MediaResource refactoring to support multiple streams

media/filters/ffmpeg_demuxer.cc

Index: media/filters/ffmpeg_demuxer.cc
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index dd80dfccfbd0bab8a83371d31e92141ee18c4279..fca8b566dff45bb684c04d327023c1b8f9ab6ae7 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -1026,9 +1026,14 @@ base::Time FFmpegDemuxer::GetTimelineOffset() const {
   return timeline_offset_;
 }
 
-DemuxerStream* FFmpegDemuxer::GetStream(DemuxerStream::Type type) {
+std::vector<DemuxerStream*> FFmpegDemuxer::GetStreams() {
   DCHECK(task_runner_->BelongsToCurrentThread());
-  return GetFFmpegStream(type);
+  std::vector<DemuxerStream*> result;
+  for (const auto& stream : streams_) {
+    if (stream)

[tguilbert, 2017/01/24 23:24:40]

Can there ever be null streams?

[servolk, 2017/01/25 00:57:32]

Yes. Streams with unsupported audio/video codecs or unsupported stream types
will be null in the |FFmpegDemuxer::streams_| array, see
FFmpegDemuxer::OnFindStreamInfoDone.

+      result.push_back(stream.get());
+  }
+  return result;
 }
 
 FFmpegDemuxerStream* FFmpegDemuxer::GetFFmpegStream(

[tguilbert, 2017/01/24 23:24:40]

Should this be renamed to "GetFirstEnabledStream"? There are only 3 callsites,
so this might not be necessary.

[servolk, 2017/01/25 00:57:32]

Thanks for drawing my attention to this. I've fixed the GetBufferedRanges
implementation to handle multi-track cases correctly and that removed two of
those 3 call sites. As to the remaining one, it's not immediately clear to me if
we also need to change logic there to take into account that we might have
multiple audio tracks.
How about renaming this into GetFirstEnabledFFStream to emphasize the fact that
this returns FFmpeg stream pointer, and not a generic DemuxerStream pointer?

[tguilbert, 2017/01/25 02:36:46]

That name seems good to me.