Implement mapping blink track id to demuxer streams

media/blink/webmediaplayer_impl.cc

Index: media/blink/webmediaplayer_impl.cc
diff --git a/media/blink/webmediaplayer_impl.cc b/media/blink/webmediaplayer_impl.cc
index 0b6354a9f296e6f22c4cd2ec20ff7793d48f53c0..3b373485a2ae011fd57fcf8bdd8e060aa1357bb7 100644
--- a/media/blink/webmediaplayer_impl.cc
+++ b/media/blink/webmediaplayer_impl.cc
@@ -577,6 +577,22 @@ bool WebMediaPlayerImpl::hasAudio() const {
   return pipeline_metadata_.has_audio;
 }
 
+void WebMediaPlayerImpl::enabledAudioTracksChanged(
+    const blink::WebVector<blink::WebMediaPlayer::TrackId>& enabledTrackIds) {
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
+  CHECK(demuxer_.get());
+
+  // TODO(servolk): Implement disabling/enabling audio streams.
+}
+
+void WebMediaPlayerImpl::selectedVideoTrackChanged(
+    blink::WebMediaPlayer::TrackId* selectedTrackId) {
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
+  CHECK(demuxer_.get());
+
+  // TODO(servolk): Implement disabling/enabling video stream.
+}
+
 blink::WebSize WebMediaPlayerImpl::naturalSize() const {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
@@ -841,6 +857,7 @@ void WebMediaPlayerImpl::OnFFmpegMediaTracksUpdated(
   DCHECK(!chunk_demuxer_);
 
   // Report the media track information to blink.
+  std::vector<blink::WebMediaPlayer::TrackId> blinkTrackIds;
   for (const auto& track : tracks->tracks()) {
     if (track->type() == MediaTrack::Audio) {
       auto track_id = client_->addAudioTrack(
@@ -849,7 +866,7 @@ void WebMediaPlayerImpl::OnFFmpegMediaTracksUpdated(
           blink::WebString::fromUTF8(track->label()),
           blink::WebString::fromUTF8(track->language()),
           /*enabled*/ true);
-      (void)track_id;
+      blinkTrackIds.push_back(track_id);
     } else if (track->type() == MediaTrack::Video) {
       auto track_id = client_->addVideoTrack(
           blink::WebString::fromUTF8(track->id()),
@@ -857,12 +874,14 @@ void WebMediaPlayerImpl::OnFFmpegMediaTracksUpdated(
           blink::WebString::fromUTF8(track->label()),
           blink::WebString::fromUTF8(track->language()),
           /*selected*/ true);
-      (void)track_id;
+      blinkTrackIds.push_back(track_id);
     } else {
       // Text tracks are not supported through this code path yet.
       NOTREACHED();
     }
   }
+
+  demuxer_->OnTrackIdsAssigned(*tracks.get(), blinkTrackIds);
 }
 
 void WebMediaPlayerImpl::SetCdm(const CdmAttachedCB& cdm_attached_cb,