Set the start bitrate to the delay-based BWE.

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 51fc775266eb90b5af3ab30e2f654f1ae9ef4f35..fd0d070ba0350c0801f0dbba3251225c8d623e38 100644
--- a/webrtc/modules/congestion_controller/congestion_controller.cc
+++ b/webrtc/modules/congestion_controller/congestion_controller.cc
@@ -210,6 +210,7 @@ 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);
   transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps_);
   MaybeTriggerOnNetworkChanged();
 }
@@ -229,6 +230,7 @@ void CongestionController::ResetBweAndBitrates(int bitrate_bps,
   remote_bitrate_estimator_.SetMinBitrate(min_bitrate_bps);
 
   transport_feedback_adapter_.InitBwe();
+  transport_feedback_adapter_.SetStartBitrate(bitrate_bps);
   transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps);
   // TODO(holmer): Trigger a new probe once mid-call probing is implemented.
   MaybeTriggerOnNetworkChanged();