Add AudioBufferStream.

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 4b737d80aa6ae46ecd3f8c7f6aefcb2599f0faf6..a87a9332763eec8963b19362900040b058025152 100644
--- a/media/filters/decoder_stream_traits.cc
+++ b/media/filters/decoder_stream_traits.cc
@@ -4,10 +4,40 @@
 
 #include "media/filters/decoder_stream_traits.h"
 
+#include "media/base/audio_decoder.h"
+#include "media/base/audio_decoder_config.h"
 #include "media/base/video_decoder.h"
+#include "media/base/video_decoder_config.h"
 
 namespace media {
 
+bool DecoderStreamTraits<DemuxerStream::AUDIO>::FinishInitialization(
+    const StreamInitCB& init_cb,
+    DecoderType* decoder,
+    DemuxerStream* stream) {
+  DCHECK(stream);
+  if (!decoder) {
+    init_cb.Run(false);
+    return false;
+  }
+  init_cb.Run(true);
+  return true;
+}
+
+void DecoderStreamTraits<DemuxerStream::AUDIO>::ReportStatistics(
+    const StatisticsCB& statistics_cb,
+    int bytes_decoded) {
+  PipelineStatistics statistics;
+  statistics.audio_bytes_decoded = bytes_decoded;
+  statistics_cb.Run(statistics);
+}
+
+DecoderStreamTraits<DemuxerStream::AUDIO>::DecoderConfigType
+    DecoderStreamTraits<DemuxerStream::AUDIO>::GetDecoderConfig(
+        DemuxerStream& stream) {
+  return stream.audio_decoder_config();
+}
+
 bool DecoderStreamTraits<DemuxerStream::VIDEO>::FinishInitialization(
     const StreamInitCB& init_cb,
     DecoderType* decoder,
@@ -33,4 +63,10 @@ void DecoderStreamTraits<DemuxerStream::VIDEO>::ReportStatistics(
   statistics_cb.Run(statistics);
 }
 
+DecoderStreamTraits<DemuxerStream::VIDEO>::DecoderConfigType
+    DecoderStreamTraits<DemuxerStream::VIDEO>::GetDecoderConfig(
+        DemuxerStream& stream) {
+  return stream.video_decoder_config();
+}
+
 }  // namespace media