Add a unified audio I/O backend for ChromeOS.

media/audio/cras/audio_manager_cras.cc

 // 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.
 
 #include "media/audio/cras/audio_manager_cras.h"
 
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/logging.h"
 #include "base/nix/xdg_util.h"
 #include "base/process_util.h"
 #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 {
 
 // Maximum number of output streams that can be open simultaneously.
 static const int kMaxOutputStreams = 50;
 
 static const char kCrasAutomaticDeviceName[] = "Automatic";
 static const char kCrasAutomaticDeviceId[] = "automatic";
 
 bool AudioManagerCras::HasAudioOutputDevices() {
@@ skipping 49 matching lines @@
 }
 
 AudioInputStream* AudioManagerCras::MakeLowLatencyInputStream(
     const AudioParameters& params, const std::string& device_id) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
   return MakeInputStream(params, device_id);
 }
 
 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(
     const AudioParameters& params, const std::string& device_id) {
   return new CrasInputStream(params, this);
 }
 
 AudioParameters AudioManagerCras::GetPreferredLowLatencyOutputStreamParameters(
     const AudioParameters& input_params) {
   // TODO(dalecurtis): This should include bits per channel and channel layout
   // eventually.
   return AudioParameters(
       AudioParameters::AUDIO_PCM_LOW_LATENCY, input_params.channel_layout(),
       input_params.sample_rate(), 16, input_params.frames_per_buffer());
 }
 
 }  // namespace media