Pass time constanct to bwe smoothing filter.

BUG=webrtc:6443, webrtc:6303

Review-Url: https://codereview.webrtc.org/2518923003
Cr-Commit-Position: refs/heads/master@{#15266}

webrtc/tools/event_log_visualizer/analyzer.cc

@@ -451,7 +451,8 @@ class BitrateObserver : public CongestionController::Observer,
 
   void OnNetworkChanged(uint32_t bitrate_bps,
                         uint8_t fraction_loss,
-                        int64_t rtt_ms) override {
+                        int64_t rtt_ms,
+                        int64_t probing_interval_ms) override {
     last_bitrate_bps_ = bitrate_bps;
     bitrate_updated_ = true;
   }