Update the BWE when the network route changes.

webrtc/modules/congestion_controller/include/congestion_controller.h

Index: webrtc/modules/congestion_controller/include/congestion_controller.h
diff --git a/webrtc/modules/congestion_controller/include/congestion_controller.h b/webrtc/modules/congestion_controller/include/congestion_controller.h
index da8719d33a73a86c370a34fb2ac4f34658ecf58e..bb55f2c79a5a9dcc9e54a905e21a7fa6505ffe45 100644
--- a/webrtc/modules/congestion_controller/include/congestion_controller.h
+++ b/webrtc/modules/congestion_controller/include/congestion_controller.h
@@ -70,6 +70,10 @@ class CongestionController : public CallStatsObserver, public Module {
   virtual void SetBweBitrates(int min_bitrate_bps,
                               int start_bitrate_bps,
                               int max_bitrate_bps);
+  // Note the first argument is the bitrate_bps.
+  virtual void ResetBweBitrates(int bitrate_bps,
+                                int min_bitrate_bps,
+                                int max_bitrate_bps);
   virtual void SignalNetworkState(NetworkState state);
   virtual BitrateController* GetBitrateController() const;
   virtual RemoteBitrateEstimator* GetRemoteBitrateEstimator(
@@ -100,6 +104,11 @@ class CongestionController : public CallStatsObserver, public Module {
   bool HasNetworkParametersToReportChanged(uint32_t bitrate_bps,
                                            uint8_t fraction_loss,
                                            int64_t rtt);
+
+  // Makes sure that the bitrate and the min, max values are in valid range.
+  void ClampBitrates(int* bitrate_bps,
+                     int* min_bitrate_bps,
+                     int* max_bitrate_bps);
   Clock* const clock_;
   Observer* const observer_;
   const std::unique_ptr<PacketRouter> packet_router_;