MediaStreamVideo*/VideoTrackAdapter and RTCVideoRenderer (small) cleanup

content/renderer/media/rtc_video_renderer.h

 // Copyright (c) 2012 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_RENDERER_MEDIA_RTC_VIDEO_RENDERER_H_
 #define CONTENT_RENDERER_MEDIA_RTC_VIDEO_RENDERER_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
 #include "content/common/media/video_capture.h"
 #include "content/public/renderer/media_stream_video_sink.h"
 #include "content/renderer/media/video_frame_provider.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace content {
 
-// RTCVideoRenderer is a VideoFrameProvider designed for rendering
-// Video MediaStreamTracks,
-// http://dev.w3.org/2011/webrtc/editor/getusermedia.html#mediastreamtrack
-// RTCVideoRenderer implements VideoTrackSink in order to render
-// video frames provided from a VideoTrack.
-// RTCVideoRenderer register itself as a sink to the VideoTrack when the
-// VideoFrameProvider is started and deregisters itself when it is stopped.
+// RTCVideoRenderer is a VideoFrameProvider designed for rendering Video
+// MediaStreamTracks [1], RTCVideoRenderer implements MediaStreamVideoSink in
+// order to render video frames provided from a MediaStreamVideoTrack, to which
+// it AddToVideoTrack()s itself when the VideoFrameProvider is Start()ed
+// and RemoveFromVideoTrack()s itself when the latter is Stop()ed.
+//
+// [1] http://dev.w3.org/2011/webrtc/editor/getusermedia.html#mediastreamtrack
+//
 // TODO(wuchengli): Add unit test. See the link below for reference.
 // http://src.chromium.org/viewvc/chrome/trunk/src/content/renderer/media/rtc_vi
 // deo_decoder_unittest.cc?revision=180591&view=markup
 class CONTENT_EXPORT RTCVideoRenderer
     : NON_EXPORTED_BASE(public VideoFrameProvider),
       NON_EXPORTED_BASE(public MediaStreamVideoSink) {
  public:
   RTCVideoRenderer(const blink::WebMediaStreamTrack& video_track,
                    const base::Closure& error_cb,
                    const RepaintCB& repaint_cb);
@@ skipping 10 matching lines @@
  private:
   enum State {
     STARTED,
     PAUSED,
     STOPPED,
   };
 
   void OnVideoFrame(const scoped_refptr<media::VideoFrame>& frame,
                     const base::TimeTicks& estimated_capture_time);
 
-  // VideoTrackSink implementation. Called on the main thread.
+  // MediaStreamVideoSink implementation. Called on the main thread.
   void OnReadyStateChanged(
       blink::WebMediaStreamSource::ReadyState state) override;
 
   void RenderSignalingFrame();
 
-  base::Closure error_cb_;
-  RepaintCB repaint_cb_;
-  scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
+  const base::Closure error_cb_;
+  const RepaintCB repaint_cb_;
+  const scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
   State state_;
   gfx::Size frame_size_;
-  blink::WebMediaStreamTrack video_track_;
+  const blink::WebMediaStreamTrack video_track_;
   base::WeakPtrFactory<RTCVideoRenderer> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCVideoRenderer);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_VIDEO_RENDERER_H_