Implements AudioMessageFilter as member in RenderThread

content/browser/renderer_host/media/media_observer.h

 // Copyright (c) 2011 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_BROWSER_RENDERER_HOST_MEDIA_MEDIA_OBSERVER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_OBSERVER_H_
 #pragma once
 
 // A class may implement MediaObserver and register itself with ResourceContext
 // to receive callbacks as media events occur.
 class MediaObserver {
  public:
   virtual ~MediaObserver() {}
 
   // Called when an audio stream is deleted.
-  virtual void OnDeleteAudioStream(void* host, int32 render_view,
-                                   int stream_id) = 0;
+  virtual void OnDeleteAudioStream(void* host, int stream_id) = 0;
 
   // Called when an audio stream is set to playing or paused.
-  virtual void OnSetAudioStreamPlaying(void* host, int32 render_view,
-                                       int stream_id, bool playing) = 0;
+  virtual void OnSetAudioStreamPlaying(void* host, int stream_id,
+                                       bool playing) = 0;
 
   // Called when the status of an audio stream is set to "created", "flushed",
   // "closed", or "error".
-  virtual void OnSetAudioStreamStatus(void* host, int32 render_view,
-                                      int stream_id,
+  virtual void OnSetAudioStreamStatus(void* host, int stream_id,
                                       const std::string& status) = 0;
 
   // Called when the volume of an audio stream is set.
-  virtual void OnSetAudioStreamVolume(void* host, int32 render_view,
-                                      int stream_id, double volume) = 0;
+  virtual void OnSetAudioStreamVolume(void* host, int stream_id,
+                                      double volume) = 0;
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_OBSERVER_H_