Reduce the BWE with 50% when feedback is received too late.

webrtc/modules/congestion_controller/congestion_controller.cc

Index: webrtc/modules/congestion_controller/congestion_controller.cc
diff --git a/webrtc/modules/congestion_controller/congestion_controller.cc b/webrtc/modules/congestion_controller/congestion_controller.cc
index fd0d070ba0350c0801f0dbba3251225c8d623e38..81fe916e04c5a6f50cd8dd70239a31bb27bc260a 100644
--- a/webrtc/modules/congestion_controller/congestion_controller.cc
+++ b/webrtc/modules/congestion_controller/congestion_controller.cc
@@ -210,7 +210,8 @@ void CongestionController::SetBweBitrates(int min_bitrate_bps,
 
   remote_bitrate_estimator_.SetMinBitrate(min_bitrate_bps);
   min_bitrate_bps_ = min_bitrate_bps;
-  transport_feedback_adapter_.SetStartBitrate(start_bitrate_bps);
+  if (start_bitrate_bps > 0)
+    transport_feedback_adapter_.SetStartBitrate(start_bitrate_bps);
   transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps_);
   MaybeTriggerOnNetworkChanged();
 }