Pass more detailed audio hardware configuration information to the renderer

media/audio/mac/audio_unified_mac.h

Index: media/audio/mac/audio_unified_mac.h
===================================================================
--- media/audio/mac/audio_unified_mac.h	(revision 185058)
+++ media/audio/mac/audio_unified_mac.h	(working copy)
@@ -44,6 +44,17 @@
   int input_channels() const { return input_channels_; }
   int output_channels() const { return output_channels_; }
 
+  static bool GetDefaultOutputDevice(AudioDeviceID* device);
+
+  static bool GetDefaultOutputChannels(int* channels,
+                                       int* channels_per_frame);
+
+  static bool GetDeviceChannels(AudioDeviceID device,
+                                AudioObjectPropertyScope scope,
+                                int* channels,
+                                int* channels_per_frame);
+
+
  private:
   OSStatus Render(AudioDeviceID device,
                   const AudioTimeStamp* now,