Remove GetFeedbackInterval in sender side BWE.

webrtc/modules/congestion_controller/probe_bitrate_estimator.h

Index: webrtc/modules/congestion_controller/probe_bitrate_estimator.h
diff --git a/webrtc/modules/congestion_controller/probe_bitrate_estimator.h b/webrtc/modules/congestion_controller/probe_bitrate_estimator.h
index 247e905fd0b42140f25ca126250b4f7e0a44fe07..7286f72af20e94de562a99b814961c4286ee9cda 100644
--- a/webrtc/modules/congestion_controller/probe_bitrate_estimator.h
+++ b/webrtc/modules/congestion_controller/probe_bitrate_estimator.h
@@ -27,6 +27,8 @@ class ProbeBitrateEstimator {
   // Returns the estimated bitrate if the probe completes a valid cluster.
   int HandleProbeAndEstimateBitrate(const PacketFeedback& packet_feedback);
 
+  rtc::Optional<int> FetchAndResetLastEstimatedBitrateBps();
+
  private:
   struct AggregatedCluster {
     int num_probes = 0;
@@ -44,6 +46,7 @@ class ProbeBitrateEstimator {
 
   std::map<int, AggregatedCluster> clusters_;
   RtcEventLog* const event_log_;
+  rtc::Optional<int> estimated_bitrate_bps_;
 };
 
 }  // namespace webrtc