[Chromecast] Add metrics for logging platform A/V bitrate estimates.

chromecast/media/cma/pipeline/video_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_BASE_VIDEO_PIPELINE_IMPL_H_
 #define CHROMECAST_MEDIA_CMA_BASE_VIDEO_PIPELINE_IMPL_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 29 matching lines @@
 
  private:
   // AvPipelineImpl implementation:
   void OnVideoResolutionChanged(const Size& size) override;
   void OnUpdateConfig(StreamId id,
                       const ::media::AudioDecoderConfig& audio_config,
                       const ::media::VideoDecoderConfig& video_config) override;
 
   MediaPipelineBackend::VideoDecoder* const video_decoder_;
   const VideoPipelineClient::NaturalSizeChangedCB natural_size_changed_cb_;
+  base::Time last_sample_time_;
+  base::TimeDelta elapsed_time_delta_;
+  int video_bytes_for_bitrate_estimation_;

[halliwell, 2016/03/10 17:57:54]

I was about to leave 'ditto' comments on the video implementation.

But then I realised, they both inherit from AvPipelineImpl - is it possible to
share the logic up a level in the class hierarchy to avoid duplication?

[ejason, 2016/03/11 00:24:45]

Done. I refactored the code so that this calculation isn't duplicated. I think
media_pipeline_impl is the place for this given the current code structure and
make sure the calculations are accurate across state transitions. 

 
   DISALLOW_COPY_AND_ASSIGN(VideoPipelineImpl);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_CMA_BASE_VIDEO_PIPELINE_IMPL_H_