Revert of Pass time constant to bwe smoothing filter. (patchset #8 id:140001 of https://codereview.webrtc.org/2518923003/ )

Reason for revert:
Unfortunately, this change breaks internal projects. Specifically the change to the CongestionController interface means anything implementing it will be forced to change in lock-step.

Original issue's description:
> Pass time constanct to bwe smoothing filter.
>
> BUG=webrtc:6443, webrtc:6303
>
> Committed: https://crrev.com/9abbf5ae4ec7d688a9b4aa03a405f3faadb74b90
> Cr-Commit-Position: refs/heads/master@{#15266}

TBR=minyue@webrtc.org,stefan@webrtc.org,solenberg@webrtc.org,michaelt@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6443, webrtc:6303

Review-Url: https://codereview.webrtc.org/2532993002
Cr-Commit-Position: refs/heads/master@{#15272}

webrtc/tools/event_log_visualizer/analyzer.cc

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