Refactor MediaResource to be multi-stream capable

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 249f97a0c731cb5a627696d2df6f1b886ae76a6a..872db84de830d5a4fad7b32108c483aeef4ddfe7 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -742,7 +742,7 @@ void FFmpegDemuxerStream::set_enabled(bool enabled, base::TimeDelta timestamp) {
     return;
   }
   if (!stream_status_change_cb_.is_null())
-    stream_status_change_cb_.Run(is_enabled_, timestamp);
+    stream_status_change_cb_.Run(this, is_enabled_, timestamp);
 }
 
 void FFmpegDemuxerStream::SetStreamStatusChangeCB(
@@ -991,7 +991,8 @@ void FFmpegDemuxer::Seek(base::TimeDelta time, const PipelineStatusCB& cb) {
   // When seeking in an opus stream we need to ensure we deliver enough data to
   // satisfy the seek preroll; otherwise the audio at the actual seek time will
   // not be entirely accurate.
-  FFmpegDemuxerStream* audio_stream = GetFFmpegStream(DemuxerStream::AUDIO);
+  FFmpegDemuxerStream* audio_stream =
+      GetFirstEnabledFFmpegStream(DemuxerStream::AUDIO);
   if (audio_stream) {
     const AudioDecoderConfig& config = audio_stream->audio_decoder_config();
     if (config.codec() == kCodecOpus)
@@ -1026,12 +1027,24 @@ 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)
+      result.push_back(stream.get());
+  }
+  return result;
 }
 
-FFmpegDemuxerStream* FFmpegDemuxer::GetFFmpegStream(
+void FFmpegDemuxer::SetStreamStatusChangeCB(const StreamStatusChangeCB& cb) {
+  for (const auto& stream : streams_) {
+    if (stream)
+      stream->SetStreamStatusChangeCB(cb);
+  }
+}
+
+FFmpegDemuxerStream* FFmpegDemuxer::GetFirstEnabledFFmpegStream(
     DemuxerStream::Type type) const {
   for (const auto& stream : streams_) {
     if (stream && stream->type() == type && stream->enabled()) {
@@ -1088,15 +1101,16 @@ void FFmpegDemuxer::NotifyCapacityAvailable() {
 void FFmpegDemuxer::NotifyBufferingChanged() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   Ranges<base::TimeDelta> buffered;
-  FFmpegDemuxerStream* audio = GetFFmpegStream(DemuxerStream::AUDIO);
-  FFmpegDemuxerStream* video = GetFFmpegStream(DemuxerStream::VIDEO);
-  if (audio && video) {
-    buffered =
-        audio->GetBufferedRanges().IntersectionWith(video->GetBufferedRanges());
-  } else if (audio) {
-    buffered = audio->GetBufferedRanges();
-  } else if (video) {
-    buffered = video->GetBufferedRanges();
+  bool initialized_buffered_ranges = false;
+  for (const auto& stream : streams_) {
+    if (!stream)
+      continue;
+    if (initialized_buffered_ranges) {
+      buffered = buffered.IntersectionWith(stream->GetBufferedRanges());
+    } else {
+      buffered = stream->GetBufferedRanges();
+      initialized_buffered_ranges = true;
+    }
   }
   host_->OnBufferedTimeRangesChanged(buffered);
 }