Cast: Avoid retransmit if we sent the same packet recently (less than RTT)

media/cast/audio_sender/audio_sender.cc

Index: media/cast/audio_sender/audio_sender.cc
diff --git a/media/cast/audio_sender/audio_sender.cc b/media/cast/audio_sender/audio_sender.cc
index 27b42d0dc8c2ac08757cb561d208f849c5835baa..836fafd9f8484315c2c12c61ade457bbc02d90b6 100644
--- a/media/cast/audio_sender/audio_sender.cc
+++ b/media/cast/audio_sender/audio_sender.cc
@@ -106,7 +106,17 @@ void AudioSender::SendEncodedAudioFrame(
 void AudioSender::ResendPackets(
     const MissingFramesAndPacketsMap& missing_frames_and_packets) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
-  transport_sender_->ResendPackets(true, missing_frames_and_packets, false);
+
+  base::TimeDelta rtt;
+  base::TimeDelta avg_rtt;
+  base::TimeDelta min_rtt;
+  base::TimeDelta max_rtt;
+  rtcp_.Rtt(&rtt, &avg_rtt, &min_rtt, &max_rtt);
+
+  // It would probably be better to use the 10% percentile rtt
+  // rather than the min.
+  transport_sender_->ResendPackets(
+      true, missing_frames_and_packets, false, min_rtt);
 }
 
 void AudioSender::IncomingRtcpPacket(scoped_ptr<Packet> packet) {