Media track ID visibility at BWE level

webrtc/audio/audio_send_stream.cc

Index: webrtc/audio/audio_send_stream.cc
diff --git a/webrtc/audio/audio_send_stream.cc b/webrtc/audio/audio_send_stream.cc
index f89da981e44e94d54c6b723e02237f9284b8af9d..d00b13e9b0154a6dd47f6d4c859f3a869b3469d3 100644
--- a/webrtc/audio/audio_send_stream.cc
+++ b/webrtc/audio/audio_send_stream.cc
@@ -582,7 +582,7 @@ void AudioSendStream::ConfigureBitrateObserver(int min_bitrate_bps,
     config_.min_bitrate_bps = min_bitrate_bps;
     config_.max_bitrate_bps = max_bitrate_bps;
     bitrate_allocator_->AddObserver(this, min_bitrate_bps, max_bitrate_bps, 0,
-                                    true);
+                                    true, config_.track_id);
     thread_sync_event.Set();
   });
   thread_sync_event.Wait(rtc::Event::kForever);