Add OVERRIDE to chrome/renderer.

chrome/renderer/renderer_tracking.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_RENDERER_RENDERER_TRACKING_H_
 #define CHROME_RENDERER_RENDERER_TRACKING_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/process.h"
 #include "base/task.h"
 #include "content/public/renderer/render_process_observer.h"
 
 class RendererTracking : public content::RenderProcessObserver {
  public:
   RendererTracking();
   virtual ~RendererTracking();
 
  private:
   // RenderProcessObserver implementation.
-  virtual bool OnControlMessageReceived(const IPC::Message& message);
+  virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
 
   void OnGetRendererTrackingData(int sequence_number);
 
   void OnSetTrackingStatus(bool enable);
 
   // Extract tracking data from TrackedObjects and then send it off the
   // Browser process.
   void UploadAllTrackingData(int sequence_number);
 
   ScopedRunnableMethodFactory<RendererTracking> renderer_tracking_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererTracking);
 };
 
 #endif  // CHROME_RENDERER_RENDERER_TRACKING_H_