Change audio renderer to communicate with host using low latency codepath.

media/audio/audio_output_controller.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 MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
@@ skipping 45 matching lines @@
   // Internal state of the source.
   enum State {
     kEmpty,
     kCreated,
     kPlaying,
     kPaused,
     kClosed,
     kError,
   };
 
+  // Value sent by the controller to the renderer in low-latency mode
+  // indicating that the stream is paused.
+  static const int kPauseMark;
+
   // An event handler that receives events from the AudioOutputController. The
   // following methods are called on the audio controller thread.
   class EventHandler {
    public:
     virtual ~EventHandler() {}
     virtual void OnCreated(AudioOutputController* controller) = 0;
     virtual void OnPlaying(AudioOutputController* controller) = 0;
     virtual void OnPaused(AudioOutputController* controller) = 0;
     virtual void OnError(AudioOutputController* controller, int error_code) = 0;
 
@@ skipping 122 matching lines @@
 
   // The message loop of audio thread that this object runs on.
   MessageLoop* message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  //  MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_