Switch from a DataPipe per DecoderBuffer to a single one.

media/mojo/services/mojo_demuxer_stream_impl.h

Index: media/mojo/services/mojo_demuxer_stream_impl.h
diff --git a/media/mojo/services/mojo_demuxer_stream_impl.h b/media/mojo/services/mojo_demuxer_stream_impl.h
index 53a6dc3a0e6693c3b1770d8aa91389597e47f776..ec22040f80b151f58bf8474c6a568c384859186e 100644
--- a/media/mojo/services/mojo_demuxer_stream_impl.h
+++ b/media/mojo/services/mojo_demuxer_stream_impl.h
@@ -43,6 +43,9 @@ class MojoDemuxerStreamImpl : public mojo::InterfaceImpl<mojo::DemuxerStream> {
   // See constructor.  We do not own |stream_|.
   media::DemuxerStream* stream_;
 
+  // DataPipe for serializing the data section of DecoderBuffer into.
+  mojo::ScopedDataPipeProducerHandle stream_pipe_;
+
   base::WeakPtrFactory<MojoDemuxerStreamImpl> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(MojoDemuxerStreamImpl);
 };