Switch OnMoreData() to use AudioBus.

media/audio/mac/audio_output_mac.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 MEDIA_AUDIO_MAC_AUDIO_OUTPUT_MAC_H_
 #define MEDIA_AUDIO_MAC_AUDIO_OUTPUT_MAC_H_
 
 #include <AudioToolbox/AudioFormat.h>
 #include <AudioToolbox/AudioQueue.h>
 #include <AudioUnit/AudioUnit.h>
@@ skipping 87 matching lines @@
   // A flag to determine if downmix is needed from source to device layouts.
   bool should_down_mix_;
 
   // Event used for synchronization when stopping the stream.
   // Callback sets it after stream is stopped.
   base::WaitableEvent stopped_event_;
   // When stopping we keep track of number of buffers in flight and
   // signal "stop completed" from the last buffer's callback.
   int num_buffers_left_;
 
+  // Container for retrieving data from AudioSourceCallback::OnMoreData().
+  scoped_ptr<AudioBus> audio_bus_;
+  base::Lock audio_bus_lock_;
+
   DISALLOW_COPY_AND_ASSIGN(PCMQueueOutAudioOutputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_OUTPUT_MAC_H_