Support (E)AC3 passthrough

media/filters/decoder_stream_traits.cc

Index: media/filters/decoder_stream_traits.cc
diff --git a/media/filters/decoder_stream_traits.cc b/media/filters/decoder_stream_traits.cc
index deaedddc372ab73126eaf0f7ba183c2a716358e3..4aecca0623e86485e273d1488ccb83b616db8325 100644
--- a/media/filters/decoder_stream_traits.cc
+++ b/media/filters/decoder_stream_traits.cc
@@ -8,6 +8,7 @@
 #include "media/base/audio_buffer.h"
 #include "media/base/audio_decoder.h"
 #include "media/base/audio_decoder_config.h"
+#include "media/base/media_client.h"
 #include "media/base/video_decoder.h"
 #include "media/base/video_frame.h"
 
@@ -24,8 +25,18 @@ void DecoderStreamTraits<DemuxerStream::AUDIO>::InitializeDecoder(
     const InitCB& init_cb,
     const OutputCB& output_cb) {
   DCHECK(stream->audio_decoder_config().IsValidConfig());
-  decoder->Initialize(stream->audio_decoder_config(), cdm_context, init_cb,
-                      output_cb);
+
+  AudioDecoderConfig config = stream->audio_decoder_config();
+  AudioCodec codec = config.codec();
+  MediaClient* media_client = GetMediaClient();
+  if (media_client && media_client->IsPassthroughAudioSupported(codec)) {
+    config.Initialize(kCodecRaw, kSampleFormatRaw, config.channel_layout(),
+                      config.samples_per_second(), config.extra_data(),
+                      config.encryption_scheme(), config.seek_preroll(),
+                      config.codec_delay());
+  }
+
+  decoder->Initialize(config, cdm_context, init_cb, output_cb);
 }
 
 bool DecoderStreamTraits<DemuxerStream::AUDIO>::NeedsBitstreamConversion(