Implement mapping blink track id to demuxer streams

media/blink/websourcebuffer_impl.cc

Index: media/blink/websourcebuffer_impl.cc
diff --git a/media/blink/websourcebuffer_impl.cc b/media/blink/websourcebuffer_impl.cc
index 5482406070fdd66695cb7ecd1867585d141b76fd..edbd3064e82e0a142a19a814321aef8dca3adb99 100644
--- a/media/blink/websourcebuffer_impl.cc
+++ b/media/blink/websourcebuffer_impl.cc
@@ -189,7 +189,14 @@ void WebSourceBufferImpl::InitSegmentReceived(
     trackInfoVector.push_back(trackInfo);
   }
 
-  client_->initializationSegmentReceived(trackInfoVector);
+  blink::WebVector<blink::WebMediaPlayer::TrackId> blinkTrackIds =
+      client_->initializationSegmentReceived(trackInfoVector);
+
+  std::vector<blink::WebMediaPlayer::TrackId> blinkTrackIdsVector;
+  for (const auto& id : blinkTrackIds)
+    blinkTrackIdsVector.push_back(id);
+
+  demuxer_->OnTrackIdsAssigned(*tracks.get(), blinkTrackIdsVector);
 }
 
 }  // namespace media