Update from chromium https://crrev.com/302282

net/quic/congestion_control/tcp_loss_algorithm.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/congestion_control/tcp_loss_algorithm.h"
 
 #include "net/quic/congestion_control/rtt_stats.h"
 #include "net/quic/quic_protocol.h"
 
 namespace net {
 
 namespace {
-
-// TCP retransmits after 3 nacks.
-static const size_t kNumberOfNacksBeforeRetransmission = 3;
-
 // How many RTTs the algorithm waits before determining a packet is lost due
 // to early retransmission.
 static const double kEarlyRetransmitLossDelayMultiplier = 1.25;
-
 }
 
 TCPLossAlgorithm::TCPLossAlgorithm()
     : loss_detection_timeout_(QuicTime::Zero()) { }
 
 LossDetectionType TCPLossAlgorithm::GetLossDetectionType() const {
   return kNack;
 }
 
 // Uses nack counts to decide when packets are lost.
@@ skipping 42 matching lines @@
   }
 
   return lost_packets;
 }
 
 QuicTime TCPLossAlgorithm::GetLossTimeout() const {
   return loss_detection_timeout_;
 }
 
 }  // namespace net