[Chromecast] Upgrade to new CMA backend API

chromecast/media/cma/pipeline/audio_pipeline.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_AUDIO_PIPELINE_H_
-#define CHROMECAST_MEDIA_CMA_PIPELINE_AUDIO_PIPELINE_H_
-
-#include "base/macros.h"
-#include "chromecast/media/cma/pipeline/av_pipeline_client.h"
-
-namespace chromecast {
-namespace media {
-
-class AudioPipeline {
- public:
-  AudioPipeline();
-  virtual ~AudioPipeline();
-
-  // Set the audio client.
-  virtual void SetClient(const AvPipelineClient& client) = 0;
-
-  // Set the stream volume.
-  // - A value of 1.0 is the neutral value.
-  // - |volume|=0.0 mutes the stream.
-  virtual void SetVolume(float volume) = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(AudioPipeline);
-};
-
-}  // namespace media
-}  // namespace chromecast
-
-#endif  // CHROMECAST_MEDIA_CMA_PIPELINE_AUDIO_PIPELINE_H_