Standardize usage of virtual/override/final in content/

content/public/renderer/media_stream_video_sink.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 CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
 #define CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
@@ skipping 45 matching lines @@
   // Calling RemoveFromVideoTrack also not stop frame delivery through the
   // callback immediately because it may happen on another thread.
   // The added callback will be reset on the render thread.
   static void AddToVideoTrack(MediaStreamVideoSink* sink,
                               const VideoCaptureDeliverFrameCB& callback,
                               const blink::WebMediaStreamTrack& track);
   static void RemoveFromVideoTrack(MediaStreamVideoSink* sink,
                                    const blink::WebMediaStreamTrack& track);
 
  protected:
-  virtual ~MediaStreamVideoSink() {}
+  ~MediaStreamVideoSink() override {}
 };
 
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_VIDEO_SINK_H_