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..0022dae0940ae9c5cb62b9ad0cd79d52fc2425d6 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() {}
@@ -86,6 +88,7 @@ std::string AudioDecoderConfig::AsHumanReadableString() const {
   s << "codec: " << GetCodecName(codec())
     << " bytes_per_channel: " << bytes_per_channel()
     << " channel_layout: " << channel_layout()
+    << " channels: " << channels()
     << " samples_per_second: " << samples_per_second()
     << " sample_format: " << sample_format()
     << " bytes_per_frame: " << bytes_per_frame()