Update {virtual,override} to follow C++11 style in chrome.

chrome/renderer/prerender/prerender_dispatcher.h

 // Copyright (c) 2012 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_PRERENDER_PRERENDER_DISPATCHER_H_
 #define CHROME_RENDERER_PRERENDER_PRERENDER_DISPATCHER_H_
 
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/public/renderer/render_process_observer.h"
 #include "third_party/WebKit/public/platform/WebPrerender.h"
 #include "third_party/WebKit/public/platform/WebPrerenderingSupport.h"
 
 class GURL;
 
 namespace prerender {
 
 // There is one PrerenderDispatcher per render process. It keeps track of which
 // prerenders were launched from this renderer, and ensures prerender navigation
 // is triggered on navigation to those. It implements the prerendering interface
 // supplied to WebKit.
 class PrerenderDispatcher : public content::RenderProcessObserver,
                             public blink::WebPrerenderingSupport {
  public:
   PrerenderDispatcher();
-  virtual ~PrerenderDispatcher();
+  ~PrerenderDispatcher() override;
 
   bool IsPrerenderURL(const GURL& url) const;
 
  private:
   friend class PrerenderDispatcherTest;
 
   // Message handlers for messages from the browser process.
   void OnPrerenderStart(int prerender_id);
   void OnPrerenderStopLoading(int prerender_id);
   void OnPrerenderDomContentLoaded(int prerender_id);
   void OnPrerenderAddAlias(const GURL& alias);
   void OnPrerenderRemoveAliases(const std::vector<GURL>& aliases);
   void OnPrerenderStop(int prerender_id);
 
   // From RenderProcessObserver:
   bool OnControlMessageReceived(const IPC::Message& message) override;
 
   // From WebPrerenderingSupport:
-  virtual void add(const blink::WebPrerender& prerender) override;
-  virtual void cancel(const blink::WebPrerender& prerender) override;
-  virtual void abandon(const blink::WebPrerender& prerender) override;
+  void add(const blink::WebPrerender& prerender) override;
+  void cancel(const blink::WebPrerender& prerender) override;
+  void abandon(const blink::WebPrerender& prerender) override;
 
   // From WebKit, prerender elements launched by renderers in our process.
   std::map<int, blink::WebPrerender> prerenders_;
 
   // From the browser process, which prerenders are running, indexed by URL.
   // Updated by the browser processes as aliases are discovered.
   std::multiset<GURL> running_prerender_urls_;
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_RENDERER_PRERENDER_PRERENDER_DISPATCHER_H_