Part 1: Plumb render view ID to render host

content/renderer/media/audio_renderer_mixer_manager.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 CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_
 #define CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_
 
 #include <map>
 
 #include "base/synchronization/lock.h"
@@ skipping 22 matching lines @@
 // via the shared memory.  See http://crbug.com/114700.
 class CONTENT_EXPORT AudioRendererMixerManager {
  public:
   // Construct an instance using the given audio hardware configuration.
   AudioRendererMixerManager(int hardware_sample_rate, int hardware_buffer_size);
   ~AudioRendererMixerManager();
 
   // Creates an AudioRendererMixerInput with the proper callbacks necessary to
   // retrieve an AudioRendererMixer instance from AudioRendererMixerManager.
   // Caller must ensure AudioRendererMixerManager outlives the returned input.
-  media::AudioRendererMixerInput* CreateInput();
+  media::AudioRendererMixerInput* CreateInput(int render_view_id);
 
  private:
   friend class AudioRendererMixerManagerTest;
 
   // Returns a mixer instance based on AudioParameters; an existing one if one
   // with the provided AudioParameters exists or a new one if not.
-  media::AudioRendererMixer* GetMixer(const media::AudioParameters& params);
+  media::AudioRendererMixer* GetMixer(
+      int render_view_id,
+      const media::AudioParameters& params);
 
   // Remove a mixer instance given a mixer if the only other reference is held
   // by AudioRendererMixerManager.  Every AudioRendererMixer owner must call
   // this method when it's done with a mixer.
   void RemoveMixer(const media::AudioParameters& params);
 
   // Map of AudioParameters to <AudioRendererMixer, Count>.  Count allows
   // AudioRendererMixerManager to keep track explicitly (v.s. RefCounted which
   // is implicit) of the number of outstanding AudioRendererMixers.
   struct AudioRendererMixerReference {
     media::AudioRendererMixer* mixer;
     int ref_count;
   };
   typedef std::map<media::AudioParameters, AudioRendererMixerReference,
                    media::AudioParameters::Compare> AudioRendererMixerMap;
   AudioRendererMixerMap mixers_;
   base::Lock mixers_lock_;
 
   // Audio hardware configuration.  Used to construct output AudioParameters for
   // each AudioRendererMixer instance.
   int hardware_sample_rate_;
   int hardware_buffer_size_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_MIXER_MANAGER_H_