MediaStreamVideo*/VideoTrackAdapter and RTCVideoRenderer (small) cleanup

content/renderer/media/video_track_adapter.h

 // Copyright 2014 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_VIDEO_TRACK_ADAPTER_H_
 #define CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 72 matching lines @@
   void StopFrameMonitoringOnIO();
 
   // Compare |frame_counter_snapshot| with the current |frame_counter_|, and
   // inform of the situation (muted, not muted) via |set_muted_state_callback|.
   void CheckFramesReceivedOnIO(const OnMutedCallback& set_muted_state_callback,
                                uint64 old_frame_counter_snapshot);
 
   // |thread_checker_| is bound to the main render thread.
   base::ThreadChecker thread_checker_;
 
-  scoped_refptr<base::MessageLoopProxy> io_message_loop_;
+  const scoped_refptr<base::MessageLoopProxy> io_message_loop_;
 
   // |renderer_task_runner_| is used to ensure that
   // VideoCaptureDeliverFrameCB is released on the main render thread.
-  scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
+  const scoped_refptr<base::SingleThreadTaskRunner> renderer_task_runner_;
 
   // VideoFrameResolutionAdapter is an inner class that is created on the main
   // render thread but operates on the IO-thread. It does the resolution
   // adaptation and delivers frames to all registered tracks on the IO-thread.
   class VideoFrameResolutionAdapter;
   typedef std::vector<scoped_refptr<VideoFrameResolutionAdapter> >
       FrameAdapters;
   FrameAdapters adapters_;
 
   // Set to true if frame monitoring has been started. It is only accessed on
   // the IO-thread.
   bool monitoring_frame_rate_;
 
   // Keeps track of it frames have been received. It is only accessed on the
   // IO-thread.
   bool muted_state_;
 
   // Running frame counter, accessed on the IO-thread.
   uint64 frame_counter_;
 
   // Frame rate configured on the video source, accessed on the IO-thread.
   float source_frame_rate_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoTrackAdapter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_ADAPTER_H_