Standardize usage of virtual/override/final in chrome/renderer/

chrome/renderer/prefetch_helper.h

 // Copyright (c) 2014 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_PREFETCH_HELPER_H_
 #define CHROME_RENDERER_PREFETCH_HELPER_H_
 
 #include <set>
 
 #include "content/public/renderer/render_frame_observer.h"
@@ skipping 12 matching lines @@
 
   // blink::WebURLLoaderClient implementation
   virtual void didFinishLoading(blink::WebURLLoader* loader,
                                 double finishTime,
                                 int64_t totalEncodedDataLength) override;
   virtual void didFail(blink::WebURLLoader* loader,
                        const blink::WebURLError& error) override;
 
  private:
   // RenderViewObserver implementation
-  virtual bool OnMessageReceived(const IPC::Message& message) override;
+  bool OnMessageReceived(const IPC::Message& message) override;
 
   void OnPrefetch(const GURL& url);
 
   std::set<blink::WebURLLoader*> loader_set_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefetchHelper);
 };
 
 }  // namespace prefetch
 
 #endif  // CHROME_RENDERER_PREFETCH_HELPER_H_