Add support for multichannel playback to OpenSLES output.

media/audio/android/opensles_output.cc

Index: media/audio/android/opensles_output.cc
diff --git a/media/audio/android/opensles_output.cc b/media/audio/android/opensles_output.cc
index 005b0e707182b94c34049b9bd6ecf8337639ddfc..bf1957f7829bbc53935f49b6f4e6f3c115160b1e 100644
--- a/media/audio/android/opensles_output.cc
+++ b/media/audio/android/opensles_output.cc
@@ -42,12 +42,7 @@ OpenSLESOutputStream::OpenSLESOutputStream(AudioManagerAndroid* manager,
   format_.bitsPerSample = params.bits_per_sample();
   format_.containerSize = params.bits_per_sample();
   format_.endianness = SL_BYTEORDER_LITTLEENDIAN;
-  if (format_.numChannels == 1)
-    format_.channelMask = SL_SPEAKER_FRONT_CENTER;
-  else if (format_.numChannels == 2)
-    format_.channelMask = SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT;
-  else
-    NOTREACHED() << "Unsupported number of channels: " << format_.numChannels;
+  format_.channelMask = ChannelCountToSLESChannelMask(params.channels());
 
   buffer_size_bytes_ = params.GetBytesPerBuffer();
   audio_bus_ = AudioBus::Create(params);