Refactor MediaResource to be multi-stream capable

media/remoting/courier_renderer.cc

Index: media/remoting/courier_renderer.cc
diff --git a/media/remoting/courier_renderer.cc b/media/remoting/courier_renderer.cc
index ca0f5677f73b92f270d98002cbb6ca55cc6f950f..8d30578947ef342d5878dc8aed10c33097f12e5a 100644
--- a/media/remoting/courier_renderer.cc
+++ b/media/remoting/courier_renderer.cc
@@ -126,17 +126,27 @@ void CourierRenderer::Initialize(MediaResource* media_resource,
 
   state_ = STATE_CREATE_PIPE;
 
+  // TODO(servolk): Implement support for multiple streams. For now use the
+  // first enabled audio and video streams to preserve the existing behavior.
+  std::vector<::media::DemuxerStream*> streams = media_resource_->GetStreams();
+  ::media::DemuxerStream* audio_demuxer_stream = nullptr;
+  ::media::DemuxerStream* video_demuxer_stream = nullptr;
+  for (const auto& stream : streams) {
+    if (stream->type() == DemuxerStream::AUDIO && stream->enabled() &&
+        !audio_demuxer_stream)
+      audio_demuxer_stream = stream;
+    if (stream->type() == DemuxerStream::VIDEO && stream->enabled() &&
+        !video_demuxer_stream)
+      video_demuxer_stream = stream;
+  }
+
   // Create audio mojo data pipe handles if audio is available.
-  DemuxerStream* audio_demuxer_stream =
-      media_resource_->GetStream(DemuxerStream::AUDIO);
   std::unique_ptr<mojo::DataPipe> audio_data_pipe;
   if (audio_demuxer_stream) {
     audio_data_pipe = base::WrapUnique(DemuxerStreamAdapter::CreateDataPipe());
   }
 
   // Create video mojo data pipe handles if video is available.
-  DemuxerStream* video_demuxer_stream =
-      media_resource_->GetStream(DemuxerStream::VIDEO);
   std::unique_ptr<mojo::DataPipe> video_data_pipe;
   if (video_demuxer_stream) {
     video_data_pipe = base::WrapUnique(DemuxerStreamAdapter::CreateDataPipe());
@@ -326,9 +336,20 @@ void CourierRenderer::OnDataPipeCreated(
     return;  // Abort because something went wrong in the meantime.
   DCHECK_EQ(state_, STATE_CREATE_PIPE);
 
+  // TODO(erickung): Make remote renderer multi-stream capable.
+  std::vector<::media::DemuxerStream*> streams = media_resource_->GetStreams();
+  ::media::DemuxerStream* audio_demuxer_stream = nullptr;
+  ::media::DemuxerStream* video_demuxer_stream = nullptr;
+  for (const auto& s : streams) {
+    if (s->type() == DemuxerStream::AUDIO && s->enabled() &&
+        !audio_demuxer_stream)
+      audio_demuxer_stream = s;
+    if (s->type() == DemuxerStream::VIDEO && s->enabled() &&
+        !video_demuxer_stream)
+      video_demuxer_stream = s;
+  }
+
   // Create audio demuxer stream adapter if audio is available.
-  DemuxerStream* audio_demuxer_stream =
-      media_resource_->GetStream(DemuxerStream::AUDIO);
   if (audio_demuxer_stream && audio.is_valid() && audio_handle.is_valid() &&
       audio_rpc_handle != RpcBroker::kInvalidHandle) {
     VLOG(2) << "Initialize audio";
@@ -340,8 +361,6 @@ void CourierRenderer::OnDataPipeCreated(
   }
 
   // Create video demuxer stream adapter if video is available.
-  DemuxerStream* video_demuxer_stream =
-      media_resource_->GetStream(DemuxerStream::VIDEO);
   if (video_demuxer_stream && video.is_valid() && video_handle.is_valid() &&
       video_rpc_handle != RpcBroker::kInvalidHandle) {
     VLOG(2) << "Initialize video";