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

android_webview/renderer/aw_render_frame_ext.h

 // Copyright 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 ANDROID_WEBVIEW_RENDERER_AW_RENDER_FRAME_EXT_H_
 #define ANDROID_WEBVIEW_RENDERER_AW_RENDER_FRAME_EXT_H_
 
 #include "content/public/renderer/render_frame_observer.h"
 
 namespace android_webview {
 
 // Render process side of AwRenderViewHostExt, this provides cross-process
 // implementation of miscellaneous WebView functions that we need to poke
 // WebKit directly to implement (and that aren't needed in the chrome app).
 class AwRenderFrameExt : public content::RenderFrameObserver {
  public:
   AwRenderFrameExt(content::RenderFrame* render_frame);
 
  private:
-  virtual ~AwRenderFrameExt();
+  ~AwRenderFrameExt() override;
 
   // RenderFrame::Observer:
-  virtual void DidCommitProvisionalLoad(bool is_new_navigation) override;
+  void DidCommitProvisionalLoad(bool is_new_navigation) override;
   DISALLOW_COPY_AND_ASSIGN(AwRenderFrameExt);
 };
 
 }
 
 #endif  // ANDROID_WEBVIEW_RENDERER_AW_RENDER_FRAME_EXT_H_