Set send side bitrate estimate on successful probing attempt.

BUG=webrtc:5859

Review-Url: https://codereview.webrtc.org/2263973004
Cr-Commit-Position: refs/heads/master@{#13887}
diff --git a/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc b/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
index d283796..1231c78 100644
--- a/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
+++ b/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
@@ -182,6 +182,14 @@
   MaybeTriggerOnNetworkChanged();
 }
 
+void BitrateControllerImpl::UpdateProbeBitrate(uint32_t bitrate_bps) {
+  {
+    rtc::CritScope cs(&critsect_);
+    bandwidth_estimation_.SetSendBitrate(bitrate_bps);
+  }
+  MaybeTriggerOnNetworkChanged();
+}
+
 void BitrateControllerImpl::UpdateDelayBasedEstimate(uint32_t bitrate_bps) {
   {
     rtc::CritScope cs(&critsect_);