Add channel_count parameter back to AudioBuffer creation methods.

media/filters/opus_audio_decoder.cc

Index: media/filters/opus_audio_decoder.cc
diff --git a/media/filters/opus_audio_decoder.cc b/media/filters/opus_audio_decoder.cc
index 161d0c8205b7ece3425be2c2581e38145accefed..3fd28f4d05e57955bf1513d4a6635c8f4d8de429 100644
--- a/media/filters/opus_audio_decoder.cc
+++ b/media/filters/opus_audio_decoder.cc
@@ -464,10 +464,12 @@ void OpusAudioDecoder::ResetTimestampState() {
 bool OpusAudioDecoder::Decode(const scoped_refptr<DecoderBuffer>& input,
                               scoped_refptr<AudioBuffer>* output_buffer) {
   // Allocate a buffer for the output samples.
-  *output_buffer = AudioBuffer::CreateBuffer(config_.sample_format(),
-                                             config_.channel_layout(),
-                                             config_.samples_per_second(),
-                                             kMaxOpusOutputPacketSizeSamples);
+  *output_buffer = AudioBuffer::CreateBuffer(
+      config_.sample_format(),
+      config_.channel_layout(),
+      ChannelLayoutToChannelCount(config_.channel_layout()),
+      config_.samples_per_second(),
+      kMaxOpusOutputPacketSizeSamples);
   const int buffer_size =
       output_buffer->get()->channel_count() *
       output_buffer->get()->frame_count() *