Plumb render view ID from audio-related code in renderer through IPCs to AudioRendererHost in brows…

content/renderer/media/audio_renderer_mixer_manager.h

Index: content/renderer/media/audio_renderer_mixer_manager.h
diff --git a/content/renderer/media/audio_renderer_mixer_manager.h b/content/renderer/media/audio_renderer_mixer_manager.h
index 37f432b46d448ea43884d51e63a4b66c02ef7fbd..fe5bad91768dd820540f0361bf7e9311c7ad47cd 100644
--- a/content/renderer/media/audio_renderer_mixer_manager.h
+++ b/content/renderer/media/audio_renderer_mixer_manager.h
@@ -40,19 +40,20 @@ class CONTENT_EXPORT 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);
+  void RemoveMixer(int render_view_id, const media::AudioParameters& params);
 
   // Map of AudioParameters to <AudioRendererMixer, Count>.  Count allows
   // AudioRendererMixerManager to keep track explicitly (v.s. RefCounted which
@@ -62,7 +63,8 @@ class CONTENT_EXPORT AudioRendererMixerManager {
     int ref_count;
   };
   typedef std::map<media::AudioParameters, AudioRendererMixerReference,
-                   media::AudioParameters::Compare> AudioRendererMixerMap;
+                   media::AudioParameters::Compare> MixerByParamsMap;
+  typedef std::map<int, MixerByParamsMap> AudioRendererMixerMap;
   AudioRendererMixerMap mixers_;
   base::Lock mixers_lock_;