Tell CoreAudio how to interpret Chrome's channel layout.

media/audio/mac/audio_auhal_mac.h

Index: media/audio/mac/audio_auhal_mac.h
diff --git a/media/audio/mac/audio_auhal_mac.h b/media/audio/mac/audio_auhal_mac.h
index 146c492cdf7c75afef1fc69f3795439b0c54313d..14d78c41b2ff79ab45c048ec29ccdaa54eb38d6a 100644
--- a/media/audio/mac/audio_auhal_mac.h
+++ b/media/audio/mac/audio_auhal_mac.h
@@ -141,6 +141,10 @@ class AUHALStream : public AudioOutputStream {
   // 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_;