Tell CoreAudio how to interpret Chrome's channel layout.

media/audio/mac/audio_auhal_mac.h

 // Copyright 2013 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.
 //
 // Implementation notes:
 //
 // - It is recommended to first acquire the native sample rate of the default
 //   output device and then use the same rate when creating this object.
 //   Use AudioManagerMac::HardwareSampleRate() to retrieve the sample rate.
 // - Calling Close() also leads to self destruction.
 // - The latency consists of two parts:
 //   1) Hardware latency, which includes Audio Unit latency, audio device
 //      latency;
 //   2) The delay between the moment getting the callback and the scheduled time
 //      stamp that tells when the data is going to be played out.
 //
 #ifndef MEDIA_AUDIO_MAC_AUDIO_AUHAL_MAC_H_
 #define MEDIA_AUDIO_MAC_AUDIO_AUHAL_MAC_H_
 
 #include <AudioUnit/AudioUnit.h>
 #include <CoreAudio/CoreAudio.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
+#include <vector>
 
 #include "base/cancelable_callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager.h"
 #include "media/base/audio_parameters.h"
@@ skipping 98 matching lines @@
   // Returns the playout time for a given AudioTimeStamp.
   base::TimeTicks GetPlayoutTime(const AudioTimeStamp* output_time_stamp);
 
   // Updates playout timestamp, current lost frames, and total lost frames and
   // glitches.
   void UpdatePlayoutTimestamp(const AudioTimeStamp* timestamp);
 
   // Called from the dtor and when the stream is reset.
   void ReportAndResetStats();
 
+  // Converts |params_.channel_layout()| into CoreAudio format and sets up the
+  // AUHAL with our layout information so it knows how to remap the channels.
+  void SetAudioChannelLayout();
+
   // Our creator, the audio manager needs to be notified when we close.
   AudioManagerMac* const manager_;
 
   const AudioParameters params_;
   // For convenience - same as in params_.
   const int output_channels_;
 
   // Size of audio buffer requested at construction. The actual buffer size
   // is given by |actual_io_buffer_frame_size_| and it can differ from the
   // requested size.
@@ skipping 68 matching lines @@
   // Used to make sure control functions (Start(), Stop() etc) are called on the
   // right thread.
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(AUHALStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_AUHAL_MAC_H_