Add OVERRIDE to chrome/browser/.

chrome/browser/history/history.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_HISTORY_HISTORY_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_H_
 #pragma once
 
 #include <set>
 #include <vector>
@@ skipping 577 matching lines @@
   friend class HistoryURLProvider;
   friend class HistoryURLProviderTest;
   template<typename Info, typename Callback> friend class DownloadRequest;
   friend class PageUsageRequest;
   friend class RedirectRequest;
   friend class TestingProfile;
 
   // Implementation of content::NotificationObserver.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
-                       const content::NotificationDetails& details);
+                       const content::NotificationDetails& details) OVERRIDE;
 
   // Low-level Init().  Same as the public version, but adds a |no_db| parameter
   // that is only set by unittests which causes the backend to not init its DB.
   bool Init(const FilePath& history_dir,
             BookmarkService* bookmark_service,
             bool no_db);
 
   // Called by the HistoryURLProvider class to schedule an autocomplete, it
   // will be called back on the internal history thread with the history
   // database so it can query. See history_autocomplete.cc for a diagram.
@@ skipping 252 matching lines @@
   BookmarkService* bookmark_service_;
   bool no_db_;
 
   // True if needs top site migration.
   bool needs_top_sites_migration_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_H_