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

This patch was generated by running the empty_string clang tool
across the Chromium Linux compilation database. Implicitly or
explicitly constructing std::string() with a "" argument is
inefficient as the caller needs to emit extra instructions to
pass an argument, and the constructor needlessly copies a byte
into internal storage. Rewriting these instances to simply call
the default constructor appears to save ~14-18 kilobytes on an
optimized release build.

BUG=none

Review URL: https://codereview.chromium.org/13145003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193020 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 26 insertions, 21 deletions

diff --git a/sync/internal_api/sync_manager_impl_unittest.cc b/sync/internal_api/sync_manager_impl_unittest.cc
index 9a6ddee..7f96f49 100644
--- a/sync/internal_api/sync_manager_impl_unittest.cc
+++ b/sync/internal_api/sync_manager_impl_unittest.cc
@@ -723,7 +723,7 @@ class TestHttpPostProviderInterface : public HttpPostProviderInterface {
   }
   virtual const std::string GetResponseHeaderValue(
       const std::string& name) const OVERRIDE {
-    return "";
+    return std::string();
   }
   virtual void Abort() OVERRIDE {}
 };
@@ -820,20 +820,25 @@ class SyncManagerTest : public testing::Test,
     GetModelSafeRoutingInfo(&routing_info);
 
     // Takes ownership of |fake_invalidator_|.
-    sync_manager_.Init(temp_dir_.path(),
-                       WeakHandle<JsEventHandler>(),
-                       "bogus", 0, false,
-                       scoped_ptr<HttpPostProviderFactory>(
-                           new TestHttpPostProviderFactory()),
-                       workers, &extensions_activity_monitor_, this,
-                       credentials,
-                       scoped_ptr<Invalidator>(fake_invalidator_),
-                       "fake_invalidator_client_id",
-                       "", "",  // bootstrap tokens
-                       scoped_ptr<InternalComponentsFactory>(GetFactory()),
-                       &encryptor_,
-                       &handler_,
-                       NULL);
+    sync_manager_.Init(
+        temp_dir_.path(),
+        WeakHandle<JsEventHandler>(),
+        "bogus",
+        0,
+        false,
+        scoped_ptr<HttpPostProviderFactory>(new TestHttpPostProviderFactory()),
+        workers,
+        &extensions_activity_monitor_,
+        this,
+        credentials,
+        scoped_ptr<Invalidator>(fake_invalidator_),
+        "fake_invalidator_client_id",
+        std::string(),
+        std::string(),  // bootstrap tokens
+        scoped_ptr<InternalComponentsFactory>(GetFactory()),
+        &encryptor_,
+        &handler_,
+        NULL);
 
     sync_manager_.GetEncryptionHandler()->AddObserver(&encryption_observer_);
 
@@ -1181,9 +1186,9 @@ class SyncManagerGetNodesByIdTest : public SyncManagerTest {
       base::ListValue args;
       base::ListValue* ids = new base::ListValue();
       args.Append(ids);
-      ids->Append(new base::StringValue(""));
-      SendJsMessage(message_name,
-                    JsArgList(&args), reply_handler.AsWeakHandle());
+      ids->Append(new base::StringValue(std::string()));
+      SendJsMessage(
+          message_name, JsArgList(&args), reply_handler.AsWeakHandle());
     }
 
     {
@@ -1273,9 +1278,9 @@ TEST_F(SyncManagerTest, GetChildNodeIdsFailure) {
 
   {
     base::ListValue args;
-    args.Append(new base::StringValue(""));
-    SendJsMessage("getChildNodeIds",
-                  JsArgList(&args), reply_handler.AsWeakHandle());
+    args.Append(new base::StringValue(std::string()));
+    SendJsMessage(
+        "getChildNodeIds", JsArgList(&args), reply_handler.AsWeakHandle());
   }
 
   {