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

ppapi/proxy/media_stream_video_track_resource.h

Index: ppapi/proxy/media_stream_video_track_resource.h
diff --git a/ppapi/proxy/media_stream_video_track_resource.h b/ppapi/proxy/media_stream_video_track_resource.h
index 2bdbb72b24b716c93d32e886e3b0bb98ac15f8ec..b6102ecdb5076b836da807dfae40fe655f27b76f 100644
--- a/ppapi/proxy/media_stream_video_track_resource.h
+++ b/ppapi/proxy/media_stream_video_track_resource.h
@@ -28,29 +28,29 @@ class PPAPI_PROXY_EXPORT MediaStreamVideoTrackResource
 
   MediaStreamVideoTrackResource(Connection connection, PP_Instance instance);
 
-  virtual ~MediaStreamVideoTrackResource();
+  ~MediaStreamVideoTrackResource() override;
 
   // Resource overrides:
-  virtual thunk::PPB_MediaStreamVideoTrack_API*
-  AsPPB_MediaStreamVideoTrack_API() override;
+  thunk::PPB_MediaStreamVideoTrack_API* AsPPB_MediaStreamVideoTrack_API()
+      override;
 
   // PPB_MediaStreamVideoTrack_API overrides:
-  virtual PP_Var GetId() override;
-  virtual PP_Bool HasEnded() override;
-  virtual int32_t Configure(const int32_t attrib_list[],
-                            scoped_refptr<TrackedCallback> callback) override;
-  virtual int32_t GetAttrib(PP_MediaStreamVideoTrack_Attrib attrib,
-                            int32_t* value) override;
-  virtual int32_t GetFrame(PP_Resource* frame,
-                           scoped_refptr<TrackedCallback> callback) override;
-  virtual int32_t RecycleFrame(PP_Resource frame) override;
-  virtual void Close() override;
-  virtual int32_t GetEmptyFrame(
-      PP_Resource* frame, scoped_refptr<TrackedCallback> callback) override;
-  virtual int32_t PutFrame(PP_Resource frame) override;
+  PP_Var GetId() override;
+  PP_Bool HasEnded() override;
+  int32_t Configure(const int32_t attrib_list[],
+                    scoped_refptr<TrackedCallback> callback) override;
+  int32_t GetAttrib(PP_MediaStreamVideoTrack_Attrib attrib,
+                    int32_t* value) override;
+  int32_t GetFrame(PP_Resource* frame,
+                   scoped_refptr<TrackedCallback> callback) override;
+  int32_t RecycleFrame(PP_Resource frame) override;
+  void Close() override;
+  int32_t GetEmptyFrame(PP_Resource* frame,
+                        scoped_refptr<TrackedCallback> callback) override;
+  int32_t PutFrame(PP_Resource frame) override;
 
   // MediaStreamBufferManager::Delegate overrides:
-  virtual void OnNewBufferEnqueued() override;
+  void OnNewBufferEnqueued() override;
 
  private:
   PP_Resource GetVideoFrame();