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

chrome/browser/android/webapps/single_tab_mode_tab_helper.h

 // Copyright 2013 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_ANDROID_WEBAPPS_SINGLE_TAB_MODE_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_WEBAPPS_SINGLE_TAB_MODE_TAB_HELPER_H_
 
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 12 matching lines @@
 // Registers and unregisters the IDs of renderers in single tab mode, which
 // are disallowed from opening new windows via
 // ChromeContentBrowserClient::CanCreateWindow().
 class SingleTabModeTabHelper
     : public content::WebContentsObserver,
       public content::WebContentsUserData<SingleTabModeTabHelper> {
  public:
   // Checks if the ID pair is blocked from creating new windows. IO-thread only.
   static bool IsRegistered(int32 process_id, int32 routing_id);
 
-  virtual ~SingleTabModeTabHelper();
+  ~SingleTabModeTabHelper() override;
 
   // Handles opening the given URL through the TabModel.
   void HandleOpenUrl(const BlockedWindowParams& params);
 
   // Permanently block this WebContents from creating new windows -- there is no
   // current need to allow toggling this flag on or off.
   void PermanentlyBlockAllNewWindows();
 
   // content::WebContentsObserver
-  virtual void RenderViewCreated(content::RenderViewHost* render_view_host)
-      override;
-  virtual void RenderViewDeleted(content::RenderViewHost* render_view_host)
-      override;
+  void RenderViewCreated(content::RenderViewHost* render_view_host) override;
+  void RenderViewDeleted(content::RenderViewHost* render_view_host) override;
 
  private:
   explicit SingleTabModeTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<SingleTabModeTabHelper>;
 
   bool block_all_new_windows_;
 
   DISALLOW_COPY_AND_ASSIGN(SingleTabModeTabHelper);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPPS_SINGLE_TAB_MODE_TAB_HELPER_H_