Fix some grammar in chrome/browser/history

chrome/browser/history/top_sites_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/format_macros.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
@@ skipping 1359 matching lines @@
   FilePath data_path;
   ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &data_path));
   data_path = data_path.AppendASCII("top_sites");
   ASSERT_NO_FATAL_FAILURE(ExecuteSQLScript(
       data_path.AppendASCII("history.19.sql"),
       profile()->GetPath().Append(chrome::kHistoryFilename)));
   ASSERT_NO_FATAL_FAILURE(ExecuteSQLScript(
       data_path.AppendASCII("thumbnails.3.sql"),
       profile()->GetPath().Append(chrome::kThumbnailsFilename)));
 
-  // Create history and block until its loaded.
+  // Create history and block until it's loaded.
   profile()->CreateHistoryService(false, false);
   profile()->BlockUntilHistoryProcessesPendingRequests();
 
   // Create top sites and unload history.
   ui_test_utils::WindowedNotificationObserver observer(
       chrome::NOTIFICATION_TOP_SITES_LOADED,
       content::Source<Profile>(profile()));
   profile()->CreateTopSites();
   profile()->GetHistoryService(Profile::EXPLICIT_ACCESS)->UnloadBackend();
   profile()->BlockUntilHistoryProcessesPendingRequests();
   observer.Wait();
 }
 
 }  // namespace history