_host.cc
@@ -179,7 +179,7 @@ void ImporterHost::OnGoogleGAIACookieChecked(bool result) {
       chrome::AddSelectedTabWithURL(browser_, url,
                                     content::PAGE_TRANSITION_TYPED);
 
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+    base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         &ImporterHost::OnImportLockDialogEnd,
         weak_ptr_factory_.GetWeakPtr(), false));
   } else {
diff --git a/chrome/browser/importer/toolbar_importer_utils_browsertest.cc b/chrome/browser/importer/toolbar_importer_utils_browsertest.cc
index 999dbf1c..1d71fca 100644
--- a/chrome/browser/importer/toolbar_importer_utils_browsertest.cc
+++ b/chrome/browser/importer/toolbar_importer_utils_browsertest.cc
@@ -19,7 +19,7 @@ class ToolbarImporterUtilsTest : public InProcessBrowserTest {
   void Callback(bool result) {
     DCHECK(!result);
     did_run_ = true;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
  protected:
diff --git a/chrome/browser/internal_auth_unittest.cc b/chrome/browser/internal_auth_unittest.cc
index da8954e..143b151 100644
--- a/chrome/browser/internal_auth_unittest.cc
+++ b/chrome/browser/internal_auth_unittest.cc
@@ -28,7 +28,7 @@ class InternalAuthTest : public ::testing::Test {
   virtual void TearDown() {
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   std::string long_string_;
 };
 
diff --git a/chrome/browser/intranet_redirect_detector.cc b/chrome/browser/intranet_redirect_detector.cc
index d0290ad..fcc6c6e 100644
--- a/chrome/browser/intranet_redirect_detector.cc
+++ b/chrome/browser/intranet_redirect_detector.cc
@@ -35,7 +35,7 @@ IntranetRedirectDetector::IntranetRedirectDetector()
   // browser is starting up, and if so, come back later", but there is currently
   // no function to do this.
   static const int kStartFetchDelaySeconds = 7;
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(&IntranetRedirectDetector::FinishSleep,
                  weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromSeconds(kStartFetchDelaySeconds));
@@ -159,7 +159,7 @@ void IntranetRedirectDetector::OnIPAddressChanged() {
   // delay this a little bit.
   in_sleep_ = true;
   static const int kNetworkSwitchDelayMS = 1000;
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(&IntranetRedirectDetector::FinishSleep,
                  weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kNetworkSwitchDelayMS));
diff --git a/chrome/browser/invalidation/invalidator_storage_unittest.cc b/chrome/browser/invalidation/invalidator_storage_unittest.cc
index 5e59b43..76dea3a 100644
--- a/chrome/browser/invalidation/invalidator_storage_unittest.cc
+++ b/chrome/browser/invalidation/invalidator_storage_unittest.cc
@@ -58,7 +58,7 @@ class InvalidatorStorageTest : public testing::Test {
   const invalidation::ObjectId kAppNotificationsId_;
   const invalidation::ObjectId kAutofillId_;
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 };
 
 // Set invalidation states for various keys and verify that they are written and
diff --git a/chrome/browser/jankometer.cc b/chrome/browser/jankometer.cc
index b094ec6..0cc1388 100644
--- a/chrome/browser/jankometer.cc
+++ b/chrome/browser/jankometer.cc
@@ -210,8 +210,8 @@ int JankObserverHelper::discard_count_ = 99;  // Measure only 1 in 100.
 
 //------------------------------------------------------------------------------
 class IOJankObserver : public base::RefCountedThreadSafe<IOJankObserver>,
-                       public MessageLoopForIO::IOObserver,
-                       public MessageLoop::TaskObserver {
+                       public base::MessageLoopForIO::IOObserver,
+                       public base::MessageLoop::TaskObserver {
  public:
   IOJankObserver(const char* thread_name,
                  TimeDelta excessive_duration,
@@ -222,14 +222,14 @@ class IOJankObserver : public base::RefCountedThreadSafe<IOJankObserver>,
   // attach to the current thread, so this function can be invoked on another
   // thread to attach it.
   void AttachToCurrentThread() {
-    MessageLoop::current()->AddTaskObserver(this);
-    MessageLoopForIO::current()->AddIOObserver(this);
+    base::MessageLoop::current()->AddTaskObserver(this);
+    base::MessageLoopForIO::current()->AddIOObserver(this);
   }
 
   // Detaches the observer to the current thread's message loop.
   void DetachFromCurrentThread() {
-    MessageLoopForIO::current()->RemoveIOObserver(this);
-    MessageLoop::current()->RemoveTaskObserver(this);
+    base::MessageLoopForIO::current()->RemoveIOObserver(this);
+    base::MessageLoop::current()->RemoveTaskObserver(this);
   }
 
   virtual void WillProcessIOEvent() OVERRIDE {
@@ -266,8 +266,8 @@ class IOJankObserver : public base::RefCountedThreadSafe<IOJankObserver>,
 
 //------------------------------------------------------------------------------
 class UIJankObserver : public base::RefCountedThreadSafe<UIJankObserver>,
-                       public MessageLoop::TaskObserver,
-                       public MessageLoopForUI::Observer {
+                       public base::MessageLoop::TaskObserver,
+                       public base::MessageLoopForUI::Observer {
  public:
   UIJankObserver(const char* thread_name,
                  TimeDelta excessive_duration,
@@ -278,16 +278,16 @@ class UIJankObserver : public base::RefCountedThreadSafe<UIJankObserver>,
   // attach to the current thread, so this function can be invoked on another
   // thread to attach it.
   void AttachToCurrentThread() {
-    DCHECK_EQ(MessageLoop::current()->type(), MessageLoop::TYPE_UI);
-    MessageLoopForUI::current()->AddObserver(this);
-    MessageLoop::current()->AddTaskObserver(this);
+    DCHECK_EQ(base::MessageLoop::current()->type(), base::MessageLoop::TYPE_UI);
+    base::MessageLoopForUI::current()->AddObserver(this);
+    base::MessageLoop::current()->AddTaskObserver(this);
   }
 
   // Detaches the observer to the current thread's message loop.
   void DetachFromCurrentThread() {
-    DCHECK_EQ(MessageLoop::current()->type(), MessageLoop::TYPE_UI);
-    MessageLoop::current()->RemoveTaskObserver(this);
-    MessageLoopForUI::current()->RemoveObserver(this);
+    DCHECK_EQ(base::MessageLoop::current()->type(), base::MessageLoop::TYPE_UI);
+    base::MessageLoop::current()->RemoveTaskObserver(this);
+    base::MessageLoopForUI::current()->RemoveObserver(this);
   }
 
   virtual void WillProcessTask(const base::PendingTask& pending_task) OVERRIDE {
diff --git a/chrome/browser/lifetime/application_lifetime.cc b/chrome/browser/lifetime/application_lifetime.cc
index 87109c5..f0cd3d1 100644
--- a/chrome/browser/lifetime/application_lifetime.cc
+++ b/chrome/browser/lifetime/application_lifetime.cc
@@ -302,7 +302,7 @@ void EndKeepAlive() {
     // (MessageLoop::current() == null).
     if (chrome::GetTotalBrowserCount() == 0 &&
         !browser_shutdown::IsTryingToQuit() &&
-        MessageLoop::current()) {
+        base::MessageLoop::current()) {
       CloseAllBrowsers();
     }
   }
diff --git a/chrome/browser/logging_chrome_browsertest.cc b/chrome/browser/logging_chrome_browsertest.cc
index df32456..d45b3f2 100644
--- a/chrome/browser/logging_chrome_browsertest.cc
+++ b/chrome/browser/logging_chrome_browsertest.cc
@@ -81,7 +81,7 @@ class RendererCrashTest : public InProcessBrowserTest,
     if (status == base::TERMINATION_STATUS_PROCESS_CRASHED ||
         status == base::TERMINATION_STATUS_ABNORMAL_TERMINATION) {
       saw_crash_ = true;
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/managed_mode/managed_mode_unittest.cc b/chrome/browser/managed_mode/managed_mode_unittest.cc
index 2556a5a..4e26107 100644
--- a/chrome/browser/managed_mode/managed_mode_unittest.cc
+++ b/chrome/browser/managed_mode/managed_mode_unittest.cc
@@ -118,7 +118,7 @@ class MockCallback : public base::RefCountedThreadSafe<MockCallback> {
 
 class ManagedModeTest : public ::testing::Test {
  public:
-  ManagedModeTest() : message_loop_(MessageLoop::TYPE_UI),
+  ManagedModeTest() : message_loop_(base::MessageLoop::TYPE_UI),
                       ui_thread_(content::BrowserThread::UI, &message_loop_),
                       io_thread_(content::BrowserThread::IO, &message_loop_) {
   }
@@ -134,7 +134,7 @@ class ManagedModeTest : public ::testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   TestingProfile managed_mode_profile_;
diff --git a/chrome/browser/managed_mode/managed_mode_url_filter_unittest.cc b/chrome/browser/managed_mode/managed_mode_url_filter_unittest.cc
index e95f977..fb97e57 100644
--- a/chrome/browser/managed_mode/managed_mode_url_filter_unittest.cc
+++ b/chrome/browser/managed_mode/managed_mode_url_filter_unittest.cc
@@ -33,7 +33,7 @@ class ManagedModeURLFilterTest : public ::testing::Test,
            ManagedModeURLFilter::ALLOW;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   base::RunLoop run_loop_;
   scoped_refptr<ManagedModeURLFilter> filter_;
 };
diff --git a/chrome/browser/managed_mode/managed_user_service_unittest.cc b/chrome/browser/managed_mode/managed_user_service_unittest.cc
index 3cdf171..ce7b38e 100644
--- a/chrome/browser/managed_mode/managed_user_service_unittest.cc
+++ b/chrome/browser/managed_mode/managed_user_service_unittest.cc
@@ -63,7 +63,7 @@ class ManagedUserServiceTest : public ::testing::Test {
   virtual ~ManagedUserServiceTest() {}
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   TestingProfile profile_;
   ManagedUserService managed_user_service_;
diff --git a/chrome/browser/media_galleries/fileapi/itunes_finder_win_unittest.cc b/chrome/browser/media_galleries/fileapi/itunes_finder_win_unittest.cc
index ed3fb39..c8977fc 100644
--- a/chrome/browser/media_galleries/fileapi/itunes_finder_win_unittest.cc
+++ b/chrome/browser/media_galleries/fileapi/itunes_finder_win_unittest.cc
@@ -94,7 +94,7 @@ class ITunesFinderWinTest : public testing::Test {
   base::ScopedTempDir app_data_dir_;
   base::ScopedTempDir music_dir_;
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/media_galleries/fileapi/native_media_file_util_unittest.cc b/chrome/browser/media_galleries/fileapi/native_media_file_util_unittest.cc
index fbff05d..73dbd76 100644
--- a/chrome/browser/media_galleries/fileapi/native_media_file_util_unittest.cc
+++ b/chrome/browser/media_galleries/fileapi/native_media_file_util_unittest.cc
@@ -196,7 +196,7 @@ class NativeMediaFileUtilTest : public testing::Test {
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   base::ScopedTempDir data_dir_;
   scoped_refptr<fileapi::FileSystemContext> file_system_context_;
@@ -230,7 +230,7 @@ TEST_F(NativeMediaFileUtilTest, DirectoryExistsAndFileExistsFiltering) {
       operation->FileExists(
           url, base::Bind(&ExpectEqHelper, test_name, expectation));
     }
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 }
 
@@ -244,7 +244,7 @@ TEST_F(NativeMediaFileUtilTest, ReadDirectoryFiltering) {
   bool completed = false;
   NewOperation(url)->ReadDirectory(
       url, base::Bind(&DidReadDirectory, &content, &completed));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(completed);
   EXPECT_EQ(6u, content.size());
 
@@ -282,7 +282,7 @@ TEST_F(NativeMediaFileUtilTest, CreateFileAndCreateDirectoryFiltering) {
         operation->CreateFile(
             url, false, base::Bind(&ExpectEqHelper, test_name, expectation));
       }
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -321,7 +321,7 @@ TEST_F(NativeMediaFileUtilTest, CopySourceFiltering) {
       }
       operation->Copy(
           url, dest_url, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -387,7 +387,7 @@ TEST_F(NativeMediaFileUtilTest, CopyDestFiltering) {
       }
       operation->Copy(
           src_url, url, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -426,7 +426,7 @@ TEST_F(NativeMediaFileUtilTest, MoveSourceFiltering) {
       }
       operation->Move(
           url, dest_url, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -494,7 +494,7 @@ TEST_F(NativeMediaFileUtilTest, MoveDestFiltering) {
       }
       operation->Move(
           src_url, url, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -525,7 +525,7 @@ TEST_F(NativeMediaFileUtilTest, GetMetadataFiltering) {
                                         test_name,
                                         expectation,
                                         kFilteringTestCases[i].is_directory));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -553,7 +553,7 @@ TEST_F(NativeMediaFileUtilTest, RemoveFiltering) {
       }
       operation->Remove(
           url, false, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -584,7 +584,7 @@ TEST_F(NativeMediaFileUtilTest, TruncateFiltering) {
       }
       operation->Truncate(
           url, 0, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -614,7 +614,7 @@ TEST_F(NativeMediaFileUtilTest, TouchFileFiltering) {
       }
       operation->TouchFile(
           url, time, time, base::Bind(&ExpectEqHelper, test_name, expectation));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
     }
   }
 }
@@ -646,7 +646,7 @@ TEST_F(NativeMediaFileUtilTest, CreateSnapshot) {
     error = base::PLATFORM_FILE_ERROR_FAILED;
     operation->CreateSnapshotFile(url,
         base::Bind(CreateSnapshotCallback, &error));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     ASSERT_EQ(expected_error, error);
   }
 }
diff --git a/chrome/browser/media_galleries/fileapi/picasa/picasa_file_util_unittest.cc b/chrome/browser/media_galleries/fileapi/picasa/picasa_file_util_unittest.cc
index d2601e4..0ca6a9f 100644
--- a/chrome/browser/media_galleries/fileapi/picasa/picasa_file_util_unittest.cc
+++ b/chrome/browser/media_galleries/fileapi/picasa/picasa_file_util_unittest.cc
@@ -252,7 +252,7 @@ class PicasaFileUtilTest : public testing::Test {
     bool completed = false;
     NewOperation(url)->ReadDirectory(
         url, base::Bind(&DidReadDirectory, &contents, &completed));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     ASSERT_TRUE(completed);
     ASSERT_EQ(test_folders.size(), contents.size());
@@ -275,7 +275,7 @@ class PicasaFileUtilTest : public testing::Test {
           folder_url,
           base::Bind(&DidReadDirectory, &folder_contents,
                      &folder_read_completed));
-      MessageLoop::current()->RunUntilIdle();
+      base::MessageLoop::current()->RunUntilIdle();
 
       EXPECT_TRUE(folder_read_completed);
 
@@ -304,7 +304,7 @@ class PicasaFileUtilTest : public testing::Test {
     bool completed = false;
     NewOperation(url)->ReadDirectory(
         url, base::Bind(&DidReadDirectory, &contents, &completed));
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     ASSERT_FALSE(completed);
   }
@@ -324,7 +324,7 @@ class PicasaFileUtilTest : public testing::Test {
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   base::ScopedTempDir profile_dir_;
 
@@ -409,7 +409,7 @@ TEST_F(PicasaFileUtilTest, RootFolders) {
   bool completed = false;
   NewOperation(url)->ReadDirectory(
       url, base::Bind(&DidReadDirectory, &contents, &completed));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   ASSERT_TRUE(completed);
   ASSERT_EQ(2u, contents.size());
diff --git a/chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac_unittest.mm b/chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac_unittest.mm
index 67971b9..c88493b 100644
--- a/chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac_unittest.mm
+++ b/chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac_unittest.mm
@@ -298,7 +298,7 @@ class MTPDeviceDelegateImplMacTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   // Note: threads must be made in this order: UI > FILE > IO
   scoped_ptr<content::TestBrowserThread> ui_thread_;
   scoped_ptr<content::TestBrowserThread> file_thread_;
diff --git a/chrome/browser/media_galleries/media_file_system_registry_unittest.cc b/chrome/browser/media_galleries/media_file_system_registry_unittest.cc
index 10db660..414f94d 100644
--- a/chrome/browser/media_galleries/media_file_system_registry_unittest.cc
+++ b/chrome/browser/media_galleries/media_file_system_registry_unittest.cc
@@ -478,7 +478,7 @@ ProfileState::~ProfileState() {
   shared_web_contents2_.reset();
   profile_.reset();
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 MediaGalleriesPreferences* ProfileState::GetMediaGalleriesPrefs() {
@@ -500,7 +500,7 @@ void ProfileState::CheckGalleries(
       base::Bind(&ProfileState::CompareResults, base::Unretained(this),
                  base::StringPrintf("%s (no permission)", test.c_str()),
                  base::ConstRef(empty_expectation)));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(1, GetAndClearComparisonCount());
 
   // Read permission only.
@@ -509,7 +509,7 @@ void ProfileState::CheckGalleries(
       base::Bind(&ProfileState::CompareResults, base::Unretained(this),
                  base::StringPrintf("%s (regular permission)", test.c_str()),
                  base::ConstRef(regular_extension_galleries)));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(1, GetAndClearComparisonCount());
 
   // All galleries permission.
@@ -518,7 +518,7 @@ void ProfileState::CheckGalleries(
       base::Bind(&ProfileState::CompareResults, base::Unretained(this),
                  base::StringPrintf("%s (all permission)", test.c_str()),
                  base::ConstRef(all_extension_galleries)));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(1, GetAndClearComparisonCount());
 }
 
@@ -530,7 +530,7 @@ FSInfoMap ProfileState::GetGalleriesInfo(extensions::Extension* extension) {
   registry->GetMediaFileSystemsForExtension(
       rvh, extension,
       base::Bind(&GetGalleryInfoCallback, base::Unretained(&results)));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   return results;
 }
 
@@ -578,8 +578,8 @@ int ProfileState::GetAndClearComparisonCount() {
 /////////////////////////////////
 
 MediaFileSystemRegistryTest::MediaFileSystemRegistryTest()
-    : ui_thread_(content::BrowserThread::UI, MessageLoop::current()),
-      file_thread_(content::BrowserThread::FILE, MessageLoop::current()) {
+    : ui_thread_(content::BrowserThread::UI, base::MessageLoop::current()),
+      file_thread_(content::BrowserThread::FILE, base::MessageLoop::current()) {
 }
 
 void MediaFileSystemRegistryTest::CreateProfileState(size_t profile_count) {
@@ -616,14 +616,14 @@ std::string MediaFileSystemRegistryTest::AttachDevice(
   DCHECK(StorageInfo::IsRemovableDevice(device_id));
   string16 name = location.LossyDisplayName();
   ProcessAttach(device_id, name, location.value());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   return device_id;
 }
 
 void MediaFileSystemRegistryTest::DetachDevice(const std::string& device_id) {
   DCHECK(StorageInfo::IsRemovableDevice(device_id));
   ProcessDetach(device_id);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 void MediaFileSystemRegistryTest::SetGalleryPermission(
@@ -760,7 +760,7 @@ void MediaFileSystemRegistryTest::TearDown() {
       g_browser_process->media_file_system_registry();
   EXPECT_EQ(0U, registry->GetExtensionGalleriesHostCountForTests());
   BrowserThread::GetBlockingPool()->FlushForTesting();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 ///////////
@@ -861,7 +861,7 @@ TEST_F(MediaFileSystemRegistryTest,
       break;
     }
   }
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(forget_gallery);
   EXPECT_EQ(gallery_count, GetAutoAddedGalleries(profile_state).size());
 
diff --git a/chrome/browser/media_galleries/media_galleries_preferences_unittest.cc b/chrome/browser/media_galleries/media_galleries_preferences_unittest.cc
index 0ef7654..bd034d4 100644
--- a/chrome/browser/media_galleries/media_galleries_preferences_unittest.cc
+++ b/chrome/browser/media_galleries/media_galleries_preferences_unittest.cc
@@ -78,7 +78,7 @@ class MediaGalleriesPreferencesTest : public testing::Test {
     // TestExtensionSystem uses DeleteSoon, so we need to delete the profile
     // and then run the message queue to clean up.
     profile_.reset();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   virtual void SetUp() OVERRIDE {
@@ -212,7 +212,7 @@ class MediaGalleriesPreferencesTest : public testing::Test {
 
  private:
   // Needed for extension service & friends to work.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/metrics/metrics_log_unittest.cc b/chrome/browser/metrics/metrics_log_unittest.cc
index f3a931a..8dd1a3f 100644
--- a/chrome/browser/metrics/metrics_log_unittest.cc
+++ b/chrome/browser/metrics/metrics_log_unittest.cc
@@ -120,7 +120,8 @@ class TestMetricsLog : public MetricsLog {
 
 class MetricsLogTest : public testing::Test {
  public:
-  MetricsLogTest() : message_loop_(MessageLoop::TYPE_IO) {}
+  MetricsLogTest() : message_loop_(base::MessageLoop::TYPE_IO) {}
+
  protected:
   void TestRecordEnvironment(bool proto_only) {
     TestMetricsLog log(kClientId, kSessionId);
@@ -178,7 +179,7 @@ class MetricsLogTest : public testing::Test {
  private:
   // This is necessary because eventually some tests call base::RepeatingTimer
   // functions and a message loop is required for that.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
 #if defined(OS_CHROMEOS)
   chromeos::MockDBusThreadManagerWithoutGMock* mock_dbus_thread_manager_;
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index 213a288..db2f67f 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -380,7 +380,7 @@ class MetricsMemoryDetails : public MemoryDetails {
       : callback_(callback) {}
 
   virtual void OnDetailsAvailable() OVERRIDE {
-    MessageLoop::current()->PostTask(FROM_HERE, callback_);
+    base::MessageLoop::current()->PostTask(FROM_HERE, callback_);
   }
 
  private:
@@ -960,7 +960,7 @@ void MetricsService::OnInitTaskGotPluginInfo(
       FROM_HERE,
       base::Bind(&MetricsService::InitTaskGetGoogleUpdateData,
                  self_ptr_factory_.GetWeakPtr(),
-                 MessageLoop::current()->message_loop_proxy()));
+                 base::MessageLoop::current()->message_loop_proxy()));
 }
 
 // static
@@ -1071,7 +1071,7 @@ std::string MetricsService::GenerateClientID() {
 void MetricsService::ScheduleNextStateSave() {
   state_saver_factory_.InvalidateWeakPtrs();
 
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(&MetricsService::SaveLocalState,
                  state_saver_factory_.GetWeakPtr()),
       base::TimeDelta::FromMinutes(kSaveStateIntervalMinutes));
@@ -1112,7 +1112,7 @@ void MetricsService::OpenNewLog() {
         FROM_HERE,
         base::Bind(&MetricsService::InitTaskGetHardwareClass,
             self_ptr_factory_.GetWeakPtr(),
-            MessageLoop::current()->message_loop_proxy()),
+            base::MessageLoop::current()->message_loop_proxy()),
         base::TimeDelta::FromSeconds(kInitializationDelaySeconds));
   }
 }
@@ -1263,7 +1263,7 @@ void MetricsService::OnMemoryDetailCollectionDone() {
   // child processes. Wait time specifies how long to wait before absolutely
   // calling us back on the task.
   content::FetchHistogramsAsynchronously(
-      MessageLoop::current(), callback,
+      base::MessageLoop::current(), callback,
       base::TimeDelta::FromMilliseconds(kMaxHistogramGatheringWaitDuration));
 }
 
diff --git a/chrome/browser/metrics/metrics_service_unittest.cc b/chrome/browser/metrics/metrics_service_unittest.cc
index 6ae029c..e65444e4 100644
--- a/chrome/browser/metrics/metrics_service_unittest.cc
+++ b/chrome/browser/metrics/metrics_service_unittest.cc
@@ -30,7 +30,7 @@ class MetricsServiceTest : public testing::Test {
   }
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   ScopedTestingLocalState testing_local_state_;
 
diff --git a/chrome/browser/metrics/thread_watcher.cc b/chrome/browser/metrics/thread_watcher.cc
index bd5d498..4109105 100644
--- a/chrome/browser/metrics/thread_watcher.cc
+++ b/chrome/browser/metrics/thread_watcher.cc
@@ -184,7 +184,7 @@ void ThreadWatcher::ActivateThreadWatching() {
   active_ = true;
   ping_count_ = unresponsive_threshold_;
   ResetHangCounters();
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&ThreadWatcher::PostPingMessage,
                  weak_ptr_factory_.GetWeakPtr()));
@@ -240,7 +240,7 @@ void ThreadWatcher::PostPingMessage() {
           base::Bind(&ThreadWatcher::OnPingMessage, thread_id_,
                      callback))) {
       // Post a task to check the responsiveness of watched thread.
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           base::Bind(&ThreadWatcher::OnCheckResponsiveness,
                      weak_ptr_factory_.GetWeakPtr(), ping_sequence_number_),
@@ -276,7 +276,7 @@ void ThreadWatcher::OnPongMessage(uint64 ping_sequence_number) {
   if (!active_ || --ping_count_ <= 0)
     return;
 
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ThreadWatcher::PostPingMessage,
                  weak_ptr_factory_.GetWeakPtr()),
@@ -305,7 +305,7 @@ void ThreadWatcher::OnCheckResponsiveness(uint64 ping_sequence_number) {
   GotNoResponse();
 
   // Post a task to check the responsiveness of watched thread.
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ThreadWatcher::OnCheckResponsiveness,
                  weak_ptr_factory_.GetWeakPtr(), ping_sequence_number_),
@@ -787,7 +787,7 @@ WatchDogThread::~WatchDogThread() {
 bool WatchDogThread::CurrentlyOnWatchDogThread() {
   base::AutoLock lock(g_watchdog_lock.Get());
   return g_watchdog_thread &&
-    g_watchdog_thread->message_loop() == MessageLoop::current();
+      g_watchdog_thread->message_loop() == base::MessageLoop::current();
 }
 
 // static
@@ -811,7 +811,7 @@ bool WatchDogThread::PostTaskHelper(
   {
     base::AutoLock lock(g_watchdog_lock.Get());
 
-    MessageLoop* message_loop = g_watchdog_thread ?
+    base::MessageLoop* message_loop = g_watchdog_thread ?
         g_watchdog_thread->message_loop() : NULL;
     if (message_loop) {
       message_loop->PostDelayedTask(from_here, task, delay);
@@ -933,7 +933,7 @@ void StartupTimeBomb::DeleteStartupWatchdog() {
     startup_watchdog_ = NULL;
     return;
   }
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&StartupTimeBomb::DeleteStartupWatchdog,
                  base::Unretained(this)),
diff --git a/chrome/browser/metrics/variations/resource_request_allowed_notifier_unittest.cc b/chrome/browser/metrics/variations/resource_request_allowed_notifier_unittest.cc
index e0275e4..04f8e6e 100644
--- a/chrome/browser/metrics/variations/resource_request_allowed_notifier_unittest.cc
+++ b/chrome/browser/metrics/variations/resource_request_allowed_notifier_unittest.cc
@@ -26,7 +26,7 @@ class TestNetworkChangeNotifier : public net::NetworkChangeNotifier {
       net::NetworkChangeNotifier::ConnectionType type) {
     connection_type_to_return_ = type;
     net::NetworkChangeNotifier::NotifyObserversOfConnectionTypeChange();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
  private:
@@ -139,7 +139,7 @@ class ResourceRequestAllowedNotifierTest
   }
 
  private:
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread;
   TestNetworkChangeNotifier network_notifier;
   TestRequestAllowedNotifier resource_request_allowed_notifier_;
diff --git a/chrome/browser/metrics/variations/variations_http_header_provider.cc b/chrome/browser/metrics/variations/variations_http_header_provider.cc
index bcc7a4a..6a0e565 100644
--- a/chrome/browser/metrics/variations/variations_http_header_provider.cc
+++ b/chrome/browser/metrics/variations/variations_http_header_provider.cc
@@ -90,7 +90,7 @@ void VariationsHttpHeaderProvider::InitVariationIDsCacheIfNeeded() {
 
   // Register for additional cache updates. This is done first to avoid a race
   // that could cause registered FieldTrials to be missed.
-  DCHECK(MessageLoop::current());
+  DCHECK(base::MessageLoop::current());
   base::FieldTrialList::AddObserver(this);
 
   base::TimeTicks before_time = base::TimeTicks::Now();
diff --git a/chrome/browser/metrics/variations/variations_service_unittest.cc b/chrome/browser/metrics/variations/variations_service_unittest.cc
index e3700e4..cdf9e49 100644
--- a/chrome/browser/metrics/variations/variations_service_unittest.cc
+++ b/chrome/browser/metrics/variations/variations_service_unittest.cc
@@ -654,7 +654,7 @@ TEST_F(VariationsServiceTest, ValidateStudy) {
 }
 
 TEST_F(VariationsServiceTest, RequestsInitiallyNotAllowed) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(content::BrowserThread::UI,
                                        &message_loop);
   TestingPrefServiceSimple prefs;
@@ -675,7 +675,7 @@ TEST_F(VariationsServiceTest, RequestsInitiallyNotAllowed) {
 }
 
 TEST_F(VariationsServiceTest, RequestsInitiallyAllowed) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(content::BrowserThread::UI,
                                        &message_loop);
   TestingPrefServiceSimple prefs;
@@ -692,7 +692,7 @@ TEST_F(VariationsServiceTest, RequestsInitiallyAllowed) {
 }
 
 TEST_F(VariationsServiceTest, SeedStoredWhenOKStatus) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread io_thread(content::BrowserThread::IO,
                                        &message_loop);
   TestingPrefServiceSimple prefs;
@@ -723,7 +723,7 @@ TEST_F(VariationsServiceTest, SeedNotStoredWhenNonOKStatus) {
     net::HTTP_SERVICE_UNAVAILABLE,
   };
 
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread io_thread(content::BrowserThread::IO,
                                        &message_loop);
   TestingPrefServiceSimple prefs;
diff --git a/chrome/browser/nacl_host/nacl_browser.cc b/chrome/browser/nacl_host/nacl_browser.cc
index d05d42e..fd042ae 100644
--- a/chrome/browser/nacl_host/nacl_browser.cc
+++ b/chrome/browser/nacl_host/nacl_browser.cc
@@ -351,7 +351,7 @@ void NaClBrowser::CheckWaiting() {
     // process host.
     for (std::vector<base::Closure>::iterator iter = waiting_.begin();
          iter != waiting_.end(); ++iter) {
-      MessageLoop::current()->PostTask(FROM_HERE, *iter);
+      base::MessageLoop::current()->PostTask(FROM_HERE, *iter);
     }
     waiting_.clear();
   }
@@ -442,7 +442,7 @@ void NaClBrowser::MarkValidationCacheAsModified() {
   if (!validation_cache_is_modified_) {
     // Wait before persisting to disk.  This can coalesce multiple cache
     // modifications info a single disk write.
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
          FROM_HERE,
          base::Bind(&NaClBrowser::PersistValidationCache,
                     weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/nacl_host/nacl_process_host.cc b/chrome/browser/nacl_host/nacl_process_host.cc
index a2f383e..e67b0df 100644
--- a/chrome/browser/nacl_host/nacl_process_host.cc
+++ b/chrome/browser/nacl_host/nacl_process_host.cc
@@ -404,7 +404,7 @@ scoped_ptr<CommandLine> NaClProcessHost::GetCommandForLaunchWithGdb(
 }
 #elif defined(OS_LINUX)
 class NaClProcessHost::NaClGdbWatchDelegate
-    : public MessageLoopForIO::Watcher {
+    : public base::MessageLoopForIO::Watcher {
  public:
   // fd_write_ is used by nacl-gdb via /proc/browser_PID/fd/fd_write_
   NaClGdbWatchDelegate(int fd_read, int fd_write,
@@ -482,10 +482,10 @@ bool NaClProcessHost::LaunchNaClGdb(base::ProcessId pid) {
           fds[0], fds[1],
           base::Bind(&NaClProcessHost::OnNaClGdbAttached,
                      weak_factory_.GetWeakPtr())));
-  MessageLoopForIO::current()->WatchFileDescriptor(
+  base::MessageLoopForIO::current()->WatchFileDescriptor(
       fds[0],
       true,
-      MessageLoopForIO::WATCH_READ,
+      base::MessageLoopForIO::WATCH_READ,
       &nacl_gdb_watcher_,
       nacl_gdb_watcher_delegate_.get());
   return base::LaunchProcess(cmd_line, base::LaunchOptions(), NULL);
diff --git a/chrome/browser/nacl_host/nacl_process_host.h b/chrome/browser/nacl_host/nacl_process_host.h
index 584dc9a..eb70b97 100644
--- a/chrome/browser/nacl_host/nacl_process_host.h
+++ b/chrome/browser/nacl_host/nacl_process_host.h
@@ -169,7 +169,7 @@ class NaClProcessHost : public content::BrowserChildProcessHostDelegate {
   bool process_launched_by_broker_;
 #elif defined(OS_LINUX)
   bool wait_for_nacl_gdb_;
-  MessageLoopForIO::FileDescriptorWatcher nacl_gdb_watcher_;
+  base::MessageLoopForIO::FileDescriptorWatcher nacl_gdb_watcher_;
 
   class NaClGdbWatchDelegate;
   scoped_ptr<NaClGdbWatchDelegate> nacl_gdb_watcher_delegate_;
diff --git a/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc b/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc
index f1d1714..eb5677e 100644
--- a/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc
+++ b/chrome/browser/net/chrome_fraudulent_certificate_reporter_unittest.cc
@@ -184,21 +184,21 @@ TEST(ChromeFraudulentCertificateReporterTest, GoodBadInfo) {
 }
 
 TEST(ChromeFraudulentCertificateReporterTest, ReportIsSent) {
-  MessageLoop loop(MessageLoop::TYPE_IO);
+  base::MessageLoop loop(base::MessageLoop::TYPE_IO);
   content::TestBrowserThread io_thread(BrowserThread::IO, &loop);
   loop.PostTask(FROM_HERE, base::Bind(&DoReportIsSent));
   loop.RunUntilIdle();
 }
 
 TEST(ChromeFraudulentCertificateReporterTest, MockReportIsSent) {
-  MessageLoop loop(MessageLoop::TYPE_IO);
+  base::MessageLoop loop(base::MessageLoop::TYPE_IO);
   content::TestBrowserThread io_thread(BrowserThread::IO, &loop);
   loop.PostTask(FROM_HERE, base::Bind(&DoMockReportIsSent));
   loop.RunUntilIdle();
 }
 
 TEST(ChromeFraudulentCertificateReporterTest, ReportIsNotSent) {
-  MessageLoop loop(MessageLoop::TYPE_IO);
+  base::MessageLoop loop(base::MessageLoop::TYPE_IO);
   content::TestBrowserThread io_thread(BrowserThread::IO, &loop);
   loop.PostTask(FROM_HERE, base::Bind(&DoReportIsNotSent));
   loop.RunUntilIdle();
diff --git a/chrome/browser/net/chrome_network_delegate_unittest.cc b/chrome/browser/net/chrome_network_delegate_unittest.cc
index 6afbfa2..9e9d626 100644
--- a/chrome/browser/net/chrome_network_delegate_unittest.cc
+++ b/chrome/browser/net/chrome_network_delegate_unittest.cc
@@ -78,7 +78,7 @@ class ChromeNetworkDelegateTest : public testing::Test {
 
  private:
   bool never_throttle_requests_original_value_;
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
 
   scoped_refptr<extensions::EventRouterForwarder> forwarder_;
   BooleanPrefMember pref_member_;
@@ -131,13 +131,13 @@ class ChromeNetworkDelegateSafeSearchTest : public testing::Test {
         GURL(url_string), &delegate_, &context_, network_delegate_);
 
     request.Start();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     EXPECT_EQ(expected_query_parameters, request.url().query());
   }
 
  private:
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   scoped_refptr<extensions::EventRouterForwarder> forwarder_;
@@ -316,7 +316,7 @@ class ChromeNetworkDelegatePrivacyModeTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   scoped_refptr<extensions::EventRouterForwarder> forwarder_;
diff --git a/chrome/browser/net/connection_tester.cc b/chrome/browser/net/connection_tester.cc
index c28fca1..4a7d56e 100644
--- a/chrome/browser/net/connection_tester.cc
+++ b/chrome/browser/net/connection_tester.cc
@@ -388,7 +388,7 @@ void ConnectionTester::TestRunner::OnResponseCompleted(
   // Post a task to notify the parent rather than handling it right away,
   // to avoid re-entrancy problems with URLRequest. (Don't want the caller
   // to end up deleting the URLRequest while in the middle of processing).
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&TestRunner::OnExperimentCompletedWithResult,
                  weak_factory_.GetWeakPtr(), result));
diff --git a/chrome/browser/net/connection_tester_unittest.cc b/chrome/browser/net/connection_tester_unittest.cc
index aafd6fe8..c386081 100644
--- a/chrome/browser/net/connection_tester_unittest.cc
+++ b/chrome/browser/net/connection_tester_unittest.cc
@@ -54,7 +54,7 @@ class ConnectionTesterDelegate : public ConnectionTester::Delegate {
 
   virtual void OnCompletedConnectionTestSuite() OVERRIDE {
     completed_connection_test_suite_count_++;
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   int start_connection_test_suite_count() const {
@@ -87,7 +87,7 @@ class ConnectionTesterDelegate : public ConnectionTester::Delegate {
 class ConnectionTesterTest : public PlatformTest {
  public:
   ConnectionTesterTest()
-      : message_loop_(MessageLoop::TYPE_IO),
+      : message_loop_(base::MessageLoop::TYPE_IO),
         io_thread_(BrowserThread::IO, &message_loop_),
         test_server_(net::SpawnedTestServer::TYPE_HTTP,
                      net::SpawnedTestServer::kLocalhost,
@@ -103,7 +103,7 @@ class ConnectionTesterTest : public PlatformTest {
   // SSLClientAuthCache calls RemoveObserver when destroyed, but if the
   // MessageLoop is already destroyed, then the RemoveObserver will be a
   // no-op, and the ObserverList will contain invalid entries.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread io_thread_;
   net::SpawnedTestServer test_server_;
   ConnectionTesterDelegate test_delegate_;
@@ -157,7 +157,7 @@ TEST_F(ConnectionTesterTest, RunAllTests) {
   tester.RunAllTests(test_server_.GetURL("echoall"));
 
   // Wait for all the tests to complete.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   const int kNumExperiments =
       ConnectionTester::PROXY_EXPERIMENT_COUNT *
@@ -203,8 +203,9 @@ TEST_F(ConnectionTesterTest, DeleteWhileInProgress) {
   // |backup_task| that it will try to deref during the destructor, but
   // depending on the order that pending tasks were deleted in, it might
   // already be invalid! See http://crbug.com/43291.
-  MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->PostTask(FROM_HERE,
+                                         base::MessageLoop::QuitClosure());
+  base::MessageLoop::current()->Run();
 }
 
 }  // namespace
diff --git a/chrome/browser/net/dns_probe_job.cc b/chrome/browser/net/dns_probe_job.cc
index afa49cf..204484e 100644
--- a/chrome/browser/net/dns_probe_job.cc
+++ b/chrome/browser/net/dns_probe_job.cc
@@ -105,7 +105,7 @@ DnsProbeJobImpl::DnsProbeJobImpl(scoped_ptr<DnsClient> dns_client,
   DCHECK(dns_client_.get());
   DCHECK(dns_client_->GetConfig());
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&DnsProbeJobImpl::Start,
                  weak_factory_.GetWeakPtr()));
diff --git a/chrome/browser/net/dns_probe_job_unittest.cc b/chrome/browser/net/dns_probe_job_unittest.cc
index 1fe8766..d1779b1 100644
--- a/chrome/browser/net/dns_probe_job_unittest.cc
+++ b/chrome/browser/net/dns_probe_job_unittest.cc
@@ -70,7 +70,7 @@ void DnsProbeJobTest::RunProbe(MockDnsClientRule::Result good_result,
   callback_result_ = DnsProbeJob::SERVERS_UNKNOWN;
 
   // DnsProbeJob needs somewhere to post the callback.
-  scoped_ptr<MessageLoop> message_loop_(new MessageLoopForIO());
+  scoped_ptr<base::MessageLoop> message_loop_(new base::MessageLoopForIO());
 
   scoped_ptr<DnsProbeJob> job(
       DnsProbeJob::CreateJob(dns_client.Pass(), callback, net_log));
diff --git a/chrome/browser/net/dns_probe_service_unittest.cc b/chrome/browser/net/dns_probe_service_unittest.cc
index cee5475..108332a 100644
--- a/chrome/browser/net/dns_probe_service_unittest.cc
+++ b/chrome/browser/net/dns_probe_service_unittest.cc
@@ -24,7 +24,7 @@ class MockDnsProbeJob : public DnsProbeJob {
   MockDnsProbeJob(const CallbackType& callback,
                   DnsProbeJob::Result result)
       : weak_factory_(this) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&MockDnsProbeJob::CallCallback,
                    weak_factory_.GetWeakPtr(),
@@ -131,7 +131,7 @@ class DnsProbeServiceTest : public testing::Test {
     callback_called_ = false;
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   TestDnsProbeService service_;
   bool callback_called_;
   DnsProbeResult callback_result_;
diff --git a/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc b/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc
index dc46f8b..2f14235 100644
--- a/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc
+++ b/chrome/browser/net/http_pipelining_compatibility_client_unittest.cc
@@ -204,7 +204,7 @@ class HttpPipeliningCompatibilityClientTest : public testing::Test {
     }
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   net::SpawnedTestServer test_server_;
   net::TestURLRequestContextGetter* context_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/net/http_server_properties_manager_unittest.cc b/chrome/browser/net/http_server_properties_manager_unittest.cc
index f3e1061..5ce5584 100644
--- a/chrome/browser/net/http_server_properties_manager_unittest.cc
+++ b/chrome/browser/net/http_server_properties_manager_unittest.cc
@@ -126,7 +126,7 @@ class HttpServerPropertiesManagerTest : public testing::Test {
                    UpdatePrefsFromCacheOnIOConcrete));
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   TestingPrefServiceSimple pref_service_;
   scoped_ptr<TestingHttpServerPropertiesManager> http_server_props_manager_;
 
@@ -440,7 +440,7 @@ TEST_F(HttpServerPropertiesManagerTest, Clear) {
   ExpectPrefsUpdate();
 
   // Clear http server data, time out if we do not get a completion callback.
-  http_server_props_manager_->Clear(MessageLoop::QuitClosure());
+  http_server_props_manager_->Clear(base::MessageLoop::QuitClosure());
   loop_.Run();
 
   EXPECT_FALSE(http_server_props_manager_->SupportsSpdy(spdy_server_mail));
diff --git a/chrome/browser/net/load_timing_browsertest.cc b/chrome/browser/net/load_timing_browsertest.cc
index 33c492b..e08ba23 100644
--- a/chrome/browser/net/load_timing_browsertest.cc
+++ b/chrome/browser/net/load_timing_browsertest.cc
@@ -135,7 +135,7 @@ class MockUrlRequestJobWithTiming : public net::URLRequestFileJob {
                          base::TimeDelta::FromMilliseconds(100);
     }
 
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&MockUrlRequestJobWithTiming::DelayedStart,
                    weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/net/net_log_temp_file_unittest.cc b/chrome/browser/net/net_log_temp_file_unittest.cc
index 6337b03..553c820 100644
--- a/chrome/browser/net/net_log_temp_file_unittest.cc
+++ b/chrome/browser/net/net_log_temp_file_unittest.cc
@@ -155,7 +155,7 @@ class NetLogTempFileTest : public ::testing::Test {
   base::FilePath net_export_log_;
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread file_user_blocking_thread_;
 };
 
diff --git a/chrome/browser/net/network_stats.cc b/chrome/browser/net/network_stats.cc
index 70f47ea..86a19f0 100644
--- a/chrome/browser/net/network_stats.cc
+++ b/chrome/browser/net/network_stats.cc
@@ -265,14 +265,14 @@ void NetworkStats::SendPacket() {
 
 void NetworkStats::SendNextPacketAfterDelay() {
   if (current_test_ == PACED_PACKET_TEST) {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&NetworkStats::SendPacket, weak_factory_.GetWeakPtr()),
         average_time_);
     return;
   }
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&NetworkStats::SendPacket, weak_factory_.GetWeakPtr()));
 }
@@ -324,7 +324,7 @@ void NetworkStats::OnReadComplete(int result) {
     // of 1ms so that the time-out will fire before we have time to really hog
     // the CPU too extensively (waiting for the time-out) in case of an infinite
     // loop.
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&NetworkStats::ReadData, weak_factory_.GetWeakPtr()),
         base::TimeDelta::FromMilliseconds(1));
@@ -351,7 +351,7 @@ void NetworkStats::OnWriteComplete(int result) {
     DCHECK_EQ(bytes_to_send_, 0u);
   }
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&NetworkStats::SendPacket, weak_factory_.GetWeakPtr()));
 }
@@ -432,7 +432,7 @@ void NetworkStats::DidSendData(int bytes_sent) {
 }
 
 void NetworkStats::StartReadDataTimer(int milliseconds) {
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&NetworkStats::OnReadDataTimeout,
                  weak_factory_.GetWeakPtr(),
@@ -649,7 +649,7 @@ void NetworkStats::Finish(Status status, int result) {
 
   if (next_test() == NON_PACED_PACKET_TEST ||
       next_test() == PACED_PACKET_TEST) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&NetworkStats::RestartPacketTest,
                    weak_factory_.GetWeakPtr()));
diff --git a/chrome/browser/net/network_stats_unittest.cc b/chrome/browser/net/network_stats_unittest.cc
index bb3093a..990419f 100644
--- a/chrome/browser/net/network_stats_unittest.cc
+++ b/chrome/browser/net/network_stats_unittest.cc
@@ -24,7 +24,7 @@ class NetworkStatsTest : public PlatformTest {
     // Flush the message loop to make application verifiers happy.
     message_loop_.RunUntilIdle();
   }
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
 };
 
 class NetworkStatsTestUDP : public NetworkStatsTest {
diff --git a/chrome/browser/net/network_time_tracker.cc b/chrome/browser/net/network_time_tracker.cc
index 1334fb6..ff4dae5 100644
--- a/chrome/browser/net/network_time_tracker.cc
+++ b/chrome/browser/net/network_time_tracker.cc
@@ -128,7 +128,7 @@ NetworkTimeTracker::BuildNotifierUpdateCallback() {
 net::NetworkTimeNotifier::ObserverCallback
 NetworkTimeTracker::BuildObserverCallback() {
   return base::Bind(&OnNetworkTimeUpdatedOnIOThread,
-                    MessageLoop::current()->message_loop_proxy(),
+                    base::MessageLoop::current()->message_loop_proxy(),
                     base::Bind(&NetworkTimeTracker::OnNetworkTimeUpdate,
                                weak_ptr_factory_.GetWeakPtr()));
 }
diff --git a/chrome/browser/net/network_time_tracker_unittest.cc b/chrome/browser/net/network_time_tracker_unittest.cc
index 7aa80ff..f6a33b6 100644
--- a/chrome/browser/net/network_time_tracker_unittest.cc
+++ b/chrome/browser/net/network_time_tracker_unittest.cc
@@ -124,7 +124,7 @@ class NetworkTimeTrackerTest : public testing::Test {
 
  private:
   // Message loop and threads for the tracker's internal logic.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread;
   content::TestBrowserThread io_thread;
 
diff --git a/chrome/browser/net/predictor.cc b/chrome/browser/net/predictor.cc
index c321ed2..b1a3f60 100644
--- a/chrome/browser/net/predictor.cc
+++ b/chrome/browser/net/predictor.cc
@@ -1070,7 +1070,7 @@ void Predictor::PostIncrementalTrimTask() {
     return;
   const TimeDelta kDurationBetweenTrimmingIncrements =
       TimeDelta::FromSeconds(kDurationBetweenTrimmingIncrementsSeconds);
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&Predictor::IncrementalTrimReferrers,
                  weak_factory_->GetWeakPtr(), false),
diff --git a/chrome/browser/net/predictor_browsertest.cc b/chrome/browser/net/predictor_browsertest.cc
index 946d656..975ab56 100644
--- a/chrome/browser/net/predictor_browsertest.cc
+++ b/chrome/browser/net/predictor_browsertest.cc
@@ -69,7 +69,7 @@ class HostResolutionRequestRecorder : public net::HostResolverProc {
     if (is_waiting_for_hostname_ && waiting_for_hostname_ == hostname) {
       is_waiting_for_hostname_ = false;
       waiting_for_hostname_.clear();
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/net/predictor_unittest.cc b/chrome/browser/net/predictor_unittest.cc
index f509e1c..a2940a8 100644
--- a/chrome/browser/net/predictor_unittest.cc
+++ b/chrome/browser/net/predictor_unittest.cc
@@ -49,7 +49,7 @@ class WaitForResolutionHelper {
 
     // When all hostnames have been resolved, exit the loop.
     timer_->Stop();
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
     delete timer_;
     delete this;
   }
@@ -92,14 +92,14 @@ class PredictorTest : public testing::Test {
     timer->Start(FROM_HERE, TimeDelta::FromMilliseconds(100),
                  new WaitForResolutionHelper(predictor, hosts, timer),
                  &WaitForResolutionHelper::Run);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
  private:
   // IMPORTANT: do not move this below |host_resolver_|; the host resolver
   // must not outlive the message loop, otherwise bad things can happen
   // (like posting to a deleted message loop).
-  MessageLoopForUI loop_;
+  base::MessageLoopForUI loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
@@ -127,18 +127,18 @@ TEST_F(PredictorTest, ShutdownWhenResolutionIsPendingTest) {
 
   testing_master.ResolveList(names, UrlInfo::PAGE_SCAN_MOTIVATED);
 
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
-      MessageLoop::QuitClosure(),
+      base::MessageLoop::QuitClosure(),
       base::TimeDelta::FromMilliseconds(500));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   EXPECT_FALSE(testing_master.WasFound(localhost));
 
   testing_master.Shutdown();
 
   // Clean up after ourselves.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 TEST_F(PredictorTest, SingleLookupTest) {
@@ -158,7 +158,7 @@ TEST_F(PredictorTest, SingleLookupTest) {
 
   EXPECT_TRUE(testing_master.WasFound(goog));
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_GT(testing_master.peak_pending_lookups(), names.size() / 2);
   EXPECT_LE(testing_master.peak_pending_lookups(), names.size());
@@ -203,7 +203,7 @@ TEST_F(PredictorTest, ConcurrentLookupTest) {
   EXPECT_FALSE(testing_master.WasFound(bad1));
   EXPECT_FALSE(testing_master.WasFound(bad2));
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_FALSE(testing_master.WasFound(bad1));
   EXPECT_FALSE(testing_master.WasFound(bad2));
@@ -232,7 +232,7 @@ TEST_F(PredictorTest, MassiveConcurrentLookupTest) {
 
   WaitForResolution(&testing_master, names);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_LE(testing_master.peak_pending_lookups(), names.size());
   EXPECT_LE(testing_master.peak_pending_lookups(),
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..770c8a9 100644
--- a/chrome/browser/net/pref_proxy_config_tracker_impl_unittest.cc
+++ b/chrome/browser/net/pref_proxy_config_tracker_impl_unittest.cc
@@ -105,7 +105,7 @@ class PrefProxyConfigTrackerImplTestBase : public TESTBASE {
     proxy_config_service_.reset();
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   TestProxyConfigService* delegate_service_; // weak
   scoped_ptr<ChromeProxyConfigService> proxy_config_service_;
   net::ProxyConfig fixed_config_;
diff --git a/chrome/browser/net/sdch_dictionary_fetcher.cc b/chrome/browser/net/sdch_dictionary_fetcher.cc
index 008e9a4..0e7d8c9 100644
--- a/chrome/browser/net/sdch_dictionary_fetcher.cc
+++ b/chrome/browser/net/sdch_dictionary_fetcher.cc
@@ -54,7 +54,7 @@ void SdchDictionaryFetcher::Schedule(const GURL& dictionary_url) {
 void SdchDictionaryFetcher::ScheduleDelayedRun() {
   if (fetch_queue_.empty() || current_fetch_.get() || task_is_pending_)
     return;
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(&SdchDictionaryFetcher::StartFetching,
                  weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kMsDelayFromRequestTillDownload));
diff --git a/chrome/browser/net/sqlite_server_bound_cert_store_unittest.cc b/chrome/browser/net/sqlite_server_bound_cert_store_unittest.cc
index 44af9d6..68097c2 100644
--- a/chrome/browser/net/sqlite_server_bound_cert_store_unittest.cc
+++ b/chrome/browser/net/sqlite_server_bound_cert_store_unittest.cc
@@ -97,7 +97,7 @@ class SQLiteServerBoundCertStoreTest : public testing::Test {
             "a", "b"));
   }
 
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread io_thread_;
   base::ScopedTempDir temp_dir_;
diff --git a/chrome/browser/net/ssl_config_service_manager_pref_unittest.cc b/chrome/browser/net/ssl_config_service_manager_pref_unittest.cc
index 0e8fc37..fa29093 100644
--- a/chrome/browser/net/ssl_config_service_manager_pref_unittest.cc
+++ b/chrome/browser/net/ssl_config_service_manager_pref_unittest.cc
@@ -54,7 +54,7 @@ class SSLConfigServiceManagerPrefTest : public testing::Test {
     return config.channel_id_enabled;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 };
diff --git a/chrome/browser/net/transport_security_persister_unittest.cc b/chrome/browser/net/transport_security_persister_unittest.cc
index 4177bc8..1c121e8 100644
--- a/chrome/browser/net/transport_security_persister_unittest.cc
+++ b/chrome/browser/net/transport_security_persister_unittest.cc
@@ -21,7 +21,7 @@ using net::TransportSecurityState;
 class TransportSecurityPersisterTest : public testing::Test {
  public:
   TransportSecurityPersisterTest()
-      : message_loop_(MessageLoop::TYPE_IO),
+      : message_loop_(base::MessageLoop::TYPE_IO),
         test_file_thread_(content::BrowserThread::FILE, &message_loop_),
         test_io_thread_(content::BrowserThread::IO, &message_loop_) {
   }
@@ -39,7 +39,7 @@ class TransportSecurityPersisterTest : public testing::Test {
  protected:
   // Ordering is important here. If member variables are not destroyed in the
   // right order, then DCHECKs will fail all over the place.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   // Needed for ImportantFileWriter, which TransportSecurityPersister uses.
   content::TestBrowserThread test_file_thread_;
diff --git a/chrome/browser/notifications/balloon_collection_impl.cc b/chrome/browser/notifications/balloon_collection_impl.cc
index 08971de..1d032d2 100644
--- a/chrome/browser/notifications/balloon_collection_impl.cc
+++ b/chrome/browser/notifications/balloon_collection_impl.cc
@@ -235,14 +235,14 @@ gfx::Rect BalloonCollectionImpl::GetBalloonsBoundingBox() const {
 #if USE_OFFSETS
 void BalloonCollectionImpl::AddMessageLoopObserver() {
   if (!added_as_message_loop_observer_) {
-    MessageLoopForUI::current()->AddObserver(this);
+    base::MessageLoopForUI::current()->AddObserver(this);
     added_as_message_loop_observer_ = true;
   }
 }
 
 void BalloonCollectionImpl::RemoveMessageLoopObserver() {
   if (added_as_message_loop_observer_) {
-    MessageLoopForUI::current()->RemoveObserver(this);
+    base::MessageLoopForUI::current()->RemoveObserver(this);
     added_as_message_loop_observer_ = false;
   }
 }
@@ -267,7 +267,7 @@ void BalloonCollectionImpl::HandleMouseMoveEvent() {
     // Mouse has left the region.  Schedule a reposition after
     // a short delay.
     if (!reposition_factory_.HasWeakPtrs()) {
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           base::Bind(&BalloonCollectionImpl::CancelOffsets,
                      reposition_factory_.GetWeakPtr()),
diff --git a/chrome/browser/notifications/balloon_collection_impl.h b/chrome/browser/notifications/balloon_collection_impl.h
index cff7077..07b223d 100644
--- a/chrome/browser/notifications/balloon_collection_impl.h
+++ b/chrome/browser/notifications/balloon_collection_impl.h
@@ -36,7 +36,7 @@
 class BalloonCollectionImpl : public BalloonCollection,
                               public content::NotificationObserver
 #if USE_OFFSETS
-                            , public MessageLoopForUI::Observer
+                            , public base::MessageLoopForUI::Observer
 #endif
 {
  public:
diff --git a/chrome/browser/notifications/desktop_notification_service_unittest.cc b/chrome/browser/notifications/desktop_notification_service_unittest.cc
index 389b3d2..a9626e0 100644
--- a/chrome/browser/notifications/desktop_notification_service_unittest.cc
+++ b/chrome/browser/notifications/desktop_notification_service_unittest.cc
@@ -30,7 +30,7 @@ class ThreadProxy : public base::RefCountedThreadSafe<ThreadProxy> {
     // The current message loop was already initalized by the test superclass.
     ui_thread_.reset(
         new content::TestBrowserThread(BrowserThread::UI,
-                                       MessageLoop::current()));
+                                       base::MessageLoop::current()));
 
     // Create IO thread, start its message loop.
     io_thread_.reset(new content::TestBrowserThread(BrowserThread::IO));
diff --git a/chrome/browser/notifications/desktop_notifications_unittest.cc b/chrome/browser/notifications/desktop_notifications_unittest.cc
index dbf7e1c..dfc9967 100644
--- a/chrome/browser/notifications/desktop_notifications_unittest.cc
+++ b/chrome/browser/notifications/desktop_notifications_unittest.cc
@@ -166,7 +166,7 @@ TEST_F(DesktopNotificationsTest, TestShow) {
 
   EXPECT_TRUE(service_->ShowDesktopNotification(
       params, 0, 0, DesktopNotificationService::PageNotification));
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
   EXPECT_EQ(1, balloon_collection_->count());
 
   content::ShowDesktopNotificationHostMsgParams params2;
@@ -177,7 +177,7 @@ TEST_F(DesktopNotificationsTest, TestShow) {
 
   EXPECT_TRUE(service_->ShowDesktopNotification(
       params2, 0, 0, DesktopNotificationService::PageNotification));
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
   EXPECT_EQ(2, balloon_collection_->count());
 
   EXPECT_EQ("notification displayed\n"
@@ -193,7 +193,7 @@ TEST_F(DesktopNotificationsTest, TestClose) {
   // Request a notification; should open a balloon.
   EXPECT_TRUE(service_->ShowDesktopNotification(
       params, 0, 0, DesktopNotificationService::PageNotification));
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
   EXPECT_EQ(1, balloon_collection_->count());
 
   // Close all the open balloons.
@@ -219,14 +219,14 @@ TEST_F(DesktopNotificationsTest, TestCancel) {
   EXPECT_TRUE(service_->ShowDesktopNotification(
       params, process_id, route_id,
       DesktopNotificationService::PageNotification));
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
   EXPECT_EQ(1, balloon_collection_->count());
 
   // Cancel the same notification
   service_->CancelDesktopNotification(process_id,
                                       route_id,
                                       notification_id);
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
   // Verify that the balloon collection is now empty.
   EXPECT_EQ(0, balloon_collection_->count());
 
@@ -334,7 +334,7 @@ TEST_F(DesktopNotificationsTest, TestCancelByProfile) {
         params, process_id, route_id,
         DesktopNotificationService::PageNotification));
   }
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
 
   ui_manager_->CancelAllByProfile(second_profile);
 
@@ -371,7 +371,7 @@ TEST_F(DesktopNotificationsTest, TestCancelBySourceOrigin) {
         odd_params, process_id, route_id,
         DesktopNotificationService::PageNotification));
   }
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
 
   ui_manager_->CancelAllBySourceOrigin(odd_params.origin);
 
@@ -394,7 +394,7 @@ TEST_F(DesktopNotificationsTest, TestQueueing) {
         params, process_id, route_id,
         DesktopNotificationService::PageNotification));
   }
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
 
   // Build up an expected log of what should be happening.
   std::string expected_log;
@@ -416,7 +416,7 @@ TEST_F(DesktopNotificationsTest, TestQueueing) {
          id <= kLotsOfToasts - balloon_collection_->max_balloon_count();
          ++id) {
       service_->CancelDesktopNotification(process_id, route_id, id);
-      MessageLoopForUI::current()->RunUntilIdle();
+      base::MessageLoopForUI::current()->RunUntilIdle();
       expected_log.append("notification closed by script\n");
       expected_log.append("notification displayed\n");
       EXPECT_EQ(balloon_collection_->max_balloon_count(),
@@ -428,7 +428,7 @@ TEST_F(DesktopNotificationsTest, TestQueueing) {
     for (; id <= kLotsOfToasts; ++id) {
       service_->CancelDesktopNotification(process_id, route_id, id);
       expected_log.append("notification closed by script\n");
-      MessageLoopForUI::current()->RunUntilIdle();
+      base::MessageLoopForUI::current()->RunUntilIdle();
       EXPECT_EQ(expected_log, log_output_);
     }
   }
@@ -461,7 +461,7 @@ TEST_F(DesktopNotificationsTest, TestUserInputEscaping) {
   EXPECT_TRUE(service_->ShowDesktopNotification(
       params, 0, 0, DesktopNotificationService::PageNotification));
 
-  MessageLoopForUI::current()->RunUntilIdle();
+  base::MessageLoopForUI::current()->RunUntilIdle();
   EXPECT_EQ(1, balloon_collection_->count());
   Balloon* balloon = (*balloon_collection_->balloons().begin());
   GURL data_url = balloon->notification().content_url();
diff --git a/chrome/browser/notifications/desktop_notifications_unittest.h b/chrome/browser/notifications/desktop_notifications_unittest.h
index 2fda90d..1aa5947 100644
--- a/chrome/browser/notifications/desktop_notifications_unittest.h
+++ b/chrome/browser/notifications/desktop_notifications_unittest.h
@@ -96,7 +96,7 @@ class DesktopNotificationsTest : public testing::Test {
 
   // Create a message loop to allow notifications code to post tasks,
   // and a thread so that notifications code runs on the expected thread.
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   // Local state mock.
diff --git a/chrome/browser/omnibox_search_hint.cc b/chrome/browser/omnibox_search_hint.cc
index a4c93e2..b888623 100644
--- a/chrome/browser/omnibox_search_hint.cc
+++ b/chrome/browser/omnibox_search_hint.cc
@@ -136,7 +136,7 @@ HintInfoBarDelegate::HintInfoBarDelegate(OmniboxSearchHint* omnibox_hint,
       weak_factory_(this) {
   // We want the info-bar to stick-around for few seconds and then be hidden
   // on the next navigation after that.
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&HintInfoBarDelegate::AllowExpiry, weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromSeconds(8));
diff --git a/chrome/browser/page_cycler/page_cycler_browsertest.cc b/chrome/browser/page_cycler/page_cycler_browsertest.cc
index 00c52a2..6edf4f2 100644
--- a/chrome/browser/page_cycler/page_cycler_browsertest.cc
+++ b/chrome/browser/page_cycler/page_cycler_browsertest.cc
@@ -117,7 +117,8 @@ class PageCyclerBrowserTest : public content::NotificationObserver,
                        const content::NotificationDetails& details) OVERRIDE {
     switch (type) {
       case chrome::NOTIFICATION_BROWSER_CLOSED:
-        MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+        base::MessageLoop::current()->PostTask(
+            FROM_HERE, base::MessageLoop::QuitClosure());
         break;
       default:
         NOTREACHED();
diff --git a/chrome/browser/password_manager/native_backend_gnome_x_unittest.cc b/chrome/browser/password_manager/native_backend_gnome_x_unittest.cc
index 393ecdb..25cce09 100644
--- a/chrome/browser/password_manager/native_backend_gnome_x_unittest.cc
+++ b/chrome/browser/password_manager/native_backend_gnome_x_unittest.cc
@@ -307,8 +307,9 @@ class NativeBackendGnomeTest : public testing::Test {
   }
 
   virtual void TearDown() {
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
     db_thread_.Stop();
   }
 
@@ -320,11 +321,11 @@ class NativeBackendGnomeTest : public testing::Test {
     // quit so we can get on with the rest of the test.
     BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
         base::Bind(&PostQuitTask, &message_loop_));
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
-  static void PostQuitTask(MessageLoop* loop) {
-    loop->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+  static void PostQuitTask(base::MessageLoop* loop) {
+    loop->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
   void CheckUint32Attribute(const MockKeyringItem* item,
@@ -378,7 +379,7 @@ class NativeBackendGnomeTest : public testing::Test {
     CheckStringAttribute(item, "application", app_string);
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
 
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..0da3455 100644
--- a/chrome/browser/password_manager/native_backend_kwallet_x_unittest.cc
+++ b/chrome/browser/password_manager/native_backend_kwallet_x_unittest.cc
@@ -212,7 +212,7 @@ class NativeBackendKWalletTest : public NativeBackendKWalletTestBase {
   void CheckPasswordForms(const std::string& folder,
                           const ExpectationArray& sorted_expected);
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   TestingProfile profile_;
@@ -278,8 +278,9 @@ void NativeBackendKWalletTest::SetUp() {
 }
 
 void NativeBackendKWalletTest::TearDown() {
-  MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->PostTask(FROM_HERE,
+                                         base::MessageLoop::QuitClosure());
+  base::MessageLoop::current()->Run();
   db_thread_.Stop();
 }
 
diff --git a/chrome/browser/password_manager/password_manager_unittest.cc b/chrome/browser/password_manager/password_manager_unittest.cc
index 661d34f..dfdd956 100644
--- a/chrome/browser/password_manager/password_manager_unittest.cc
+++ b/chrome/browser/password_manager/password_manager_unittest.cc
@@ -50,7 +50,7 @@ ACTION_P(SaveToScopedPtr, scoped) {
 class PasswordManagerTest : public ChromeRenderViewHostTestHarness {
  public:
   PasswordManagerTest()
-      : ui_thread_(BrowserThread::UI, MessageLoopForUI::current()) {}
+      : ui_thread_(BrowserThread::UI, base::MessageLoopForUI::current()) {}
   virtual ~PasswordManagerTest() {}
 
  protected:
diff --git a/chrome/browser/password_manager/password_store_default_unittest.cc b/chrome/browser/password_manager/password_store_default_unittest.cc
index 92d0e98..825f2ab 100644
--- a/chrome/browser/password_manager/password_store_default_unittest.cc
+++ b/chrome/browser/password_manager/password_store_default_unittest.cc
@@ -112,12 +112,13 @@ class PasswordStoreDefaultTest : public testing::Test {
   }
 
   virtual void TearDown() {
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
     db_thread_.Stop();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   // PasswordStore, WDS schedule work on this thread.
   content::TestBrowserThread db_thread_;
@@ -132,7 +133,7 @@ ACTION(STLDeleteElements0) {
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 TEST_F(PasswordStoreDefaultTest, NonASCIIData) {
@@ -184,7 +185,7 @@ TEST_F(PasswordStoreDefaultTest, NonASCIIData) {
       .WillOnce(DoAll(WithArg<1>(STLDeleteElements0()), QuitUIMessageLoop()));
 
   store->GetAutofillableLogins(&consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   STLDeleteElements(&expected_forms);
 }
diff --git a/chrome/browser/password_manager/password_store_mac.cc b/chrome/browser/password_manager/password_store_mac.cc
index 33aec57..5d18ff2 100644
--- a/chrome/browser/password_manager/password_store_mac.cc
+++ b/chrome/browser/password_manager/password_store_mac.cc
@@ -935,7 +935,7 @@ void PasswordStoreMac::GetAutofillableLoginsImpl(GetLoginsRequest* request) {
 
 bool PasswordStoreMac::FillAutofillableLogins(
          std::vector<PasswordForm*>* forms) {
-  DCHECK(thread_->message_loop() == MessageLoop::current());
+  DCHECK(thread_->message_loop() == base::MessageLoop::current());
 
   std::vector<PasswordForm*> database_forms;
   login_metadata_db_->GetAutofillableLogins(&database_forms);
@@ -954,7 +954,7 @@ bool PasswordStoreMac::FillAutofillableLogins(
 
 bool PasswordStoreMac::FillBlacklistLogins(
          std::vector<PasswordForm*>* forms) {
-  DCHECK(thread_->message_loop() == MessageLoop::current());
+  DCHECK(thread_->message_loop() == base::MessageLoop::current());
   return login_metadata_db_->GetBlacklistLogins(forms);
 }
 
diff --git a/chrome/browser/password_manager/password_store_mac_unittest.cc b/chrome/browser/password_manager/password_store_mac_unittest.cc
index 5107a3d..4dcef68 100644
--- a/chrome/browser/password_manager/password_store_mac_unittest.cc
+++ b/chrome/browser/password_manager/password_store_mac_unittest.cc
@@ -42,7 +42,7 @@ ACTION(STLDeleteElements0) {
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 }  // namespace
@@ -916,12 +916,13 @@ class PasswordStoreMacTest : public testing::Test {
 
   virtual void TearDown() {
     store_->ShutdownOnUIThread();
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
 
   MockAppleKeychain* keychain_;  // Owned by store_.
@@ -1002,7 +1003,7 @@ TEST_F(PasswordStoreMacTest, TestStoreUpdate) {
   EXPECT_CALL(consumer, OnGetPasswordStoreResults(_)).WillOnce(
       DoAll(WithArg<0>(STLDeleteElements0()), QuitUIMessageLoop()));
   store_->GetLogins(*joint_form, &consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   MacKeychainPasswordFormAdapter keychain_adapter(keychain_);
   for (unsigned int i = 0; i < ARRAYSIZE_UNSAFE(updates); ++i) {
diff --git a/chrome/browser/password_manager/password_store_unittest.cc b/chrome/browser/password_manager/password_store_unittest.cc
index 0c5f083..5a32bcd 100644
--- a/chrome/browser/password_manager/password_store_unittest.cc
+++ b/chrome/browser/password_manager/password_store_unittest.cc
@@ -106,11 +106,12 @@ class PasswordStoreTest : public testing::Test {
 
   virtual void TearDown() {
     db_thread_.Stop();
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   // PasswordStore schedules work on this thread.
   content::TestBrowserThread db_thread_;
@@ -125,7 +126,7 @@ ACTION(STLDeleteElements0) {
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 TEST_F(PasswordStoreTest, IgnoreOldWwwGoogleLogins) {
@@ -262,7 +263,7 @@ TEST_F(PasswordStoreTest, IgnoreOldWwwGoogleLogins) {
   store->GetLogins(accounts_google, &consumer);
   store->GetLogins(bar_example, &consumer);
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   STLDeleteElements(&all_forms);
 }
diff --git a/chrome/browser/password_manager/password_store_win_unittest.cc b/chrome/browser/password_manager/password_store_win_unittest.cc
index e6fe9dd..6fdb985 100644
--- a/chrome/browser/password_manager/password_store_win_unittest.cc
+++ b/chrome/browser/password_manager/password_store_win_unittest.cc
@@ -137,12 +137,13 @@ class PasswordStoreWinTest : public testing::Test {
     BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
         base::Bind(&base::WaitableEvent::Signal, base::Unretained(&done)));
     done.Wait();
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
     db_thread_.Stop();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   // PasswordStore, WDS schedule work on this thread.
   content::TestBrowserThread db_thread_;
@@ -161,7 +162,7 @@ ACTION(STLDeleteElements0) {
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 MATCHER(EmptyWDResult, "") {
@@ -234,7 +235,7 @@ TEST_F(PasswordStoreWinTest, DISABLED_ConvertIE7Login) {
       .WillOnce(QuitUIMessageLoop());
 
   store_->GetLogins(*form, &consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   STLDeleteElements(&forms);
 }
@@ -267,7 +268,7 @@ TEST_F(PasswordStoreWinTest, DISABLED_OutstandingWDSQueries) {
   store_ = NULL;
   wds_ = NULL;
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 // Hangs flakily, see http://crbug.com/43836.
@@ -341,8 +342,8 @@ TEST_F(PasswordStoreWinTest, DISABLED_MultipleWDSQueriesOnDifferentThreads) {
   // Run the MessageLoop twice: once for the GetIE7Login that PasswordStoreWin
   // schedules on the DB thread and once for the one we just scheduled on the UI
   // thread.
-  MessageLoop::current()->Run();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   STLDeleteElements(&forms);
 }
@@ -379,7 +380,7 @@ TEST_F(PasswordStoreWinTest, EmptyLogins) {
       .WillOnce(DoAll(WithArg<0>(STLDeleteElements0()), QuitUIMessageLoop()));
 
   store_->GetLogins(*form, &consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 TEST_F(PasswordStoreWinTest, EmptyBlacklistLogins) {
@@ -401,7 +402,7 @@ TEST_F(PasswordStoreWinTest, EmptyBlacklistLogins) {
       .WillOnce(DoAll(WithArg<1>(STLDeleteElements0()), QuitUIMessageLoop()));
 
   store_->GetBlacklistLogins(&consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 TEST_F(PasswordStoreWinTest, EmptyAutofillableLogins) {
@@ -423,5 +424,5 @@ TEST_F(PasswordStoreWinTest, EmptyAutofillableLogins) {
       .WillOnce(DoAll(WithArg<1>(STLDeleteElements0()), QuitUIMessageLoop()));
 
   store_->GetAutofillableLogins(&consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
diff --git a/chrome/browser/password_manager/password_store_x_unittest.cc b/chrome/browser/password_manager/password_store_x_unittest.cc
index 8ba62cc..6be0ab9 100644
--- a/chrome/browser/password_manager/password_store_x_unittest.cc
+++ b/chrome/browser/password_manager/password_store_x_unittest.cc
@@ -285,8 +285,9 @@ class PasswordStoreXTest : public testing::TestWithParam<BackendType> {
   }
 
   virtual void TearDown() {
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
     db_thread_.Stop();
   }
 
@@ -301,7 +302,7 @@ class PasswordStoreXTest : public testing::TestWithParam<BackendType> {
     }
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   // PasswordStore, WDS schedule work on this thread.
   content::TestBrowserThread db_thread_;
@@ -317,7 +318,7 @@ ACTION(STLDeleteElements0) {
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 TEST_P(PasswordStoreXTest, Notifications) {
@@ -472,7 +473,7 @@ TEST_P(PasswordStoreXTest, NativeMigration) {
       .WillOnce(DoAll(WithArg<1>(STLDeleteElements0()), QuitUIMessageLoop()));
 
   store->GetAutofillableLogins(&consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // The blacklisted forms should have been migrated to the native backend.
   EXPECT_CALL(consumer,
@@ -481,7 +482,7 @@ TEST_P(PasswordStoreXTest, NativeMigration) {
       .WillOnce(DoAll(WithArg<1>(STLDeleteElements0()), QuitUIMessageLoop()));
 
   store->GetBlacklistLogins(&consumer);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   VectorOfForms empty;
   MockLoginDatabaseReturn ld_return;
diff --git a/chrome/browser/plugins/plugin_prefs.cc b/chrome/browser/plugins/plugin_prefs.cc
index 56e33e2..e570c00 100644
--- a/chrome/browser/plugins/plugin_prefs.cc
+++ b/chrome/browser/plugins/plugin_prefs.cc
@@ -164,8 +164,8 @@ void PluginPrefs::EnablePlugin(
   }
 
   if (!can_enable) {
-    MessageLoop::current()->PostTask(FROM_HERE,
-                                     base::Bind(callback, false));
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(callback, false));
     return;
   }
 
diff --git a/chrome/browser/plugins/plugin_prefs_unittest.cc b/chrome/browser/plugins/plugin_prefs_unittest.cc
index ad1aa8e..42d1b05 100644
--- a/chrome/browser/plugins/plugin_prefs_unittest.cc
+++ b/chrome/browser/plugins/plugin_prefs_unittest.cc
@@ -180,7 +180,7 @@ TEST_F(PluginPrefsTest, EnabledAndDisabledByPolicy) {
 TEST_F(PluginPrefsTest, UnifiedPepperFlashState) {
   base::ShadowingAtExitManager at_exit_manager_;  // Destroys the PluginService.
 
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   webkit::npapi::MockPluginList plugin_list;
   PluginService::GetInstance()->SetPluginListForTesting(&plugin_list);
diff --git a/chrome/browser/policy/async_policy_provider_unittest.cc b/chrome/browser/policy/async_policy_provider_unittest.cc
index 3520a87..0d04efe 100644
--- a/chrome/browser/policy/async_policy_provider_unittest.cc
+++ b/chrome/browser/policy/async_policy_provider_unittest.cc
@@ -80,7 +80,7 @@ class AsyncPolicyProviderTest : public testing::Test {
   MockPolicyLoader* loader_;
   scoped_ptr<AsyncPolicyProvider> provider_;
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 
  private:
   content::TestBrowserThread ui_thread_;
diff --git a/chrome/browser/policy/browser_policy_connector.cc b/chrome/browser/policy/browser_policy_connector.cc
index 465ba2e..393edac 100644
--- a/chrome/browser/policy/browser_policy_connector.cc
+++ b/chrome/browser/policy/browser_policy_connector.cc
@@ -204,7 +204,7 @@ void BrowserPolicyConnector::Init(
       new policy::PolicyStatisticsCollector(
           GetPolicyService(),
           local_state_,
-          MessageLoop::current()->message_loop_proxy()));
+          base::MessageLoop::current()->message_loop_proxy()));
   policy_statistics_collector_->Initialize();
 
   is_initialized_ = true;
diff --git a/chrome/browser/policy/cloud/cloud_policy_core.cc b/chrome/browser/policy/cloud/cloud_policy_core.cc
index f40e025..232ddc1 100644
--- a/chrome/browser/policy/cloud/cloud_policy_core.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_core.cc
@@ -46,7 +46,7 @@ void CloudPolicyCore::StartRefreshScheduler() {
     refresh_scheduler_.reset(
         new CloudPolicyRefreshScheduler(
             client_.get(), store_,
-            MessageLoop::current()->message_loop_proxy()));
+            base::MessageLoop::current()->message_loop_proxy()));
     UpdateRefreshDelayFromPref();
   }
 }
diff --git a/chrome/browser/policy/cloud/cloud_policy_core_unittest.cc b/chrome/browser/policy/cloud/cloud_policy_core_unittest.cc
index 95a3a25..6e7e447 100644
--- a/chrome/browser/policy/cloud/cloud_policy_core_unittest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_core_unittest.cc
@@ -26,7 +26,7 @@ class CloudPolicyCoreTest : public testing::Test {
     chrome::RegisterLocalState(prefs_.registry());
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 
   TestingPrefServiceSimple prefs_;
   MockCloudPolicyStore store_;
diff --git a/chrome/browser/policy/cloud/cloud_policy_manager_unittest.cc b/chrome/browser/policy/cloud/cloud_policy_manager_unittest.cc
index f7d9564..0b3bdbb 100644
--- a/chrome/browser/policy/cloud/cloud_policy_manager_unittest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_manager_unittest.cc
@@ -179,7 +179,7 @@ class CloudPolicyManagerTest : public testing::Test {
   }
 
   // Required by the refresh scheduler that's created by the manager.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 
   // Testing policy.
   const PolicyNamespaceKey policy_ns_key_;
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..9b15cbf 100644
--- a/chrome/browser/policy/cloud/cloud_policy_refresh_scheduler_unittest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_refresh_scheduler_unittest.cc
@@ -80,7 +80,7 @@ class CloudPolicyRefreshSchedulerTest : public testing::Test {
     EXPECT_LE(GetLastDelay(), expected_delay);
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   MockCloudPolicyClient client_;
   MockCloudPolicyStore store_;
   scoped_refptr<base::TestSimpleTaskRunner> task_runner_;
diff --git a/chrome/browser/policy/cloud/cloud_policy_validator.cc b/chrome/browser/policy/cloud/cloud_policy_validator.cc
index 7d975dd..422f8dc 100644
--- a/chrome/browser/policy/cloud/cloud_policy_validator.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_validator.cc
@@ -131,7 +131,7 @@ void CloudPolicyValidatorBase::PostValidationTask(
       content::BrowserThread::FILE, FROM_HERE,
       base::Bind(&CloudPolicyValidatorBase::PerformValidation,
                  base::Passed(scoped_ptr<CloudPolicyValidatorBase>(this)),
-                 MessageLoop::current()->message_loop_proxy(),
+                 base::MessageLoop::current()->message_loop_proxy(),
                  completion_callback));
 }
 
diff --git a/chrome/browser/policy/cloud/cloud_policy_validator_unittest.cc b/chrome/browser/policy/cloud/cloud_policy_validator_unittest.cc
index 55f9dbf..5c28fb7 100644
--- a/chrome/browser/policy/cloud/cloud_policy_validator_unittest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_validator_unittest.cc
@@ -32,7 +32,7 @@ ACTION_P(CheckStatus, expected_status) {
 class CloudPolicyValidatorTest : public testing::Test {
  public:
   CloudPolicyValidatorTest()
-      : loop_(MessageLoop::TYPE_UI),
+      : loop_(base::MessageLoop::TYPE_UI),
         timestamp_(base::Time::UnixEpoch() +
                    base::TimeDelta::FromMilliseconds(
                        PolicyBuilder::kFakeTimestamp)),
@@ -90,7 +90,7 @@ class CloudPolicyValidatorTest : public testing::Test {
               validator->payload()->SerializeAsString());
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   base::Time timestamp_;
   CloudPolicyValidatorBase::ValidateTimestampOption ignore_missing_timestamp_;
   CloudPolicyValidatorBase::ValidateDMTokenOption ignore_missing_dm_token_;
diff --git a/chrome/browser/policy/cloud/component_cloud_policy_service_unittest.cc b/chrome/browser/policy/cloud/component_cloud_policy_service_unittest.cc
index 37a4fac..d4e54d6 100644
--- a/chrome/browser/policy/cloud/component_cloud_policy_service_unittest.cc
+++ b/chrome/browser/policy/cloud/component_cloud_policy_service_unittest.cc
@@ -196,7 +196,7 @@ class ComponentCloudPolicyServiceTest : public testing::Test {
     return schema.Pass();
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   base::ScopedTempDir temp_dir_;
diff --git a/chrome/browser/policy/cloud/device_management_service.cc b/chrome/browser/policy/cloud/device_management_service.cc
index 8a755a6..3b065897 100644
--- a/chrome/browser/policy/cloud/device_management_service.cc
+++ b/chrome/browser/policy/cloud/device_management_service.cc
@@ -557,7 +557,7 @@ DeviceManagementRequestJob* DeviceManagementService::CreateJob(
 void DeviceManagementService::ScheduleInitialization(int64 delay_milliseconds) {
   if (initialized_)
     return;
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&DeviceManagementService::Initialize,
                  weak_ptr_factory_.GetWeakPtr()),
diff --git a/chrome/browser/policy/cloud/device_management_service_browsertest.cc b/chrome/browser/policy/cloud/device_management_service_browsertest.cc
index 30c4aa6..7a40776 100644
--- a/chrome/browser/policy/cloud/device_management_service_browsertest.cc
+++ b/chrome/browser/policy/cloud/device_management_service_browsertest.cc
@@ -120,8 +120,8 @@ class DeviceManagementServiceIntegrationTest
         .WillOnce(
             DoAll(Invoke(this,
                          &DeviceManagementServiceIntegrationTest::RecordToken),
-                  InvokeWithoutArgs(MessageLoop::current(),
-                                    &MessageLoop::Quit)));
+                  InvokeWithoutArgs(base::MessageLoop::current(),
+                                    &base::MessageLoop::Quit)));
     scoped_ptr<DeviceManagementRequestJob> job(
         service_->CreateJob(DeviceManagementRequestJob::TYPE_REGISTRATION));
     job->SetGaiaToken("gaia_auth_token");
@@ -130,7 +130,7 @@ class DeviceManagementServiceIntegrationTest
     job->GetRequest()->mutable_register_request();
     job->Start(base::Bind(&DeviceManagementServiceIntegrationTest::OnJobDone,
                           base::Unretained(this)));
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   virtual void SetUpOnMainThread() OVERRIDE {
@@ -178,8 +178,8 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest,
       .WillOnce(
           DoAll(Invoke(this,
                        &DeviceManagementServiceIntegrationTest::RecordAuthCode),
-                InvokeWithoutArgs(MessageLoop::current(),
-                                  &MessageLoop::Quit)));
+                InvokeWithoutArgs(base::MessageLoop::current(),
+                                  &base::MessageLoop::Quit)));
   scoped_ptr<DeviceManagementRequestJob> job(service_->CreateJob(
       DeviceManagementRequestJob::TYPE_API_AUTH_CODE_FETCH));
   job->SetDMToken(token_);
@@ -190,7 +190,7 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest,
   request->set_oauth2_client_id("oauth2ClientId4Test");
   job->Start(base::Bind(&DeviceManagementServiceIntegrationTest::OnJobDone,
                         base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   ASSERT_EQ("fake_auth_code", robot_auth_code_);
 }
 
@@ -199,7 +199,8 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, PolicyFetch) {
 
   ExpectRequest();
   EXPECT_CALL(*this, OnJobDone(DM_STATUS_SUCCESS, _, _))
-      .WillOnce(InvokeWithoutArgs(MessageLoop::current(), &MessageLoop::Quit));
+      .WillOnce(InvokeWithoutArgs(base::MessageLoop::current(),
+                                  &base::MessageLoop::Quit));
   scoped_ptr<DeviceManagementRequestJob> job(
       service_->CreateJob(DeviceManagementRequestJob::TYPE_POLICY_FETCH));
   job->SetDMToken(token_);
@@ -210,7 +211,7 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, PolicyFetch) {
   request->add_request()->set_policy_type(dm_protocol::kChromeUserPolicyType);
   job->Start(base::Bind(&DeviceManagementServiceIntegrationTest::OnJobDone,
                         base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, Unregistration) {
@@ -218,7 +219,8 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, Unregistration) {
 
   ExpectRequest();
   EXPECT_CALL(*this, OnJobDone(DM_STATUS_SUCCESS, _, _))
-      .WillOnce(InvokeWithoutArgs(MessageLoop::current(), &MessageLoop::Quit));
+      .WillOnce(InvokeWithoutArgs(base::MessageLoop::current(),
+                                  &base::MessageLoop::Quit));
   scoped_ptr<DeviceManagementRequestJob> job(
       service_->CreateJob(DeviceManagementRequestJob::TYPE_UNREGISTRATION));
   job->SetDMToken(token_);
@@ -226,13 +228,14 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, Unregistration) {
   job->GetRequest()->mutable_unregister_request();
   job->Start(base::Bind(&DeviceManagementServiceIntegrationTest::OnJobDone,
                         base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, AutoEnrollment) {
   ExpectRequest();
   EXPECT_CALL(*this, OnJobDone(DM_STATUS_SUCCESS, _, _))
-      .WillOnce(InvokeWithoutArgs(MessageLoop::current(), &MessageLoop::Quit));
+      .WillOnce(InvokeWithoutArgs(base::MessageLoop::current(),
+                                  &base::MessageLoop::Quit));
   scoped_ptr<DeviceManagementRequestJob> job(
       service_->CreateJob(DeviceManagementRequestJob::TYPE_AUTO_ENROLLMENT));
   job->SetClientID("testid");
@@ -240,7 +243,7 @@ IN_PROC_BROWSER_TEST_P(DeviceManagementServiceIntegrationTest, AutoEnrollment) {
   job->GetRequest()->mutable_auto_enrollment_request()->set_modulus(1);
   job->Start(base::Bind(&DeviceManagementServiceIntegrationTest::OnJobDone,
                         base::Unretained(this)));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 INSTANTIATE_TEST_CASE_P(
diff --git a/chrome/browser/policy/cloud/device_management_service_unittest.cc b/chrome/browser/policy/cloud/device_management_service_unittest.cc
index 2e4ee82..78e7d00 100644
--- a/chrome/browser/policy/cloud/device_management_service_unittest.cc
+++ b/chrome/browser/policy/cloud/device_management_service_unittest.cc
@@ -166,7 +166,7 @@ class DeviceManagementServiceTestBase : public testing::Test {
   scoped_ptr<DeviceManagementService> service_;
 
  private:
-  MessageLoopForUI loop_;
+  base::MessageLoopForUI loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 };
diff --git a/chrome/browser/policy/cloud/user_cloud_policy_manager_unittest.cc b/chrome/browser/policy/cloud/user_cloud_policy_manager_unittest.cc
index 026c149..6f4629d 100644
--- a/chrome/browser/policy/cloud/user_cloud_policy_manager_unittest.cc
+++ b/chrome/browser/policy/cloud/user_cloud_policy_manager_unittest.cc
@@ -55,7 +55,7 @@ class UserCloudPolicyManagerTest : public testing::Test {
   }
 
   // Required by the refresh scheduler that's created by the manager.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 
   // Convenience policy objects.
   PolicyMap policy_map_;
diff --git a/chrome/browser/policy/cloud/user_cloud_policy_store_unittest.cc b/chrome/browser/policy/cloud/user_cloud_policy_store_unittest.cc
index d2e5035..aa3f9084 100644
--- a/chrome/browser/policy/cloud/user_cloud_policy_store_unittest.cc
+++ b/chrome/browser/policy/cloud/user_cloud_policy_store_unittest.cc
@@ -37,7 +37,7 @@ void RunUntilIdle() {
 class UserCloudPolicyStoreTest : public testing::Test {
  public:
   UserCloudPolicyStoreTest()
-      : loop_(MessageLoop::TYPE_UI),
+      : loop_(base::MessageLoop::TYPE_UI),
         ui_thread_(content::BrowserThread::UI, &loop_),
         file_thread_(content::BrowserThread::FILE, &loop_),
         profile_(new TestingProfile()) {}
@@ -93,7 +93,7 @@ class UserCloudPolicyStoreTest : public testing::Test {
   // CloudPolicyValidator() requires a FILE thread so declare one here. Both
   // |ui_thread_| and |file_thread_| share the same MessageLoop |loop_| so
   // callers can use RunLoop to manage both virtual threads.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/policy/cloud/user_policy_signin_service.cc b/chrome/browser/policy/cloud/user_policy_signin_service.cc
index 11400a7..46b60ca5 100644
--- a/chrome/browser/policy/cloud/user_policy_signin_service.cc
+++ b/chrome/browser/policy/cloud/user_policy_signin_service.cc
@@ -533,7 +533,7 @@ void UserPolicySigninService::OnClientError(CloudPolicyClient* client) {
 
       // Can't shutdown now because we're in the middle of a callback from
       // the CloudPolicyClient, so queue up a task to do the shutdown.
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&UserPolicySigninService::ShutdownUserCloudPolicyManager,
                      weak_factory_.GetWeakPtr()));
diff --git a/chrome/browser/policy/cloud/user_policy_signin_service_unittest.cc b/chrome/browser/policy/cloud/user_policy_signin_service_unittest.cc
index cb2e8c9..1dc0afd 100644
--- a/chrome/browser/policy/cloud/user_policy_signin_service_unittest.cc
+++ b/chrome/browser/policy/cloud/user_policy_signin_service_unittest.cc
@@ -83,7 +83,7 @@ class SigninManagerFake : public FakeSigninManager {
 class UserPolicySigninServiceTest : public testing::Test {
  public:
   UserPolicySigninServiceTest()
-      : loop_(MessageLoop::TYPE_IO),
+      : loop_(base::MessageLoop::TYPE_IO),
         ui_thread_(content::BrowserThread::UI, &loop_),
         file_thread_(content::BrowserThread::FILE, &loop_),
         io_thread_(content::BrowserThread::IO, &loop_),
@@ -264,7 +264,7 @@ class UserPolicySigninServiceTest : public testing::Test {
 
   // BrowserPolicyConnector and UrlFetcherFactory want to initialize and free
   // various components asynchronously via tasks, so create fake threads here.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
diff --git a/chrome/browser/policy/configuration_policy_pref_store_unittest.cc b/chrome/browser/policy/configuration_policy_pref_store_unittest.cc
index 5ab8c10..7471b0b 100644
--- a/chrome/browser/policy/configuration_policy_pref_store_unittest.cc
+++ b/chrome/browser/policy/configuration_policy_pref_store_unittest.cc
@@ -69,7 +69,7 @@ class ConfigurationPolicyPrefStoreTest : public testing::Test {
   MockConfigurationPolicyProvider provider_;
   scoped_ptr<PolicyServiceImpl> policy_service_;
   scoped_refptr<ConfigurationPolicyPrefStore> store_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 };
 
 // Test cases for list-valued policy settings.
diff --git a/chrome/browser/policy/configuration_policy_provider_test.h b/chrome/browser/policy/configuration_policy_provider_test.h
index 1c98836..397e55a 100644
--- a/chrome/browser/policy/configuration_policy_provider_test.h
+++ b/chrome/browser/policy/configuration_policy_provider_test.h
@@ -52,7 +52,7 @@ class PolicyTestBase : public testing::Test {
 
  protected:
   // Create an actual IO loop (needed by FilePathWatcher).
-  MessageLoopForIO loop_;
+  base::MessageLoopForIO loop_;
 
  private:
   content::TestBrowserThread ui_thread_;
diff --git a/chrome/browser/policy/policy_browsertest.cc b/chrome/browser/policy/policy_browsertest.cc
index 195bb18..4fc5c21 100644
--- a/chrome/browser/policy/policy_browsertest.cc
+++ b/chrome/browser/policy/policy_browsertest.cc
@@ -209,14 +209,14 @@ class MakeRequestFail {
     BrowserThread::PostTaskAndReply(
         BrowserThread::IO, FROM_HERE,
         base::Bind(MakeRequestFailOnIO, host_),
-        MessageLoop::QuitClosure());
+        base::MessageLoop::QuitClosure());
     content::RunMessageLoop();
   }
   ~MakeRequestFail() {
     BrowserThread::PostTaskAndReply(
         BrowserThread::IO, FROM_HERE,
         base::Bind(UndoMakeRequestFailOnIO, host_),
-        MessageLoop::QuitClosure());
+        base::MessageLoop::QuitClosure());
     content::RunMessageLoop();
   }
 
@@ -333,13 +333,13 @@ bool IsJavascriptEnabled(content::WebContents* contents) {
 void CopyPluginListAndQuit(std::vector<webkit::WebPluginInfo>* out,
                            const std::vector<webkit::WebPluginInfo>& in) {
   *out = in;
-  MessageLoop::current()->QuitWhenIdle();
+  base::MessageLoop::current()->QuitWhenIdle();
 }
 
 template<typename T>
 void CopyValueAndQuit(T* out, T in) {
   *out = in;
-  MessageLoop::current()->QuitWhenIdle();
+  base::MessageLoop::current()->QuitWhenIdle();
 }
 
 void GetPluginList(std::vector<webkit::WebPluginInfo>* plugins) {
@@ -462,7 +462,7 @@ class PolicyTest : public InProcessBrowserTest {
     BrowserThread::PostTaskAndReply(
         BrowserThread::IO, FROM_HERE,
         base::Bind(URLRequestMockHTTPJob::AddUrlHandler, root_http),
-        MessageLoop::current()->QuitWhenIdleClosure());
+        base::MessageLoop::current()->QuitWhenIdleClosure());
     content::RunMessageLoop();
   }
 
@@ -531,7 +531,7 @@ class PolicyTest : public InProcessBrowserTest {
         BrowserThread::IO,
         FROM_HERE,
         base::Bind(base::DoNothing),
-        MessageLoop::QuitClosure());
+        base::MessageLoop::QuitClosure());
     content::RunMessageLoop();
   }
 #endif
@@ -586,7 +586,7 @@ class PolicyTest : public InProcessBrowserTest {
 
   void UpdateProviderPolicy(const PolicyMap& policy) {
     provider_.UpdateChromePolicy(policy);
-    DCHECK(MessageLoop::current());
+    DCHECK(base::MessageLoop::current());
     base::RunLoop loop;
     loop.RunUntilIdle();
   }
@@ -2094,7 +2094,7 @@ class MediaStreamDevicesControllerBrowserTest
         base::Bind(&MediaStreamDevicesControllerBrowserTest::Accept, this));
     controller.DismissInfoBarAndTakeActionOnSettings();
 
-    MessageLoop::current()->QuitWhenIdle();
+    base::MessageLoop::current()->QuitWhenIdle();
   }
 
   void FinishVideoTest() {
@@ -2107,7 +2107,7 @@ class MediaStreamDevicesControllerBrowserTest
         base::Bind(&MediaStreamDevicesControllerBrowserTest::Accept, this));
     controller.DismissInfoBarAndTakeActionOnSettings();
 
-    MessageLoop::current()->QuitWhenIdle();
+    base::MessageLoop::current()->QuitWhenIdle();
   }
 
   bool policy_value_;
@@ -2139,7 +2139,7 @@ IN_PROC_BROWSER_TEST_P(MediaStreamDevicesControllerBrowserTest,
       base::Bind(&MediaStreamDevicesControllerBrowserTest::FinishAudioTest,
                  this));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 IN_PROC_BROWSER_TEST_P(MediaStreamDevicesControllerBrowserTest,
@@ -2196,7 +2196,7 @@ IN_PROC_BROWSER_TEST_P(MediaStreamDevicesControllerBrowserTest,
       base::Bind(&MediaStreamDevicesControllerBrowserTest::FinishVideoTest,
                  this));
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 IN_PROC_BROWSER_TEST_P(MediaStreamDevicesControllerBrowserTest,
diff --git a/chrome/browser/policy/policy_service_impl.cc b/chrome/browser/policy/policy_service_impl.cc
index 2cf3734..9302269 100644
--- a/chrome/browser/policy/policy_service_impl.cc
+++ b/chrome/browser/policy/policy_service_impl.cc
@@ -120,7 +120,7 @@ void PolicyServiceImpl::NotifyNamespaceUpdated(
     const PolicyMap& current) {
   // If running a unit test that hasn't setup a MessageLoop, don't send any
   // notifications.
-  if (!MessageLoop::current())
+  if (!base::MessageLoop::current())
     return;
 
   // Don't queue up a task if we have no observers - that way Observers added
@@ -132,7 +132,7 @@ void PolicyServiceImpl::NotifyNamespaceUpdated(
   // call to MergeAndTriggerUpdates() by modifying policy.
   scoped_ptr<PolicyChangeInfo> changes(
       new PolicyChangeInfo(ns, previous, current));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&PolicyServiceImpl::NotifyNamespaceUpdatedTask,
                  weak_ptr_factory_.GetWeakPtr(),
diff --git a/chrome/browser/policy/policy_service_impl_unittest.cc b/chrome/browser/policy/policy_service_impl_unittest.cc
index 9e56f3f..00b88af 100644
--- a/chrome/browser/policy/policy_service_impl_unittest.cc
+++ b/chrome/browser/policy/policy_service_impl_unittest.cc
@@ -160,7 +160,7 @@ class PolicyServiceTest : public testing::Test {
   PolicyMap policy1_;
   PolicyMap policy2_;
   scoped_ptr<PolicyServiceImpl> policy_service_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PolicyServiceTest);
diff --git a/chrome/browser/policy/url_blacklist_manager.cc b/chrome/browser/policy/url_blacklist_manager.cc
index a4525ed..9cc00bc 100644
--- a/chrome/browser/policy/url_blacklist_manager.cc
+++ b/chrome/browser/policy/url_blacklist_manager.cc
@@ -334,7 +334,7 @@ void URLBlacklistManager::ScheduleUpdate() {
   // change the blacklist are updated in one message loop cycle. In those cases,
   // only rebuild the blacklist after all the preference updates are processed.
   ui_weak_ptr_factory_.InvalidateWeakPtrs();
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&URLBlacklistManager::Update,
                  ui_weak_ptr_factory_.GetWeakPtr()));
diff --git a/chrome/browser/policy/url_blacklist_manager_unittest.cc b/chrome/browser/policy/url_blacklist_manager_unittest.cc
index 7fed421..b64ddda 100644
--- a/chrome/browser/policy/url_blacklist_manager_unittest.cc
+++ b/chrome/browser/policy/url_blacklist_manager_unittest.cc
@@ -70,7 +70,7 @@ class TestingURLBlacklistManager : public URLBlacklistManager {
 class URLBlacklistManagerTest : public testing::Test {
  protected:
   URLBlacklistManagerTest()
-      : loop_(MessageLoop::TYPE_IO),
+      : loop_(base::MessageLoop::TYPE_IO),
         ui_thread_(BrowserThread::UI, &loop_),
         file_thread_(BrowserThread::FILE, &loop_),
         io_thread_(BrowserThread::IO, &loop_) {
@@ -93,7 +93,7 @@ class URLBlacklistManagerTest : public testing::Test {
     blacklist_manager_.reset();
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   TestingPrefServiceSimple pref_service_;
   scoped_ptr<TestingURLBlacklistManager> blacklist_manager_;
 
diff --git a/chrome/browser/predictors/autocomplete_action_predictor_table_unittest.cc b/chrome/browser/predictors/autocomplete_action_predictor_table_unittest.cc
index bbd6cb3..10c44e9 100644
--- a/chrome/browser/predictors/autocomplete_action_predictor_table_unittest.cc
+++ b/chrome/browser/predictors/autocomplete_action_predictor_table_unittest.cc
@@ -54,7 +54,7 @@ class AutocompleteActionPredictorTableTest : public testing::Test {
  private:
   TestingProfile profile_;
   scoped_ptr<PredictorDatabase> db_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread db_thread_;
 };
 
@@ -71,7 +71,7 @@ class AutocompleteActionPredictorTableReopenTest
 };
 
 AutocompleteActionPredictorTableTest::AutocompleteActionPredictorTableTest()
-    : loop_(MessageLoop::TYPE_DEFAULT),
+    : loop_(base::MessageLoop::TYPE_DEFAULT),
       db_thread_(BrowserThread::DB, &loop_) {
 }
 
diff --git a/chrome/browser/predictors/autocomplete_action_predictor_unittest.cc b/chrome/browser/predictors/autocomplete_action_predictor_unittest.cc
index 675df556..1ac2e7f 100644
--- a/chrome/browser/predictors/autocomplete_action_predictor_unittest.cc
+++ b/chrome/browser/predictors/autocomplete_action_predictor_unittest.cc
@@ -82,7 +82,7 @@ namespace predictors {
 class AutocompleteActionPredictorTest : public testing::Test {
  public:
   AutocompleteActionPredictorTest()
-      : loop_(MessageLoop::TYPE_DEFAULT),
+      : loop_(base::MessageLoop::TYPE_DEFAULT),
         ui_thread_(BrowserThread::UI, &loop_),
         db_thread_(BrowserThread::DB, &loop_),
         file_thread_(BrowserThread::FILE, &loop_),
@@ -214,7 +214,7 @@ class AutocompleteActionPredictorTest : public testing::Test {
   }
 
  private:
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread file_thread_;
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc b/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc
index fa5be14..7ae4d31 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_tables_unittest.cc
@@ -31,7 +31,7 @@ class ResourcePrefetchPredictorTablesTest : public testing::Test {
   void TestDeleteSingleDataPoint();
   void TestDeleteAllData();
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread db_thread_;
   TestingProfile profile_;
   scoped_ptr<PredictorDatabase> db_;
@@ -88,7 +88,7 @@ class ResourcePrefetchPredictorTablesReopenTest
 };
 
 ResourcePrefetchPredictorTablesTest::ResourcePrefetchPredictorTablesTest()
-    : loop_(MessageLoop::TYPE_DEFAULT),
+    : loop_(base::MessageLoop::TYPE_DEFAULT),
       db_thread_(content::BrowserThread::DB, &loop_),
       db_(new PredictorDatabase(&profile_)),
       tables_(db_->resource_prefetch_tables()) {
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc b/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc
index b6203da..aa1e02a 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_unittest.cc
@@ -155,7 +155,7 @@ class ResourcePrefetchPredictorTest : public testing::Test {
 
   void InitializeSampleData();
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   scoped_ptr<TestingProfile> profile_;
@@ -170,7 +170,7 @@ class ResourcePrefetchPredictorTest : public testing::Test {
 };
 
 ResourcePrefetchPredictorTest::ResourcePrefetchPredictorTest()
-    : loop_(MessageLoop::TYPE_DEFAULT),
+    : loop_(base::MessageLoop::TYPE_DEFAULT),
       ui_thread_(content::BrowserThread::UI, &loop_),
       db_thread_(content::BrowserThread::DB, &loop_),
       profile_(new TestingProfile()),
diff --git a/chrome/browser/predictors/resource_prefetcher_unittest.cc b/chrome/browser/predictors/resource_prefetcher_unittest.cc
index 865c8af..b53dae1 100644
--- a/chrome/browser/predictors/resource_prefetcher_unittest.cc
+++ b/chrome/browser/predictors/resource_prefetcher_unittest.cc
@@ -47,7 +47,7 @@ class TestResourcePrefetcher : public ResourcePrefetcher {
 // Delegate for ResourcePrefetcher.
 class TestResourcePrefetcherDelegate : public ResourcePrefetcher::Delegate {
  public:
-  explicit TestResourcePrefetcherDelegate(MessageLoop* loop)
+  explicit TestResourcePrefetcherDelegate(base::MessageLoop* loop)
       : request_context_getter_(new net::TestURLRequestContextGetter(
           loop->message_loop_proxy())) { }
   ~TestResourcePrefetcherDelegate() { }
@@ -128,7 +128,7 @@ class ResourcePrefetcherTest : public testing::Test {
     prefetcher_->OnResponseStarted(GetInFlightRequest(url));
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread io_thread_;
   ResourcePrefetchPredictorConfig config_;
   TestResourcePrefetcherDelegate prefetcher_delegate_;
@@ -139,7 +139,7 @@ class ResourcePrefetcherTest : public testing::Test {
 };
 
 ResourcePrefetcherTest::ResourcePrefetcherTest()
-    : loop_(MessageLoop::TYPE_IO),
+    : loop_(base::MessageLoop::TYPE_IO),
       io_thread_(content::BrowserThread::IO, &loop_),
       prefetcher_delegate_(&loop_) {
   config_.max_prefetches_inflight_per_navigation = 5;
diff --git a/chrome/browser/prefs/chrome_pref_service_unittest.cc b/chrome/browser/prefs/chrome_pref_service_unittest.cc
index 4dab4fc..ffe54f7 100644
--- a/chrome/browser/prefs/chrome_pref_service_unittest.cc
+++ b/chrome/browser/prefs/chrome_pref_service_unittest.cc
@@ -87,7 +87,7 @@ class ChromePrefServiceUserFilePrefsTest : public testing::Test {
   // The path to the directory where the test data is stored.
   base::FilePath data_dir_;
   // A message loop that we can use as the file thread message loop.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 };
 
 // Verifies that ListValue and DictionaryValue pref with non emtpy default
diff --git a/chrome/browser/prerender/prerender_browsertest.cc b/chrome/browser/prerender/prerender_browsertest.cc
index bf5c1a6..80199b5 100644
--- a/chrome/browser/prerender/prerender_browsertest.cc
+++ b/chrome/browser/prerender/prerender_browsertest.cc
@@ -192,7 +192,7 @@ class ChannelDestructionWatcher {
     channel_destroyed_ = true;
     if (waiting_for_channel_destruction_) {
       waiting_for_channel_destruction_ = false;
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
@@ -230,7 +230,7 @@ class TestPrerenderContents : public PrerenderContents {
         prerender_should_wait_for_ready_title_(
             prerender_should_wait_for_ready_title) {
     if (expected_number_of_loads == 0)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   virtual ~TestPrerenderContents() {
@@ -263,7 +263,7 @@ class TestPrerenderContents : public PrerenderContents {
     if (quit_message_loop_on_destruction_) {
       // The message loop may not be running if this is swapped in
       // synchronously on a Navigation.
-      MessageLoop* loop = MessageLoopForUI::current();
+      base::MessageLoop* loop = base::MessageLoopForUI::current();
       if (loop->is_running())
         loop->Quit();
     }
@@ -299,7 +299,7 @@ class TestPrerenderContents : public PrerenderContents {
     ++number_of_loads_;
     if (ShouldRenderPrerenderedPageCorrectly(expected_final_status_) &&
         number_of_loads_ == expected_number_of_loads_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
@@ -308,7 +308,7 @@ class TestPrerenderContents : public PrerenderContents {
     PrerenderContents::AddPendingPrerender(pending_prerender_info.Pass());
     if (expected_pending_prerenders_ > 0 &&
         pending_prerender_count() == expected_pending_prerenders_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
@@ -2406,7 +2406,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderClearHistory) {
 
   // Post a task to clear the history, and run the message loop until it
   // destroys the prerender.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&ClearBrowsingData, current_browser(),
                  BrowsingDataRemover::REMOVE_HISTORY));
@@ -2425,7 +2425,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderClearCache) {
 
   // Post a task to clear the cache, and run the message loop until it
   // destroys the prerender.
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ClearBrowsingData, current_browser(),
                  BrowsingDataRemover::REMOVE_CACHE));
   content::RunMessageLoop();
@@ -2440,7 +2440,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderCancelAll) {
                    FINAL_STATUS_CANCELLED,
                    1);
   // Post a task to cancel all the prerenders.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&CancelAllPrerenders, GetPrerenderManager()));
   content::RunMessageLoop();
   EXPECT_TRUE(GetPrerenderContents() == NULL);
@@ -2453,7 +2453,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PrerenderEvents) {
   EXPECT_TRUE(DidReceivePrerenderLoadEventForLinkNumber(0));
   EXPECT_FALSE(DidReceivePrerenderStopEventForLinkNumber(0));
 
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&CancelAllPrerenders, GetPrerenderManager()));
   content::RunMessageLoop();
 
@@ -2470,7 +2470,7 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest,
                    FINAL_STATUS_CANCELLED,
                    1);
   // Post a task to cancel all the prerenders.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&CancelAllPrerenders, GetPrerenderManager()));
   content::RunMessageLoop();
   EXPECT_TRUE(GetPrerenderContents() == NULL);
diff --git a/chrome/browser/prerender/prerender_local_predictor.cc b/chrome/browser/prerender/prerender_local_predictor.cc
index d5e06ff..2284237 100644
--- a/chrome/browser/prerender/prerender_local_predictor.cc
+++ b/chrome/browser/prerender/prerender_local_predictor.cc
@@ -312,7 +312,7 @@ PrerenderLocalPredictor::PrerenderLocalPredictor(
       weak_factory_(this),
       current_prerender_would_have_matched_(false) {
   RecordEvent(EVENT_CONSTRUCTED);
-  if (MessageLoop::current()) {
+  if (base::MessageLoop::current()) {
     timer_.Start(FROM_HERE,
                  base::TimeDelta::FromMilliseconds(kInitDelayMs),
                  this,
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index 1374fd1..3ead07f 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -156,7 +156,7 @@ class PrerenderManager::OnCloseWebContentsDeleter
       : manager_(manager),
         tab_(tab) {
     tab_->SetDelegate(this);
-    MessageLoop::current()->PostDelayedTask(FROM_HERE,
+    base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
         base::Bind(&OnCloseWebContentsDeleter::ScheduleWebContentsForDeletion,
                    AsWeakPtr(), true),
         base::TimeDelta::FromSeconds(kDeleteWithExtremePrejudiceSeconds));
@@ -1187,7 +1187,7 @@ void PrerenderManager::PeriodicCleanup() {
 
 void PrerenderManager::PostCleanupTask() {
   DCHECK(CalledOnValidThread());
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&PrerenderManager::PeriodicCleanup, AsWeakPtr()));
 }
diff --git a/chrome/browser/prerender/prerender_manager_unittest.cc b/chrome/browser/prerender/prerender_manager_unittest.cc
index 86d6f33..677deab 100644
--- a/chrome/browser/prerender/prerender_manager_unittest.cc
+++ b/chrome/browser/prerender/prerender_manager_unittest.cc
@@ -23,7 +23,7 @@ class PrerenderManagerTest : public testing::Test {
 
   PrerenderManager* prerender_manager() { return &prerender_manager_; }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   PrerenderManager prerender_manager_;
 };
diff --git a/chrome/browser/prerender/prerender_tracker_unittest.cc b/chrome/browser/prerender/prerender_tracker_unittest.cc
index a736b0b..81e6db6 100644
--- a/chrome/browser/prerender/prerender_tracker_unittest.cc
+++ b/chrome/browser/prerender/prerender_tracker_unittest.cc
@@ -134,7 +134,7 @@ class PrerenderTrackerTest : public testing::Test {
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
diff --git a/chrome/browser/prerender/prerender_unittest.cc b/chrome/browser/prerender/prerender_unittest.cc
index 036742a..dba0e3a 100644
--- a/chrome/browser/prerender/prerender_unittest.cc
+++ b/chrome/browser/prerender/prerender_unittest.cc
@@ -349,7 +349,7 @@ class PrerenderTest : public testing::Test {
 
   // Needed to pass PrerenderManager's DCHECKs.
   TestingProfile profile_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<UnitTestPrerenderManager> prerender_manager_;
   scoped_ptr<PrerenderLinkManager> prerender_link_manager_;
diff --git a/chrome/browser/printing/background_printing_manager.cc b/chrome/browser/printing/background_printing_manager.cc
index 953a38e..c97f89a 100644
--- a/chrome/browser/printing/background_printing_manager.cc
+++ b/chrome/browser/printing/background_printing_manager.cc
@@ -153,7 +153,7 @@ void BackgroundPrintingManager::DeletePreviewContents(
                     content::Source<WebContents>(preview_contents));
   printing_contents_set_.erase(preview_contents);
   printing_contents_pending_deletion_set_.insert(preview_contents);
-  MessageLoop::current()->DeleteSoon(FROM_HERE, preview_contents);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, preview_contents);
 }
 
 bool BackgroundPrintingManager::HasSharedRenderProcessHost(
diff --git a/chrome/browser/printing/cloud_print/cloud_print_proxy_service.cc b/chrome/browser/printing/cloud_print/cloud_print_proxy_service.cc
index 682dbc0..2fffdb3 100644
--- a/chrome/browser/printing/cloud_print/cloud_print_proxy_service.cc
+++ b/chrome/browser/printing/cloud_print/cloud_print_proxy_service.cc
@@ -114,22 +114,23 @@ bool CloudPrintProxyService::ApplyCloudPrintConnectorPolicy() {
       DisableForUser();
       profile_->GetPrefs()->SetString(prefs::kCloudPrintEmail, std::string());
       if (enforcing_connector_policy_) {
-        MessageLoop::current()->PostTask(
+        base::MessageLoop::current()->PostTask(
             FROM_HERE,
             base::Bind(&CloudPrintProxyService::RefreshCloudPrintProxyStatus,
                        weak_factory_.GetWeakPtr()));
       }
       return false;
     } else if (enforcing_connector_policy_) {
-      MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+      base::MessageLoop::current()->PostTask(FROM_HERE,
+                                             base::MessageLoop::QuitClosure());
     }
   }
   return true;
 }
 
 void CloudPrintProxyService::OnCloudPrintSetupClosed() {
-  MessageLoop::current()->PostTask(FROM_HERE,
-                                   base::Bind(&chrome::EndKeepAlive));
+  base::MessageLoop::current()->PostTask(FROM_HERE,
+                                         base::Bind(&chrome::EndKeepAlive));
 }
 
 void CloudPrintProxyService::GetPrintersAvalibleForRegistration(
diff --git a/chrome/browser/printing/cloud_print/cloud_print_proxy_service_unittest.cc b/chrome/browser/printing/cloud_print/cloud_print_proxy_service_unittest.cc
index d6eefc5..ce27b95 100644
--- a/chrome/browser/printing/cloud_print/cloud_print_proxy_service_unittest.cc
+++ b/chrome/browser/printing/cloud_print/cloud_print_proxy_service_unittest.cc
@@ -87,7 +87,7 @@ void CallTask(const base::Closure& task) {
 
 void PostTask(const base::Closure& task) {
   if (!task.is_null())
-    MessageLoop::current()->PostTask(FROM_HERE, task);
+    base::MessageLoop::current()->PostTask(FROM_HERE, task);
 }
 
 void MockServiceProcessControl::SetConnectSuccessMockExpectations(
@@ -196,7 +196,7 @@ class CloudPrintProxyPolicyTest : public ::testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   TestingProfile profile_;
 };
@@ -432,7 +432,7 @@ BrowserContextKeyedService* TestCloudPrintProxyServiceFactory(
   service->GetMockServiceProcessControl()->SetWillBeDisabledExpectations();
 
   service->Initialize();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   return service;
 }
 
@@ -450,5 +450,5 @@ TEST_F(CloudPrintProxyPolicyTest, StartupBrowserCreatorWithCommandLine) {
   command_line.AppendSwitch(switches::kCheckCloudPrintConnectorPolicy);
 
   EXPECT_FALSE(LaunchBrowser(command_line, &profile_));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
diff --git a/chrome/browser/printing/cloud_print/test/cloud_print_proxy_process_browsertest.cc b/chrome/browser/printing/cloud_print/test/cloud_print_proxy_process_browsertest.cc
index 2f8de5e..fd41ece 100644
--- a/chrome/browser/printing/cloud_print/test/cloud_print_proxy_process_browsertest.cc
+++ b/chrome/browser/printing/cloud_print/test/cloud_print_proxy_process_browsertest.cc
@@ -92,20 +92,21 @@ class TestServiceProcess : public ServiceProcess {
   TestServiceProcess() { }
   virtual ~TestServiceProcess() { }
 
-  bool Initialize(MessageLoopForUI* message_loop, ServiceProcessState* state);
+  bool Initialize(base::MessageLoopForUI* message_loop,
+                  ServiceProcessState* state);
 
   base::MessageLoopProxy* IOMessageLoopProxy() {
     return io_thread_->message_loop_proxy();
   }
 };
 
-bool TestServiceProcess::Initialize(MessageLoopForUI* message_loop,
+bool TestServiceProcess::Initialize(base::MessageLoopForUI* message_loop,
                                     ServiceProcessState* state) {
   main_message_loop_ = message_loop;
 
   service_process_state_.reset(state);
 
-  base::Thread::Options options(MessageLoop::TYPE_IO, 0);
+  base::Thread::Options options(base::MessageLoop::TYPE_IO, 0);
   io_thread_.reset(new base::Thread("TestServiceProcess_IO"));
   return io_thread_->StartWithOptions(options);
 }
@@ -202,7 +203,7 @@ typedef base::Callback<void(MockServiceIPCServer* server)>
 // service process. Any non-zero return value will be printed out and can help
 // determine the failure.
 int CloudPrintMockService_Main(SetExpectationsCallback set_expectations) {
-  MessageLoopForUI main_message_loop;
+  base::MessageLoopForUI main_message_loop;
   main_message_loop.set_thread_name("Main Thread");
 
 #if defined(OS_MACOSX)
@@ -315,7 +316,7 @@ class CloudPrintProxyPolicyStartupTest : public base::MultiProcessTest,
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   base::Thread io_thread_;
 
@@ -346,7 +347,7 @@ class CloudPrintProxyPolicyStartupTest : public base::MultiProcessTest,
     void Notify() {
       seen_ = true;
       if (running_)
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
     }
 
    private:
@@ -366,7 +367,7 @@ CloudPrintProxyPolicyStartupTest::~CloudPrintProxyPolicyStartupTest() {
 }
 
 void CloudPrintProxyPolicyStartupTest::SetUp() {
-  base::Thread::Options options(MessageLoop::TYPE_IO, 0);
+  base::Thread::Options options(base::MessageLoop::TYPE_IO, 0);
   ASSERT_TRUE(io_thread_.StartWithOptions(options));
 
 #if defined(OS_MACOSX)
@@ -487,14 +488,15 @@ TEST_F(CloudPrintProxyPolicyStartupTest, StartBrowserWithoutPolicy) {
   test_launcher_utils::PrepareBrowserCommandLineForTests(&command_line);
 
   WaitForConnect();
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-                                          MessageLoop::QuitClosure(),
-                                          TestTimeouts::action_timeout());
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::MessageLoop::QuitClosure(),
+      TestTimeouts::action_timeout());
 
   bool run_loop = LaunchBrowser(command_line, profile);
   EXPECT_FALSE(run_loop);
   if (run_loop)
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
   EXPECT_EQ(MockServiceIPCServer::EnabledUserId(),
             prefs->GetString(prefs::kCloudPrintEmail));
@@ -529,16 +531,17 @@ TEST_F(CloudPrintProxyPolicyStartupTest, StartBrowserWithPolicy) {
   test_launcher_utils::PrepareBrowserCommandLineForTests(&command_line);
 
   WaitForConnect();
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-                                          MessageLoop::QuitClosure(),
-                                          TestTimeouts::action_timeout());
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::MessageLoop::QuitClosure(),
+      TestTimeouts::action_timeout());
 
   bool run_loop = LaunchBrowser(command_line, profile);
 
   // No expectations on run_loop being true here; that would be a race
   // condition.
   if (run_loop)
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
   EXPECT_EQ("", prefs->GetString(prefs::kCloudPrintEmail));
 
diff --git a/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc b/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc
index eb8eef4..36b8af6 100644
--- a/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc
+++ b/chrome/browser/printing/print_dialog_cloud_interative_uitest.cc
@@ -161,7 +161,7 @@ class PrintDialogCloudTest : public InProcessBrowserTest {
 
     virtual void OnResponseCompleted(net::URLRequest* request) OVERRIDE {
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                              MessageLoop::QuitClosure());
+                              base::MessageLoop::QuitClosure());
     }
   };
 
diff --git a/chrome/browser/printing/print_dialog_cloud_unittest.cc b/chrome/browser/printing/print_dialog_cloud_unittest.cc
index ce50f28..72f18ed 100644
--- a/chrome/browser/printing/print_dialog_cloud_unittest.cc
+++ b/chrome/browser/printing/print_dialog_cloud_unittest.cc
@@ -235,7 +235,7 @@ class CloudPrintDataSenderTest : public testing::Test {
   scoped_refptr<CloudPrintDataSender> print_data_sender_;
   scoped_ptr<MockCloudPrintDataSenderHelper> mock_helper_;
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread io_thread_;
 };
@@ -253,7 +253,7 @@ TEST_F(CloudPrintDataSenderTest, CanSend) {
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&CloudPrintDataSender::SendPrintData, print_data_sender));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 TEST_F(CloudPrintDataSenderTest, NoData) {
@@ -264,7 +264,7 @@ TEST_F(CloudPrintDataSenderTest, NoData) {
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&CloudPrintDataSender::SendPrintData, print_data_sender));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 TEST_F(CloudPrintDataSenderTest, EmptyData) {
@@ -277,7 +277,7 @@ TEST_F(CloudPrintDataSenderTest, EmptyData) {
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&CloudPrintDataSender::SendPrintData, print_data_sender));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 }
 
 // Testing for CloudPrintFlowHandler needs a mock
@@ -316,7 +316,7 @@ class CloudPrintWebDialogDelegateTest : public testing::Test {
       delete mock_flow_handler_.get();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   base::WeakPtr<MockCloudPrintFlowHandler> mock_flow_handler_;
   scoped_ptr<CloudPrintWebDialogDelegate> delegate_;
diff --git a/chrome/browser/printing/print_job.cc b/chrome/browser/printing/print_job.cc
index 6c91282..2e95728 100644
--- a/chrome/browser/printing/print_job.cc
+++ b/chrome/browser/printing/print_job.cc
@@ -31,7 +31,7 @@ void HoldRefCallback(const scoped_refptr<printing::PrintJobWorkerOwner>& owner,
 namespace printing {
 
 PrintJob::PrintJob()
-    : ui_message_loop_(MessageLoop::current()),
+    : ui_message_loop_(base::MessageLoop::current()),
       source_(NULL),
       worker_(),
       settings_(),
@@ -44,8 +44,8 @@ PrintJob::PrintJob()
   DCHECK(ui_message_loop_);
   // This is normally a UI message loop, but in unit tests, the message loop is
   // of the 'default' type.
-  DCHECK(ui_message_loop_->type() == MessageLoop::TYPE_UI ||
-         ui_message_loop_->type() == MessageLoop::TYPE_DEFAULT);
+  DCHECK(ui_message_loop_->type() == base::MessageLoop::TYPE_UI ||
+         ui_message_loop_->type() == base::MessageLoop::TYPE_DEFAULT);
   ui_message_loop_->AddDestructionObserver(this);
 }
 
@@ -56,7 +56,7 @@ PrintJob::~PrintJob() {
   DCHECK(!is_canceling_);
   if (worker_.get())
     DCHECK(worker_->message_loop() == NULL);
-  DCHECK_EQ(ui_message_loop_, MessageLoop::current());
+  DCHECK_EQ(ui_message_loop_, base::MessageLoop::current());
 }
 
 void PrintJob::Initialize(PrintJobWorkerOwner* job,
@@ -84,7 +84,7 @@ void PrintJob::Initialize(PrintJobWorkerOwner* job,
 void PrintJob::Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) {
-  DCHECK_EQ(ui_message_loop_, MessageLoop::current());
+  DCHECK_EQ(ui_message_loop_, base::MessageLoop::current());
   switch (type) {
     case chrome::NOTIFICATION_PRINT_JOB_EVENT: {
       OnNotifyPrintJobEvent(*content::Details<JobEventDetails>(details).ptr());
@@ -126,7 +126,7 @@ void PrintJob::WillDestroyCurrentMessageLoop() {
 }
 
 void PrintJob::StartPrinting() {
-  DCHECK_EQ(ui_message_loop_, MessageLoop::current());
+  DCHECK_EQ(ui_message_loop_, base::MessageLoop::current());
   DCHECK(worker_->message_loop());
   DCHECK(!is_job_pending_);
   if (!worker_->message_loop() || is_job_pending_)
@@ -151,7 +151,7 @@ void PrintJob::StartPrinting() {
 }
 
 void PrintJob::Stop() {
-  DCHECK_EQ(ui_message_loop_, MessageLoop::current());
+  DCHECK_EQ(ui_message_loop_, base::MessageLoop::current());
 
   if (quit_factory_.HasWeakPtrs()) {
     // In case we're running a nested message loop to wait for a job to finish,
@@ -163,7 +163,7 @@ void PrintJob::Stop() {
   // Be sure to live long enough.
   scoped_refptr<PrintJob> handle(this);
 
-  MessageLoop* worker_loop = worker_->message_loop();
+  base::MessageLoop* worker_loop = worker_->message_loop();
   if (worker_loop) {
     ControlledWorkerShutdown();
 
@@ -183,8 +183,9 @@ void PrintJob::Cancel() {
   // Be sure to live long enough.
   scoped_refptr<PrintJob> handle(this);
 
-  DCHECK_EQ(ui_message_loop_, MessageLoop::current());
-  MessageLoop* worker_loop = worker_.get() ? worker_->message_loop() : NULL;
+  DCHECK_EQ(ui_message_loop_, base::MessageLoop::current());
+  base::MessageLoop* worker_loop =
+      worker_.get() ? worker_->message_loop() : NULL;
   if (worker_loop) {
     // Call this right now so it renders the context invalid. Do not use
     // InvokeLater since it would take too much time.
@@ -205,11 +206,12 @@ bool PrintJob::FlushJob(base::TimeDelta timeout) {
   // Make sure the object outlive this message loop.
   scoped_refptr<PrintJob> handle(this);
 
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(&PrintJob::Quit, quit_factory_.GetWeakPtr()), timeout);
 
-  MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
-  MessageLoop::current()->Run();
+  base::MessageLoop::ScopedNestableTaskAllower allow(
+      base::MessageLoop::current());
+  base::MessageLoop::current()->Run();
 
   return true;
 }
@@ -281,7 +283,7 @@ void PrintJob::OnNotifyPrintJobEvent(const JobEventDetails& event_details) {
     }
     case JobEventDetails::DOC_DONE: {
       // This will call Stop() and broadcast a JOB_DONE message.
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE, base::Bind(&PrintJob::OnDocumentDone, this));
       break;
     }
@@ -309,7 +311,7 @@ void PrintJob::OnDocumentDone() {
 }
 
 void PrintJob::ControlledWorkerShutdown() {
-  DCHECK_EQ(ui_message_loop_, MessageLoop::current());
+  DCHECK_EQ(ui_message_loop_, base::MessageLoop::current());
 
   // The deadlock this code works around is specific to window messaging on
   // Windows, so we aren't likely to need it on any other platforms.
@@ -375,7 +377,7 @@ void PrintJob::HoldUntilStopIsCalled(const scoped_refptr<PrintJob>&) {
 }
 
 void PrintJob::Quit() {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 // Takes settings_ ownership and will be deleted in the receiving thread.
diff --git a/chrome/browser/printing/print_job.h b/chrome/browser/printing/print_job.h
index 1cb6eda..83b4bca 100644
--- a/chrome/browser/printing/print_job.h
+++ b/chrome/browser/printing/print_job.h
@@ -34,7 +34,7 @@ class PrinterQuery;
 // runs in the UI thread.
 class PrintJob : public PrintJobWorkerOwner,
                  public content::NotificationObserver,
-                 public MessageLoop::DestructionObserver {
+                 public base::MessageLoop::DestructionObserver {
  public:
   // Create a empty PrintJob. When initializing with this constructor,
   // post-constructor initialization must be done with Initialize().
@@ -54,7 +54,7 @@ class PrintJob : public PrintJobWorkerOwner,
   virtual void GetSettingsDone(const PrintSettings& new_settings,
                                PrintingContext::Result result) OVERRIDE;
   virtual PrintJobWorker* DetachWorker(PrintJobWorkerOwner* new_owner) OVERRIDE;
-  virtual MessageLoop* message_loop() OVERRIDE;
+  virtual base::MessageLoop* message_loop() OVERRIDE;
   virtual const PrintSettings& settings() const OVERRIDE;
   virtual int cookie() const OVERRIDE;
 
@@ -124,7 +124,7 @@ class PrintJob : public PrintJobWorkerOwner,
 
   // Main message loop reference. Used to send notifications in the right
   // thread.
-  MessageLoop* const ui_message_loop_;
+  base::MessageLoop* const ui_message_loop_;
 
   // Source that generates the PrintedPage's (i.e. a WebContents). It will be
   // set back to NULL if the source is deleted before this object.
diff --git a/chrome/browser/printing/print_job_unittest.cc b/chrome/browser/printing/print_job_unittest.cc
index 24ddfa3..eb41acd 100644
--- a/chrome/browser/printing/print_job_unittest.cc
+++ b/chrome/browser/printing/print_job_unittest.cc
@@ -46,7 +46,7 @@ class TestOwner : public printing::PrintJobWorkerOwner {
     settings_ = worker->printing_context()->settings();
     return worker;
   }
-  virtual MessageLoop* message_loop() OVERRIDE {
+  virtual base::MessageLoop* message_loop() OVERRIDE {
     EXPECT_FALSE(true);
     return NULL;
   }
@@ -93,7 +93,7 @@ TEST_F(PrintJobTest, SimplePrint) {
   // known lifetime.
 
   // This message loop is actually never run.
-  MessageLoop current;
+  base::MessageLoop current;
 
   content::NotificationRegistrar registrar_;
   TestPrintNotifObserv observ;
@@ -101,7 +101,7 @@ TEST_F(PrintJobTest, SimplePrint) {
                  content::NotificationService::AllSources());
   volatile bool check = false;
   scoped_refptr<printing::PrintJob> job(new TestPrintJob(&check));
-  EXPECT_EQ(MessageLoop::current(), job->message_loop());
+  EXPECT_EQ(base::MessageLoop::current(), job->message_loop());
   scoped_refptr<TestOwner> owner(new TestOwner);
   TestSource source;
   job->Initialize(owner, &source, 1);
@@ -120,7 +120,7 @@ TEST_F(PrintJobTest, SimplePrint) {
 
 TEST_F(PrintJobTest, SimplePrintLateInit) {
   volatile bool check = false;
-  MessageLoop current;
+  base::MessageLoop current;
   scoped_refptr<printing::PrintJob> job(new TestPrintJob(&check));
   job = NULL;
   EXPECT_TRUE(check);
diff --git a/chrome/browser/printing/print_job_worker.cc b/chrome/browser/printing/print_job_worker.cc
index 70459ed..a90cda0 100644
--- a/chrome/browser/printing/print_job_worker.cc
+++ b/chrome/browser/printing/print_job_worker.cc
@@ -53,7 +53,7 @@ PrintJobWorker::PrintJobWorker(PrintJobWorkerOwner* owner)
       owner_(owner),
       weak_factory_(this) {
   // The object is created in the IO thread.
-  DCHECK_EQ(owner_->message_loop(), MessageLoop::current());
+  DCHECK_EQ(owner_->message_loop(), base::MessageLoop::current());
 
   printing_context_.reset(PrintingContext::Create(
       g_browser_process->GetApplicationLocale()));
@@ -63,7 +63,7 @@ PrintJobWorker::~PrintJobWorker() {
   // The object is normally deleted in the UI thread, but when the user
   // cancels printing or in the case of print preview, the worker is destroyed
   // on the I/O thread.
-  DCHECK_EQ(owner_->message_loop(), MessageLoop::current());
+  DCHECK_EQ(owner_->message_loop(), base::MessageLoop::current());
   Stop();
 }
 
@@ -82,7 +82,7 @@ void PrintJobWorker::GetSettings(bool ask_user_for_settings,
                                  int document_page_count,
                                  bool has_selection,
                                  MarginType margin_type) {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
   DCHECK_EQ(page_number_, PageNumber::npos());
 
   // Recursive task processing is needed for the dialog in case it needs to be
@@ -112,7 +112,7 @@ void PrintJobWorker::GetSettings(bool ask_user_for_settings,
 }
 
 void PrintJobWorker::SetSettings(const DictionaryValue* const new_settings) {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
@@ -194,7 +194,7 @@ void PrintJobWorker::UseDefaultSettings() {
 }
 
 void PrintJobWorker::StartPrinting(PrintedDocument* new_document) {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
   DCHECK_EQ(page_number_, PageNumber::npos());
   DCHECK_EQ(document_, new_document);
   DCHECK(document_.get());
@@ -228,7 +228,7 @@ void PrintJobWorker::StartPrinting(PrintedDocument* new_document) {
 }
 
 void PrintJobWorker::OnDocumentChanged(PrintedDocument* new_document) {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
   DCHECK_EQ(page_number_, PageNumber::npos());
   DCHECK(!new_document ||
          new_document->settings().Equals(printing_context_->settings()));
@@ -244,7 +244,7 @@ void PrintJobWorker::OnNewPage() {
     return;
 
   // message_loop() could return NULL when the print job is cancelled.
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
 
   if (page_number_ == PageNumber::npos()) {
     // Find first page to print.
@@ -267,7 +267,7 @@ void PrintJobWorker::OnNewPage() {
     scoped_refptr<PrintedPage> page;
     if (!document_->GetPage(page_number_.ToInt(), &page)) {
       // We need to wait for the page to be available.
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           base::Bind(&PrintJobWorker::OnNewPage, weak_factory_.GetWeakPtr()),
           base::TimeDelta::FromMilliseconds(500));
@@ -292,7 +292,7 @@ void PrintJobWorker::Cancel() {
 }
 
 void PrintJobWorker::OnDocumentDone() {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
   DCHECK_EQ(page_number_, PageNumber::npos());
   DCHECK(document_.get());
 
@@ -311,7 +311,7 @@ void PrintJobWorker::OnDocumentDone() {
 }
 
 void PrintJobWorker::SpoolPage(PrintedPage* page) {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
   DCHECK_NE(page_number_, PageNumber::npos());
 
   // Signal everyone that the page is about to be printed.
@@ -360,7 +360,7 @@ void PrintJobWorker::SpoolPage(PrintedPage* page) {
 }
 
 void PrintJobWorker::OnFailure() {
-  DCHECK_EQ(message_loop(), MessageLoop::current());
+  DCHECK_EQ(message_loop(), base::MessageLoop::current());
 
   // We may loose our last reference by broadcasting the FAILED event.
   scoped_refptr<PrintJobWorkerOwner> handle(owner_);
diff --git a/chrome/browser/printing/print_view_manager.cc b/chrome/browser/printing/print_view_manager.cc
index b9b2497..8aed1a0 100644
--- a/chrome/browser/printing/print_view_manager.cc
+++ b/chrome/browser/printing/print_view_manager.cc
@@ -490,7 +490,7 @@ void PrintViewManager::ShouldQuitFromInnerMessageLoop() {
       inside_inner_message_loop_) {
     // We are in a message loop created by RenderAllMissingPagesNow. Quit from
     // it.
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
     inside_inner_message_loop_ = false;
   }
 }
@@ -595,17 +595,18 @@ bool PrintViewManager::RunInnerMessageLoop() {
   // be CPU bound, the page overly complex/large or the system just
   // memory-bound.
   static const int kPrinterSettingsTimeout = 60000;
-  base::OneShotTimer<MessageLoop> quit_timer;
+  base::OneShotTimer<base::MessageLoop> quit_timer;
   quit_timer.Start(FROM_HERE,
                    TimeDelta::FromMilliseconds(kPrinterSettingsTimeout),
-                   MessageLoop::current(), &MessageLoop::Quit);
+                   base::MessageLoop::current(), &base::MessageLoop::Quit);
 
   inside_inner_message_loop_ = true;
 
   // Need to enable recursive task.
   {
-    MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
-    MessageLoop::current()->Run();
+    base::MessageLoop::ScopedNestableTaskAllower allow(
+        base::MessageLoop::current());
+    base::MessageLoop::current()->Run();
   }
 
   bool success = true;
diff --git a/chrome/browser/printing/printer_query.cc b/chrome/browser/printing/printer_query.cc
index b9d9ed9..07ae0d8 100644
--- a/chrome/browser/printing/printer_query.cc
+++ b/chrome/browser/printing/printer_query.cc
@@ -14,12 +14,12 @@
 namespace printing {
 
 PrinterQuery::PrinterQuery()
-    : io_message_loop_(MessageLoop::current()),
+    : io_message_loop_(base::MessageLoop::current()),
       worker_(new PrintJobWorker(this)),
       is_print_dialog_box_shown_(false),
       cookie_(PrintSettings::NewCookie()),
       last_status_(PrintingContext::FAILED) {
-  DCHECK_EQ(io_message_loop_->type(), MessageLoop::TYPE_IO);
+  DCHECK_EQ(io_message_loop_->type(), base::MessageLoop::TYPE_IO);
 }
 
 PrinterQuery::~PrinterQuery() {
@@ -74,7 +74,7 @@ void PrinterQuery::GetSettings(GetSettingsAskParam ask_user_for_settings,
                                bool has_selection,
                                MarginType margin_type,
                                const base::Closure& callback) {
-  DCHECK_EQ(io_message_loop_, MessageLoop::current());
+  DCHECK_EQ(io_message_loop_, base::MessageLoop::current());
   DCHECK(!is_print_dialog_box_shown_);
 
   StartWorker(callback);
diff --git a/chrome/browser/printing/printing_layout_browsertest.cc b/chrome/browser/printing/printing_layout_browsertest.cc
index 2e00618..d97762b 100644
--- a/chrome/browser/printing/printing_layout_browsertest.cc
+++ b/chrome/browser/printing/printing_layout_browsertest.cc
@@ -78,14 +78,16 @@ class PrintingLayoutTest : public PrintingTest<InProcessBrowserTest>,
     switch (content::Details<printing::JobEventDetails>(details)->type()) {
       case printing::JobEventDetails::JOB_DONE: {
         // Succeeded.
-        MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+        base::MessageLoop::current()->PostTask(
+            FROM_HERE, base::MessageLoop::QuitClosure());
         break;
       }
       case printing::JobEventDetails::USER_INIT_CANCELED:
       case printing::JobEventDetails::FAILED: {
         // Failed.
         ASSERT_TRUE(false);
-        MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+        base::MessageLoop::current()->PostTask(
+            FROM_HERE, base::MessageLoop::QuitClosure());
         break;
       }
       case printing::JobEventDetails::NEW_DOC:
diff --git a/chrome/browser/process_singleton_browsertest.cc b/chrome/browser/process_singleton_browsertest.cc
index 5ff8f00..d5dc29d 100644
--- a/chrome/browser/process_singleton_browsertest.cc
+++ b/chrome/browser/process_singleton_browsertest.cc
@@ -252,7 +252,7 @@ IN_PROC_BROWSER_TEST_F(ProcessSingletonTest, MAYBE_StartupRaceCondition) {
       chrome_starters_[i]->Reset();
 
       ASSERT_TRUE(chrome_starter_threads_[i]->IsRunning());
-      ASSERT_NE(static_cast<MessageLoop*>(NULL),
+      ASSERT_NE(static_cast<base::MessageLoop*>(NULL),
                 chrome_starter_threads_[i]->message_loop());
 
       chrome_starter_threads_[i]->message_loop()->PostTask(
diff --git a/chrome/browser/process_singleton_linux.cc b/chrome/browser/process_singleton_linux.cc
index d77e083..908637f 100644
--- a/chrome/browser/process_singleton_linux.cc
+++ b/chrome/browser/process_singleton_linux.cc
@@ -406,16 +406,16 @@ bool ConnectSocket(ScopedSocket* socket,
 // This class sets up a listener on the singleton socket and handles parsing
 // messages that come in on the singleton socket.
 class ProcessSingleton::LinuxWatcher
-    : public MessageLoopForIO::Watcher,
-      public MessageLoop::DestructionObserver,
+    : public base::MessageLoopForIO::Watcher,
+      public base::MessageLoop::DestructionObserver,
       public base::RefCountedThreadSafe<ProcessSingleton::LinuxWatcher,
                                         BrowserThread::DeleteOnIOThread> {
  public:
   // A helper class to read message from an established socket.
-  class SocketReader : public MessageLoopForIO::Watcher {
+  class SocketReader : public base::MessageLoopForIO::Watcher {
    public:
     SocketReader(ProcessSingleton::LinuxWatcher* parent,
-                 MessageLoop* ui_message_loop,
+                 base::MessageLoop* ui_message_loop,
                  int fd)
         : parent_(parent),
           ui_message_loop_(ui_message_loop),
@@ -423,8 +423,8 @@ class ProcessSingleton::LinuxWatcher
           bytes_read_(0) {
       DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
       // Wait for reads.
-      MessageLoopForIO::current()->WatchFileDescriptor(
-          fd, true, MessageLoopForIO::WATCH_READ, &fd_reader_, this);
+      base::MessageLoopForIO::current()->WatchFileDescriptor(
+          fd, true, base::MessageLoopForIO::WATCH_READ, &fd_reader_, this);
       // If we haven't completed in a reasonable amount of time, give up.
       timer_.Start(FROM_HERE, base::TimeDelta::FromSeconds(kTimeoutInSeconds),
                    this, &SocketReader::CleanupAndDeleteSelf);
@@ -453,13 +453,13 @@ class ProcessSingleton::LinuxWatcher
       // We're deleted beyond this point.
     }
 
-    MessageLoopForIO::FileDescriptorWatcher fd_reader_;
+    base::MessageLoopForIO::FileDescriptorWatcher fd_reader_;
 
     // The ProcessSingleton::LinuxWatcher that owns us.
     ProcessSingleton::LinuxWatcher* const parent_;
 
     // A reference to the UI message loop.
-    MessageLoop* const ui_message_loop_;
+    base::MessageLoop* const ui_message_loop_;
 
     // The file descriptor we're reading.
     const int fd_;
@@ -478,7 +478,7 @@ class ProcessSingleton::LinuxWatcher
 
   // We expect to only be constructed on the UI thread.
   explicit LinuxWatcher(ProcessSingleton* parent)
-      : ui_message_loop_(MessageLoop::current()),
+      : ui_message_loop_(base::MessageLoop::current()),
         parent_(parent) {
   }
 
@@ -513,18 +513,18 @@ class ProcessSingleton::LinuxWatcher
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
     STLDeleteElements(&readers_);
 
-    MessageLoopForIO* ml = MessageLoopForIO::current();
+    base::MessageLoopForIO* ml = base::MessageLoopForIO::current();
     ml->RemoveDestructionObserver(this);
   }
 
   // Removes and deletes the SocketReader.
   void RemoveSocketReader(SocketReader* reader);
 
-  MessageLoopForIO::FileDescriptorWatcher fd_watcher_;
+  base::MessageLoopForIO::FileDescriptorWatcher fd_watcher_;
 
   // A reference to the UI message loop (i.e., the message loop we were
   // constructed on).
-  MessageLoop* ui_message_loop_;
+  base::MessageLoop* ui_message_loop_;
 
   // The ProcessSingleton that owns us.
   ProcessSingleton* const parent_;
@@ -556,16 +556,16 @@ void ProcessSingleton::LinuxWatcher::OnFileCanReadWithoutBlocking(int fd) {
 void ProcessSingleton::LinuxWatcher::StartListening(int socket) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   // Watch for client connections on this socket.
-  MessageLoopForIO* ml = MessageLoopForIO::current();
+  base::MessageLoopForIO* ml = base::MessageLoopForIO::current();
   ml->AddDestructionObserver(this);
-  ml->WatchFileDescriptor(socket, true, MessageLoopForIO::WATCH_READ,
+  ml->WatchFileDescriptor(socket, true, base::MessageLoopForIO::WATCH_READ,
                           &fd_watcher_, this);
 }
 
 void ProcessSingleton::LinuxWatcher::HandleMessage(
     const std::string& current_dir, const std::vector<std::string>& argv,
     SocketReader* reader) {
-  DCHECK(ui_message_loop_ == MessageLoop::current());
+  DCHECK(ui_message_loop_ == base::MessageLoop::current());
   DCHECK(reader);
 
   if (parent_->notification_callback_.Run(CommandLine(argv),
diff --git a/chrome/browser/profiles/profile_destroyer.cc b/chrome/browser/profiles/profile_destroyer.cc
index 8c98be2..7aa57d2 100644
--- a/chrome/browser/profiles/profile_destroyer.cc
+++ b/chrome/browser/profiles/profile_destroyer.cc
@@ -141,7 +141,7 @@ void ProfileDestroyer::Observe(int type,
   if (num_hosts_ == 0) {
     // Delay the destruction one step further in case other observers of this
     // notification need to look at the profile attached to the host.
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(&ProfileDestroyer::DestroyProfile, this));
   }
 }
diff --git a/chrome/browser/profiles/profile_destroyer_unittest.cc b/chrome/browser/profiles/profile_destroyer_unittest.cc
index c1c9297..3c04289 100644
--- a/chrome/browser/profiles/profile_destroyer_unittest.cc
+++ b/chrome/browser/profiles/profile_destroyer_unittest.cc
@@ -86,12 +86,12 @@ TEST_F(ProfileDestroyerTest, DelayProfileDestruction) {
   render_process_host1.release()->Cleanup();
 
   // And asynchronicity kicked in properly.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(off_the_record_profile_->destroyed_otr_profile_);
 
   // I meant, ALL the render process hosts... :-)
   render_process_host2.release()->Cleanup();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(off_the_record_profile_->destroyed_otr_profile_);
 }
 
@@ -118,7 +118,7 @@ TEST_F(ProfileDestroyerTest, DelayOriginalProfileDestruction) {
   EXPECT_FALSE(original_profile->destroyed_otr_profile_);
 
   render_process_host1.release()->Cleanup();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(NULL, TestingOriginalDestructionProfile::living_instance_);
 
   // And the same protection should apply to the main profile.
@@ -133,6 +133,6 @@ TEST_F(ProfileDestroyerTest, DelayOriginalProfileDestruction) {
   ProfileDestroyer::DestroyProfileWhenAppropriate(main_profile);
   EXPECT_EQ(main_profile, TestingOriginalDestructionProfile::living_instance_);
   render_process_host2.release()->Cleanup();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(NULL, TestingOriginalDestructionProfile::living_instance_);
 }
diff --git a/chrome/browser/profiles/profile_info_cache_unittest.h b/chrome/browser/profiles/profile_info_cache_unittest.h
index ec2ec70..79b9cf5 100644
--- a/chrome/browser/profiles/profile_info_cache_unittest.h
+++ b/chrome/browser/profiles/profile_info_cache_unittest.h
@@ -62,7 +62,7 @@ class ProfileInfoCacheTest : public testing::Test {
   TestingProfileManager testing_profile_manager_;
 
  private:
-  MessageLoopForUI ui_loop_;
+  base::MessageLoopForUI ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   ProfileNameVerifierObserver name_observer_;
diff --git a/chrome/browser/profiles/profile_manager_browsertest.cc b/chrome/browser/profiles/profile_manager_browsertest.cc
index 4499aa8..9cf447b 100644
--- a/chrome/browser/profiles/profile_manager_browsertest.cc
+++ b/chrome/browser/profiles/profile_manager_browsertest.cc
@@ -23,7 +23,7 @@ namespace {
 void OnUnblockOnProfileCreation(Profile* profile,
                                 Profile::CreateStatus status) {
   if (status == Profile::CREATE_STATUS_INITIALIZED)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void ProfileCreationComplete(Profile* profile, Profile::CreateStatus status) {
@@ -32,7 +32,7 @@ void ProfileCreationComplete(Profile* profile, Profile::CreateStatus status) {
   EXPECT_EQ(chrome::GetTotalBrowserCountForProfile(profile), 0U);
   EXPECT_EQ(chrome::GetTotalBrowserCount(), 1U);
   if (status == Profile::CREATE_STATUS_INITIALIZED)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 class ProfileRemovalObserver : public ProfileInfoCacheObserver {
diff --git a/chrome/browser/profiles/profile_manager_unittest.cc b/chrome/browser/profiles/profile_manager_unittest.cc
index 42c2ac2..ecd48e9 100644
--- a/chrome/browser/profiles/profile_manager_unittest.cc
+++ b/chrome/browser/profiles/profile_manager_unittest.cc
@@ -138,7 +138,7 @@ class ProfileManagerTest : public testing::Test {
   scoped_refptr<extensions::EventRouterForwarder>
       extension_event_router_forwarder_;
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread file_thread_;
diff --git a/chrome/browser/profiles/profile_shortcut_manager_unittest_win.cc b/chrome/browser/profiles/profile_shortcut_manager_unittest_win.cc
index 7835a0e..aedcfb2 100644
--- a/chrome/browser/profiles/profile_shortcut_manager_unittest_win.cc
+++ b/chrome/browser/profiles/profile_shortcut_manager_unittest_win.cc
@@ -86,8 +86,9 @@ class ProfileShortcutManagerTest : public testing::Test {
   }
 
   void RunPendingTasks() {
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
   }
 
   void SetupDefaultProfileShortcut(const tracked_objects::Location& location) {
@@ -269,7 +270,7 @@ class ProfileShortcutManagerTest : public testing::Test {
     return system_shortcuts_directory;
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_ptr<TestingProfileManager> profile_manager_;
diff --git a/chrome/browser/renderer_host/plugin_info_message_filter_unittest.cc b/chrome/browser/renderer_host/plugin_info_message_filter_unittest.cc
index f7e905f..9356849 100644
--- a/chrome/browser/renderer_host/plugin_info_message_filter_unittest.cc
+++ b/chrome/browser/renderer_host/plugin_info_message_filter_unittest.cc
@@ -111,10 +111,10 @@ class PluginInfoMessageFilterTest : public ::testing::Test {
 
  private:
   void PluginsLoaded(const std::vector<webkit::WebPluginInfo>& plugins) {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   // PluginService::GetPlugins on Windows jumps to the FILE thread even with
   // a MockPluginList.
   content::TestBrowserThread file_thread_;
diff --git a/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc b/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
index df850d1..d92ec09 100644
--- a/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
+++ b/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
@@ -78,8 +78,8 @@ class ChromeRenderProcessHostTest : public InProcessBrowserTest {
     // Ensure that the backgrounding / foregrounding gets a chance to run.
     content::BrowserThread::PostTaskAndReply(
         content::BrowserThread::PROCESS_LAUNCHER, FROM_HERE,
-        base::Bind(&base::DoNothing), MessageLoop::QuitClosure());
-    MessageLoop::current()->Run();
+        base::Bind(&base::DoNothing), base::MessageLoop::QuitClosure());
+    base::MessageLoop::current()->Run();
 
     return wc->GetRenderProcessHost()->GetHandle();
   }
diff --git a/chrome/browser/renderer_host/web_cache_manager.cc b/chrome/browser/renderer_host/web_cache_manager.cc
index b7966a4..812fcca 100644
--- a/chrome/browser/renderer_host/web_cache_manager.cc
+++ b/chrome/browser/renderer_host/web_cache_manager.cc
@@ -418,7 +418,7 @@ void WebCacheManager::ReviseAllocationStrategy() {
 void WebCacheManager::ReviseAllocationStrategyLater() {
   // Ask to be called back in a few milliseconds to actually recompute our
   // allocation.
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(
           &WebCacheManager::ReviseAllocationStrategy,
           weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/renderer_host/web_cache_manager_unittest.cc b/chrome/browser/renderer_host/web_cache_manager_unittest.cc
index 80f1716..9cd53cb 100644
--- a/chrome/browser/renderer_host/web_cache_manager_unittest.cc
+++ b/chrome/browser/renderer_host/web_cache_manager_unittest.cc
@@ -93,7 +93,7 @@ class WebCacheManagerTest : public testing::Test {
 
  private:
   WebCacheManager manager_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
 };
 
diff --git a/chrome/browser/safe_browsing/browser_feature_extractor.cc b/chrome/browser/safe_browsing/browser_feature_extractor.cc
index 48c166c..00cc9d1 100644
--- a/chrome/browser/safe_browsing/browser_feature_extractor.cc
+++ b/chrome/browser/safe_browsing/browser_feature_extractor.cc
@@ -221,7 +221,7 @@ void BrowserFeatureExtractor::ExtractFeatures(const BrowseInfo* info,
 
   ExtractBrowseInfoFeatures(*info, request);
   pending_extractions_[request] = callback;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&BrowserFeatureExtractor::StartExtractFeatures,
                  weak_factory_.GetWeakPtr(), request, callback));
diff --git a/chrome/browser/safe_browsing/browser_feature_extractor_unittest.cc b/chrome/browser/safe_browsing/browser_feature_extractor_unittest.cc
index 726d175..034cbdc 100644
--- a/chrome/browser/safe_browsing/browser_feature_extractor_unittest.cc
+++ b/chrome/browser/safe_browsing/browser_feature_extractor_unittest.cc
@@ -116,7 +116,7 @@ class BrowserFeatureExtractorTest : public ChromeRenderViewHostTestHarness {
 
   bool ExtractFeatures(ClientPhishingRequest* request) {
     StartExtractFeatures(request);
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     EXPECT_EQ(1U, success_.count(request));
     return success_.count(request) ? success_[request] : false;
   }
@@ -173,7 +173,7 @@ class BrowserFeatureExtractorTest : public ChromeRenderViewHostTestHarness {
     ASSERT_EQ(0U, success_.count(request));
     success_[request] = success;
     if (--num_pending_ == 0) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 };
@@ -279,7 +279,7 @@ TEST_F(BrowserFeatureExtractorTest, MultipleRequestsAtOnce) {
   request2.set_client_score(1.0);
   StartExtractFeatures(&request2);
 
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(success_[&request]);
   // Success is false because the second URL is not in the history and we are
   // not able to distinguish between a missing URL in the history and an error.
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 2b63648..4042396 100644
--- a/chrome/browser/safe_browsing/client_side_detection_host_unittest.cc
+++ b/chrome/browser/safe_browsing/client_side_detection_host_unittest.cc
@@ -74,7 +74,7 @@ MATCHER(CallbackIsNull, "") {
 
 ACTION(QuitUIMessageLoop) {
   EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoopForUI::current()->Quit();
+  base::MessageLoopForUI::current()->Quit();
 }
 
 // It's kind of insane that InvokeArgument doesn't work with callbacks, but it
@@ -177,7 +177,7 @@ void QuitUIMessageLoopFromIO() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   BrowserThread::PostTask(BrowserThread::UI,
                           FROM_HERE,
-                          MessageLoop::QuitClosure());
+                          base::MessageLoop::QuitClosure());
 }
 }  // namespace
 
@@ -222,7 +222,7 @@ class ClientSideDetectionHostTest : public ChromeRenderViewHostTestHarness {
   }
 
   static void RunAllPendingOnIO(base::WaitableEvent* event) {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     event->Signal();
   }
 
@@ -266,7 +266,7 @@ class ClientSideDetectionHostTest : public ChromeRenderViewHostTestHarness {
     BrowserThread::PostTask(BrowserThread::IO,
                             FROM_HERE,
                             base::Bind(&QuitUIMessageLoopFromIO));
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   void ExpectPreClassificationChecks(const GURL& url,
@@ -306,7 +306,7 @@ class ClientSideDetectionHostTest : public ChromeRenderViewHostTestHarness {
     // Wait for CheckCsdWhitelist to be called if at all.
     FlushIOMessageLoop();
     // Checks for CheckCache() to be called if at all.
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     EXPECT_TRUE(Mock::VerifyAndClear(csd_service_.get()));
     EXPECT_TRUE(Mock::VerifyAndClear(ui_manager_.get()));
     EXPECT_TRUE(Mock::VerifyAndClear(database_manager_.get()));
@@ -403,7 +403,7 @@ TEST_F(ClientSideDetectionHostTest, OnPhishingDetectionDoneNotPhishing) {
   // Make sure DoDisplayBlockingPage is not going to be called.
   EXPECT_CALL(*ui_manager_, DoDisplayBlockingPage(_)).Times(0);
   cb.Run(GURL(verdict.url()), false);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(Mock::VerifyAndClear(ui_manager_.get()));
 }
 
@@ -435,7 +435,7 @@ TEST_F(ClientSideDetectionHostTest, OnPhishingDetectionDoneDisabled) {
   // Make sure DoDisplayBlockingPage is not going to be called.
   EXPECT_CALL(*ui_manager_, DoDisplayBlockingPage(_)).Times(0);
   cb.Run(GURL(verdict.url()), false);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(Mock::VerifyAndClear(ui_manager_.get()));
 }
 
@@ -470,7 +470,7 @@ TEST_F(ClientSideDetectionHostTest, OnPhishingDetectionDoneShowInterstitial) {
       .WillOnce(SaveArg<0>(&resource));
   cb.Run(phishing_url, true);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(Mock::VerifyAndClear(ui_manager_.get()));
   EXPECT_EQ(phishing_url, resource.url);
   EXPECT_EQ(phishing_url, resource.original_url);
@@ -548,7 +548,7 @@ TEST_F(ClientSideDetectionHostTest, OnPhishingDetectionDoneMultiplePings) {
   redirect_chain.push_back(other_phishing_url);
   SetRedirectChain(redirect_chain);
   OnPhishingDetectionDone(verdict.SerializeAsString());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(Mock::VerifyAndClear(csd_service_.get()));
   ASSERT_FALSE(cb_other.is_null());
 
@@ -561,7 +561,7 @@ TEST_F(ClientSideDetectionHostTest, OnPhishingDetectionDoneMultiplePings) {
   cb.Run(phishing_url, true);  // Should have no effect.
   cb_other.Run(other_phishing_url, true);  // Should show interstitial.
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(Mock::VerifyAndClear(ui_manager_.get()));
   EXPECT_EQ(other_phishing_url, resource.url);
   EXPECT_EQ(other_phishing_url, resource.original_url);
@@ -627,7 +627,7 @@ TEST_F(ClientSideDetectionHostTest,
   redirect_chain.push_back(url);
   SetRedirectChain(redirect_chain);
   OnPhishingDetectionDone(verdict.SerializeAsString());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(Mock::VerifyAndClear(csd_service_.get()));
 }
 
@@ -954,7 +954,7 @@ TEST_F(ClientSideDetectionHostTest, ShouldClassifyUrl) {
   // Wait for CheckCsdWhitelist to be called on the IO thread.
   FlushIOMessageLoop();
   // Wait for CheckCache() to be called on the UI thread.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   // Now we check that all expected functions were indeed called on the two
   // service objects.
   EXPECT_TRUE(Mock::VerifyAndClear(csd_service_.get()));
diff --git a/chrome/browser/safe_browsing/client_side_detection_service.cc b/chrome/browser/safe_browsing/client_side_detection_service.cc
index 5372789..7ec973d 100644
--- a/chrome/browser/safe_browsing/client_side_detection_service.cc
+++ b/chrome/browser/safe_browsing/client_side_detection_service.cc
@@ -164,7 +164,7 @@ void ClientSideDetectionService::SendClientReportPhishingRequest(
     ClientPhishingRequest* verdict,
     const ClientReportPhishingRequestCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&ClientSideDetectionService::StartClientReportPhishingRequest,
                  weak_factory_.GetWeakPtr(), verdict, callback));
@@ -174,7 +174,7 @@ void ClientSideDetectionService::SendClientReportMalwareRequest(
     ClientMalwareRequest* verdict,
     const ClientReportMalwareRequestCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&ClientSideDetectionService::StartClientReportMalwareRequest,
                  weak_factory_.GetWeakPtr(), verdict, callback));
@@ -294,7 +294,7 @@ void ClientSideDetectionService::ScheduleFetchModel(int64 delay_ms) {
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kSbDisableAutoUpdate))
     return;
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ClientSideDetectionService::StartFetchModel,
                  weak_factory_.GetWeakPtr()),
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 829bfeb..87d471e 100644
--- a/chrome/browser/safe_browsing/client_side_detection_service_unittest.cc
+++ b/chrome/browser/safe_browsing/client_side_detection_service_unittest.cc
@@ -54,7 +54,7 @@ class MockClientSideDetectionService : public ClientSideDetectionService {
 };
 
 ACTION(QuitCurrentMessageLoop) {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 }  // namespace
@@ -216,7 +216,7 @@ class ClientSideDetectionServiceTest : public testing::Test {
  protected:
   scoped_ptr<ClientSideDetectionService> csd_service_;
   scoped_ptr<net::FakeURLFetcherFactory> factory_;
-  MessageLoop msg_loop_;
+  base::MessageLoop msg_loop_;
 
  private:
   void SendRequestDone(GURL phishing_url, bool is_phishing) {
diff --git a/chrome/browser/safe_browsing/database_manager.cc b/chrome/browser/safe_browsing/database_manager.cc
index 7444720..ed89563 100644
--- a/chrome/browser/safe_browsing/database_manager.cc
+++ b/chrome/browser/safe_browsing/database_manager.cc
@@ -597,7 +597,8 @@ void SafeBrowsingDatabaseManager::CloseDatabase() {
 }
 
 SafeBrowsingDatabase* SafeBrowsingDatabaseManager::GetDatabase() {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   if (database_)
     return database_;
   startup_metric_utils::ScopedSlowStartupUMA
@@ -682,7 +683,8 @@ void SafeBrowsingDatabaseManager::OnCheckDone(SafeBrowsingCheck* check) {
 
 void SafeBrowsingDatabaseManager::GetAllChunksFromDatabase(
     GetChunksCallback callback) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
 
   bool database_error = true;
   std::vector<SBListChunkRanges> lists;
@@ -749,7 +751,8 @@ void SafeBrowsingDatabaseManager::DatabaseLoadComplete() {
 void SafeBrowsingDatabaseManager::AddDatabaseChunks(
     const std::string& list_name, SBChunkList* chunks,
     AddChunksCallback callback) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   if (chunks) {
     GetDatabase()->InsertChunks(list_name, *chunks);
     delete chunks;
@@ -762,7 +765,8 @@ void SafeBrowsingDatabaseManager::AddDatabaseChunks(
 
 void SafeBrowsingDatabaseManager::DeleteDatabaseChunks(
     std::vector<SBChunkDelete>* chunk_deletes) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   if (chunk_deletes) {
     GetDatabase()->DeleteChunks(*chunk_deletes);
     delete chunk_deletes;
@@ -797,7 +801,8 @@ SBThreatType SafeBrowsingDatabaseManager::GetThreatTypeFromListname(
 
 void SafeBrowsingDatabaseManager::DatabaseUpdateFinished(
     bool update_succeeded) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   GetDatabase()->UpdateFinished(update_succeeded);
   DCHECK(database_update_in_progress_);
   database_update_in_progress_ = false;
@@ -816,7 +821,8 @@ void SafeBrowsingDatabaseManager::NotifyDatabaseUpdateFinished(
 }
 
 void SafeBrowsingDatabaseManager::OnCloseDatabase() {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   DCHECK(closing_database_);
 
   // Because |closing_database_| is true, nothing on the IO thread will be
@@ -833,14 +839,16 @@ void SafeBrowsingDatabaseManager::OnCloseDatabase() {
 }
 
 void SafeBrowsingDatabaseManager::OnResetDatabase() {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   GetDatabase()->ResetDatabase();
 }
 
 void SafeBrowsingDatabaseManager::CacheHashResults(
   const std::vector<SBPrefix>& prefixes,
   const std::vector<SBFullHashResult>& full_hashes) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   GetDatabase()->CacheHashResults(prefixes, full_hashes);
 }
 
@@ -914,7 +922,8 @@ bool SafeBrowsingDatabaseManager::HandleOneCheck(
 
 void SafeBrowsingDatabaseManager::CheckDownloadHashOnSBThread(
     SafeBrowsingCheck* check) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   DCHECK(enable_download_protection_);
 
   DCHECK_EQ(1u, check->full_hashes.size());
@@ -938,7 +947,8 @@ void SafeBrowsingDatabaseManager::CheckDownloadHashOnSBThread(
 
 void SafeBrowsingDatabaseManager::CheckDownloadUrlOnSBThread(
     SafeBrowsingCheck* check) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
   DCHECK(enable_download_protection_);
 
   std::vector<SBPrefix> prefix_hits;
@@ -962,7 +972,8 @@ void SafeBrowsingDatabaseManager::CheckDownloadUrlOnSBThread(
 
 void SafeBrowsingDatabaseManager::CheckExtensionIDsOnSBThread(
     SafeBrowsingCheck* check) {
-  DCHECK_EQ(MessageLoop::current(), safe_browsing_thread_->message_loop());
+  DCHECK_EQ(base::MessageLoop::current(),
+            safe_browsing_thread_->message_loop());
 
   std::vector<SBPrefix> prefixes;
   for (std::vector<SBFullHash>::iterator it = check->full_hashes.begin();
@@ -1040,7 +1051,7 @@ void SafeBrowsingDatabaseManager::StartSafeBrowsingCheck(
 
   safe_browsing_thread_->message_loop()->PostTask(FROM_HERE, task);
 
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+  base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
       base::Bind(&SafeBrowsingDatabaseManager::TimeoutCallback,
                  check->timeout_factory_->GetWeakPtr(), check),
       check_timeout_);
diff --git a/chrome/browser/safe_browsing/download_protection_service_unittest.cc b/chrome/browser/safe_browsing/download_protection_service_unittest.cc
index 99bccc2..c497c2b 100644
--- a/chrome/browser/safe_browsing/download_protection_service_unittest.cc
+++ b/chrome/browser/safe_browsing/download_protection_service_unittest.cc
@@ -246,7 +246,7 @@ class DownloadProtectionServiceTest : public testing::Test {
  private:
   // Helper functions for FlushThreadMessageLoops.
   void RunAllPendingAndQuitUI() {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
@@ -255,7 +255,7 @@ class DownloadProtectionServiceTest : public testing::Test {
   }
 
   void QuitMessageLoop() {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void PostRunMessageLoopTask(BrowserThread::ID thread) {
@@ -308,7 +308,7 @@ class DownloadProtectionServiceTest : public testing::Test {
   scoped_refptr<FakeSafeBrowsingService> sb_service_;
   scoped_refptr<MockSignatureUtil> signature_util_;
   DownloadProtectionService* download_service_;
-  MessageLoop msg_loop_;
+  base::MessageLoop msg_loop_;
   DownloadProtectionService::DownloadCheckResult result_;
   bool has_result_;
   scoped_ptr<content::TestBrowserThread> io_thread_;
@@ -827,7 +827,7 @@ TEST_F(DownloadProtectionServiceTest, CheckClientDownloadValidateRequest) {
   EXPECT_EQ("dummy cert data", chain.element(0).certificate());
 
   // Simulate the request finishing.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&DownloadProtectionServiceTest::SendURLFetchComplete,
                  base::Unretained(this), fetcher));
@@ -898,7 +898,7 @@ TEST_F(DownloadProtectionServiceTest,
   EXPECT_EQ(0, request.signature().certificate_chain_size());
 
   // Simulate the request finishing.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&DownloadProtectionServiceTest::SendURLFetchComplete,
                  base::Unretained(this), fetcher));
diff --git a/chrome/browser/safe_browsing/malware_details_unittest.cc b/chrome/browser/safe_browsing/malware_details_unittest.cc
index cf54beb..10daca1 100644
--- a/chrome/browser/safe_browsing/malware_details_unittest.cc
+++ b/chrome/browser/safe_browsing/malware_details_unittest.cc
@@ -126,7 +126,7 @@ void QuitUIMessageLoop() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   BrowserThread::PostTask(BrowserThread::UI,
                           FROM_HERE,
-                          MessageLoop::QuitClosure());
+                          base::MessageLoop::QuitClosure());
 }
 
 // Lets us provide a MockURLRequestContext with an HTTP Cache we pre-populate.
@@ -214,7 +214,7 @@ class MalwareDetailsTest : public ChromeRenderViewHostTestHarness {
         base::Bind(&MalwareDetails::FinishCollection, report));
     // Wait for the callback (SendSerializedMalwareDetails).
     DVLOG(1) << "Waiting for SendSerializedMalwareDetails";
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     return ui_manager_->GetSerialized();
   }
 
@@ -421,7 +421,7 @@ TEST_F(MalwareDetailsTest, MalwareDOMDetails) {
   params.push_back(parent_node);
   report->OnReceivedMalwareDOMDetails(params);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   std::string serialized = WaitForSerializedReport(report);
   ClientMalwareReportRequest actual;
@@ -553,7 +553,7 @@ TEST_F(MalwareDetailsTest, HTTPCache) {
   report->OnReceivedMalwareDOMDetails(params);
 
   // Let the cache callbacks complete
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   DVLOG(1) << "Getting serialized report";
   std::string serialized = WaitForSerializedReport(report);
@@ -624,7 +624,7 @@ TEST_F(MalwareDetailsTest, HTTPCacheNoEntries) {
   report->OnReceivedMalwareDOMDetails(params);
 
   // Let the cache callbacks complete
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   DVLOG(1) << "Getting serialized report";
   std::string serialized = WaitForSerializedReport(report);
@@ -673,7 +673,7 @@ TEST_F(MalwareDetailsTest, HistoryServiceUrls) {
   report->OnReceivedMalwareDOMDetails(params);
 
   // Let the redirects callbacks complete.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   std::string serialized = WaitForSerializedReport(report);
   ClientMalwareReportRequest actual;
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
index 6eb42fe..0ba350d 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc
@@ -133,7 +133,7 @@ class FakeSafeBrowsingUIManager :  public SafeBrowsingUIManager {
 
   void OnMalwareDetailsDone() {
     EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::UI));
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   std::string GetReport() {
@@ -247,7 +247,7 @@ class FakeMalwareDetails : public MalwareDetails {
   void OnDOMDetailsDone() {
     got_dom_ = true;
     if (waiting_) {
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
     }
   }
 
@@ -296,7 +296,7 @@ class TestSafeBrowsingBlockingPage : public SafeBrowsingBlockingPageV2 {
       return;
 
     // Notify that we are gone
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
     wait_for_delete_ = false;
   }
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page_unittest.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page_unittest.cc
index 4200984..21ed753 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page_unittest.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page_unittest.cc
@@ -120,10 +120,10 @@ class SafeBrowsingBlockingPageTest : public ChromeRenderViewHostTestHarness {
   };
 
   SafeBrowsingBlockingPageTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
         file_user_blocking_thread_(
-            BrowserThread::FILE_USER_BLOCKING, MessageLoop::current()),
-        io_thread_(BrowserThread::IO, MessageLoop::current()) {
+            BrowserThread::FILE_USER_BLOCKING, base::MessageLoop::current()),
+        io_thread_(BrowserThread::IO, base::MessageLoop::current()) {
     ResetUserResponse();
     // The safe browsing UI manager does not need a service for this test.
     ui_manager_ = new TestSafeBrowsingUIManager(NULL);
@@ -196,14 +196,14 @@ class SafeBrowsingBlockingPageTest : public ChromeRenderViewHostTestHarness {
       SafeBrowsingBlockingPage* sb_interstitial) {
     sb_interstitial->interstitial_page_->Proceed();
     // Proceed() posts a task to update the SafeBrowsingService::Client.
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   static void DontProceedThroughInterstitial(
       SafeBrowsingBlockingPage* sb_interstitial) {
     sb_interstitial->interstitial_page_->DontProceed();
     // DontProceed() posts a task to update the SafeBrowsingService::Client.
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   void DontProceedThroughSubresourceInterstitial(
@@ -212,7 +212,7 @@ class SafeBrowsingBlockingPageTest : public ChromeRenderViewHostTestHarness {
     // subresource interstitials.
     GoBack(false);
     // DontProceed() posts a task to update the SafeBrowsingService::Client.
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   scoped_refptr<TestSafeBrowsingUIManager> ui_manager_;
@@ -257,7 +257,7 @@ TEST_F(SafeBrowsingBlockingPageTest, MalwarePageDontProceed) {
   SafeBrowsingBlockingPage* sb_interstitial = GetSafeBrowsingBlockingPage();
   ASSERT_TRUE(sb_interstitial);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Simulate the user clicking "don't proceed".
   DontProceedThroughInterstitial(sb_interstitial);
@@ -586,7 +586,7 @@ TEST_F(SafeBrowsingBlockingPageTest, ProceedThenDontProceed) {
   SafeBrowsingBlockingPage* sb_interstitial = GetSafeBrowsingBlockingPage();
   ASSERT_TRUE(sb_interstitial);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Simulate the user clicking "proceed" then "don't proceed" (before the
   // interstitial is shown).
@@ -594,7 +594,7 @@ TEST_F(SafeBrowsingBlockingPageTest, ProceedThenDontProceed) {
   sb_interstitial->interstitial_page_->DontProceed();
   // Proceed() and DontProceed() post a task to update the
   // SafeBrowsingService::Client.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // The interstitial should be gone.
   EXPECT_EQ(OK, user_response());
@@ -621,7 +621,7 @@ TEST_F(SafeBrowsingBlockingPageTest, MalwareReportsDisabled) {
   SafeBrowsingBlockingPage* sb_interstitial = GetSafeBrowsingBlockingPage();
   ASSERT_TRUE(sb_interstitial);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Simulate the user clicking "don't proceed".
   DontProceedThroughInterstitial(sb_interstitial);
@@ -654,7 +654,7 @@ TEST_F(SafeBrowsingBlockingPageTest, MalwareReports) {
   SafeBrowsingBlockingPage* sb_interstitial = GetSafeBrowsingBlockingPage();
   ASSERT_TRUE(sb_interstitial);
 
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   EXPECT_FALSE(profile->GetPrefs()->GetBoolean(
       prefs::kSafeBrowsingReportingEnabled));
diff --git a/chrome/browser/safe_browsing/safe_browsing_database.cc b/chrome/browser/safe_browsing/safe_browsing_database.cc
index 3ed33ed..db81dc9 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database.cc
@@ -438,7 +438,7 @@ void SafeBrowsingDatabase::RecordFailure(FailureType failure_type) {
 }
 
 SafeBrowsingDatabaseNew::SafeBrowsingDatabaseNew()
-    : creation_loop_(MessageLoop::current()),
+    : creation_loop_(base::MessageLoop::current()),
       browse_store_(new SafeBrowsingStoreFile),
       download_store_(NULL),
       csd_whitelist_store_(NULL),
@@ -461,7 +461,7 @@ SafeBrowsingDatabaseNew::SafeBrowsingDatabaseNew(
     SafeBrowsingStore* download_whitelist_store,
     SafeBrowsingStore* extension_blacklist_store,
     SafeBrowsingStore* side_effect_free_whitelist_store)
-    : creation_loop_(MessageLoop::current()),
+    : creation_loop_(base::MessageLoop::current()),
       browse_store_(browse_store),
       download_store_(download_store),
       csd_whitelist_store_(csd_whitelist_store),
@@ -474,11 +474,11 @@ SafeBrowsingDatabaseNew::SafeBrowsingDatabaseNew(
 }
 
 SafeBrowsingDatabaseNew::~SafeBrowsingDatabaseNew() {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 }
 
 void SafeBrowsingDatabaseNew::Init(const base::FilePath& filename_base) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
   // Ensure we haven't been run before.
   DCHECK(browse_filename_.empty());
   DCHECK(download_filename_.empty());
@@ -598,7 +598,7 @@ void SafeBrowsingDatabaseNew::Init(const base::FilePath& filename_base) {
 }
 
 bool SafeBrowsingDatabaseNew::ResetDatabase() {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   // Delete files on disk.
   // TODO(shess): Hard to see where one might want to delete without a
@@ -678,7 +678,7 @@ bool SafeBrowsingDatabaseNew::ContainsBrowseUrl(
 bool SafeBrowsingDatabaseNew::ContainsDownloadUrl(
     const std::vector<GURL>& urls,
     std::vector<SBPrefix>* prefix_hits) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   // Ignore this check when download checking is not enabled.
   if (!download_store_.get())
@@ -694,7 +694,7 @@ bool SafeBrowsingDatabaseNew::ContainsDownloadUrl(
 
 bool SafeBrowsingDatabaseNew::ContainsDownloadHashPrefix(
     const SBPrefix& prefix) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   // Ignore this check when download store is not available.
   if (!download_store_.get())
@@ -725,7 +725,7 @@ bool SafeBrowsingDatabaseNew::ContainsDownloadWhitelistedUrl(const GURL& url) {
 bool SafeBrowsingDatabaseNew::ContainsExtensionPrefixes(
     const std::vector<SBPrefix>& prefixes,
     std::vector<SBPrefix>* prefix_hits) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
   if (!extension_blacklist_store_)
     return false;
 
@@ -786,7 +786,7 @@ bool SafeBrowsingDatabaseNew::ContainsWhitelistedHashes(
 // |entry| into the store.
 void SafeBrowsingDatabaseNew::InsertAdd(int chunk_id, SBPrefix host,
                                         const SBEntry* entry, int list_id) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   SafeBrowsingStore* store = GetStore(list_id);
   if (!store) return;
@@ -828,7 +828,7 @@ void SafeBrowsingDatabaseNew::InsertAdd(int chunk_id, SBPrefix host,
 void SafeBrowsingDatabaseNew::InsertAddChunks(
     const safe_browsing_util::ListType list_id,
     const SBChunkList& chunks) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   SafeBrowsingStore* store = GetStore(list_id);
   if (!store) return;
@@ -857,7 +857,7 @@ void SafeBrowsingDatabaseNew::InsertAddChunks(
 // |entry| into the store.
 void SafeBrowsingDatabaseNew::InsertSub(int chunk_id, SBPrefix host,
                                         const SBEntry* entry, int list_id) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   SafeBrowsingStore* store = GetStore(list_id);
   if (!store) return;
@@ -903,7 +903,7 @@ void SafeBrowsingDatabaseNew::InsertSub(int chunk_id, SBPrefix host,
 void SafeBrowsingDatabaseNew::InsertSubChunks(
     safe_browsing_util::ListType list_id,
     const SBChunkList& chunks) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   SafeBrowsingStore* store = GetStore(list_id);
   if (!store) return;
@@ -928,7 +928,7 @@ void SafeBrowsingDatabaseNew::InsertSubChunks(
 
 void SafeBrowsingDatabaseNew::InsertChunks(const std::string& list_name,
                                            const SBChunkList& chunks) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   if (corruption_detected_ || chunks.empty())
     return;
@@ -957,7 +957,7 @@ void SafeBrowsingDatabaseNew::InsertChunks(const std::string& list_name,
 
 void SafeBrowsingDatabaseNew::DeleteChunks(
     const std::vector<SBChunkDelete>& chunk_deletes) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   if (corruption_detected_ || chunk_deletes.empty())
     return;
@@ -1021,7 +1021,7 @@ void SafeBrowsingDatabaseNew::CacheHashResults(
 
 bool SafeBrowsingDatabaseNew::UpdateStarted(
     std::vector<SBListChunkRanges>* lists) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
   DCHECK(lists);
 
   // If |BeginUpdate()| fails, reset the database.
@@ -1133,7 +1133,7 @@ bool SafeBrowsingDatabaseNew::UpdateStarted(
 }
 
 void SafeBrowsingDatabaseNew::UpdateFinished(bool update_succeeded) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   // The update may have failed due to corrupt storage (for instance,
   // an excessive number of invalid add_chunks and sub_chunks).
@@ -1461,7 +1461,7 @@ void SafeBrowsingDatabaseNew::HandleCorruptDatabase() {
   // reset once within the scope of a given task).
   if (!reset_factory_.HasWeakPtrs()) {
     RecordFailure(FAILURE_DATABASE_CORRUPT);
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(&SafeBrowsingDatabaseNew::OnHandleCorruptDatabase,
                    reset_factory_.GetWeakPtr()));
   }
@@ -1477,7 +1477,7 @@ void SafeBrowsingDatabaseNew::OnHandleCorruptDatabase() {
 // TODO(shess): I'm not clear why this code doesn't have any
 // real error-handling.
 void SafeBrowsingDatabaseNew::LoadPrefixSet() {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
   DCHECK(!browse_prefix_set_filename_.empty());
 
   // If there is no database, the filter cannot be used.
@@ -1503,7 +1503,7 @@ void SafeBrowsingDatabaseNew::LoadPrefixSet() {
 }
 
 bool SafeBrowsingDatabaseNew::Delete() {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   const bool r1 = browse_store_->Delete();
   if (!r1)
@@ -1552,7 +1552,7 @@ bool SafeBrowsingDatabaseNew::Delete() {
 }
 
 void SafeBrowsingDatabaseNew::WritePrefixSet() {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
 
   if (!browse_prefix_set_.get())
     return;
@@ -1581,7 +1581,7 @@ void SafeBrowsingDatabaseNew::WhitelistEverything(SBWhitelist* whitelist) {
 void SafeBrowsingDatabaseNew::LoadWhitelist(
     const std::vector<SBAddFullHash>& full_hashes,
     SBWhitelist* whitelist) {
-  DCHECK_EQ(creation_loop_, MessageLoop::current());
+  DCHECK_EQ(creation_loop_, base::MessageLoop::current());
   if (full_hashes.size() > kMaxWhitelistSize) {
     WhitelistEverything(whitelist);
     return;
diff --git a/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc b/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
index dbe83b4..ca61644 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database_unittest.cc
@@ -363,7 +363,7 @@ TEST_F(SafeBrowsingDatabaseTest, ListNameForBrowse) {
 
 TEST_F(SafeBrowsingDatabaseTest, ListNameForBrowseAndDownload) {
   database_.reset();
-  MessageLoop loop(MessageLoop::TYPE_DEFAULT);
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
   SafeBrowsingStoreFile* browse_store = new SafeBrowsingStoreFile();
   SafeBrowsingStoreFile* download_store = new SafeBrowsingStoreFile();
   SafeBrowsingStoreFile* csd_whitelist_store = new SafeBrowsingStoreFile();
@@ -1079,7 +1079,7 @@ TEST_F(SafeBrowsingDatabaseTest, DISABLED_FileCorruptionHandling) {
   // influence task-posting.  Database specifically needs to the
   // file-backed.
   database_.reset();
-  MessageLoop loop(MessageLoop::TYPE_DEFAULT);
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
   SafeBrowsingStoreFile* store = new SafeBrowsingStoreFile();
   database_.reset(new SafeBrowsingDatabaseNew(store, NULL, NULL, NULL, NULL,
                                               NULL));
@@ -1130,7 +1130,7 @@ TEST_F(SafeBrowsingDatabaseTest, DISABLED_FileCorruptionHandling) {
 
     // Flush through the corruption-handler task.
     VLOG(1) << "Expect failed check on: SafeBrowsing database reset";
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   // Database file should not exist.
@@ -1148,7 +1148,7 @@ TEST_F(SafeBrowsingDatabaseTest, DISABLED_FileCorruptionHandling) {
 // Checks database reading and writing.
 TEST_F(SafeBrowsingDatabaseTest, ContainsDownloadUrl) {
   database_.reset();
-  MessageLoop loop(MessageLoop::TYPE_DEFAULT);
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
   SafeBrowsingStoreFile* browse_store = new SafeBrowsingStoreFile();
   SafeBrowsingStoreFile* download_store = new SafeBrowsingStoreFile();
   SafeBrowsingStoreFile* csd_whitelist_store = new SafeBrowsingStoreFile();
@@ -1252,7 +1252,7 @@ TEST_F(SafeBrowsingDatabaseTest, ContainsDownloadUrl) {
 // Checks that the whitelists are handled properly.
 TEST_F(SafeBrowsingDatabaseTest, Whitelists) {
   database_.reset();
-  MessageLoop loop(MessageLoop::TYPE_DEFAULT);
+  base::MessageLoop loop(base::MessageLoop::TYPE_DEFAULT);
   // We expect all calls to ContainsCsdWhitelistedUrl in particular to be made
   // from the IO thread.  In general the whitelist lookups are thread-safe.
   content::TestBrowserThread io_thread(BrowserThread::IO, &loop);
diff --git a/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc b/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc
index d4e5594..f043d7b 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_service_browsertest.cc
@@ -597,7 +597,7 @@ class TestSBClient
   }
 
   void DownloadCheckDone() {
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   SBThreatType threat_type_;
@@ -818,7 +818,7 @@ class SafeBrowsingServiceShutdownTest : public SafeBrowsingServiceTest {
                                   Profile::CreateStatus status) {
     if (status == Profile::CREATE_STATUS_INITIALIZED) {
       profile2_ = profile;
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_test.cc b/chrome/browser/safe_browsing/safe_browsing_test.cc
index 7fe39eb..78a225c 100644
--- a/chrome/browser/safe_browsing/safe_browsing_test.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_test.cc
@@ -203,7 +203,7 @@ class SafeBrowsingServerTest : public InProcessBrowserTest {
     return is_update_scheduled_;
   }
 
-  MessageLoop* SafeBrowsingMessageLoop() {
+  base::MessageLoop* SafeBrowsingMessageLoop() {
     return database_manager()->safe_browsing_thread_->message_loop();
   }
 
@@ -350,7 +350,7 @@ class SafeBrowsingServerTestHelper
 
   // Checks status in SafeBrowsing Thread.
   void CheckIsDatabaseReady() {
-    EXPECT_EQ(MessageLoop::current(),
+    EXPECT_EQ(base::MessageLoop::current(),
               safe_browsing_test_->SafeBrowsingMessageLoop());
     safe_browsing_test_->CheckIsDatabaseReady();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
@@ -422,7 +422,7 @@ class SafeBrowsingServerTestHelper
   // Stops UI loop after desired status is updated.
   void StopUILoop() {
     EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::UI));
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
   // Fetch a URL. If message_loop_started is true, starts the message loop
diff --git a/chrome/browser/safe_browsing/two_phase_uploader_unittest.cc b/chrome/browser/safe_browsing/two_phase_uploader_unittest.cc
index 596f95f4..8a58e2f 100644
--- a/chrome/browser/safe_browsing/two_phase_uploader_unittest.cc
+++ b/chrome/browser/safe_browsing/two_phase_uploader_unittest.cc
@@ -70,7 +70,7 @@ class TwoPhaseUploaderTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForIO message_loop_;
+  base::MessageLoopForIO message_loop_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread io_thread_;
 
diff --git a/chrome/browser/search/iframe_source_unittest.cc b/chrome/browser/search/iframe_source_unittest.cc
index 3e007ac..0091531 100644
--- a/chrome/browser/search/iframe_source_unittest.cc
+++ b/chrome/browser/search/iframe_source_unittest.cc
@@ -140,7 +140,7 @@ class IframeSourceTest : public testing::Test {
     response_ = data;
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
 
diff --git a/chrome/browser/search_engines/search_provider_install_data_unittest.cc b/chrome/browser/search_engines/search_provider_install_data_unittest.cc
index 4911e95..c0ca6c4 100644
--- a/chrome/browser/search_engines/search_provider_install_data_unittest.cc
+++ b/chrome/browser/search_engines/search_provider_install_data_unittest.cc
@@ -64,7 +64,7 @@ class TestGetInstallState :
                           const std::string& url);
 
   SearchProviderInstallData* install_data_;
-  MessageLoop* main_loop_;
+  base::MessageLoop* main_loop_;
 
   // A host which should be a search provider but not the default.
   std::string search_provider_host_;
@@ -88,14 +88,14 @@ TestGetInstallState::TestGetInstallState(
 bool TestGetInstallState::RunTests() {
   passed_ = true;
 
-  main_loop_ = MessageLoop::current();
+  main_loop_ = base::MessageLoop::current();
 
   BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)->PostTask(
       FROM_HERE,
       base::Bind(&TestGetInstallState::StartTestOnIOThread, this));
   // Run the current message loop. When the test is finished on the I/O thread,
   // it invokes Quit, which unblocks this.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   main_loop_ = NULL;
 
   // Let the testing code know what the result is.
@@ -136,7 +136,7 @@ void TestGetInstallState::DoInstallStateTests() {
   }
 
   // All done.
-  main_loop_->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+  main_loop_->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
 }
 
 void TestGetInstallState::VerifyInstallState(
diff --git a/chrome/browser/search_engines/template_url_fetcher_unittest.cc b/chrome/browser/search_engines/template_url_fetcher_unittest.cc
index 765660b..bfb6cdf 100644
--- a/chrome/browser/search_engines/template_url_fetcher_unittest.cc
+++ b/chrome/browser/search_engines/template_url_fetcher_unittest.cc
@@ -120,7 +120,7 @@ void TemplateURLFetcherTest::DestroyedCallback(
     TemplateURLFetcherTestCallbacks* callbacks) {
   callbacks_destroyed_++;
   if (waiting_for_download_)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 void TemplateURLFetcherTest::ConfirmAddSearchProvider(
@@ -156,7 +156,7 @@ void TemplateURLFetcherTest::StartDownload(
 void TemplateURLFetcherTest::WaitForDownloadToFinish() {
   ASSERT_FALSE(waiting_for_download_);
   waiting_for_download_ = true;
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   waiting_for_download_ = false;
 }
 
diff --git a/chrome/browser/search_engines/template_url_scraper_unittest.cc b/chrome/browser/search_engines/template_url_scraper_unittest.cc
index 999c525..6d9b011 100644
--- a/chrome/browser/search_engines/template_url_scraper_unittest.cc
+++ b/chrome/browser/search_engines/template_url_scraper_unittest.cc
@@ -39,7 +39,7 @@ class TemplateURLServiceLoader : public content::NotificationObserver {
                        const content::NotificationDetails& details) {
     if (type == chrome::NOTIFICATION_TEMPLATE_URL_SERVICE_LOADED &&
         content::Source<TemplateURLService>(source).ptr() == model_) {
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/search_engines/template_url_service_test_util.cc b/chrome/browser/search_engines/template_url_service_test_util.cc
index 5336300..34894ab 100644
--- a/chrome/browser/search_engines/template_url_service_test_util.cc
+++ b/chrome/browser/search_engines/template_url_service_test_util.cc
@@ -36,8 +36,8 @@ namespace {
 // requests. See note in BlockTillServiceProcessesRequests for details.
 //
 // Schedules a QuitClosure on the message loop it was created with.
-void QuitCallback(MessageLoop* message_loop) {
-  message_loop->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+void QuitCallback(base::MessageLoop* message_loop) {
+  message_loop->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
 }
 
 // Blocks the caller until thread has finished servicing all pending
@@ -45,9 +45,11 @@ void QuitCallback(MessageLoop* message_loop) {
 static void WaitForThreadToProcessRequests(BrowserThread::ID identifier) {
   // Schedule a task on the thread that is processed after all
   // pending requests on the thread.
-  BrowserThread::PostTask(identifier, FROM_HERE,
-                          base::Bind(&QuitCallback, MessageLoop::current()));
-  MessageLoop::current()->Run();
+  BrowserThread::PostTask(
+      identifier,
+      FROM_HERE,
+      base::Bind(&QuitCallback, base::MessageLoop::current()));
+  base::MessageLoop::current()->Run();
 }
 
 }  // namespace
@@ -135,8 +137,9 @@ void TemplateURLServiceTestUtil::TearDown() {
   BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
       base::Bind(&base::WaitableEvent::Signal, base::Unretained(&done)));
   done.Wait();
-  MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->PostTask(FROM_HERE,
+                                         base::MessageLoop::QuitClosure());
+  base::MessageLoop::current()->Run();
   db_thread_.Stop();
 
   UIThreadSearchTermsData::SetGoogleBaseURL(std::string());
diff --git a/chrome/browser/search_engines/template_url_service_test_util.h b/chrome/browser/search_engines/template_url_service_test_util.h
index 80c3fe3..3b546e1 100644
--- a/chrome/browser/search_engines/template_url_service_test_util.h
+++ b/chrome/browser/search_engines/template_url_service_test_util.h
@@ -109,7 +109,7 @@ class TemplateURLServiceTestUtil : public TemplateURLServiceObserver {
   void PumpLoop();
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   // Needed to make the DeleteOnUIThread trait of WebDataService work
   // properly.
   content::TestBrowserThread ui_thread_;
diff --git a/chrome/browser/service/service_process_control.cc b/chrome/browser/service/service_process_control.cc
index 72f61cd..70b0157 100644
--- a/chrome/browser/service/service_process_control.cc
+++ b/chrome/browser/service/service_process_control.cc
@@ -290,7 +290,7 @@ void ServiceProcessControl::Launcher::DoDetectLaunched() {
 
   // If the service process is not launched yet then check again in 2 seconds.
   const base::TimeDelta kDetectLaunchRetry = base::TimeDelta::FromSeconds(2);
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE, base::Bind(&Launcher::DoDetectLaunched, this),
       kDetectLaunchRetry);
 }
diff --git a/chrome/browser/service/service_process_control_browsertest.cc b/chrome/browser/service/service_process_control_browsertest.cc
index 4c5bb8d..5922b46 100644
--- a/chrome/browser/service/service_process_control_browsertest.cc
+++ b/chrome/browser/service/service_process_control_browsertest.cc
@@ -55,7 +55,7 @@ class ServiceProcessControlBrowserTest
 
   void CloudPrintInfoCallback(
       const cloud_print::CloudPrintProxyInfo& proxy_info) {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void Disconnect() {
@@ -82,13 +82,15 @@ class ServiceProcessControlBrowserTest
     // Quit the current message. Post a QuitTask instead of just calling Quit()
     // because this can get invoked in the context of a Launch() call and we
     // may not be in Run() yet.
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
   }
 
   void ProcessControlLaunchFailed() {
     ADD_FAILURE();
     // Quit the current message.
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
   }
 
  private:
@@ -132,7 +134,8 @@ IN_PROC_BROWSER_TEST_F(ServiceProcessControlBrowserTest, LaunchTwice) {
 static void DecrementUntilZero(int* count) {
   (*count)--;
   if (!(*count))
-    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::MessageLoop::QuitClosure());
 }
 
 // Invoke multiple Launch calls in succession and ensure that all the tasks
@@ -144,7 +147,7 @@ IN_PROC_BROWSER_TEST_F(ServiceProcessControlBrowserTest,
   for (int i = 0; i < launch_count; i++) {
     // Launch the process asynchronously.
     process->Launch(base::Bind(&DecrementUntilZero, &launch_count),
-                    MessageLoop::QuitClosure());
+                    base::MessageLoop::QuitClosure());
   }
   // Then run the message loop to keep things running.
   content::RunMessageLoop();
diff --git a/chrome/browser/sessions/base_session_service.cc b/chrome/browser/sessions/base_session_service.cc
index 64c094c..afc75d0 100644
--- a/chrome/browser/sessions/base_session_service.cc
+++ b/chrome/browser/sessions/base_session_service.cc
@@ -116,8 +116,9 @@ void BaseSessionService::ScheduleCommand(SessionCommand* command) {
 void BaseSessionService::StartSaveTimer() {
   // Don't start a timer when testing (profile == NULL or
   // MessageLoop::current() is NULL).
-  if (MessageLoop::current() && profile() && !weak_factory_.HasWeakPtrs()) {
-    MessageLoop::current()->PostDelayedTask(
+  if (base::MessageLoop::current() && profile() &&
+      !weak_factory_.HasWeakPtrs()) {
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&BaseSessionService::Save, weak_factory_.GetWeakPtr()),
         base::TimeDelta::FromMilliseconds(kSaveDelayMS));
diff --git a/chrome/browser/sessions/session_restore.cc b/chrome/browser/sessions/session_restore.cc
index 479338b..ee6c5e1 100644
--- a/chrome/browser/sessions/session_restore.cc
+++ b/chrome/browser/sessions/session_restore.cc
@@ -538,8 +538,9 @@ class SessionRestoreImpl : public content::NotificationObserver {
 
     if (synchronous_) {
       {
-        MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
-        MessageLoop::current()->Run();
+        base::MessageLoop::ScopedNestableTaskAllower allow(
+            base::MessageLoop::current());
+        base::MessageLoop::current()->Run();
       }
       Browser* browser = ProcessSessionWindows(&windows_, active_window_id_);
       delete this;
@@ -716,7 +717,7 @@ class SessionRestoreImpl : public content::NotificationObserver {
       // NOTE: we must use DeleteLater here as most likely we're in a callback
       // from the history service which doesn't deal well with deleting the
       // object it is notifying.
-      MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+      base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 
       // The delete may take a while and at this point we no longer care about
       // if the browser is deleted. Don't listen to anything. This avoid a
@@ -750,7 +751,7 @@ class SessionRestoreImpl : public content::NotificationObserver {
       // See comment above windows_ as to why we don't process immediately.
       windows_.swap(windows.get());
       active_window_id_ = active_window_id;
-      MessageLoop::current()->QuitNow();
+      base::MessageLoop::current()->QuitNow();
       return;
     }
 
diff --git a/chrome/browser/shell_integration_unittest.cc b/chrome/browser/shell_integration_unittest.cc
index 274537f..bb28274 100644
--- a/chrome/browser/shell_integration_unittest.cc
+++ b/chrome/browser/shell_integration_unittest.cc
@@ -78,7 +78,7 @@ TEST(ShellIntegrationTest, GetExistingShortcutLocations) {
   base::FilePath kTemplateFilepath(kTemplateFilename);
   const char kNoDisplayDesktopFile[] = "[Desktop Entry]\nNoDisplay=true";
 
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread file_thread(BrowserThread::FILE, &message_loop);
 
   // No existing shortcuts.
@@ -192,7 +192,7 @@ TEST(ShellIntegrationTest, GetExistingShortcutContents) {
   const char kTestData1[] = "a magical testing string";
   const char kTestData2[] = "a different testing string";
 
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread file_thread(BrowserThread::FILE, &message_loop);
 
   // Test that it searches $XDG_DATA_HOME/applications.
diff --git a/chrome/browser/signin/oauth2_token_service.cc b/chrome/browser/signin/oauth2_token_service.cc
index abddb4e..aeacd41 100644
--- a/chrome/browser/signin/oauth2_token_service.cc
+++ b/chrome/browser/signin/oauth2_token_service.cc
@@ -213,7 +213,7 @@ void OAuth2TokenService::Fetcher::OnGetTokenSuccess(
   // be added when it calls back the waiting requests.
   oauth2_token_service_->OnFetchComplete(this);
   InformWaitingRequests();
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 void OAuth2TokenService::Fetcher::OnGetTokenFailure(
@@ -238,7 +238,7 @@ void OAuth2TokenService::Fetcher::OnGetTokenFailure(
   // added when it calls back the waiting requests.
   oauth2_token_service_->OnFetchComplete(this);
   InformWaitingRequests();
-  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 // static
@@ -324,7 +324,7 @@ scoped_ptr<OAuth2TokenService::Request> OAuth2TokenService::StartRequest(
 
   std::string refresh_token = GetRefreshToken();
   if (refresh_token.empty()) {
-    MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+    base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         &OAuth2TokenService::InformConsumer,
         request->AsWeakPtr(),
         GoogleServiceAuthError(
@@ -360,7 +360,7 @@ scoped_ptr<OAuth2TokenService::Request>
   CHECK(HasCacheEntry(scopes));
   const CacheEntry* cache_entry = GetCacheEntry(scopes);
   scoped_ptr<RequestImpl> request(new RequestImpl(consumer));
-  MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+  base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
       &OAuth2TokenService::InformConsumer,
       request->AsWeakPtr(),
       GoogleServiceAuthError(GoogleServiceAuthError::NONE),
diff --git a/chrome/browser/signin/profile_oauth2_token_service_request_unittest.cc b/chrome/browser/signin/profile_oauth2_token_service_request_unittest.cc
index 3cbb7ea..fb3b07d 100644
--- a/chrome/browser/signin/profile_oauth2_token_service_request_unittest.cc
+++ b/chrome/browser/signin/profile_oauth2_token_service_request_unittest.cc
@@ -152,7 +152,7 @@ scoped_ptr<OAuth2TokenService::Request>
         GoogleServiceAuthError(GoogleServiceAuthError::SERVICE_UNAVAILABLE),
         std::string()));
   }
-  MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
+  base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
     &MockProfileOAuth2TokenService::InformConsumer, request->AsWeakPtr()));
   return request.PassAs<OAuth2TokenService::Request>();
 }
@@ -167,7 +167,7 @@ class ProfileOAuth2TokenServiceRequestTest : public testing::Test {
   virtual void SetUp() OVERRIDE;
 
  protected:
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
 
   scoped_ptr<Profile> profile_;
diff --git a/chrome/browser/signin/signin_manager_unittest.cc b/chrome/browser/signin/signin_manager_unittest.cc
index b1b655a..83a360d 100644
--- a/chrome/browser/signin/signin_manager_unittest.cc
+++ b/chrome/browser/signin/signin_manager_unittest.cc
@@ -176,7 +176,7 @@ class SigninManagerTest : public TokenServiceTestHarness {
         BrowserThread::IO, FROM_HERE,
         base::Bind(&SigninManagerTest::NotifyUIOnComplete,
                    base::Unretained(this)));
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
   void NotifyUIOnComplete () {
@@ -187,7 +187,7 @@ class SigninManagerTest : public TokenServiceTestHarness {
                      base::Unretained(this)));
       return;
     }
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void ExpectSignInWithCredentialsSuccess() {
diff --git a/chrome/browser/signin/signin_names_io_thread_unittest.cc b/chrome/browser/signin/signin_names_io_thread_unittest.cc
index 699b244..dfecc28 100644
--- a/chrome/browser/signin/signin_names_io_thread_unittest.cc
+++ b/chrome/browser/signin/signin_names_io_thread_unittest.cc
@@ -29,7 +29,7 @@ class SigninNamesOnIOThreadTest : public testing::Test {
   void SimulateSignout(const string16& email);
   void AddNewProfile(const string16& name, const string16& email);
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   TestingProfileManager testing_profile_manager_;
diff --git a/chrome/browser/signin/token_service_unittest.cc b/chrome/browser/signin/token_service_unittest.cc
index 528d7d1..bfe08ea 100644
--- a/chrome/browser/signin/token_service_unittest.cc
+++ b/chrome/browser/signin/token_service_unittest.cc
@@ -97,8 +97,9 @@ void TokenServiceTestHarness::TearDown() {
   BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
       base::Bind(&base::WaitableEvent::Signal, base::Unretained(&done)));
   done.Wait();
-  MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->PostTask(FROM_HERE,
+                                         base::MessageLoop::QuitClosure());
+  base::MessageLoop::current()->Run();
   db_thread_.Stop();
 }
 
diff --git a/chrome/browser/signin/token_service_unittest.h b/chrome/browser/signin/token_service_unittest.h
index bc0d307..9730b2a 100644
--- a/chrome/browser/signin/token_service_unittest.h
+++ b/chrome/browser/signin/token_service_unittest.h
@@ -66,7 +66,7 @@ class TokenServiceTestHarness : public testing::Test {
 
   void WaitForDBLoadCompletion();
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;  // Mostly so DCHECKS pass.
   content::TestBrowserThread db_thread_;  // WDS on here
 
diff --git a/chrome/browser/speech/extension_api/tts_extension_apitest.cc b/chrome/browser/speech/extension_api/tts_extension_apitest.cc
index e704f5d..dc4dc90 100644
--- a/chrome/browser/speech/extension_api/tts_extension_apitest.cc
+++ b/chrome/browser/speech/extension_api/tts_extension_apitest.cc
@@ -58,7 +58,7 @@ class MockTtsPlatformImpl : public TtsPlatformImpl {
                     const std::string& lang,
                     const VoiceData& voice,
                     const UtteranceContinuousParameters& params) {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE, base::Bind(
             &MockTtsPlatformImpl::SendEvent,
             ptr_factory_.GetWeakPtr(),
@@ -73,7 +73,7 @@ class MockTtsPlatformImpl : public TtsPlatformImpl {
       const std::string& lang,
       const VoiceData& voice,
       const UtteranceContinuousParameters& params) {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE, base::Bind(
             &MockTtsPlatformImpl::SendEvent,
             ptr_factory_.GetWeakPtr(),
@@ -88,7 +88,7 @@ class MockTtsPlatformImpl : public TtsPlatformImpl {
                       const UtteranceContinuousParameters& params) {
     for (int i = 0; i < static_cast<int>(utterance.size()); i++) {
       if (i == 0 || utterance[i - 1] == ' ') {
-        MessageLoop::current()->PostDelayedTask(
+        base::MessageLoop::current()->PostDelayedTask(
             FROM_HERE, base::Bind(
                 &MockTtsPlatformImpl::SendEvent,
                 ptr_factory_.GetWeakPtr(),
@@ -106,7 +106,7 @@ class MockTtsPlatformImpl : public TtsPlatformImpl {
                  const std::string& message) {
     TtsController* controller = TtsController::GetInstance();
     if (wait_for_non_empty_queue && controller->QueueSize() == 0) {
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE, base::Bind(
               &MockTtsPlatformImpl::SendEvent,
               ptr_factory_.GetWeakPtr(),
diff --git a/chrome/browser/speech/speech_recognition_bubble.cc b/chrome/browser/speech/speech_recognition_bubble.cc
index 2ab8657..d1f1546 100644
--- a/chrome/browser/speech/speech_recognition_bubble.cc
+++ b/chrome/browser/speech/speech_recognition_bubble.cc
@@ -177,7 +177,7 @@ void SpeechRecognitionBubbleBase::SetWarmUpMode() {
 
 void SpeechRecognitionBubbleBase::DoWarmingUpAnimationStep() {
   SetImage(g_images.Get().warm_up()[animation_step_]);
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&SpeechRecognitionBubbleBase::DoWarmingUpAnimationStep,
           weak_factory_.GetWeakPtr()),
@@ -206,7 +206,7 @@ void SpeechRecognitionBubbleBase::DoRecognizingAnimationStep() {
   SetImage(g_images.Get().spinner()[animation_step_]);
   if (++animation_step_ >= static_cast<int>(g_images.Get().spinner().size()))
     animation_step_ = 0;
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&SpeechRecognitionBubbleBase::DoRecognizingAnimationStep,
           weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/speech/speech_recognition_bubble_controller_unittest.cc b/chrome/browser/speech/speech_recognition_bubble_controller_unittest.cc
index 2026cda..658fb94 100644
--- a/chrome/browser/speech/speech_recognition_bubble_controller_unittest.cc
+++ b/chrome/browser/speech/speech_recognition_bubble_controller_unittest.cc
@@ -34,7 +34,7 @@ class MockSpeechRecognitionBubble : public SpeechRecognitionBubbleBase {
                         const gfx::Rect&)
       : SpeechRecognitionBubbleBase(web_contents) {
     VLOG(1) << "MockSpeechRecognitionBubble created";
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(&InvokeDelegate, delegate));
   }
 
@@ -103,14 +103,14 @@ class SpeechRecognitionBubbleControllerTest
     } else if (button == SpeechRecognitionBubble::BUTTON_TRY_AGAIN) {
       try_again_clicked_ = true;
     }
-    message_loop()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    message_loop()->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
   virtual void InfoBubbleFocusChanged(int session_id) OVERRIDE {
     VLOG(1) << "Received InfoBubbleFocusChanged";
     EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::IO));
     focus_changed_ = true;
-    message_loop()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    message_loop()->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
   // testing::Test methods.
@@ -142,8 +142,8 @@ class SpeechRecognitionBubbleControllerTest
     // Set up to activate the bubble soon after it gets created, since we test
     // events sent by the bubble and those are handled only when the bubble is
     // active.
-    MessageLoop::current()->PostTask(FROM_HERE,
-                                     base::Bind(&ActivateBubble));
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(&ActivateBubble));
 
     // The |web_contents| parameter would be NULL since the dummy session id
     // passed to CreateBubble would not have matched any active tab. So get a
@@ -184,7 +184,7 @@ TEST_F(SpeechRecognitionBubbleControllerTest, TestFocusChanged) {
       MockSpeechRecognitionBubble::BUBBLE_TEST_FOCUS_CHANGED);
 
   controller_->CreateBubble(kBubbleSessionId, 1, 1, gfx::Rect(1, 1));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(focus_changed_);
   EXPECT_FALSE(cancel_clicked_);
   EXPECT_FALSE(try_again_clicked_);
@@ -198,7 +198,7 @@ TEST_F(SpeechRecognitionBubbleControllerTest, TestRecognitionCancelled) {
       MockSpeechRecognitionBubble::BUBBLE_TEST_CLICK_CANCEL);
 
   controller_->CreateBubble(kBubbleSessionId, 1, 1, gfx::Rect(1, 1));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(cancel_clicked_);
   EXPECT_FALSE(try_again_clicked_);
   EXPECT_FALSE(focus_changed_);
@@ -212,7 +212,7 @@ TEST_F(SpeechRecognitionBubbleControllerTest, TestTryAgainClicked) {
       MockSpeechRecognitionBubble::BUBBLE_TEST_CLICK_TRY_AGAIN);
 
   controller_->CreateBubble(kBubbleSessionId, 1, 1, gfx::Rect(1, 1));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_FALSE(cancel_clicked_);
   EXPECT_TRUE(try_again_clicked_);
   EXPECT_FALSE(focus_changed_);
diff --git a/chrome/browser/spellchecker/feedback_sender.cc b/chrome/browser/spellchecker/feedback_sender.cc
index c7cbdb8..a2673b9 100644
--- a/chrome/browser/spellchecker/feedback_sender.cc
+++ b/chrome/browser/spellchecker/feedback_sender.cc
@@ -257,7 +257,7 @@ void FeedbackSender::RequestDocumentMarkers() {
   for (std::vector<int>::const_iterator it = dead_renderers.begin();
        it != dead_renderers.end();
        ++it) {
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&FeedbackSender::OnReceiveDocumentMarkers,
                    AsWeakPtr(),
diff --git a/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc b/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
index 59c6116..1d5b7cb 100644
--- a/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
+++ b/chrome/browser/spellchecker/spellcheck_custom_dictionary_unittest.cc
@@ -75,7 +75,7 @@ class SpellcheckCustomDictionaryTest : public testing::Test {
   }
 
   virtual void TearDown() OVERRIDE {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   // A wrapper around SpellcheckCustomDictionary::LoadDictionaryFile private
@@ -112,7 +112,7 @@ class SpellcheckCustomDictionaryTest : public testing::Test {
     return dictionary.Apply(change);
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/spellchecker/spellcheck_host_metrics_unittest.cc b/chrome/browser/spellchecker/spellcheck_host_metrics_unittest.cc
index c6eb968..e81b1c8 100644
--- a/chrome/browser/spellchecker/spellcheck_host_metrics_unittest.cc
+++ b/chrome/browser/spellchecker/spellcheck_host_metrics_unittest.cc
@@ -19,7 +19,7 @@ using base::StatisticsRecorder;
 
 class SpellcheckHostMetricsTest : public testing::Test {
  public:
-  SpellcheckHostMetricsTest() : loop_(MessageLoop::TYPE_DEFAULT) {
+  SpellcheckHostMetricsTest() : loop_(base::MessageLoop::TYPE_DEFAULT) {
   }
 
   virtual void SetUp() OVERRIDE {
@@ -31,8 +31,8 @@ class SpellcheckHostMetricsTest : public testing::Test {
   void RecordWordCountsForTesting() { metrics_->RecordWordCounts(); }
 
  private:
-   MessageLoop loop_;
-   scoped_ptr<SpellCheckHostMetrics> metrics_;
+  base::MessageLoop loop_;
+  scoped_ptr<SpellCheckHostMetrics> metrics_;
 };
 
 TEST_F(SpellcheckHostMetricsTest, RecordEnabledStats) {
diff --git a/chrome/browser/spellchecker/spellcheck_hunspell_dictionary.cc b/chrome/browser/spellchecker/spellcheck_hunspell_dictionary.cc
index 3e12941..0693b96 100644
--- a/chrome/browser/spellchecker/spellcheck_hunspell_dictionary.cc
+++ b/chrome/browser/spellchecker/spellcheck_hunspell_dictionary.cc
@@ -182,7 +182,7 @@ void SpellcheckHunspellDictionary::Load() {
       spellcheck_mac::PlatformSupportsLanguage(language_)) {
     use_platform_spellchecker_ = true;
     spellcheck_mac::SetLanguage(language_);
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(
             &SpellcheckHunspellDictionary::InformListenersOfInitialization,
             weak_ptr_factory_.GetWeakPtr()));
diff --git a/chrome/browser/spellchecker/spellcheck_message_filter_mac_browsertest.cc b/chrome/browser/spellchecker/spellcheck_message_filter_mac_browsertest.cc
index 0a25eeb..28c71dd 100644
--- a/chrome/browser/spellchecker/spellcheck_message_filter_mac_browsertest.cc
+++ b/chrome/browser/spellchecker/spellcheck_message_filter_mac_browsertest.cc
@@ -18,18 +18,18 @@
 // allows verification by the test case.
 class TestingSpellCheckMessageFilter : public SpellCheckMessageFilterMac {
  public:
-  explicit TestingSpellCheckMessageFilter(MessageLoopForUI* loop)
+  explicit TestingSpellCheckMessageFilter(base::MessageLoopForUI* loop)
       : SpellCheckMessageFilterMac(0),
         loop_(loop) { }
 
   virtual bool Send(IPC::Message* message) OVERRIDE {
     sent_messages_.push_back(message);
-    loop_->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    loop_->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
     return true;
   }
 
   ScopedVector<IPC::Message> sent_messages_;
-  MessageLoopForUI* loop_;
+  base::MessageLoopForUI* loop_;
 
  private:
   virtual ~TestingSpellCheckMessageFilter() {}
@@ -41,7 +41,7 @@ typedef InProcessBrowserTest SpellCheckMessageFilterMacBrowserTest;
 IN_PROC_BROWSER_TEST_F(SpellCheckMessageFilterMacBrowserTest,
                        SpellCheckReturnMessage) {
   scoped_refptr<TestingSpellCheckMessageFilter> target(
-      new TestingSpellCheckMessageFilter(MessageLoopForUI::current()));
+      new TestingSpellCheckMessageFilter(base::MessageLoopForUI::current()));
 
   SpellCheckHostMsg_RequestTextCheck to_be_received(
       123, 456, UTF8ToUTF16("zz."));
@@ -49,7 +49,7 @@ IN_PROC_BROWSER_TEST_F(SpellCheckMessageFilterMacBrowserTest,
   target->OnMessageReceived(to_be_received, &handled);
   EXPECT_TRUE(handled);
 
-  MessageLoopForUI::current()->Run();
+  base::MessageLoopForUI::current()->Run();
   EXPECT_EQ(1U, target->sent_messages_.size());
 
   int sent_identifier;
diff --git a/chrome/browser/spellchecker/spellcheck_platform_mac_unittest.cc b/chrome/browser/spellchecker/spellcheck_platform_mac_unittest.cc
index ec59957..ee7490a 100644
--- a/chrome/browser/spellchecker/spellcheck_platform_mac_unittest.cc
+++ b/chrome/browser/spellchecker/spellcheck_platform_mac_unittest.cc
@@ -19,7 +19,7 @@ class SpellcheckMacTest: public testing::Test {
       : callback_(base::Bind(&SpellcheckMacTest::CompletionCallback,
                              base::Unretained(this))),
         callback_finished_(false),
-        message_loop_(MessageLoop::TYPE_UI) {}
+        message_loop_(base::MessageLoop::TYPE_UI) {}
 
   void WaitForCallback() {
     content::RunMessageLoop();
@@ -31,8 +31,8 @@ class SpellcheckMacTest: public testing::Test {
 
  private:
   void QuitMessageLoop() {
-    CHECK(MessageLoop::current() == &message_loop_);
-    MessageLoop::current()->Quit();
+    CHECK(base::MessageLoop::current() == &message_loop_);
+    base::MessageLoop::current()->Quit();
   }
 
   void CompletionCallback(const std::vector<SpellCheckResult>& results) {
@@ -43,7 +43,7 @@ class SpellcheckMacTest: public testing::Test {
                                       base::Unretained(this)));
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   spellcheck_mac::ScopedEnglishLanguageForTest scoped_language_;
 };
 
diff --git a/chrome/browser/spellchecker/spellcheck_service_unittest.cc b/chrome/browser/spellchecker/spellcheck_service_unittest.cc
index 9be0fe5..3189a0e 100644
--- a/chrome/browser/spellchecker/spellcheck_service_unittest.cc
+++ b/chrome/browser/spellchecker/spellcheck_service_unittest.cc
@@ -38,10 +38,10 @@ class SpellcheckServiceTest : public testing::Test {
   }
 
   virtual void TearDown() OVERRIDE {
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/ssl/ssl_browser_tests.cc b/chrome/browser/ssl/ssl_browser_tests.cc
index 9e5a17a..ea62264 100644
--- a/chrome/browser/ssl/ssl_browser_tests.cc
+++ b/chrome/browser/ssl/ssl_browser_tests.cc
@@ -82,7 +82,7 @@ class ProvisionalLoadWaiter : public content::WebContentsObserver {
       content::RenderViewHost* render_view_host) OVERRIDE {
     seen_ = true;
     if (waiting_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
  private:
@@ -191,9 +191,9 @@ class SSLUITest : public InProcessBrowserTest {
         break;
 
       // Wait a bit.
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
-          MessageLoop::QuitClosure(),
+          base::MessageLoop::QuitClosure(),
           base::TimeDelta::FromMilliseconds(timeout_ms));
       content::RunMessageLoop();
     }
@@ -1157,8 +1157,10 @@ IN_PROC_BROWSER_TEST_F(SSLUITest, DISABLED_TestCloseTabWithUnsafePopup) {
   for (int i = 0; i < 10; i++) {
     if (IsShowingWebContentsModalDialog())
       break;
-    MessageLoop::current()->PostDelayedTask(
-        FROM_HERE, MessageLoop::QuitClosure(), base::TimeDelta::FromSeconds(1));
+    base::MessageLoop::current()->PostDelayedTask(
+        FROM_HERE,
+        base::MessageLoop::QuitClosure(),
+        base::TimeDelta::FromSeconds(1));
     content::RunMessageLoop();
   }
   ASSERT_TRUE(IsShowingWebContentsModalDialog());
diff --git a/chrome/browser/status_icons/desktop_notification_balloon.cc b/chrome/browser/status_icons/desktop_notification_balloon.cc
index e5c8caa..5946418 100644
--- a/chrome/browser/status_icons/desktop_notification_balloon.cc
+++ b/chrome/browser/status_icons/desktop_notification_balloon.cc
@@ -39,7 +39,7 @@ class DummyNotificationDelegate : public NotificationDelegate {
       : id_(kNotificationPrefix + id) {}
 
   virtual void Display() OVERRIDE {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&CloseBalloon, id()),
         base::TimeDelta::FromSeconds(kTimeoutSeconds));
diff --git a/chrome/browser/storage_monitor/image_capture_device_manager_unittest.mm b/chrome/browser/storage_monitor/image_capture_device_manager_unittest.mm
index 5add140..cd7f18f 100644
--- a/chrome/browser/storage_monitor/image_capture_device_manager_unittest.mm
+++ b/chrome/browser/storage_monitor/image_capture_device_manager_unittest.mm
@@ -276,7 +276,7 @@ class ImageCaptureDeviceManagerTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
   chrome::test::TestStorageMonitor monitor_;
   TestCameraListener listener_;
diff --git a/chrome/browser/storage_monitor/media_storage_util_unittest.cc b/chrome/browser/storage_monitor/media_storage_util_unittest.cc
index a378df1..90d2da0 100644
--- a/chrome/browser/storage_monitor/media_storage_util_unittest.cc
+++ b/chrome/browser/storage_monitor/media_storage_util_unittest.cc
@@ -73,17 +73,17 @@ class MediaStorageUtilTest : public testing::Test {
   static void PostQuitToUIThread() {
     BrowserThread::PostTask(BrowserThread::UI,
                             FROM_HERE,
-                            MessageLoop::QuitClosure());
+                            base::MessageLoop::QuitClosure());
   }
 
   static void WaitForFileThread() {
     BrowserThread::PostTask(BrowserThread::FILE,
                             FROM_HERE,
                             base::Bind(&PostQuitToUIThread));
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
  private:
   chrome::test::TestStorageMonitor monitor_;
diff --git a/chrome/browser/storage_monitor/media_transfer_protocol_device_observer_linux_unittest.cc b/chrome/browser/storage_monitor/media_transfer_protocol_device_observer_linux_unittest.cc
index 2b60d5b..408fded 100644
--- a/chrome/browser/storage_monitor/media_transfer_protocol_device_observer_linux_unittest.cc
+++ b/chrome/browser/storage_monitor/media_transfer_protocol_device_observer_linux_unittest.cc
@@ -84,7 +84,7 @@ class TestMediaTransferProtocolDeviceObserverLinux
 class MediaTransferProtocolDeviceObserverLinuxTest : public testing::Test {
  public:
   MediaTransferProtocolDeviceObserverLinuxTest()
-      : message_loop_(MessageLoop::TYPE_IO),
+      : message_loop_(base::MessageLoop::TYPE_IO),
         file_thread_(content::BrowserThread::FILE, &message_loop_) {}
 
   virtual ~MediaTransferProtocolDeviceObserverLinuxTest() {}
@@ -112,7 +112,7 @@ class MediaTransferProtocolDeviceObserverLinuxTest : public testing::Test {
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread file_thread_;
 
   chrome::test::TestStorageMonitor monitor_;
diff --git a/chrome/browser/storage_monitor/storage_monitor_chromeos_unittest.cc b/chrome/browser/storage_monitor/storage_monitor_chromeos_unittest.cc
index 3b1372d..039cc52 100644
--- a/chrome/browser/storage_monitor/storage_monitor_chromeos_unittest.cc
+++ b/chrome/browser/storage_monitor/storage_monitor_chromeos_unittest.cc
@@ -133,7 +133,7 @@ class StorageMonitorCrosTest : public testing::Test {
     return *mock_storage_observer_;
   }
 
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
 
   scoped_ptr<TestStorageMonitorCros> monitor_;
 
@@ -243,14 +243,14 @@ base::FilePath StorageMonitorCrosTest::CreateMountPoint(
 // static
 void StorageMonitorCrosTest::PostQuitToUIThread() {
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          MessageLoop::QuitClosure());
+                          base::MessageLoop::QuitClosure());
 }
 
 // static
 void StorageMonitorCrosTest::WaitForFileThread() {
   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
                           base::Bind(&PostQuitToUIThread));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 }
 
 void StorageMonitorCrosTest::EjectNotify(
diff --git a/chrome/browser/storage_monitor/storage_monitor_linux_unittest.cc b/chrome/browser/storage_monitor/storage_monitor_linux_unittest.cc
index 46a4aad..0287ade 100644
--- a/chrome/browser/storage_monitor/storage_monitor_linux_unittest.cc
+++ b/chrome/browser/storage_monitor/storage_monitor_linux_unittest.cc
@@ -122,7 +122,8 @@ std::string GetDeviceId(const std::string& device) {
 
 class TestStorageMonitorLinux : public StorageMonitorLinux {
  public:
-  TestStorageMonitorLinux(const base::FilePath& path, MessageLoop* message_loop)
+  TestStorageMonitorLinux(const base::FilePath& path,
+                          base::MessageLoop* message_loop)
       : StorageMonitorLinux(path),
         message_loop_(message_loop) {
     SetMediaTransferProtocolManagerForTest(
@@ -135,10 +136,10 @@ class TestStorageMonitorLinux : public StorageMonitorLinux {
   virtual void UpdateMtab(
       const MtabWatcherLinux::MountPointDeviceMap& new_mtab) OVERRIDE {
     StorageMonitorLinux::UpdateMtab(new_mtab);
-    message_loop_->PostTask(FROM_HERE, MessageLoop::QuitClosure());
+    message_loop_->PostTask(FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
-  MessageLoop* message_loop_;
+  base::MessageLoop* message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(TestStorageMonitorLinux);
 };
@@ -160,7 +161,7 @@ class StorageMonitorLinuxTest : public testing::Test {
   };
 
   StorageMonitorLinuxTest()
-      : message_loop_(MessageLoop::TYPE_IO),
+      : message_loop_(base::MessageLoop::TYPE_IO),
         ui_thread_(content::BrowserThread::UI, &message_loop_),
         file_thread_(content::BrowserThread::FILE, &message_loop_) {
   }
@@ -304,7 +305,7 @@ class StorageMonitorLinuxTest : public testing::Test {
   }
 
   // The message loop and file thread to run tests on.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/storage_monitor/storage_monitor_mac_unittest.mm b/chrome/browser/storage_monitor/storage_monitor_mac_unittest.mm
index 2427a93..45e549a 100644
--- a/chrome/browser/storage_monitor/storage_monitor_mac_unittest.mm
+++ b/chrome/browser/storage_monitor/storage_monitor_mac_unittest.mm
@@ -67,7 +67,7 @@ class StorageMonitorMacTest : public testing::Test {
 
  protected:
   // The message loop and file thread to run tests on.
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/storage_monitor/storage_monitor_unittest.cc b/chrome/browser/storage_monitor/storage_monitor_unittest.cc
index 1190960..63234b4 100644
--- a/chrome/browser/storage_monitor/storage_monitor_unittest.cc
+++ b/chrome/browser/storage_monitor/storage_monitor_unittest.cc
@@ -26,7 +26,7 @@ TEST(StorageMonitorTest, TestInitialize) {
 }
 
 TEST(StorageMonitorTest, DeviceAttachDetachNotifications) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   const string16 kDeviceName = ASCIIToUTF16("media device");
   const std::string kDeviceId1 = "1";
   const std::string kDeviceId2 = "2";
@@ -73,14 +73,14 @@ TEST(StorageMonitorTest, DeviceAttachDetachNotifications) {
 }
 
 TEST(StorageMonitorTest, GetAttachedStorageEmpty) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   test::TestStorageMonitor monitor;
   std::vector<StorageInfo> devices = monitor.GetAttachedStorage();
   EXPECT_EQ(0U, devices.size());
 }
 
 TEST(StorageMonitorTest, GetRemovableStorageAttachDetach) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   test::TestStorageMonitor monitor;
   const std::string kDeviceId1 = "42";
   const string16 kDeviceName1 = ASCIIToUTF16("test");
diff --git a/chrome/browser/storage_monitor/storage_monitor_win_unittest.cc b/chrome/browser/storage_monitor/storage_monitor_win_unittest.cc
index 578f43e..a90dc44 100644
--- a/chrome/browser/storage_monitor/storage_monitor_win_unittest.cc
+++ b/chrome/browser/storage_monitor/storage_monitor_win_unittest.cc
@@ -71,7 +71,7 @@ class StorageMonitorWinTest : public testing::Test {
   MockRemovableStorageObserver observer_;
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 };
diff --git a/chrome/browser/sync/about_sync_util_unittest.cc b/chrome/browser/sync/about_sync_util_unittest.cc
index 02ca59b..342a1f2 100644
--- a/chrome/browser/sync/about_sync_util_unittest.cc
+++ b/chrome/browser/sync/about_sync_util_unittest.cc
@@ -19,7 +19,7 @@ namespace sync_ui_util {
 namespace {
 
 TEST(SyncUIUtilTest, ConstructAboutInformationWithUnrecoverableErrorTest) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   scoped_ptr<Profile> profile(
       ProfileSyncServiceMock::MakeSignedInTestingProfile());
diff --git a/chrome/browser/sync/abstract_profile_sync_service_test.h b/chrome/browser/sync/abstract_profile_sync_service_test.h
index 491e084..bf01250 100644
--- a/chrome/browser/sync/abstract_profile_sync_service_test.h
+++ b/chrome/browser/sync/abstract_profile_sync_service_test.h
@@ -52,7 +52,7 @@ class AbstractProfileSyncServiceTest : public testing::Test {
       content::BrowserContext* profile);
 
  protected:
-  MessageLoopForUI ui_loop_;
+  base::MessageLoopForUI ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread file_thread_;
diff --git a/chrome/browser/sync/backend_migrator.cc b/chrome/browser/sync/backend_migrator.cc
index 2c0472a..5a0967f 100644
--- a/chrome/browser/sync/backend_migrator.cc
+++ b/chrome/browser/sync/backend_migrator.cc
@@ -115,7 +115,7 @@ void BackendMigrator::OnConfigureDone(
   // |manager_|'s methods aren't re-entrant, and we're notified from
   // them, so post a task to avoid problems.
   SDVLOG(1) << "Posting OnConfigureDoneImpl";
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&BackendMigrator::OnConfigureDoneImpl,
                  weak_ptr_factory_.GetWeakPtr(), result));
diff --git a/chrome/browser/sync/backend_migrator_unittest.cc b/chrome/browser/sync/backend_migrator_unittest.cc
index eea2589..9605154 100644
--- a/chrome/browser/sync/backend_migrator_unittest.cc
+++ b/chrome/browser/sync/backend_migrator_unittest.cc
@@ -101,7 +101,7 @@ class SyncBackendMigratorTest : public testing::Test {
 
  private:
   scoped_ptr<SyncSessionSnapshot> snap_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   syncer::ModelTypeSet preferred_types_;
   NiceMock<ProfileSyncServiceMock> service_;
   NiceMock<DataTypeManagerMock> manager_;
diff --git a/chrome/browser/sync/glue/android_invalidator_bridge_proxy_unittest.cc b/chrome/browser/sync/glue/android_invalidator_bridge_proxy_unittest.cc
index 5fc8ec2..d3b9011 100644
--- a/chrome/browser/sync/glue/android_invalidator_bridge_proxy_unittest.cc
+++ b/chrome/browser/sync/glue/android_invalidator_bridge_proxy_unittest.cc
@@ -58,7 +58,7 @@ class AndroidInvalidatorBridgeProxyTest : public testing::Test {
     ui_loop_.RunUntilIdle();
   }
 
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   ::testing::NiceMock<ProfileMock> mock_profile_;
   AndroidInvalidatorBridge bridge_;
diff --git a/chrome/browser/sync/glue/android_invalidator_bridge_unittest.cc b/chrome/browser/sync/glue/android_invalidator_bridge_unittest.cc
index b1c1fc3..8298c2a 100644
--- a/chrome/browser/sync/glue/android_invalidator_bridge_unittest.cc
+++ b/chrome/browser/sync/glue/android_invalidator_bridge_unittest.cc
@@ -149,7 +149,7 @@ class AndroidInvalidatorBridgeTest : public testing::Test {
     run_loop.Run();
   }
 
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   base::Thread sync_thread_;
   NiceMock<ProfileMock> mock_profile_;
diff --git a/chrome/browser/sync/glue/autofill_data_type_controller_unittest.cc b/chrome/browser/sync/glue/autofill_data_type_controller_unittest.cc
index 6183101..d5b827e 100644
--- a/chrome/browser/sync/glue/autofill_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/autofill_data_type_controller_unittest.cc
@@ -220,7 +220,7 @@ class SyncAutofillDataTypeControllerTest : public testing::Test {
 
  protected:
   base::WeakPtrFactory<SyncAutofillDataTypeControllerTest> weak_ptr_factory_;
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
 
diff --git a/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc b/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc
index 8504801..2703dbc0 100644
--- a/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/bookmark_data_type_controller_unittest.cc
@@ -144,7 +144,7 @@ class SyncBookmarkDataTypeControllerTest : public testing::Test {
                    base::Unretained(&start_callback_)));
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<BookmarkDataTypeController> bookmark_dtc_;
   scoped_ptr<ProfileSyncComponentsFactoryMock> profile_sync_factory_;
diff --git a/chrome/browser/sync/glue/bookmark_model_associator.cc b/chrome/browser/sync/glue/bookmark_model_associator.cc
index fe443fe..febc8b4 100644
--- a/chrome/browser/sync/glue/bookmark_model_associator.cc
+++ b/chrome/browser/sync/glue/bookmark_model_associator.cc
@@ -645,7 +645,7 @@ void BookmarkModelAssociator::PostPersistAssociationsTask() {
   // No need to post a task if a task is already pending.
   if (weak_factory_.HasWeakPtrs())
     return;
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(
           &BookmarkModelAssociator::PersistAssociations,
diff --git a/chrome/browser/sync/glue/browser_thread_model_worker_unittest.cc b/chrome/browser/sync/glue/browser_thread_model_worker_unittest.cc
index 895302db..e2174d1 100644
--- a/chrome/browser/sync/glue/browser_thread_model_worker_unittest.cc
+++ b/chrome/browser/sync/glue/browser_thread_model_worker_unittest.cc
@@ -58,7 +58,7 @@ class SyncBrowserThreadModelWorkerTest : public testing::Test {
     EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::DB));
     timer_.Stop();  // Stop the failure timer so the test succeeds.
     BrowserThread::PostTask(
-        BrowserThread::IO, FROM_HERE, MessageLoop::QuitClosure());
+        BrowserThread::IO, FROM_HERE, base::MessageLoop::QuitClosure());
     did_do_work_ = true;
     return syncer::SYNCER_OK;
   }
@@ -68,7 +68,7 @@ class SyncBrowserThreadModelWorkerTest : public testing::Test {
   void Timeout() {
     ADD_FAILURE() << "Timed out waiting for work to be done on the DB thread.";
     BrowserThread::PostTask(
-        BrowserThread::IO, FROM_HERE, MessageLoop::QuitClosure());
+        BrowserThread::IO, FROM_HERE, base::MessageLoop::QuitClosure());
   }
 
  protected:
@@ -88,17 +88,17 @@ class SyncBrowserThreadModelWorkerTest : public testing::Test {
   OneShotTimer<SyncBrowserThreadModelWorkerTest> timer_;
 
   content::TestBrowserThread db_thread_;
-  MessageLoopForIO io_loop_;
+  base::MessageLoopForIO io_loop_;
   content::TestBrowserThread io_thread_;
 
   base::WeakPtrFactory<SyncBrowserThreadModelWorkerTest> weak_factory_;
 };
 
 TEST_F(SyncBrowserThreadModelWorkerTest, DoesWorkOnDatabaseThread) {
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&SyncBrowserThreadModelWorkerTest::ScheduleWork,
                  factory()->GetWeakPtr()));
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   EXPECT_TRUE(did_do_work());
 }
 
diff --git a/chrome/browser/sync/glue/chrome_extensions_activity_monitor_unittest.cc b/chrome/browser/sync/glue/chrome_extensions_activity_monitor_unittest.cc
index 27b3e91..799ff7d 100644
--- a/chrome/browser/sync/glue/chrome_extensions_activity_monitor_unittest.cc
+++ b/chrome/browser/sync/glue/chrome_extensions_activity_monitor_unittest.cc
@@ -70,7 +70,7 @@ class SyncChromeExtensionsActivityMonitorTest : public testing::Test {
   virtual ~SyncChromeExtensionsActivityMonitorTest() {}
 
  private:
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
 
  protected:
diff --git a/chrome/browser/sync/glue/data_type_manager_impl.cc b/chrome/browser/sync/glue/data_type_manager_impl.cc
index a487866..5675c01 100644
--- a/chrome/browser/sync/glue/data_type_manager_impl.cc
+++ b/chrome/browser/sync/glue/data_type_manager_impl.cc
@@ -167,7 +167,7 @@ bool DataTypeManagerImpl::ProcessReconfigure() {
 
   // Unwind the stack before executing configure. The method configure and its
   // callees are not re-entrant.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&DataTypeManagerImpl::ConfigureImpl,
                  weak_ptr_factory_.GetWeakPtr(),
diff --git a/chrome/browser/sync/glue/data_type_manager_impl_unittest.cc b/chrome/browser/sync/glue/data_type_manager_impl_unittest.cc
index 44b80cb..7477b08 100644
--- a/chrome/browser/sync/glue/data_type_manager_impl_unittest.cc
+++ b/chrome/browser/sync/glue/data_type_manager_impl_unittest.cc
@@ -144,7 +144,7 @@ class SyncDataTypeManagerImplTest : public testing::Test {
         static_cast<FakeDataTypeController*>(it->second.get()));
   }
 
-  MessageLoopForUI ui_loop_;
+  base::MessageLoopForUI ui_loop_;
   content::TestBrowserThread ui_thread_;
   DataTypeController::TypeMap controllers_;
   FakeBackendDataTypeConfigurer configurer_;
diff --git a/chrome/browser/sync/glue/favicon_cache.cc b/chrome/browser/sync/glue/favicon_cache.cc
index c94528e..3193791 100644
--- a/chrome/browser/sync/glue/favicon_cache.cc
+++ b/chrome/browser/sync/glue/favicon_cache.cc
@@ -538,7 +538,7 @@ void FaviconCache::OnReceivedSyncFavicon(const GURL& page_url,
 
   // Post a task to do the actual association because this method may have been
   // called while in a transaction.
-  MessageLoop::current()->PostTask(
+  base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&FaviconCache::OnReceivedSyncFaviconImpl,
                  weak_ptr_factory_.GetWeakPtr(),
diff --git a/chrome/browser/sync/glue/favicon_cache_unittest.cc b/chrome/browser/sync/glue/favicon_cache_unittest.cc
index ad3a91a..bf1d26c 100644
--- a/chrome/browser/sync/glue/favicon_cache_unittest.cc
+++ b/chrome/browser/sync/glue/favicon_cache_unittest.cc
@@ -295,7 +295,7 @@ class SyncFaviconCacheTest : public testing::Test {
                                   int64 last_visit_time_ms);
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   FaviconCache cache_;
 
   // Our dummy ChangeProcessor used to inspect changes pushed to Sync.
diff --git a/chrome/browser/sync/glue/frontend_data_type_controller_unittest.cc b/chrome/browser/sync/glue/frontend_data_type_controller_unittest.cc
index f78d5e4..981e848 100644
--- a/chrome/browser/sync/glue/frontend_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/frontend_data_type_controller_unittest.cc
@@ -151,7 +151,7 @@ class SyncFrontendDataTypeControllerTest : public testing::Test {
     message_loop_.RunUntilIdle();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_refptr<FrontendDataTypeControllerFake> frontend_dtc_;
   scoped_ptr<ProfileSyncComponentsFactoryMock> profile_sync_factory_;
diff --git a/chrome/browser/sync/glue/model_association_manager_unittest.cc b/chrome/browser/sync/glue/model_association_manager_unittest.cc
index 8d38176..4f5a43f 100644
--- a/chrome/browser/sync/glue/model_association_manager_unittest.cc
+++ b/chrome/browser/sync/glue/model_association_manager_unittest.cc
@@ -60,7 +60,7 @@ class SyncModelAssociationManagerTest : public testing::Test {
   }
 
  protected:
-  MessageLoopForUI ui_loop_;
+  base::MessageLoopForUI ui_loop_;
   content::TestBrowserThread ui_thread_;
   MockModelAssociationResultProcessor result_processor_;
   DataTypeController::TypeMap controllers_;
diff --git a/chrome/browser/sync/glue/non_frontend_data_type_controller_unittest.cc b/chrome/browser/sync/glue/non_frontend_data_type_controller_unittest.cc
index f9a8d50..91cd8bb 100644
--- a/chrome/browser/sync/glue/non_frontend_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/non_frontend_data_type_controller_unittest.cc
@@ -190,7 +190,7 @@ class SyncNonFrontendDataTypeControllerTest : public testing::Test {
     if (!done.IsSignaled()) {
       ADD_FAILURE() << "Timed out waiting for DB thread to finish.";
     }
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   void Start() {
@@ -202,7 +202,7 @@ class SyncNonFrontendDataTypeControllerTest : public testing::Test {
                    base::Unretained(&start_callback_)));
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   scoped_refptr<NonFrontendDataTypeControllerFake> non_frontend_dtc_;
diff --git a/chrome/browser/sync/glue/non_ui_data_type_controller_unittest.cc b/chrome/browser/sync/glue/non_ui_data_type_controller_unittest.cc
index fa68314..4be7a1b 100644
--- a/chrome/browser/sync/glue/non_ui_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/non_ui_data_type_controller_unittest.cc
@@ -184,7 +184,7 @@ class SyncNonUIDataTypeControllerTest : public testing::Test {
     if (!done.IsSignaled()) {
       ADD_FAILURE() << "Timed out waiting for DB thread to finish.";
     }
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
  protected:
@@ -241,7 +241,7 @@ class SyncNonUIDataTypeControllerTest : public testing::Test {
     done->Signal();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   ProfileMock profile_;
diff --git a/chrome/browser/sync/glue/password_change_processor.cc b/chrome/browser/sync/glue/password_change_processor.cc
index 2ebe5c1..23c7452 100644
--- a/chrome/browser/sync/glue/password_change_processor.cc
+++ b/chrome/browser/sync/glue/password_change_processor.cc
@@ -36,7 +36,7 @@ PasswordChangeProcessor::PasswordChangeProcessor(
     : ChangeProcessor(error_handler),
       model_associator_(model_associator),
       password_store_(password_store),
-      expected_loop_(MessageLoop::current()) {
+      expected_loop_(base::MessageLoop::current()) {
   DCHECK(model_associator);
   DCHECK(error_handler);
 #if defined(OS_MACOSX)
@@ -47,14 +47,14 @@ PasswordChangeProcessor::PasswordChangeProcessor(
 }
 
 PasswordChangeProcessor::~PasswordChangeProcessor() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 }
 
 void PasswordChangeProcessor::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK(chrome::NOTIFICATION_LOGINS_CHANGED == type);
 
   syncer::WriteTransaction trans(FROM_HERE, share_handle());
@@ -162,7 +162,7 @@ void PasswordChangeProcessor::ApplyChangesFromSyncModel(
     const syncer::BaseTransaction* trans,
     int64 model_version,
     const syncer::ImmutableChangeRecordList& changes) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   syncer::ReadNode password_root(trans);
   if (password_root.InitByTagLookup(kPasswordTag) !=
@@ -220,7 +220,7 @@ void PasswordChangeProcessor::ApplyChangesFromSyncModel(
 }
 
 void PasswordChangeProcessor::CommitChangesFromSyncModel() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   ScopedStopObserving<PasswordChangeProcessor> stop_observing(this);
 
   syncer::SyncError error = model_associator_->WriteToPasswordStore(
@@ -239,19 +239,19 @@ void PasswordChangeProcessor::CommitChangesFromSyncModel() {
 }
 
 void PasswordChangeProcessor::StartImpl(Profile* profile) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   StartObserving();
 }
 
 void PasswordChangeProcessor::StartObserving() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   notification_registrar_.Add(this,
                               chrome::NOTIFICATION_LOGINS_CHANGED,
                               content::Source<PasswordStore>(password_store_));
 }
 
 void PasswordChangeProcessor::StopObserving() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   notification_registrar_.Remove(
       this,
       chrome::NOTIFICATION_LOGINS_CHANGED,
diff --git a/chrome/browser/sync/glue/password_model_associator.cc b/chrome/browser/sync/glue/password_model_associator.cc
index 33e0e2f..99bc3ec 100644
--- a/chrome/browser/sync/glue/password_model_associator.cc
+++ b/chrome/browser/sync/glue/password_model_associator.cc
@@ -34,7 +34,7 @@ PasswordModelAssociator::PasswordModelAssociator(
       password_store_(password_store),
       password_node_id_(syncer::kInvalidId),
       abort_association_pending_(false),
-      expected_loop_(MessageLoop::current()),
+      expected_loop_(base::MessageLoop::current()),
       error_handler_(error_handler) {
   DCHECK(sync_service_);
 #if defined(OS_MACOSX)
@@ -50,7 +50,7 @@ syncer::SyncError PasswordModelAssociator::AssociateModels(
     syncer::SyncMergeResult* local_merge_result,
     syncer::SyncMergeResult* syncer_merge_result) {
   syncer::SyncError error;
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   {
     base::AutoLock lock(abort_association_pending_lock_);
     abort_association_pending_ = false;
@@ -181,7 +181,7 @@ syncer::SyncError PasswordModelAssociator::AssociateModels(
 
 bool PasswordModelAssociator::DeleteAllNodes(
     syncer::WriteTransaction* trans) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   for (PasswordToSyncIdMap::iterator node_id = id_map_.begin();
        node_id != id_map_.end(); ++node_id) {
     syncer::WriteNode sync_node(trans);
@@ -266,7 +266,7 @@ int64 PasswordModelAssociator::GetSyncIdFromChromeId(
 
 void PasswordModelAssociator::Associate(
     const std::string* password, int64 sync_id) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK_NE(syncer::kInvalidId, sync_id);
   DCHECK(id_map_.find(*password) == id_map_.end());
   DCHECK(id_map_inverse_.find(sync_id) == id_map_inverse_.end());
@@ -275,7 +275,7 @@ void PasswordModelAssociator::Associate(
 }
 
 void PasswordModelAssociator::Disassociate(int64 sync_id) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   SyncIdToPasswordMap::iterator iter = id_map_inverse_.find(sync_id);
   if (iter == id_map_inverse_.end())
     return;
diff --git a/chrome/browser/sync/glue/session_model_associator.cc b/chrome/browser/sync/glue/session_model_associator.cc
index 2bed2ae..e65c4bd 100644
--- a/chrome/browser/sync/glue/session_model_associator.cc
+++ b/chrome/browser/sync/glue/session_model_associator.cc
@@ -1120,10 +1120,10 @@ bool SessionModelAssociator::ShouldSyncTab(const SyncedTabDelegate& tab) const {
 
 void SessionModelAssociator::QuitLoopForSubtleTesting() {
   if (waiting_for_change_) {
-    DVLOG(1) << "Quitting MessageLoop for test.";
+    DVLOG(1) << "Quitting base::MessageLoop for test.";
     waiting_for_change_ = false;
     test_weak_factory_.InvalidateWeakPtrs();
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 }
 
@@ -1136,7 +1136,7 @@ void SessionModelAssociator::BlockUntilLocalChangeForTest(
   if (test_weak_factory_.HasWeakPtrs())
     return;
   waiting_for_change_ = true;
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&SessionModelAssociator::QuitLoopForSubtleTesting,
                  test_weak_factory_.GetWeakPtr()),
diff --git a/chrome/browser/sync/glue/session_model_associator_unittest.cc b/chrome/browser/sync/glue/session_model_associator_unittest.cc
index c272480..12ccd3c 100644
--- a/chrome/browser/sync/glue/session_model_associator_unittest.cc
+++ b/chrome/browser/sync/glue/session_model_associator_unittest.cc
@@ -79,7 +79,7 @@ class SyncSessionModelAssociatorTest : public testing::Test {
   }
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   NiceMock<ProfileMock> profile_;
   NiceMock<ProfileSyncServiceMock> sync_service_;
diff --git a/chrome/browser/sync/glue/shared_change_processor_unittest.cc b/chrome/browser/sync/glue/shared_change_processor_unittest.cc
index 755990c..795d738 100644
--- a/chrome/browser/sync/glue/shared_change_processor_unittest.cc
+++ b/chrome/browser/sync/glue/shared_change_processor_unittest.cc
@@ -112,7 +112,7 @@ class SyncSharedChangeProcessorTest : public testing::Test {
         base::WeakPtr<syncer::SyncMergeResult>()));
   }
 
-  MessageLoopForUI ui_loop_;
+  base::MessageLoopForUI ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
 
diff --git a/chrome/browser/sync/glue/sync_backend_host.cc b/chrome/browser/sync/glue/sync_backend_host.cc
index 8820876..15e7967 100644
--- a/chrome/browser/sync/glue/sync_backend_host.cc
+++ b/chrome/browser/sync/glue/sync_backend_host.cc
@@ -272,7 +272,7 @@ class SyncBackendHost::Core
 
   // The loop where all the sync backend operations happen.
   // Non-NULL only between calls to DoInitialize() and DoShutdown().
-  MessageLoop* sync_loop_;
+  base::MessageLoop* sync_loop_;
 
   // Our parent's registrar (not owned).  Non-NULL only between
   // calls to DoInitialize() and DoShutdown().
@@ -353,7 +353,7 @@ SyncBackendHost::SyncBackendHost(
     const base::WeakPtr<invalidation::InvalidatorStorage>& invalidator_storage)
     : weak_ptr_factory_(this),
       sync_thread_("Chrome_SyncThread"),
-      frontend_loop_(MessageLoop::current()),
+      frontend_loop_(base::MessageLoop::current()),
       profile_(profile),
       name_(name),
       core_(new Core(name, profile_->GetPath().Append(kSyncDataFolderName),
@@ -372,7 +372,7 @@ SyncBackendHost::SyncBackendHost(
 SyncBackendHost::SyncBackendHost(Profile* profile)
     : weak_ptr_factory_(this),
       sync_thread_("Chrome_SyncThread"),
-      frontend_loop_(MessageLoop::current()),
+      frontend_loop_(base::MessageLoop::current()),
       profile_(profile),
       name_("Unknown"),
       initialization_state_(NOT_ATTEMPTED),
@@ -478,7 +478,7 @@ void SyncBackendHost::UpdateCredentials(const SyncCredentials& credentials) {
 
 void SyncBackendHost::UpdateRegisteredInvalidationIds(
     const syncer::ObjectIdSet& ids) {
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   DCHECK(sync_thread_.IsRunning());
   sync_thread_.message_loop()->PostTask(FROM_HERE,
       base::Bind(&SyncBackendHost::Core::DoUpdateRegisteredInvalidationIds,
@@ -487,7 +487,7 @@ void SyncBackendHost::UpdateRegisteredInvalidationIds(
 
 void SyncBackendHost::AcknowledgeInvalidation(
     const invalidation::ObjectId& id, const syncer::AckHandle& ack_handle) {
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   DCHECK(sync_thread_.IsRunning());
   sync_thread_.message_loop()->PostTask(FROM_HERE,
       base::Bind(&SyncBackendHost::Core::DoAcknowledgeInvalidation,
@@ -518,7 +518,7 @@ void SyncBackendHost::SetEncryptionPassphrase(const std::string& passphrase,
   DCHECK(!passphrase.empty());
 
   // This should only be called by the frontend.
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   // SetEncryptionPassphrase should never be called if we are currently
   // encrypted with an explicit passphrase.
@@ -542,7 +542,7 @@ bool SyncBackendHost::SetDecryptionPassphrase(const std::string& passphrase) {
   DCHECK(!passphrase.empty());
 
   // This should only be called by the frontend.
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   // This should only be called when we have cached pending keys.
   DCHECK(cached_pending_keys_.has_blob());
@@ -591,7 +591,7 @@ void SyncBackendHost::StopSyncManagerForShutdown(
 }
 
 void SyncBackendHost::StopSyncingForShutdown() {
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   // Immediately stop sending messages to the frontend.
   frontend_ = NULL;
@@ -848,7 +848,7 @@ void SyncBackendHost::FinishConfigureDataTypesOnFrontendLoop(
                               syncer::ModelTypeSet)>& ready_task) {
   if (!frontend_)
     return;
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   if (!ready_task.is_null())
     ready_task.Run(succeeded_configuration_types, failed_configuration_types);
 }
@@ -906,7 +906,7 @@ void SyncBackendHost::Observe(
 }
 
 SyncBackendHost::DoInitializeOptions::DoInitializeOptions(
-    MessageLoop* sync_loop,
+    base::MessageLoop* sync_loop,
     SyncBackendRegistrar* registrar,
     const syncer::ModelSafeRoutingInfo& routing_info,
     const std::vector<syncer::ModelSafeWorker*>& workers,
@@ -970,7 +970,7 @@ void SyncBackendHost::Core::OnSyncCycleCompleted(
     const SyncSessionSnapshot& snapshot) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
 
   host_.Call(
       FROM_HERE,
@@ -1000,7 +1000,7 @@ void SyncBackendHost::Core::DoDownloadControlTypes(
 }
 
 void SyncBackendHost::Core::DoRefreshTypes(syncer::ModelTypeSet types) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->RefreshTypes(types);
 }
 
@@ -1015,7 +1015,7 @@ void SyncBackendHost::Core::OnInitializationComplete(
         debug_info_listener,
     bool success,
     const syncer::ModelTypeSet restored_types) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
 
   if (!success) {
     DoDestroySyncManager();
@@ -1047,7 +1047,7 @@ void SyncBackendHost::Core::OnConnectionStatusChange(
     syncer::ConnectionStatus status) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::HandleConnectionStatusChangeOnFrontendLoop, status);
@@ -1058,7 +1058,7 @@ void SyncBackendHost::Core::OnPassphraseRequired(
     const sync_pb::EncryptedData& pending_keys) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::NotifyPassphraseRequired, reason, pending_keys);
@@ -1067,7 +1067,7 @@ void SyncBackendHost::Core::OnPassphraseRequired(
 void SyncBackendHost::Core::OnPassphraseAccepted() {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::NotifyPassphraseAccepted);
@@ -1078,7 +1078,7 @@ void SyncBackendHost::Core::OnBootstrapTokenUpdated(
     syncer::BootstrapTokenType type) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(FROM_HERE,
              &SyncBackendHost::PersistEncryptionBootstrapToken,
              bootstrap_token,
@@ -1088,7 +1088,7 @@ void SyncBackendHost::Core::OnBootstrapTokenUpdated(
 void SyncBackendHost::Core::OnStopSyncingPermanently() {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::HandleStopSyncingPermanentlyOnFrontendLoop);
@@ -1097,7 +1097,7 @@ void SyncBackendHost::Core::OnStopSyncingPermanently() {
 void SyncBackendHost::Core::OnUpdatedToken(const std::string& token) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::NotifyUpdatedToken, token);
@@ -1108,7 +1108,7 @@ void SyncBackendHost::Core::OnEncryptedTypesChanged(
     bool encrypt_everything) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   // NOTE: We're in a transaction.
   host_.Call(
       FROM_HERE,
@@ -1119,7 +1119,7 @@ void SyncBackendHost::Core::OnEncryptedTypesChanged(
 void SyncBackendHost::Core::OnEncryptionComplete() {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   // NOTE: We're in a transaction.
   host_.Call(
       FROM_HERE,
@@ -1143,7 +1143,7 @@ void SyncBackendHost::Core::OnActionableError(
     const syncer::SyncProtocolError& sync_error) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::HandleActionableErrorEventOnFrontendLoop,
@@ -1154,7 +1154,7 @@ void SyncBackendHost::Core::OnInvalidatorStateChange(
     syncer::InvalidatorState state) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(FROM_HERE,
              &SyncBackendHost::HandleInvalidatorStateChangeOnFrontendLoop,
              state);
@@ -1164,7 +1164,7 @@ void SyncBackendHost::Core::OnIncomingInvalidation(
     const syncer::ObjectIdInvalidationMap& invalidation_map) {
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(FROM_HERE,
              &SyncBackendHost::HandleIncomingInvalidationOnFrontendLoop,
              invalidation_map);
@@ -1244,7 +1244,7 @@ void SyncBackendHost::Core::DoInitialize(const DoInitializeOptions& options) {
 
 void SyncBackendHost::Core::DoUpdateCredentials(
     const SyncCredentials& credentials) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   // UpdateCredentials can be called during backend initialization, possibly
   // when backend initialization has failed but hasn't notified the UI thread
   // yet. In that case, the sync manager may have been destroyed on the sync
@@ -1256,7 +1256,7 @@ void SyncBackendHost::Core::DoUpdateCredentials(
 
 void SyncBackendHost::Core::DoUpdateRegisteredInvalidationIds(
     const syncer::ObjectIdSet& ids) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   // |sync_manager_| may end up being NULL here in tests (in
   // synchronous initialization mode) since this is called during
   // shutdown.
@@ -1269,7 +1269,7 @@ void SyncBackendHost::Core::DoUpdateRegisteredInvalidationIds(
 
 void SyncBackendHost::Core::DoAcknowledgeInvalidation(
     const invalidation::ObjectId& id, const syncer::AckHandle& ack_handle) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   // |sync_manager_| may end up being NULL here in tests (in
   // synchronous initialization mode).
   //
@@ -1281,20 +1281,20 @@ void SyncBackendHost::Core::DoAcknowledgeInvalidation(
 
 void SyncBackendHost::Core::DoStartSyncing(
     const syncer::ModelSafeRoutingInfo& routing_info) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->StartSyncingNormally(routing_info);
 }
 
 void SyncBackendHost::Core::DoSetEncryptionPassphrase(
     const std::string& passphrase,
     bool is_explicit) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->GetEncryptionHandler()->SetEncryptionPassphrase(
       passphrase, is_explicit);
 }
 
 void SyncBackendHost::Core::DoInitialProcessControlTypes() {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
 
   DVLOG(1) << "Initilalizing Control Types";
 
@@ -1347,13 +1347,13 @@ void SyncBackendHost::Core::DoFinishInitialProcessControlTypes() {
 
 void SyncBackendHost::Core::DoSetDecryptionPassphrase(
     const std::string& passphrase) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->GetEncryptionHandler()->SetDecryptionPassphrase(
       passphrase);
 }
 
 void SyncBackendHost::Core::DoEnableEncryptEverything() {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->GetEncryptionHandler()->EnableEncryptEverything();
 }
 
@@ -1367,7 +1367,7 @@ void SyncBackendHost::Core::DoStopSyncManagerForShutdown(
 }
 
 void SyncBackendHost::Core::DoShutdown(bool sync_disabled) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   // It's safe to do this even if the type was never activated.
   registrar_->DeactivateDataType(syncer::DEVICE_INFO);
   synced_device_tracker_.reset();
@@ -1385,7 +1385,7 @@ void SyncBackendHost::Core::DoShutdown(bool sync_disabled) {
 }
 
 void SyncBackendHost::Core::DoDestroySyncManager() {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   if (sync_manager_) {
     save_changes_timer_.reset();
     if (registered_as_invalidation_handler_) {
@@ -1406,7 +1406,7 @@ void SyncBackendHost::Core::DoConfigureSyncer(
     const base::Callback<void(syncer::ModelTypeSet,
                               syncer::ModelTypeSet)>& ready_task,
     const base::Closure& retry_callback) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->ConfigureSyncer(
       reason,
       types_to_config,
@@ -1425,7 +1425,7 @@ void SyncBackendHost::Core::DoFinishConfigureDataTypes(
     syncer::ModelTypeSet types_to_config,
     const base::Callback<void(syncer::ModelTypeSet,
                               syncer::ModelTypeSet)>& ready_task) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
 
   // Update the enabled types for the bridge and sync manager.
   syncer::ModelSafeRoutingInfo routing_info;
@@ -1446,14 +1446,14 @@ void SyncBackendHost::Core::DoFinishConfigureDataTypes(
 
 void SyncBackendHost::Core::DoRetryConfiguration(
     const base::Closure& retry_callback) {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(FROM_HERE,
              &SyncBackendHost::RetryConfigurationOnFrontendLoop,
              retry_callback);
 }
 
 void SyncBackendHost::Core::DeleteSyncDataFolder() {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   if (file_util::DirectoryExists(sync_data_folder_path_)) {
     if (!file_util::Delete(sync_data_folder_path_, true))
       SLOG(DFATAL) << "Could not delete the Sync Data folder.";
@@ -1464,7 +1464,7 @@ void SyncBackendHost::Core::StartSavingChanges() {
   // We may already be shut down.
   if (!sync_loop_)
     return;
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   DCHECK(!save_changes_timer_.get());
   save_changes_timer_.reset(new base::RepeatingTimer<Core>());
   save_changes_timer_->Start(FROM_HERE,
@@ -1473,7 +1473,7 @@ void SyncBackendHost::Core::StartSavingChanges() {
 }
 
 void SyncBackendHost::Core::SaveChanges() {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->SaveChanges();
 }
 
@@ -1485,7 +1485,7 @@ void SyncBackendHost::AddExperimentalTypes() {
 }
 
 void SyncBackendHost::HandleControlTypesDownloadRetry() {
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   if (!frontend_)
     return;
 
@@ -1498,7 +1498,7 @@ void SyncBackendHost::HandleInitializationCompletedOnFrontendLoop(
   if (!frontend_)
     return;
 
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   if (!success) {
     js_backend_.Reset();
     initialization_state_ = NOT_INITIALIZED;
@@ -1525,7 +1525,7 @@ void SyncBackendHost::HandleSyncCycleCompletedOnFrontendLoop(
     const SyncSessionSnapshot& snapshot) {
   if (!frontend_)
     return;
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   last_snapshot_ = snapshot;
 
@@ -1566,7 +1566,7 @@ void SyncBackendHost::HandleActionableErrorEventOnFrontendLoop(
     const syncer::SyncProtocolError& sync_error) {
   if (!frontend_)
     return;
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   frontend_->OnActionableError(sync_error);
 }
 
@@ -1574,7 +1574,7 @@ void SyncBackendHost::HandleInvalidatorStateChangeOnFrontendLoop(
     syncer::InvalidatorState state) {
   if (!frontend_)
     return;
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   frontend_->OnInvalidatorStateChange(state);
 }
 
@@ -1582,7 +1582,7 @@ void SyncBackendHost::HandleIncomingInvalidationOnFrontendLoop(
     const syncer::ObjectIdInvalidationMap& invalidation_map) {
   if (!frontend_)
     return;
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   frontend_->OnIncomingInvalidation(invalidation_map);
 }
 
@@ -1604,7 +1604,7 @@ void SyncBackendHost::NotifyPassphraseRequired(
   if (!frontend_)
     return;
 
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   // Update our cache of the cryptographer's pending keys.
   cached_pending_keys_ = pending_keys;
@@ -1616,7 +1616,7 @@ void SyncBackendHost::NotifyPassphraseAccepted() {
   if (!frontend_)
     return;
 
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   // Clear our cache of the cryptographer's pending keys.
   cached_pending_keys_.clear_blob();
@@ -1638,7 +1638,7 @@ void SyncBackendHost::NotifyEncryptedTypesChanged(
   if (!frontend_)
     return;
 
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   frontend_->OnEncryptedTypesChanged(
       encrypted_types, encrypt_everything);
 }
@@ -1647,14 +1647,14 @@ void SyncBackendHost::NotifyEncryptionComplete() {
   if (!frontend_)
     return;
 
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   frontend_->OnEncryptionComplete();
 }
 
 void SyncBackendHost::HandlePassphraseTypeChangedOnFrontendLoop(
     syncer::PassphraseType type,
     base::Time explicit_passphrase_time) {
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
   DVLOG(1) << "Passphrase type changed to "
            << syncer::PassphraseTypeToString(type);
   cached_passphrase_type_ = type;
@@ -1672,7 +1672,7 @@ void SyncBackendHost::HandleConnectionStatusChangeOnFrontendLoop(
   if (!frontend_)
     return;
 
-  DCHECK_EQ(MessageLoop::current(), frontend_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), frontend_loop_);
 
   DVLOG(1) << "Connection status changed: "
            << syncer::ConnectionStatusToString(status);
diff --git a/chrome/browser/sync/glue/sync_backend_host_unittest.cc b/chrome/browser/sync/glue/sync_backend_host_unittest.cc
index 1379825..4474035 100644
--- a/chrome/browser/sync/glue/sync_backend_host_unittest.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_unittest.cc
@@ -53,7 +53,7 @@ ACTION_P(Signal, event) {
 }
 
 void QuitMessageLoop() {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 class MockSyncFrontend : public SyncFrontend {
@@ -249,14 +249,14 @@ class SyncBackendHostTest : public testing::Test {
  protected:
   void DownloadReady(syncer::ModelTypeSet succeeded_types,
                      syncer::ModelTypeSet failed_types) {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   void OnDownloadRetry() {
     NOTIMPLEMENTED();
   }
 
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread io_thread_;
   StrictMock<MockSyncFrontend> mock_frontend_;
diff --git a/chrome/browser/sync/glue/sync_backend_registrar.cc b/chrome/browser/sync/glue/sync_backend_registrar.cc
index 47ee4a4..cebd473 100644
--- a/chrome/browser/sync/glue/sync_backend_registrar.cc
+++ b/chrome/browser/sync/glue/sync_backend_registrar.cc
@@ -55,7 +55,7 @@ bool IsOnThreadForGroup(syncer::ModelType type, syncer::ModelSafeGroup group) {
 
 SyncBackendRegistrar::SyncBackendRegistrar(
     const std::string& name, Profile* profile,
-    MessageLoop* sync_loop) :
+    base::MessageLoop* sync_loop) :
     name_(name),
     profile_(profile),
     sync_loop_(sync_loop),
@@ -175,7 +175,7 @@ void SyncBackendRegistrar::StopOnUIThread() {
 }
 
 void SyncBackendRegistrar::OnSyncerShutdownComplete() {
-  DCHECK_EQ(MessageLoop::current(), sync_loop_);
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   ui_worker_->OnSyncerShutdownComplete();
 }
 
diff --git a/chrome/browser/sync/glue/sync_backend_registrar_unittest.cc b/chrome/browser/sync/glue/sync_backend_registrar_unittest.cc
index a628f77..3761067 100644
--- a/chrome/browser/sync/glue/sync_backend_registrar_unittest.cc
+++ b/chrome/browser/sync/glue/sync_backend_registrar_unittest.cc
@@ -65,7 +65,7 @@ class SyncBackendRegistrarTest : public testing::Test {
     }
   }
 
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   syncer::TestUserShare test_user_share_;
 
  private:
diff --git a/chrome/browser/sync/glue/synced_device_tracker_unittest.cc b/chrome/browser/sync/glue/synced_device_tracker_unittest.cc
index ee89fd7..2af2780 100644
--- a/chrome/browser/sync/glue/synced_device_tracker_unittest.cc
+++ b/chrome/browser/sync/glue/synced_device_tracker_unittest.cc
@@ -70,7 +70,7 @@ class SyncedDeviceTrackerTest : public ::testing::Test {
     return test_user_share_.transaction_observer()->transactions_observed();
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   syncer::TestUserShare test_user_share_;
   int transaction_count_baseline_;
 };
diff --git a/chrome/browser/sync/glue/typed_url_change_processor.cc b/chrome/browser/sync/glue/typed_url_change_processor.cc
index 6281bbb..5ac4df5 100644
--- a/chrome/browser/sync/glue/typed_url_change_processor.cc
+++ b/chrome/browser/sync/glue/typed_url_change_processor.cc
@@ -43,7 +43,7 @@ TypedUrlChangeProcessor::TypedUrlChangeProcessor(
       profile_(profile),
       model_associator_(model_associator),
       history_backend_(history_backend),
-      expected_loop_(MessageLoop::current()) {
+      expected_loop_(base::MessageLoop::current()) {
   DCHECK(model_associator);
   DCHECK(history_backend);
   DCHECK(error_handler);
@@ -55,14 +55,14 @@ TypedUrlChangeProcessor::TypedUrlChangeProcessor(
 }
 
 TypedUrlChangeProcessor::~TypedUrlChangeProcessor() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 }
 
 void TypedUrlChangeProcessor::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   DVLOG(1) << "Observed typed_url change.";
   if (type == chrome::NOTIFICATION_HISTORY_URLS_MODIFIED) {
@@ -239,7 +239,7 @@ void TypedUrlChangeProcessor::ApplyChangesFromSyncModel(
     const syncer::BaseTransaction* trans,
     int64 model_version,
     const syncer::ImmutableChangeRecordList& changes) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   syncer::ReadNode typed_url_root(trans);
   if (typed_url_root.InitByTagLookup(kTypedUrlTag) !=
@@ -295,7 +295,7 @@ void TypedUrlChangeProcessor::ApplyChangesFromSyncModel(
 }
 
 void TypedUrlChangeProcessor::CommitChangesFromSyncModel() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   // Make sure we stop listening for changes while we're modifying the backend,
   // so we don't try to re-apply these changes to the sync DB.
@@ -318,13 +318,13 @@ void TypedUrlChangeProcessor::CommitChangesFromSyncModel() {
 }
 
 void TypedUrlChangeProcessor::StartImpl(Profile* profile) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK_EQ(profile, profile_);
   StartObserving();
 }
 
 void TypedUrlChangeProcessor::StartObserving() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK(profile_);
   notification_registrar_.Add(
       this, chrome::NOTIFICATION_HISTORY_URLS_MODIFIED,
@@ -338,7 +338,7 @@ void TypedUrlChangeProcessor::StartObserving() {
 }
 
 void TypedUrlChangeProcessor::StopObserving() {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   DCHECK(profile_);
   notification_registrar_.Remove(
       this, chrome::NOTIFICATION_HISTORY_URLS_MODIFIED,
diff --git a/chrome/browser/sync/glue/typed_url_model_associator.cc b/chrome/browser/sync/glue/typed_url_model_associator.cc
index 4ad83a4..afa4a99 100644
--- a/chrome/browser/sync/glue/typed_url_model_associator.cc
+++ b/chrome/browser/sync/glue/typed_url_model_associator.cc
@@ -64,7 +64,7 @@ TypedUrlModelAssociator::TypedUrlModelAssociator(
     DataTypeErrorHandler* error_handler)
     : sync_service_(sync_service),
       history_backend_(history_backend),
-      expected_loop_(MessageLoop::current()),
+      expected_loop_(base::MessageLoop::current()),
       pending_abort_(false),
       error_handler_(error_handler),
       num_db_accesses_(0),
@@ -174,7 +174,7 @@ int TypedUrlModelAssociator::GetErrorPercentage() const {
 syncer::SyncError TypedUrlModelAssociator::DoAssociateModels() {
   DVLOG(1) << "Associating TypedUrl Models";
   syncer::SyncError error;
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
   if (IsAbortPending())
     return syncer::SyncError();
   history::URLRows typed_urls;
@@ -452,7 +452,7 @@ sync_pb::TypedUrlSpecifics TypedUrlModelAssociator::FilterExpiredVisits(
 
 bool TypedUrlModelAssociator::DeleteAllNodes(
     syncer::WriteTransaction* trans) {
-  DCHECK(expected_loop_ == MessageLoop::current());
+  DCHECK(expected_loop_ == base::MessageLoop::current());
 
   // Just walk through all our child nodes and delete them.
   syncer::ReadNode typed_url_root(trans);
diff --git a/chrome/browser/sync/glue/ui_data_type_controller_unittest.cc b/chrome/browser/sync/glue/ui_data_type_controller_unittest.cc
index 911007d..ce64106 100644
--- a/chrome/browser/sync/glue/ui_data_type_controller_unittest.cc
+++ b/chrome/browser/sync/glue/ui_data_type_controller_unittest.cc
@@ -96,7 +96,7 @@ class SyncUIDataTypeControllerTest : public testing::Test {
     message_loop_.RunUntilIdle();
   }
 
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   ProfileMock profile_;
   scoped_ptr<ProfileSyncComponentsFactoryMock> profile_sync_factory_;
diff --git a/chrome/browser/sync/glue/ui_model_worker_unittest.cc b/chrome/browser/sync/glue/ui_model_worker_unittest.cc
index e4de282..dd76963 100644
--- a/chrome/browser/sync/glue/ui_model_worker_unittest.cc
+++ b/chrome/browser/sync/glue/ui_model_worker_unittest.cc
@@ -32,7 +32,7 @@ class UIModelWorkerVisitor {
     EXPECT_TRUE(BrowserThread::CurrentlyOn(BrowserThread::UI));
     was_run_->Signal();
     if (quit_loop_when_run_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
     return syncer::SYNCER_OK;
   }
 
@@ -98,7 +98,7 @@ class SyncUIModelWorkerTest : public testing::Test {
   base::Thread* core_thread() { return &faux_core_thread_; }
   base::Thread* syncer_thread() { return &faux_syncer_thread_; }
  private:
-  MessageLoop faux_ui_loop_;
+  base::MessageLoop faux_ui_loop_;
   scoped_ptr<content::TestBrowserThread> ui_thread_;
   base::Thread faux_syncer_thread_;
   base::Thread faux_core_thread_;
@@ -116,7 +116,7 @@ TEST_F(SyncUIModelWorkerTest, ScheduledWorkRunsOnUILoop) {
 
   // We are on the UI thread, so run our loop to process the
   // (hopefully) scheduled task from a SyncShare invocation.
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   bmw()->OnSyncerShutdownComplete();
   bmw()->Stop();
diff --git a/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc b/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc
index 16f9db0..a32eb8af 100644
--- a/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc
+++ b/chrome/browser/sync/profile_sync_components_factory_impl_unittest.cc
@@ -97,7 +97,7 @@ class ProfileSyncComponentsFactoryImplTest : public testing::Test {
     CheckDefaultDatatypesInMapExcept(&controller_states, type);
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   scoped_ptr<Profile> profile_;
   scoped_ptr<CommandLine> command_line_;
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 40ee817..bfea304 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -841,7 +841,7 @@ void ProfileSyncService::OnUnrecoverableErrorImpl(
       << " -- ProfileSyncService unusable: " << message;
 
   // Shut all data types down.
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ProfileSyncService::ShutdownImpl, weak_factory_.GetWeakPtr(),
                  delete_sync_database));
 }
@@ -864,7 +864,7 @@ void ProfileSyncService::DisableBrokenDatatype(
   failed_datatypes_handler_.UpdateFailedDatatypes(errors,
       FailedDatatypesHandler::RUNTIME);
 
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ProfileSyncService::ReconfigureDatatypeManager,
                  weak_factory_.GetWeakPtr()));
 }
@@ -967,7 +967,7 @@ void ProfileSyncService::OnSyncCycleCompleted() {
     // model associator listens too. Also consider somehow plumbing the current
     // server time as last reported by CheckServerReachable, so we don't have to
     // rely on the local clock, which may be off significantly.
-    MessageLoop::current()->PostTask(FROM_HERE,
+    base::MessageLoop::current()->PostTask(FROM_HERE,
         base::Bind(&browser_sync::SessionModelAssociator::DeleteStaleSessions,
                    GetSessionModelAssociator()->AsWeakPtr()));
   }
@@ -1302,7 +1302,7 @@ void ProfileSyncService::OnConfigureDone(
   }
 
   // Now handle partial success and full success.
-  MessageLoop::current()->PostTask(FROM_HERE,
+  base::MessageLoop::current()->PostTask(FROM_HERE,
       base::Bind(&ProfileSyncService::OnSyncConfigureDone,
                  weak_factory_.GetWeakPtr(), result));
 
diff --git a/chrome/browser/sync/profile_sync_service_autofill_unittest.cc b/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
index b2d88c2..8ffcbb0 100644
--- a/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_autofill_unittest.cc
@@ -592,7 +592,7 @@ class ProfileSyncServiceAutofillTest
 
     sync_service_->RegisterDataTypeController(data_type_controller);
     sync_service_->Initialize();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // It's possible this test triggered an unrecoverable error, in which case
     // we can't get the sync count.
diff --git a/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc b/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
index 193f167..1f98c7b 100644
--- a/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_bookmark_unittest.cc
@@ -468,7 +468,7 @@ class ProfileSyncServiceBookmarkTest : public testing::Test {
     EXPECT_EQ(GetSyncBookmarkCount(),
               syncer_merge_result_.num_items_after_association());
 
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
 
     // Set up change processor.
     change_processor_.reset(
@@ -655,7 +655,7 @@ class ProfileSyncServiceBookmarkTest : public testing::Test {
 
  private:
   // Used by both |ui_thread_| and |file_thread_|.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   // Needed by |model_|.
   content::TestBrowserThread file_thread_;
@@ -1867,7 +1867,7 @@ TEST_F(ProfileSyncServiceBookmarkTestWithData, UpdateTransactionVersion) {
   LoadBookmarkModel(DELETE_EXISTING_STORAGE, DONT_SAVE_TO_STORAGE);
   StartSync();
   WriteTestDataToBookmarkModel();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   BookmarkNodeVersionMap initial_versions;
 
@@ -1892,7 +1892,7 @@ TEST_F(ProfileSyncServiceBookmarkTestWithData, UpdateTransactionVersion) {
   // the same.
   const BookmarkNode* bookmark_bar = model_->bookmark_bar_node();
   model_->Remove(bookmark_bar, 0);
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   BookmarkNodeVersionMap new_versions;
   GetTransactionVersions(model_->root_node(), &new_versions);
   EXPECT_EQ(initial_versions[model_->root_node()->id()] + 1,
@@ -1906,7 +1906,7 @@ TEST_F(ProfileSyncServiceBookmarkTestWithData, UpdateTransactionVersion) {
   const BookmarkNode* changed_bookmark =
       model_->bookmark_bar_node()->GetChild(0);
   model_->SetTitle(changed_bookmark, WideToUTF16Hack(L"test"));
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   GetTransactionVersions(model_->root_node(), &new_versions);
   EXPECT_EQ(initial_versions[model_->root_node()->id()] + 2,
             new_versions[model_->root_node()->id()]);
diff --git a/chrome/browser/sync/profile_sync_service_harness.cc b/chrome/browser/sync/profile_sync_service_harness.cc
index 90dc180..3d42e91 100644
--- a/chrome/browser/sync/profile_sync_service_harness.cc
+++ b/chrome/browser/sync/profile_sync_service_harness.cc
@@ -292,7 +292,7 @@ void ProfileSyncServiceHarness::SignalStateCompleteWithNextState(
 
 void ProfileSyncServiceHarness::SignalStateComplete() {
   if (waiting_for_status_change_)
-    MessageLoop::current()->QuitWhenIdle();
+    base::MessageLoop::current()->QuitWhenIdle();
 }
 
 bool ProfileSyncServiceHarness::RunStateChangeMachine() {
@@ -754,8 +754,8 @@ bool ProfileSyncServiceHarness::AwaitStatusChangeWithTimeout(
     // Set the flag to tell SignalStateComplete() that it's OK to quit out of
     // the MessageLoop if we hit a state transition.
     waiting_for_status_change_ = true;
-    MessageLoop* loop = MessageLoop::current();
-    MessageLoop::ScopedNestableTaskAllower allow(loop);
+    base::MessageLoop* loop = base::MessageLoop::current();
+    base::MessageLoop::ScopedNestableTaskAllower allow(loop);
     loop->PostDelayedTask(
         FROM_HERE,
         base::Bind(&StateChangeTimeoutEvent::Callback,
diff --git a/chrome/browser/sync/profile_sync_service_password_unittest.cc b/chrome/browser/sync/profile_sync_service_password_unittest.cc
index fa0e680..a5fd446 100644
--- a/chrome/browser/sync/profile_sync_service_password_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_password_unittest.cc
@@ -78,7 +78,7 @@ ACTION_P(AcquireSyncTransaction, password_test_service) {
 }
 
 static void QuitMessageLoop() {
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 class NullPasswordStore : public MockPasswordStore {
@@ -248,12 +248,12 @@ class ProfileSyncServicePasswordTest : public AbstractProfileSyncServiceTest {
 
       sync_service_->RegisterDataTypeController(data_type_controller);
       sync_service_->Initialize();
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
       FlushLastDBTask();
 
       sync_service_->SetEncryptionPassphrase("foo",
                                              ProfileSyncService::IMPLICIT);
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
     }
   }
 
diff --git a/chrome/browser/sync/profile_sync_service_preference_unittest.cc b/chrome/browser/sync/profile_sync_service_preference_unittest.cc
index e7d56f0..ce02d29 100644
--- a/chrome/browser/sync/profile_sync_service_preference_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_preference_unittest.cc
@@ -182,7 +182,7 @@ class ProfileSyncServicePreferenceTest
         GaiaConstants::kSyncService, "token");
 
     sync_service_->Initialize();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
 
     // It's possible this test triggered an unrecoverable error, in which case
     // we can't get the preference count.
diff --git a/chrome/browser/sync/profile_sync_service_session_unittest.cc b/chrome/browser/sync/profile_sync_service_session_unittest.cc
index 44d1dfb..91cef4b 100644
--- a/chrome/browser/sync/profile_sync_service_session_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_session_unittest.cc
@@ -249,9 +249,9 @@ class ProfileSyncServiceSessionTest
 
     // Pump messages posted by the sync core thread (which may end up
     // posting on the IO thread).
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     io_thread_.Stop();
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
     BrowserWithTestWindowTest::TearDown();
   }
 
@@ -293,7 +293,7 @@ class ProfileSyncServiceSessionTest
     TokenServiceFactory::GetForProfile(profile())->IssueAuthTokenForTest(
         GaiaConstants::kSyncService, "token");
     sync_service_->Initialize();
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
     return true;
   }
 
@@ -1200,7 +1200,7 @@ TEST_F(ProfileSyncServiceSessionTest, Favicons) {
   // Update associator.
   model_associator_->AssociateForeignSpecifics(meta, base::Time());
   model_associator_->AssociateForeignSpecifics(tab, base::Time());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   ASSERT_FALSE(model_associator_->GetSyncedFaviconForPageURL(url, &favicon));
 
   // Now add a favicon.
@@ -1208,7 +1208,7 @@ TEST_F(ProfileSyncServiceSessionTest, Favicons) {
   tab.mutable_tab()->set_favicon_type(sync_pb::SessionTab::TYPE_WEB_FAVICON);
   tab.mutable_tab()->set_favicon("data");
   model_associator_->AssociateForeignSpecifics(tab, base::Time());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   ASSERT_TRUE(model_associator_->GetSyncedFaviconForPageURL(url, &favicon));
   ASSERT_TRUE(CompareMemoryToString("data", favicon));
 
@@ -1219,7 +1219,7 @@ TEST_F(ProfileSyncServiceSessionTest, Favicons) {
   tab.mutable_tab()->clear_favicon_type();
   tab.mutable_tab()->clear_favicon();
   model_associator_->AssociateForeignSpecifics(tab, base::Time());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   ASSERT_TRUE(model_associator_->GetSyncedFaviconForPageURL(url, &favicon));
 }
 
diff --git a/chrome/browser/sync/profile_sync_service_startup_unittest.cc b/chrome/browser/sync/profile_sync_service_startup_unittest.cc
index b2fc564..168667a 100644
--- a/chrome/browser/sync/profile_sync_service_startup_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_startup_unittest.cc
@@ -132,7 +132,7 @@ class ProfileSyncServiceStartupTest : public testing::Test {
     return data_type_manager;
   }
 
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   content::TestBrowserThread file_thread_;
@@ -318,7 +318,7 @@ TEST_F(ProfileSyncServiceStartupTest, StartInvalidCredentials) {
   token_service->IssueAuthTokenForTest(
       GaiaConstants::kSyncService, "sync_token");
   sync_->SetSetupInProgress(false);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
 
   // Verify we successfully finish startup and configuration.
   EXPECT_TRUE(sync_->ShouldPushChanges());
diff --git a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
index 0dd8d0f..15b88f1 100644
--- a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
@@ -230,7 +230,7 @@ class ProfileSyncServiceTypedUrlTest : public AbstractProfileSyncServiceTest {
       sync_service_->RegisterDataTypeController(data_type_controller);
 
       sync_service_->Initialize();
-      MessageLoop::current()->Run();
+      base::MessageLoop::current()->Run();
     }
     return model_associator;
   }
diff --git a/chrome/browser/sync/profile_sync_service_unittest.cc b/chrome/browser/sync/profile_sync_service_unittest.cc
index 0c8d0b9..00afd97 100644
--- a/chrome/browser/sync/profile_sync_service_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_unittest.cc
@@ -139,7 +139,7 @@ class ProfileSyncServiceTestHarness {
   scoped_ptr<TestingProfile> profile;
 
  private:
-  MessageLoop ui_loop_;
+  base::MessageLoop ui_loop_;
   // Needed by |service|.
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
diff --git a/chrome/browser/sync/profile_sync_test_util.h b/chrome/browser/sync/profile_sync_test_util.h
index 509bcf5..aedc4c5 100644
--- a/chrome/browser/sync/profile_sync_test_util.h
+++ b/chrome/browser/sync/profile_sync_test_util.h
@@ -30,7 +30,7 @@ ACTION_P(Notify, type) {
 
 ACTION(QuitUIMessageLoop) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  MessageLoop::current()->Quit();
+  base::MessageLoop::current()->Quit();
 }
 
 class ProfileSyncServiceObserverMock : public ProfileSyncServiceObserver {
diff --git a/chrome/browser/sync/sync_prefs_unittest.cc b/chrome/browser/sync/sync_prefs_unittest.cc
index 1b78842..042df83 100644
--- a/chrome/browser/sync/sync_prefs_unittest.cc
+++ b/chrome/browser/sync/sync_prefs_unittest.cc
@@ -30,7 +30,7 @@ class SyncPrefsTest : public testing::Test {
   TestingPrefServiceSyncable pref_service_;
 
  private:
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 };
 
 TEST_F(SyncPrefsTest, Basic) {
diff --git a/chrome/browser/sync/sync_ui_util_unittest.cc b/chrome/browser/sync/sync_ui_util_unittest.cc
index 275dcc9..7b8dd84 100644
--- a/chrome/browser/sync/sync_ui_util_unittest.cc
+++ b/chrome/browser/sync/sync_ui_util_unittest.cc
@@ -69,7 +69,7 @@ void VerifySyncGlobalErrorResult(NiceMock<ProfileSyncServiceMock>* service,
 // Test that GetStatusLabelsForSyncGlobalError returns an error if a
 // passphrase is required.
 TEST(SyncUIUtilTest, PassphraseGlobalError) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   scoped_ptr<Profile> profile(
       ProfileSyncServiceMock::MakeSignedInTestingProfile());
@@ -89,7 +89,7 @@ TEST(SyncUIUtilTest, PassphraseGlobalError) {
 // Test that GetStatusLabelsForSyncGlobalError returns an error if a
 // passphrase is required and not for auth errors.
 TEST(SyncUIUtilTest, AuthAndPassphraseGlobalError) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   scoped_ptr<Profile> profile(
       ProfileSyncServiceMock::MakeSignedInTestingProfile());
@@ -121,7 +121,7 @@ TEST(SyncUIUtilTest, AuthAndPassphraseGlobalError) {
 // Test that GetStatusLabelsForSyncGlobalError does not indicate errors for
 // auth errors (these are reported through SigninGlobalError).
 TEST(SyncUIUtilTest, AuthStateGlobalError) {
-  MessageLoopForUI message_loop;
+  base::MessageLoopForUI message_loop;
   content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop);
   scoped_ptr<Profile> profile(
       ProfileSyncServiceMock::MakeSignedInTestingProfile());
diff --git a/chrome/browser/sync/test/integration/autofill_helper.cc b/chrome/browser/sync/test/integration/autofill_helper.cc
index ed4adfd..e848a17 100644
--- a/chrome/browser/sync/test/integration/autofill_helper.cc
+++ b/chrome/browser/sync/test/integration/autofill_helper.cc
@@ -241,7 +241,7 @@ void SetProfiles(int profile, std::vector<AutofillProfile>* autofill_profiles) {
   PersonalDataManager* pdm = GetPersonalDataManager(profile);
   pdm->AddObserver(&observer);
   pdm->SetProfiles(autofill_profiles);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   pdm->RemoveObserver(&observer);
 }
 
@@ -252,7 +252,7 @@ void SetCreditCards(int profile, std::vector<CreditCard>* credit_cards) {
   PersonalDataManager* pdm = GetPersonalDataManager(profile);
   pdm->AddObserver(&observer);
   pdm->SetCreditCards(credit_cards);
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   pdm->RemoveObserver(&observer);
 }
 
@@ -297,7 +297,7 @@ const std::vector<AutofillProfile*>& GetAllProfiles(
   PersonalDataManager* pdm = GetPersonalDataManager(profile);
   pdm->AddObserver(&observer);
   pdm->Refresh();
-  MessageLoop::current()->Run();
+  base::MessageLoop::current()->Run();
   pdm->RemoveObserver(&observer);
   return pdm->web_profiles();
 }
diff --git a/chrome/browser/sync/test/integration/bookmarks_helper.cc b/chrome/browser/sync/test/integration/bookmarks_helper.cc
index dc4a341..57f0931 100644
--- a/chrome/browser/sync/test/integration/bookmarks_helper.cc
+++ b/chrome/browser/sync/test/integration/bookmarks_helper.cc
@@ -110,7 +110,7 @@ class FaviconChangeObserver : public BookmarkModelObserver {
       const BookmarkNode* node) OVERRIDE {
     if (model == model_ && node == node_) {
       if (!wait_for_load_ || (wait_for_load_ && node->is_favicon_loaded()))
-        MessageLoopForUI::current()->Quit();
+        base::MessageLoopForUI::current()->Quit();
     }
   }
 
diff --git a/chrome/browser/sync/test/integration/passwords_helper.cc b/chrome/browser/sync/test/integration/passwords_helper.cc
index f06f261..dfc4e1a 100644
--- a/chrome/browser/sync/test/integration/passwords_helper.cc
+++ b/chrome/browser/sync/test/integration/passwords_helper.cc
@@ -59,7 +59,7 @@ class PasswordStoreConsumerHelper : public PasswordStoreConsumer {
     }
 
     // Quit the message loop to wake up passwords_helper::GetLogins.
-    MessageLoopForUI::current()->Quit();
+    base::MessageLoopForUI::current()->Quit();
   }
 
  private:
diff --git a/chrome/browser/sync/test/integration/sync_test.cc b/chrome/browser/sync/test/integration/sync_test.cc
index aa599a6..2b61276 100644
--- a/chrome/browser/sync/test/integration/sync_test.cc
+++ b/chrome/browser/sync/test/integration/sync_test.cc
@@ -79,7 +79,7 @@ class SyncServerStatusChecker : public net::URLFetcherDelegate {
     running_ =
         (source->GetStatus().status() == net::URLRequestStatus::SUCCESS &&
         source->GetResponseCode() == 200 && data.find("ok") == 0);
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   bool running() const { return running_; }
diff --git a/chrome/browser/sync/test_profile_sync_service.cc b/chrome/browser/sync/test_profile_sync_service.cc
index 73415c06..06d586a 100644
--- a/chrome/browser/sync/test_profile_sync_service.cc
+++ b/chrome/browser/sync/test_profile_sync_service.cc
@@ -88,7 +88,7 @@ void SyncBackendHostForProfileSyncTest::InitCore(
   if (synchronous_init_) {
     // The SyncBackend posts a task to the current loop when
     // initialization completes.
-    MessageLoop::current()->Run();
+    base::MessageLoop::current()->Run();
   }
 }
 
@@ -169,7 +169,7 @@ void SyncBackendHostForProfileSyncTest
   if (fail_initial_download_) {
     frontend()->OnSyncConfigureRetry();
     if (synchronous_init_)
-      MessageLoop::current()->Quit();
+      base::MessageLoop::current()->Quit();
   } else {
     initial_download_closure_.Run();
     initial_download_closure_.Reset();
@@ -258,7 +258,7 @@ void TestProfileSyncService::OnBackendInitialized(
 
   // TODO(akalin): Figure out a better way to do this.
   if (synchronous_backend_initialization_) {
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 }
 
@@ -266,7 +266,7 @@ void TestProfileSyncService::OnConfigureDone(
     const browser_sync::DataTypeManager::ConfigureResult& result) {
   ProfileSyncService::OnConfigureDone(result);
   if (!synchronous_sync_configuration_)
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
 }
 
 UserShare* TestProfileSyncService::GetUserShare() const {
diff --git a/chrome/browser/sync_file_system/drive/api_util_unittest.cc b/chrome/browser/sync_file_system/drive/api_util_unittest.cc
index e698684..aa24407 100644
--- a/chrome/browser/sync_file_system/drive/api_util_unittest.cc
+++ b/chrome/browser/sync_file_system/drive/api_util_unittest.cc
@@ -144,10 +144,10 @@ class APIUtilTest : public testing::Test {
     return mock_drive_service_;
   }
 
-  MessageLoop* message_loop() { return &message_loop_; }
+  base::MessageLoop* message_loop() { return &message_loop_; }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
 
   TestingProfile profile_;
   scoped_ptr<APIUtil> api_util_;
diff --git a/chrome/browser/sync_file_system/drive/fake_api_util_unittest.cc b/chrome/browser/sync_file_system/drive/fake_api_util_unittest.cc
index aff971e..ba146a2 100644
--- a/chrome/browser/sync_file_system/drive/fake_api_util_unittest.cc
+++ b/chrome/browser/sync_file_system/drive/fake_api_util_unittest.cc
@@ -43,7 +43,7 @@ void DidDeleteFile(google_apis::GDataErrorCode* error_out,
 }  // namespace
 
 TEST(FakeAPIUtilTest, ChangeSquashTest) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   FakeAPIUtil api_util;
   std::string kParentResourceId("parent resource id");
   std::string kParentTitle("app-id");
@@ -117,7 +117,7 @@ TEST(FakeAPIUtilTest, ChangeSquashTest) {
 }
 
 TEST(FakeAPIUtilTest, DeleteFile) {
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   FakeAPIUtil api_util;
   std::string resource_id = "resource_id_to_be_deleted";
   api_util.PushRemoteChange("parent_id",
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc b/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc
index 785115b..e22b505 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc
@@ -386,7 +386,7 @@ class DriveFileSyncServiceMockTest : public testing::Test {
     return &mock_remote_processor_;
   }
 
-  MessageLoop* message_loop() { return &message_loop_; }
+  base::MessageLoop* message_loop() { return &message_loop_; }
   DriveFileSyncService* sync_service() { return sync_service_.get(); }
   std::map<GURL, std::string>* pending_batch_sync_origins() {
     return &(sync_service()->pending_batch_sync_origins_);
@@ -570,7 +570,7 @@ class DriveFileSyncServiceMockTest : public testing::Test {
   // End of mock setup helpers -----------------------------------------------
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service_sync_unittest.cc b/chrome/browser/sync_file_system/drive_file_sync_service_sync_unittest.cc
index 16c161c..005b085 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service_sync_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service_sync_unittest.cc
@@ -326,7 +326,7 @@ class DriveFileSyncServiceSyncTest : public testing::Test {
     }
   }
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service_unittest.cc b/chrome/browser/sync_file_system/drive_file_sync_service_unittest.cc
index 4ace28d..3c44599 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service_unittest.cc
@@ -80,14 +80,14 @@ class DriveFileSyncServiceTest : public testing::Test {
   }
 
  protected:
-  MessageLoop* message_loop() { return &message_loop_; }
+  base::MessageLoop* message_loop() { return &message_loop_; }
   drive::FakeAPIUtil* fake_api_util() { return fake_api_util_; }
   DriveMetadataStore* metadata_store() { return metadata_store_; }
   DriveFileSyncService* sync_service() { return sync_service_.get(); }
 
  private:
   base::ScopedTempDir scoped_base_dir_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/sync_file_system/drive_metadata_store_unittest.cc b/chrome/browser/sync_file_system/drive_metadata_store_unittest.cc
index 1f459cf..6ded310 100644
--- a/chrome/browser/sync_file_system/drive_metadata_store_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_metadata_store_unittest.cc
@@ -305,7 +305,7 @@ class DriveMetadataStoreTest : public testing::Test {
 
   base::ScopedTempDir base_dir_;
 
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   scoped_ptr<base::Thread> file_thread_;
 
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
diff --git a/chrome/browser/sync_file_system/sync_file_system_test_util.cc b/chrome/browser/sync_file_system/sync_file_system_test_util.cc
index c6cd2cb..37e0e1d 100644
--- a/chrome/browser/sync_file_system/sync_file_system_test_util.cc
+++ b/chrome/browser/sync_file_system/sync_file_system_test_util.cc
@@ -43,11 +43,11 @@ MultiThreadTestHelper::~MultiThreadTestHelper() {}
 void MultiThreadTestHelper::SetUp() {
   file_thread_->Start();
   io_thread_->StartWithOptions(
-      base::Thread::Options(MessageLoop::TYPE_IO, 0));
+      base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
 
   browser_ui_thread_.reset(
       new TestBrowserThread(BrowserThread::UI,
-                            MessageLoop::current()));
+                            base::MessageLoop::current()));
   browser_file_thread_.reset(
       new TestBrowserThread(BrowserThread::FILE,
                             file_thread_->message_loop()));
diff --git a/chrome/browser/sync_file_system/sync_file_system_test_util.h b/chrome/browser/sync_file_system/sync_file_system_test_util.h
index 7c87896..fadd5ec 100644
--- a/chrome/browser/sync_file_system/sync_file_system_test_util.h
+++ b/chrome/browser/sync_file_system/sync_file_system_test_util.h
@@ -37,7 +37,7 @@ class MultiThreadTestHelper {
   void SetUp();
   void TearDown();
 
-  MessageLoop* message_loop() { return &message_loop_; }
+  base::MessageLoop* message_loop() { return &message_loop_; }
 
   base::SingleThreadTaskRunner* ui_task_runner() {
     return ui_task_runner_.get();
@@ -52,7 +52,7 @@ class MultiThreadTestHelper {
   }
 
  private:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   scoped_ptr<base::Thread> file_thread_;
   scoped_ptr<base::Thread> io_thread_;
 
diff --git a/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc b/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
index 8a7d371..864e589 100644
--- a/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
+++ b/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
@@ -29,7 +29,7 @@ void ContextMenuNotificationObserver::Observe(
     case chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN: {
       RenderViewContextMenu* context_menu =
           content::Source<RenderViewContextMenu>(source).ptr();
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&ContextMenuNotificationObserver::ExecuteCommand,
                      base::Unretained(this), context_menu));
diff --git a/chrome/browser/task_manager/task_manager.cc b/chrome/browser/task_manager/task_manager.cc
index 86d08e4..1f525ce 100644
--- a/chrome/browser/task_manager/task_manager.cc
+++ b/chrome/browser/task_manager/task_manager.cc
@@ -1077,7 +1077,7 @@ void TaskManagerModel::StartUpdating() {
   // If update_state_ is STOPPING, it means a task is still pending.  Setting
   // it to TASK_PENDING ensures the tasks keep being posted (by Refresh()).
   if (update_state_ == IDLE) {
-      MessageLoop::current()->PostTask(
+      base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&TaskManagerModel::RefreshCallback, this));
   }
@@ -1233,7 +1233,7 @@ void TaskManagerModel::NotifyBytesRead(const net::URLRequest& request,
     origin_pid = info->GetOriginPID();
 
   if (bytes_read_buffer_.empty()) {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&TaskManagerModel::NotifyMultipleBytesRead, this),
         base::TimeDelta::FromSeconds(1));
@@ -1259,7 +1259,7 @@ void TaskManagerModel::RefreshCallback() {
   Refresh();
 
   // Schedule the next update.
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&TaskManagerModel::RefreshCallback, this),
       base::TimeDelta::FromMilliseconds(kUpdateTimeMs));
diff --git a/chrome/browser/task_manager/task_manager_browsertest_util.cc b/chrome/browser/task_manager/task_manager_browsertest_util.cc
index 362aac0..e812b3d 100644
--- a/chrome/browser/task_manager/task_manager_browsertest_util.cc
+++ b/chrome/browser/task_manager/task_manager_browsertest_util.cc
@@ -67,7 +67,7 @@ class ResourceChangeObserver : public TaskManagerModelObserver {
  private:
   void OnResourceChange() {
     if (GetWebResourceCount(model_) == target_resource_count_)
-      MessageLoopForUI::current()->Quit();
+      base::MessageLoopForUI::current()->Quit();
   }
 
   const TaskManagerModel* model_;
diff --git a/chrome/browser/task_manager/task_manager_unittest.cc b/chrome/browser/task_manager/task_manager_unittest.cc
index 17c33b0..1e85db2 100644
--- a/chrome/browser/task_manager/task_manager_unittest.cc
+++ b/chrome/browser/task_manager/task_manager_unittest.cc
@@ -111,7 +111,7 @@ TEST_F(TaskManagerTest, Resources) {
 
 // Tests that the model is calling Refresh() on its resources.
 TEST_F(TaskManagerTest, RefreshCalled) {
-  MessageLoop loop;
+  base::MessageLoop loop;
   TaskManager task_manager;
   TaskManagerModel* model = task_manager.model_;
   TestResource resource;
diff --git a/chrome/browser/themes/browser_theme_pack_unittest.cc b/chrome/browser/themes/browser_theme_pack_unittest.cc
index 68f4f13..39fedaf 100644
--- a/chrome/browser/themes/browser_theme_pack_unittest.cc
+++ b/chrome/browser/themes/browser_theme_pack_unittest.cc
@@ -194,7 +194,7 @@ class BrowserThemePackTest : public ::testing::Test {
     EXPECT_FALSE(pack->GetTint(ThemeProperties::TINT_FRAME, &actual));
   }
 
-  MessageLoop message_loop;
+  base::MessageLoop message_loop;
   content::TestBrowserThread fake_ui_thread;
   content::TestBrowserThread fake_file_thread;
 
diff --git a/chrome/browser/themes/theme_service_unittest.cc b/chrome/browser/themes/theme_service_unittest.cc
index e107679..e6bcf15 100644
--- a/chrome/browser/themes/theme_service_unittest.cc
+++ b/chrome/browser/themes/theme_service_unittest.cc
@@ -53,7 +53,7 @@ TEST_F(ThemeServiceTest, ThemeInstallUninstall) {
       MakeThemeExtension(temp_dir.path());
   service_->FinishInstallationForTest(extension);
   // Let ThemeService finish creating the theme pack.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(theme_service->UsingDefaultTheme());
   EXPECT_EQ(extension->id(), theme_service->GetThemeID());
 
@@ -75,7 +75,7 @@ TEST_F(ThemeServiceTest, ThemeUpgrade) {
       MakeThemeExtension(temp_dir.path());
   service_->FinishInstallationForTest(extension);
   // Let ThemeService finish creating the theme pack.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(theme_service->UsingDefaultTheme());
   EXPECT_EQ(extension->id(), theme_service->GetThemeID());
 
diff --git a/chrome/browser/themes/theme_syncable_service_unittest.cc b/chrome/browser/themes/theme_syncable_service_unittest.cc
index c445a23..be32f67 100644
--- a/chrome/browser/themes/theme_syncable_service_unittest.cc
+++ b/chrome/browser/themes/theme_syncable_service_unittest.cc
@@ -162,7 +162,7 @@ scoped_refptr<extensions::Extension> MakeThemeExtension(
 class ThemeSyncableServiceTest : public testing::Test {
  protected:
   ThemeSyncableServiceTest()
-      : loop_(MessageLoop::TYPE_DEFAULT),
+      : loop_(base::MessageLoop::TYPE_DEFAULT),
         ui_thread_(BrowserThread::UI, &loop_),
         file_thread_(BrowserThread::FILE, &loop_),
         fake_theme_service_(NULL) {}
@@ -234,7 +234,7 @@ class ThemeSyncableServiceTest : public testing::Test {
   }
 
   // Needed for setting up extension service.
-  MessageLoop loop_;
+  base::MessageLoop loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 
diff --git a/chrome/browser/translate/translate_manager.cc b/chrome/browser/translate/translate_manager.cc
index 34ce89f..ed130e3 100644
--- a/chrome/browser/translate/translate_manager.cc
+++ b/chrome/browser/translate/translate_manager.cc
@@ -204,7 +204,7 @@ void TranslateManager::Observe(int type,
       // before the WebContents and the WebContents processing might remove the
       // current infobars.  Since InitTranslation might add an infobar, it must
       // be done after that.
-      MessageLoop::current()->PostTask(FROM_HERE,
+      base::MessageLoop::current()->PostTask(FROM_HERE,
           base::Bind(
               &TranslateManager::InitiateTranslationPosted,
               weak_method_factory_.GetWeakPtr(),
@@ -298,7 +298,7 @@ void TranslateManager::OnURLFetchComplete(const net::URLFetcher* source) {
       // We'll expire the cached script after some time, to make sure long
       // running browsers still get fixes that might get pushed with newer
       // scripts.
-      MessageLoop::current()->PostDelayedTask(FROM_HERE,
+      base::MessageLoop::current()->PostDelayedTask(FROM_HERE,
           base::Bind(&TranslateManager::ClearTranslateScript,
                      weak_method_factory_.GetWeakPtr()),
           translate_script_expiration_delay_);
@@ -496,7 +496,7 @@ void TranslateManager::InitiateTranslationPosted(
   // has finished.
   if ((web_contents->IsLoading()) && attempt < kMaxTranslateLoadCheckAttempts) {
     int backoff = attempt * max_reload_check_attempts_;
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE, base::Bind(&TranslateManager::InitiateTranslationPosted,
                               weak_method_factory_.GetWeakPtr(), process_id,
                               render_id, page_lang, ++attempt),
diff --git a/chrome/browser/translate/translate_manager_browsertest.cc b/chrome/browser/translate/translate_manager_browsertest.cc
index 205d9f6..1267e2a 100644
--- a/chrome/browser/translate/translate_manager_browsertest.cc
+++ b/chrome/browser/translate/translate_manager_browsertest.cc
@@ -212,7 +212,7 @@ class TranslateManagerBrowserTest : public ChromeRenderViewHostTestHarness,
 
     // The TranslateManager class processes the navigation entry committed
     // notification in a posted task; process that task.
-    MessageLoop::current()->RunUntilIdle();
+    base::MessageLoop::current()->RunUntilIdle();
   }
 
   virtual void Observe(int type,
@@ -808,7 +808,7 @@ TEST_F(TranslateManagerBrowserTest, ReloadFromLocationBar) {
 
   // The TranslateManager class processes the navigation entry committed
   // notification in a posted task; process that task.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_TRUE(GetTranslateInfoBar() != NULL);
 }
 
@@ -1454,7 +1454,7 @@ TEST_F(TranslateManagerBrowserTest, ScriptExpires) {
           0, 0, "fr", "en", TranslateErrors::NONE));
 
   // A task should have been posted to clear the script, run it.
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Do another navigation and translation.
   SimulateNavigation(GURL("http://www.google.es"), "es", true);
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_app_browsertest.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_app_browsertest.cc
index eeddc6f..7844a38 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_app_browsertest.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_app_browsertest.cc
@@ -1367,7 +1367,7 @@ IN_PROC_BROWSER_TEST_F(LauncherPerAppAppBrowserTest, DragAndDrop) {
       test.launcher_view()->GetAppListButtonView()->GetBoundsInScreen();
   generator.MoveMouseTo(app_list_bounds.CenterPoint().x(),
                         app_list_bounds.CenterPoint().y());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   generator.ClickLeftButton();
 
   EXPECT_TRUE(service->IsAppListVisible());
@@ -1389,7 +1389,7 @@ IN_PROC_BROWSER_TEST_F(LauncherPerAppAppBrowserTest, DragAndDrop) {
   gfx::Rect bounds_grid_1 = item1->GetBoundsInScreen();
   generator.MoveMouseTo(bounds_grid_1.CenterPoint().x(),
                         bounds_grid_1.CenterPoint().y());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   generator.PressLeftButton();
 
   EXPECT_FALSE(grid_view->forward_events_to_drag_and_drop_host_for_test());
@@ -1401,7 +1401,7 @@ IN_PROC_BROWSER_TEST_F(LauncherPerAppAppBrowserTest, DragAndDrop) {
   gfx::Rect bounds_launcher_1 = launcher1->GetBoundsInScreen();
   generator.MoveMouseTo(bounds_launcher_1.CenterPoint().x(),
                         bounds_launcher_1.CenterPoint().y());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
 
   // Check that a new item got created.
   EXPECT_EQ(3, model_->item_count());
@@ -1410,13 +1410,13 @@ IN_PROC_BROWSER_TEST_F(LauncherPerAppAppBrowserTest, DragAndDrop) {
   // Move it where the item originally was and check that it disappears again.
   generator.MoveMouseTo(bounds_grid_1.CenterPoint().x(),
                         bounds_grid_1.CenterPoint().y());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(2, model_->item_count());
   EXPECT_FALSE(grid_view->forward_events_to_drag_and_drop_host_for_test());
 
   // Dropping it should keep the launcher as it originally was.
   generator.ReleaseLeftButton();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(2, model_->item_count());
   // There are a few animations which need finishing before we can continue.
   test.RunMessageLoopUntilAnimationsDone();
@@ -1430,11 +1430,11 @@ IN_PROC_BROWSER_TEST_F(LauncherPerAppAppBrowserTest, DragAndDrop) {
   generator.PressLeftButton();
   generator.MoveMouseTo(bounds_launcher_1.CenterPoint().x(),
                         bounds_launcher_1.CenterPoint().y());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(3, model_->item_count());
   EXPECT_TRUE(grid_view->forward_events_to_drag_and_drop_host_for_test());
   generator.ReleaseLeftButton();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(grid_view->forward_events_to_drag_and_drop_host_for_test());
   EXPECT_EQ(3, model_->item_count());  // It should be still there.
   test.RunMessageLoopUntilAnimationsDone();
@@ -1446,11 +1446,11 @@ IN_PROC_BROWSER_TEST_F(LauncherPerAppAppBrowserTest, DragAndDrop) {
   generator.PressLeftButton();
   generator.MoveMouseTo(bounds_launcher_1.CenterPoint().x(),
                         bounds_launcher_1.CenterPoint().y());
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(3, model_->item_count());  // No new item got added.
   EXPECT_TRUE(grid_view->forward_events_to_drag_and_drop_host_for_test());
   generator.ReleaseLeftButton();
-  MessageLoop::current()->RunUntilIdle();
+  base::MessageLoop::current()->RunUntilIdle();
   EXPECT_FALSE(grid_view->forward_events_to_drag_and_drop_host_for_test());
   EXPECT_EQ(3, model_->item_count());  // And it remains that way.
 }
diff --git a/chrome/browser/ui/bookmarks/recently_used_folders_combo_model_unittest.cc b/chrome/browser/ui/bookmarks/recently_used_folders_combo_model_unittest.cc
index 73f5b51..60e4a66 100644
--- a/chrome/browser/ui/bookmarks/recently_used_folders_combo_model_unittest.cc
+++ b/chrome/browser/ui/bookmarks/recently_used_folders_combo_model_unittest.cc
@@ -26,7 +26,7 @@ class RecentlyUsedFoldersComboModelTest : public testing::Test {
   BookmarkModel* GetModel();
 
  private:
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
   scoped_ptr<TestingProfile> profile_;
diff --git a/chrome/browser/ui/search/instant_controller_unittest.cc b/chrome/browser/ui/search/instant_controller_unittest.cc
index cf70d141..fb2ddea 100644
--- a/chrome/browser/ui/search/instant_controller_unittest.cc
+++ b/chrome/browser/ui/search/instant_controller_unittest.cc
@@ -88,7 +88,7 @@ private:
 class InstantControllerTest : public testing::Test {
  public:
   InstantControllerTest()
-      : loop_(MessageLoop::TYPE_DEFAULT),
+      : loop_(base::MessageLoop::TYPE_DEFAULT),
         instant_controller_(new TestableInstantController()) {
   }
 
@@ -101,8 +101,8 @@ class InstantControllerTest : public testing::Test {
   }
 
  private:
-   MessageLoop loop_;
-   scoped_ptr<TestableInstantController> instant_controller_;
+  base::MessageLoop loop_;
+  scoped_ptr<TestableInstantController> instant_controller_;
 };
 
 TEST_F(InstantControllerTest, ShouldSwitchToLocalOverlayReturn) {
diff --git a/chrome/browser/ui/views/app_list/app_list_controller_win.cc b/chrome/browser/ui/views/app_list/app_list_controller_win.cc
index 96a9470..b1e5e64 100644
--- a/chrome/browser/ui/views/app_list/app_list_controller_win.cc
+++ b/chrome/browser/ui/views/app_list/app_list_controller_win.cc
@@ -919,7 +919,7 @@ void AppListController::ScheduleWarmup() {
 
   // Send app list usage stats after a delay.
   const int kSendUsageStatsDelay = 5;
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&AppListController::SendAppListStats),
       base::TimeDelta::FromSeconds(kSendUsageStatsDelay));
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
index b7d6917..e7df985 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -558,7 +558,7 @@ void SigninScreenHandler::UpdateStateInternal(
         base::Bind(
             &SigninScreenHandler::UpdateStateInternal,
             weak_factory_.GetWeakPtr(), state, reason, force_update));
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         update_state_closure_.callback(),
         base::TimeDelta::FromSeconds(kOfflineTimeoutSec));
@@ -573,7 +573,7 @@ void SigninScreenHandler::UpdateStateInternal(
       connecting_closure_.Reset(
           base::Bind(&SigninScreenHandler::UpdateStateInternal,
                      weak_factory_.GetWeakPtr(), state, reason, true));
-      MessageLoop::current()->PostDelayedTask(
+      base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           connecting_closure_.callback(),
           base::TimeDelta::FromSeconds(kConnectingTimeoutSec));
diff --git a/chrome/browser/ui/webui/sync_setup_handler.cc b/chrome/browser/ui/webui/sync_setup_handler.cc
index d2a0e8f..ec7e461 100644
--- a/chrome/browser/ui/webui/sync_setup_handler.cc
+++ b/chrome/browser/ui/webui/sync_setup_handler.cc
@@ -1357,7 +1357,7 @@ void SyncSetupHandler::CloseGaiaSigninPage() {
     // if the user clicks 'cancel' in the enterprise signin dialog), so
     // closing this tab in mid-handler can cause crashes. Instead, close it
     // via a task so we know we aren't in the middle of any webui code.
-    MessageLoop::current()->PostTask(
+    base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&CloseTab, base::Unretained(active_gaia_signin_tab_)));
 
diff --git a/chrome/browser/user_style_sheet_watcher_unittest.cc b/chrome/browser/user_style_sheet_watcher_unittest.cc
index 004e271..3f1e614 100644
--- a/chrome/browser/user_style_sheet_watcher_unittest.cc
+++ b/chrome/browser/user_style_sheet_watcher_unittest.cc
@@ -28,9 +28,9 @@ TEST(UserStyleSheetWatcherTest, StyleLoad) {
   ASSERT_TRUE(file_util::WriteFile(style_sheet_file,
               css_file_contents.data(), css_file_contents.length()));
 
-  MessageLoop loop(MessageLoop::TYPE_UI);
+  base::MessageLoop loop(base::MessageLoop::TYPE_UI);
   base::Thread io_thread("UserStyleSheetWatcherTestIOThread");
-  base::Thread::Options options(MessageLoop::TYPE_IO, 0);
+  base::Thread::Options options(base::MessageLoop::TYPE_IO, 0);
   ASSERT_TRUE(io_thread.StartWithOptions(options));
   content::TestBrowserThread browser_ui_thread(BrowserThread::UI, &loop);
   content::TestBrowserThread browser_file_thread(BrowserThread::FILE,
diff --git a/chrome/browser/value_store/value_store_frontend_unittest.cc b/chrome/browser/value_store/value_store_frontend_unittest.cc
index 6cd7b4b..cc3ca1f 100644
--- a/chrome/browser/value_store/value_store_frontend_unittest.cc
+++ b/chrome/browser/value_store/value_store_frontend_unittest.cc
@@ -19,8 +19,8 @@ using content::BrowserThread;
 class ValueStoreFrontendTest : public testing::Test {
  public:
   ValueStoreFrontendTest()
-      : ui_thread_(BrowserThread::UI, MessageLoop::current()),
-        file_thread_(BrowserThread::FILE, MessageLoop::current()) {
+      : ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+        file_thread_(BrowserThread::FILE, base::MessageLoop::current()) {
   }
 
   virtual void SetUp() {
@@ -36,7 +36,7 @@ class ValueStoreFrontendTest : public testing::Test {
   }
 
   virtual void TearDown() {
-    MessageLoop::current()->RunUntilIdle();  // wait for storage to delete
+    base::MessageLoop::current()->RunUntilIdle();  // wait for storage to delete
     storage_.reset();
   }
 
@@ -48,7 +48,7 @@ class ValueStoreFrontendTest : public testing::Test {
   bool Get(const std::string& key, scoped_ptr<base::Value>* output) {
     storage_->Get(key, base::Bind(&ValueStoreFrontendTest::GetAndWait,
                                   base::Unretained(this), output));
-    MessageLoop::current()->Run();  // wait for GetAndWait
+    base::MessageLoop::current()->Run();  // wait for GetAndWait
     return !!output->get();
   }
 
@@ -56,13 +56,13 @@ class ValueStoreFrontendTest : public testing::Test {
   void GetAndWait(scoped_ptr<base::Value>* output,
                   scoped_ptr<base::Value> result) {
     *output = result.Pass();
-    MessageLoop::current()->Quit();
+    base::MessageLoop::current()->Quit();
   }
 
   scoped_ptr<ValueStoreFrontend> storage_;
   base::ScopedTempDir temp_dir_;
   base::FilePath db_path_;
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 };
diff --git a/chrome/browser/value_store/value_store_unittest.cc b/chrome/browser/value_store/value_store_unittest.cc
index 9759fff..d45f647 100644
--- a/chrome/browser/value_store/value_store_unittest.cc
+++ b/chrome/browser/value_store/value_store_unittest.cc
@@ -131,8 +131,8 @@ ValueStoreTest::ValueStoreTest()
       dict3_(new DictionaryValue()),
       dict12_(new DictionaryValue()),
       dict123_(new DictionaryValue()),
-      ui_thread_(BrowserThread::UI, MessageLoop::current()),
-      file_thread_(BrowserThread::FILE, MessageLoop::current()) {
+      ui_thread_(BrowserThread::UI, base::MessageLoop::current()),
+      file_thread_(BrowserThread::FILE, base::MessageLoop::current()) {
   val1_.reset(Value::CreateStringValue(key1_ + "Value"));
   val2_.reset(Value::CreateStringValue(key2_ + "Value"));
   val3_.reset(Value::CreateStringValue(key3_ + "Value"));
diff --git a/chrome/browser/value_store/value_store_unittest.h b/chrome/browser/value_store/value_store_unittest.h
index 513963a..ec372a0 100644
--- a/chrome/browser/value_store/value_store_unittest.h
+++ b/chrome/browser/value_store/value_store_unittest.h
@@ -66,7 +66,7 @@ class ValueStoreTest : public testing::TestWithParam<ValueStoreTestParam> {
   base::ScopedTempDir temp_dir_;
 
   // Need these so that the DCHECKs for running on FILE or UI threads pass.
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread file_thread_;
 };
diff --git a/chrome/browser/web_resource/promo_resource_service.cc b/chrome/browser/web_resource/promo_resource_service.cc
index 605c3ac..02c1655 100644
--- a/chrome/browser/web_resource/promo_resource_service.cc
+++ b/chrome/browser/web_resource/promo_resource_service.cc
@@ -149,7 +149,7 @@ void PromoResourceService::PostNotification(int64 delay_ms) {
   // TODO(achuith): This crashes if we post delay_ms = 0 to the message loop.
   // during startup.
   if (delay_ms > 0) {
-    MessageLoop::current()->PostDelayedTask(
+    base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&PromoResourceService::PromoResourceStateChange,
                    weak_ptr_factory_.GetWeakPtr()),
diff --git a/chrome/browser/web_resource/promo_resource_service_mobile_ntp_unittest.cc b/chrome/browser/web_resource/promo_resource_service_mobile_ntp_unittest.cc
index a0a9a5f..dc72b92 100644
--- a/chrome/browser/web_resource/promo_resource_service_mobile_ntp_unittest.cc
+++ b/chrome/browser/web_resource/promo_resource_service_mobile_ntp_unittest.cc
@@ -33,7 +33,7 @@ class PromoResourceServiceMobileNtpTest : public testing::Test {
  protected:
   ScopedTestingLocalState local_state_;
   scoped_refptr<PromoResourceService> promo_resource_service_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 };
 
 class NotificationPromoMobileNtpTest {
diff --git a/chrome/browser/web_resource/promo_resource_service_unittest.cc b/chrome/browser/web_resource/promo_resource_service_unittest.cc
index c903c38..30c7662 100644
--- a/chrome/browser/web_resource/promo_resource_service_unittest.cc
+++ b/chrome/browser/web_resource/promo_resource_service_unittest.cc
@@ -67,7 +67,7 @@ class PromoResourceServiceTest : public testing::Test {
  protected:
   ScopedTestingLocalState local_state_;
   scoped_refptr<PromoResourceService> promo_resource_service_;
-  MessageLoop loop_;
+  base::MessageLoop loop_;
 };
 
 class NotificationPromoTest {
diff --git a/chrome/browser/web_resource/web_resource_service.cc b/chrome/browser/web_resource/web_resource_service.cc
index f9af253..f4fd3db 100644
--- a/chrome/browser/web_resource/web_resource_service.cc
+++ b/chrome/browser/web_resource/web_resource_service.cc
@@ -93,7 +93,7 @@ void WebResourceService::OnResourceRequestsAllowed() {
 // Delay initial load of resource data into cache so as not to interfere
 // with startup time.
 void WebResourceService::ScheduleFetch(int64 delay_ms) {
-  MessageLoop::current()->PostDelayedTask(
+  base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&WebResourceService::StartFetch,
                  weak_ptr_factory_.GetWeakPtr()),
diff --git a/chrome/browser/webdata/autofill_profile_syncable_service_unittest.cc b/chrome/browser/webdata/autofill_profile_syncable_service_unittest.cc
index 5c1a069..75709e7 100644
--- a/chrome/browser/webdata/autofill_profile_syncable_service_unittest.cc
+++ b/chrome/browser/webdata/autofill_profile_syncable_service_unittest.cc
@@ -112,7 +112,7 @@ class AutofillProfileSyncableServiceTest : public testing::Test {
   }
 
  protected:
-  MessageLoop message_loop_;
+  base::MessageLoop message_loop_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
   MockAutofillProfileSyncableService autofill_syncable_service_;
diff --git a/chrome/test/chromedriver/chrome/device_manager.cc b/chrome/test/chromedriver/chrome/device_manager.cc
index 305c69f..69e3343 100644
--- a/chrome/test/chromedriver/chrome/device_manager.cc
+++ b/chrome/test/chromedriver/chrome/device_manager.cc
@@ -182,7 +182,7 @@ Status DeviceManager::ExecuteHostShellCommand(
 void DeviceManager::ExecuteCommandOnIOThread(
     const std::string& command, std::string* response, bool* success,
     base::WaitableEvent* event) {
-  CHECK(MessageLoop::current()->IsType(MessageLoop::TYPE_IO));
+  CHECK(base::MessageLoop::current()->IsType(base::MessageLoop::TYPE_IO));
   AdbClientSocket::AdbQuery(kAdbPort, command,
       base::Bind(&ReceiveAdbResponse, response, success, event));
 }
diff --git a/chrome/test/perf/perf_ui_test_suite.cc b/chrome/test/perf/perf_ui_test_suite.cc
index 05ebde4..1f15015 100644
--- a/chrome/test/perf/perf_ui_test_suite.cc
+++ b/chrome/test/perf/perf_ui_test_suite.cc
@@ -160,7 +160,7 @@ void PerfUITestSuite::BuildCachedThemePakIn(
   // both because committing large binary files is bad in a git world and
   // because people don't remember to update it anyway, meaning we usually
   // have the theme rebuild penalty in our data.)
-  MessageLoopForUI message_loop_;
+  base::MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_(BrowserThread::UI, &message_loop_);
   content::TestBrowserThread file_thread_(BrowserThread::FILE,
                                           &message_loop_);