Allow audio system to handle synchronized low-latency audio I/O

content/renderer/media/audio_message_filter.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.
 //
 // MessageFilter that handles audio messages and delegates them to audio
 // renderers. Created on render thread, AudioMessageFilter is operated on
 // IO thread (secondary thread of render process) it intercepts audio messages
 // and process them on IO thread since these messages are time critical.
 
 #ifndef CONTENT_RENDERER_MEDIA_AUDIO_MESSAGE_FILTER_H_
@@ skipping 14 matching lines @@
  public:
   AudioMessageFilter();
 
   // Getter for the one AudioMessageFilter object.
   static AudioMessageFilter* Get();
 
   // media::AudioOutputIPCDelegate implementation.
   virtual int AddDelegate(media::AudioOutputIPCDelegate* delegate) OVERRIDE;
   virtual void RemoveDelegate(int id) OVERRIDE;
   virtual void CreateStream(int stream_id,
-      const media::AudioParameters& params) OVERRIDE;
+      const media::AudioParameters& params, int input_channels) OVERRIDE;
   virtual void PlayStream(int stream_id) OVERRIDE;
   virtual void PauseStream(int stream_id) OVERRIDE;
   virtual void FlushStream(int stream_id) OVERRIDE;
   virtual void CloseStream(int stream_id) OVERRIDE;
   virtual void SetVolume(int stream_id, double volume) OVERRIDE;
 
   // IPC::ChannelProxy::MessageFilter override. Called on IO thread.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
   virtual void OnFilterRemoved() OVERRIDE;
@@ skipping 28 matching lines @@
 
   // A map of stream ids to delegates.
   IDMap<media::AudioOutputIPCDelegate> delegates_;
 
   IPC::Channel* channel_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioMessageFilter);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_MESSAGE_FILTER_H_