Move VideoDecoder out of media pipeline.

media/base/pipeline.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 MEDIA_BASE_PIPELINE_H_
 #define MEDIA_BASE_PIPELINE_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
@@ skipping 585 matching lines @@
   PipelineStatusCB ended_cb_;
   PipelineStatusCB error_cb_;
   NetworkEventCB network_cb_;
 
   // Reference to the filter(s) that constitute the pipeline.
   scoped_refptr<Filter> pipeline_filter_;
 
   // Decoder reference used for signalling imminent shutdown.
   // This is a HACK necessary because WebMediaPlayerImpl::Destroy() holds the
   // renderer thread loop hostage for until PipelineImpl::Stop() calls its
-  // callback.  http://crbug.com/110228 tracks removing this hack.
+  // callback.
+  // This reference should only be used for this hack and no other purposes.
+  // http://crbug.com/110228 tracks removing this hack.
   scoped_refptr<VideoDecoder> video_decoder_;
 
   // Renderer references used for setting the volume and determining
   // when playback has finished.
   scoped_refptr<AudioRenderer> audio_renderer_;
   scoped_refptr<VideoRenderer> video_renderer_;
 
   // Demuxer reference used for setting the preload value.
   scoped_refptr<Demuxer> demuxer_;
 
@@ skipping 13 matching lines @@
 
   // True if the pipeline is actively downloading bytes, false otherwise.
   bool is_downloading_data_;
 
   DISALLOW_COPY_AND_ASSIGN(Pipeline);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_H_