Pass time constant to bwe smoothing filter.

webrtc/modules/congestion_controller/delay_based_bwe.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 119 matching lines @@
 }
 
 DelayBasedBwe::DelayBasedBwe(Clock* clock)
     : clock_(clock),
       inter_arrival_(),
       estimator_(),
       detector_(OverUseDetectorOptions()),
       receiver_incoming_bitrate_(),
       last_update_ms_(-1),
       last_seen_packet_ms_(-1),
-      uma_recorded_(false) {
+      uma_recorded_(false),
+      probing_interval_estimator_(&rate_control_) {
   network_thread_.DetachFromThread();
 }
 
 DelayBasedBwe::Result DelayBasedBwe::IncomingPacketFeedbackVector(
     const std::vector<PacketInfo>& packet_feedback_vector) {
   RTC_DCHECK(network_thread_.CalledOnValidThread());
   if (!uma_recorded_) {
     RTC_HISTOGRAM_ENUMERATION(kBweTypeHistogram,
                               BweNames::kSendSideTransportSeqNum,
                               BweNames::kBweNamesMax);
@@ skipping 111 matching lines @@
   *ssrcs = {kFixedSsrc};
   *bitrate_bps = rate_control_.LatestEstimate();
   return true;
 }
 
 void DelayBasedBwe::SetMinBitrate(int min_bitrate_bps) {
   // Called from both the configuration thread and the network thread. Shouldn't
   // be called from the network thread in the future.
   rate_control_.SetMinBitrate(min_bitrate_bps);
 }
+
+int DelayBasedBwe::GetProbingIntervalMs() const {
+  auto probing_interval_ms = probing_interval_estimator_.GetIntervalMs();

[stefan-webrtc, 2016/11/22 16:39:05]

int

[michaelt, 2016/11/23 12:28:29]

Its not a int.
GetIntervalMs() returns a optional. 

I changed auto to Optional<int64_t>.

[stefan-webrtc, 2016/11/24 10:40:45]

Ah. Why do we return an optional from the estimator if we're not making use of
it?

[michaelt, 2016/11/24 13:47:18]

Right this don't make sense here. 
I removed the optional and report a default interval instead.

+  if (!probing_interval_ms)
+    return 0;
+
+  return *probing_interval_ms;
+}
 }  // namespace webrtc