Support Opus Ambisonics playback

media/base/audio_decoder_config.cc

Index: media/base/audio_decoder_config.cc
diff --git a/media/base/audio_decoder_config.cc b/media/base/audio_decoder_config.cc
index 225f19a7f796c34c42c31e2dfcf78dd11f8181d5..5fabc1083344a5e02427c9c5c8df6229a13ce109 100644
--- a/media/base/audio_decoder_config.cc
+++ b/media/base/audio_decoder_config.cc
@@ -51,8 +51,10 @@ void AudioDecoderConfig::Initialize(AudioCodec codec,
   seek_preroll_ = seek_preroll;
   codec_delay_ = codec_delay;
 
-  int channels = ChannelLayoutToChannelCount(channel_layout_);
-  bytes_per_frame_ = channels * bytes_per_channel_;
+  // If |channel_layout_| is CHANNEL_LAYOUT_DISCRETE, |channels_| and
+  // |bytes_per_frame_| will be overwritten in SetChannelsForDiscrete()
+  channels_ = ChannelLayoutToChannelCount(channel_layout_);
+  bytes_per_frame_ = channels_ * bytes_per_channel_;
 }
 
 AudioDecoderConfig::~AudioDecoderConfig() {}