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

ppapi/proxy/video_source_resource.h

 // Copyright (c) 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 PPAPI_PROXY_VIDEO_SOURCE_RESOURCE_H_
 #define PPAPI_PROXY_VIDEO_SOURCE_RESOURCE_H_
 
 #include <string>
 
 #include "ppapi/c/pp_time.h"
@@ skipping 11 matching lines @@
 class TrackedCallback;
 
 namespace proxy {
 
 class PPAPI_PROXY_EXPORT VideoSourceResource
     : public PluginResource,
       public thunk::PPB_VideoSource_Private_API {
  public:
   VideoSourceResource(Connection connection,
                       PP_Instance instance);
-  virtual ~VideoSourceResource();
+  ~VideoSourceResource() override;
 
   // Resource overrides.
-  virtual thunk::PPB_VideoSource_Private_API*
-      AsPPB_VideoSource_Private_API() override;
+  thunk::PPB_VideoSource_Private_API* AsPPB_VideoSource_Private_API() override;
 
   // PPB_VideoSource_Private_API implementation.
-  virtual int32_t Open(
+  int32_t Open(
       const PP_Var& stream_url,
       scoped_refptr<TrackedCallback> callback) override;
-  virtual int32_t GetFrame(
+  int32_t GetFrame(
       PP_VideoFrame_Private* frame,
       scoped_refptr<TrackedCallback> callback) override;
-  virtual void Close() override;
+  void Close() override;
 
  private:
   void OnPluginMsgOpenComplete(
       const ResourceMessageReplyParams& reply_params);
   void OnPluginMsgGetFrameComplete(
       PP_VideoFrame_Private* frame,
       const ResourceMessageReplyParams& reply_params,
       const HostResource& image_data,
       const PP_ImageDataDesc& image_desc_data,
       PP_TimeTicks timestamp);
 
   scoped_refptr<TrackedCallback> open_callback_;
   scoped_refptr<TrackedCallback> get_frame_callback_;
   bool is_open_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoSourceResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_VIDEO_SOURCE_RESOURCE_H_