Remove DCHECK on duplicate packets in RemoteEstimatorProxy.

webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.cc

Index: webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.cc b/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.cc
index 51f93f96ce88a1ceeded24bb3b743d00c80c3cfc..eace9fc8b0a825b69a754706a217d5812cdc61b5 100644
--- a/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.cc
+++ b/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.cc
@@ -106,7 +106,9 @@ void RemoteEstimatorProxy::OnPacketArrival(uint16_t sequence_number,
     window_start_seq_ = seq;
   }
 
-  RTC_DCHECK(packet_arrival_times_.end() == packet_arrival_times_.find(seq));
+  // We are only interested in the first time a packet is received.

[sprang_webrtc, 2016/02/25 10:40:35]

Note that the same sequence can appear again in the next feedback packet though,
but I guess that's fine.

+  if (packet_arrival_times_.find(seq) != packet_arrival_times_.end())
+    return;
 
   packet_arrival_times_[seq] = arrival_time;
 }