Add OVERRIDE to chrome/browser/.

chrome/browser/web_resource/gpu_blacklist_updater.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_WEB_RESOURCE_GPU_BLACKLIST_UPDATER_H_
 #define CHROME_BROWSER_WEB_RESOURCE_GPU_BLACKLIST_UPDATER_H_
 #pragma once
 
 #include "chrome/browser/web_resource/web_resource_service.h"
 
 class GpuBlacklistUpdater : public WebResourceService {
  public:
   GpuBlacklistUpdater();
 
   // Initialize GpuDataManager, and post a SetupOnUIThread task.
   static void SetupOnFileThread();
 
   // URL of the up-to-date gpu_blacklist.json file.
   static const char* kDefaultGpuBlacklistURL;
 
  private:
   virtual ~GpuBlacklistUpdater();
 
-  virtual void Unpack(const base::DictionaryValue& parsed_json);
+  virtual void Unpack(const base::DictionaryValue& parsed_json) OVERRIDE;
 
   // Initialize GpuBlacklistUpdater and schedule an auto update.
   static void SetupOnUIThread();
 
   void InitializeGpuBlacklist();
 
   void UpdateGpuBlacklist(
       const base::DictionaryValue& gpu_blacklist_cache, bool preliminary);
 
   DISALLOW_COPY_AND_ASSIGN(GpuBlacklistUpdater);
 };
 
 #endif  // CHROME_BROWSER_WEB_RESOURCE_GPU_BLACKLIST_UPDATER_H_