Remove GetFeedbackInterval in sender side BWE.

webrtc/modules/congestion_controller/probe_bitrate_estimator.cc

Index: webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
diff --git a/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc b/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
index 8406387eceb8aaa158d3883594e6a29211be60b0..2d66198ef833744eadf6c4184c00bdbc00b76ef4 100644
--- a/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
+++ b/webrtc/modules/congestion_controller/probe_bitrate_estimator.cc
@@ -133,10 +133,19 @@ int ProbeBitrateEstimator::HandleProbeAndEstimateBitrate(
                << " [receive: " << receive_size << " bytes / "
                << receive_interval_ms << " ms = " << receive_bps / 1000
                << " kb/s]";
+
   float res = std::min(send_bps, receive_bps);
   if (event_log_)
     event_log_->LogProbeResultSuccess(cluster_id, res);
-  return res;
+  estimated_bitrate_bps_ = rtc::Optional<int>(std::min(send_bps, res));
+  return *estimated_bitrate_bps_;
+}
+
+rtc::Optional<int>
+ProbeBitrateEstimator::FetchAndResetLastEstimatedBitrateBps() {
+  rtc::Optional<int> estimated_bitrate_bps = estimated_bitrate_bps_;
+  estimated_bitrate_bps_.reset();
+  return estimated_bitrate_bps;
 }
 
 void ProbeBitrateEstimator::EraseOldClusters(int64_t timestamp_ms) {