Add OVERRIDE to content/.

content/renderer/mhtml_generator.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 CONTENT_RENDERER_MHTML_GENERATOR_H_
 #define CONTENT_RENDERER_MHTML_GENERATOR_H_
 
 #include "content/public/renderer/render_view_observer.h"
 
 #include "ipc/ipc_platform_file.h"
 
 class RenderViewImpl;
 
 class MHTMLGenerator : public content::RenderViewObserver {
  public:
   explicit MHTMLGenerator(RenderViewImpl* render_view);
   virtual ~MHTMLGenerator();
 
  private:
   // RenderViewObserver implementation:
-  virtual bool OnMessageReceived(const IPC::Message& message);
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
   void OnSavePageAsMHTML(int job_id,
                          IPC::PlatformFileForTransit file_for_transit);
 
   void NotifyBrowser(int job_id, int64 data_size);
   // Returns the size of the generated MHTML, -1 if it failed.
   int64 GenerateMHTML();
 
   base::PlatformFile file_;
 
   DISALLOW_COPY_AND_ASSIGN(MHTMLGenerator);
 };
 
 #endif  // CONTENT_RENDERER_MHTML_GENERATOR_H_