[chromecast] Deletes dead code to track MediaPipelineBackend.

chromecast/media/cma/pipeline/media_pipeline_impl.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 CHROMECAST_MEDIA_CMA_PIPELINE_MEDIA_PIPELINE_IMPL_H_
 #define CHROMECAST_MEDIA_CMA_PIPELINE_MEDIA_PIPELINE_IMPL_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 81 matching lines @@
   MediaPipelineClient client_;
   std::unique_ptr<BufferingController> buffering_controller_;
   CastCdmContext* cdm_context_;
 
   // Interface with the underlying hardware media pipeline.
   BackendState backend_state_;
   // Playback rate set by the upper layer.
   // Cached here because CMA pipeline backend does not support rate == 0,
   // which is emulated by pausing the backend.
   float playback_rate_;
+
+  // Since av pipeline still need to access device components in their
+  // destructor, it's important to delete them first.
   std::unique_ptr<MediaPipelineBackend> media_pipeline_backend_;
   std::unique_ptr<AudioDecoderSoftwareWrapper> audio_decoder_;
   MediaPipelineBackend::VideoDecoder* video_decoder_;
-
   std::unique_ptr<AudioPipelineImpl> audio_pipeline_;
   std::unique_ptr<VideoPipelineImpl> video_pipeline_;
   std::unique_ptr<FlushTask> pending_flush_task_;
 
   // The media time is retrieved at regular intervals.
   bool pending_time_update_task_;
   base::TimeDelta last_media_time_;
 
   // Used to make the statistics update period a multiplier of the time update
   // period.
@@ skipping 11 matching lines @@
   base::WeakPtr<MediaPipelineImpl> weak_this_;
   base::WeakPtrFactory<MediaPipelineImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaPipelineImpl);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_CMA_PIPELINE_MEDIA_PIPELINE_IMPL_H_