[Cast] RTT clean-up to the max!

media/cast/sender/video_sender.cc

Index: media/cast/sender/video_sender.cc
diff --git a/media/cast/sender/video_sender.cc b/media/cast/sender/video_sender.cc
index 7e356924c9151a79e6ffb0151a89d8c8448f969f..e17ea9427a2ad2c53b50f81c518e6550616df961 100644
--- a/media/cast/sender/video_sender.cc
+++ b/media/cast/sender/video_sender.cc
@@ -19,10 +19,10 @@
 namespace media {
 namespace cast {
 
-const int kNumAggressiveReportsSentAtStart = 100;
-
 namespace {
 
+const int kNumAggressiveReportsSentAtStart = 100;
+
 // Returns a fixed bitrate value when external video encoder is used.
 // Some hardware encoder shows bad behavior if we set the bitrate too
 // frequently, e.g. quality drop, not abiding by target bitrate, etc.
@@ -86,7 +86,8 @@ VideoSender::VideoSender(
       transport_config,
       base::Bind(&VideoSender::OnReceivedCastFeedback,
                  weak_factory_.GetWeakPtr()),
-      base::Bind(&VideoSender::OnReceivedRtt, weak_factory_.GetWeakPtr()));
+      base::Bind(&VideoSender::OnMeasuredRoundTripTime,
+                 weak_factory_.GetWeakPtr()));
 }
 
 VideoSender::~VideoSender() {
@@ -217,22 +218,10 @@ void VideoSender::SendEncodedVideoFrame(
 void VideoSender::OnReceivedCastFeedback(const RtcpCastMessage& cast_feedback) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
 
-  base::TimeDelta rtt;
-  base::TimeDelta avg_rtt;
-  base::TimeDelta min_rtt;
-  base::TimeDelta max_rtt;
   if (is_rtt_available()) {
-    rtt = rtt_;
-    avg_rtt = avg_rtt_;
-    min_rtt = min_rtt_;
-    max_rtt = max_rtt_;
+    congestion_control_.UpdateRtt(current_round_trip_time());
 
-    congestion_control_.UpdateRtt(rtt);
-
-    // Don't use a RTT lower than our average.
-    rtt = std::max(rtt, avg_rtt);
-
-    // Having the RTT values implies the receiver sent back a receiver report
+    // Having the RTT value implies the receiver sent back a receiver report
     // based on it having received a report from here.  Therefore, ensure this
     // sender stops aggressively sending reports.
     if (num_aggressive_rtcp_reports_sent_ < kNumAggressiveReportsSentAtStart) {
@@ -241,9 +230,6 @@ void VideoSender::OnReceivedCastFeedback(const RtcpCastMessage& cast_feedback) {
       num_aggressive_rtcp_reports_sent_ = kNumAggressiveReportsSentAtStart;
       ScheduleNextRtcpReport();
     }
-  } else {
-    // We have no measured value use default.
-    rtt = base::TimeDelta::FromMilliseconds(kStartRttMs);
   }
 
   if (last_send_time_.is_null())