[Chromecast] Implement new volume control API

chromecast/media/cma/backend/alsa/audio_filter_interface.h

 // Copyright 2016 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_BACKEND_ALSA_AUDIO_FILTER_INTERFACE_H_
 #define CHROMECAST_MEDIA_CMA_BACKEND_ALSA_AUDIO_FILTER_INTERFACE_H_
 
 #include <stdint.h>
 
 #include "media/base/sample_format.h"
 
 namespace chromecast {
 namespace media {
 
 class AudioFilterInterface {
  public:
   virtual ~AudioFilterInterface() = default;
   virtual bool SetSampleRateAndFormat(int sample_rate,
                                       ::media::SampleFormat sample_format) = 0;
 
   // Process data frames. Must be interleaved. |data| will be overwritten.
-  virtual bool ProcessInterleaved(uint8_t* data, int frames) = 0;
+  virtual bool ProcessInterleaved(uint8_t* data, int frames, float volume) = 0;
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_CMA_BACKEND_ALSA_AUDIO_FILTER_INTERFACE_H_