Plumb DemuxerStream::EnableBitstreamConverter through mojo pipeline.

media/mojo/interfaces/demuxer_stream.mojom

Index: media/mojo/interfaces/demuxer_stream.mojom
diff --git a/media/mojo/interfaces/demuxer_stream.mojom b/media/mojo/interfaces/demuxer_stream.mojom
index 5b880b747c4b3d43a60ff45aa4125c870a58598b..039888d173a3d9406a06db1f80f39db01614a98a 100644
--- a/media/mojo/interfaces/demuxer_stream.mojom
+++ b/media/mojo/interfaces/demuxer_stream.mojom
@@ -53,4 +53,8 @@ interface DemuxerStream {
              DecoderBuffer? buffer,
              AudioDecoderConfig? audio_config,
              VideoDecoderConfig? video_config);
+
+  // Enables converting bitstream to a format that is expected by the decoder.
+  // For example, H.264/AAC bitstream based packets into H.264 Annex B format.
+  EnableBitstreamConverter();
 };