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

android_webview/renderer/aw_permission_client.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 ANDROID_WEBVIEW_RENDERER_AW_PERMISSION_CLIENT_H_
 #define ANDROID_WEBVIEW_RENDERER_AW_PERMISSION_CLIENT_H_
 
 #include "content/public/renderer/render_frame_observer.h"
 #include "third_party/WebKit/public/web/WebPermissionClient.h"
 
 namespace android_webview {
 
 // Android WebView implementation of blink::WebPermissionClient.
 class AwPermissionClient : public content::RenderFrameObserver,
                            public blink::WebPermissionClient {
  public:
   explicit AwPermissionClient(content::RenderFrame* render_view);
 
- private:  
-  virtual ~AwPermissionClient();
+ private:
+  ~AwPermissionClient() override;
 
   // blink::WebPermissionClient implementation.
   virtual bool allowDisplayingInsecureContent(
       bool enabled_per_settings,
       const blink::WebSecurityOrigin& origin,
       const blink::WebURL& url);
   virtual bool allowRunningInsecureContent(
       bool enabled_per_settings,
       const blink::WebSecurityOrigin& origin,
       const blink::WebURL& url);
 
   DISALLOW_COPY_AND_ASSIGN(AwPermissionClient);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_RENDERER_AW_PERMISSION_CLIENT_H_