Add a unified audio I/O backend for ChromeOS.

media/audio/cras/audio_manager_cras.cc

Index: media/audio/cras/audio_manager_cras.cc
diff --git a/media/audio/cras/audio_manager_cras.cc b/media/audio/cras/audio_manager_cras.cc
index 3401cc5f62310cd41b423084013c9f30e2a0827f..253a1de0be777f46d11e9ff2466fee08eb60cd09 100644
--- a/media/audio/cras/audio_manager_cras.cc
+++ b/media/audio/cras/audio_manager_cras.cc
@@ -12,7 +12,7 @@
 #include "base/stl_util.h"
 #include "media/audio/audio_util.h"
 #include "media/audio/cras/cras_input.h"
-#include "media/audio/cras/cras_output.h"
+#include "media/audio/cras/cras_unified.h"
 
 namespace media {
 
@@ -82,7 +82,7 @@ AudioInputStream* AudioManagerCras::MakeLowLatencyInputStream(
 
 AudioOutputStream* AudioManagerCras::MakeOutputStream(
     const AudioParameters& params) {
-  return new CrasOutputStream(params, this);
+  return new CrasUnifiedStream(params, this);

[Chris Rogers, 2013/02/21 18:17:26]

For the moment, I think you'll need to put this behind the enable flag, and also
should check that the |input_channels| field is > 0 (or ==2) similar to
AudioManagerMac/Win

Very soon I'll be removing the enable flag, but for now it should be in

[dgreid, 2013/02/22 02:09:35]

the way I wired this up I'm going through the new unified path on the server
side no matter what.  The input path is optimized out if input_channels is set
to zero.  It is also limited to being the same as the number of output channels.

To get anything but zero in params I have to disable the output resampler.  It
creates new params that don't have input_channels set.  I can fix that in
another change.

 }
 
 AudioInputStream* AudioManagerCras::MakeInputStream(