audio_manager_linux: Allow CRAS to decide if sample rate conversion is needed.

media/audio/linux/audio_manager_linux.cc

Index: media/audio/linux/audio_manager_linux.cc
diff --git a/media/audio/linux/audio_manager_linux.cc b/media/audio/linux/audio_manager_linux.cc
index b19e9603b602f2f26dfbc6669d98b865f1692685..db37fd5b925a79647d5e7a79026ededdb25e8fa2 100644
--- a/media/audio/linux/audio_manager_linux.cc
+++ b/media/audio/linux/audio_manager_linux.cc
@@ -358,6 +358,14 @@ AudioParameters AudioManagerLinux::GetPreferredLowLatencyOutputStreamParameters(
     buffer_size = GetAudioHardwareBufferSize();
   }
 
+#if defined(USE_CRAS)
+  // CRAS will sample rate convert if it is needed, pass the desired frame rate.

[DaleCurtis, 2012/09/25 19:56:55]

To keep style with the above code, why not:

int sample_rate = GetAudioHardwareSampleRate();
if (UseCras())
  sample_rate = input_params.sample_rate();

I don't think the IF_DEF is necessary since UseCras is always defined and
returns false in non-cras case.

+  if (UseCras())
+    return AudioParameters(
+        AudioParameters::AUDIO_PCM_LOW_LATENCY, input_params.channel_layout(),
+        input_params.sample_rate(), 16, buffer_size);
+#endif
+
   // TODO(dalecurtis): This should include bits per channel and channel layout
   // eventually.
   return AudioParameters(