QUIC - (no behavior change) s/NULL/nullptr/g in .../quic/...

net/quic/congestion_control/loss_detection_interface.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/loss_detection_interface.h"
 
 #include "net/quic/congestion_control/tcp_loss_algorithm.h"
 #include "net/quic/congestion_control/time_loss_algorithm.h"
 
 namespace net {
 
 // Factory for loss detection algorithm.
 LossDetectionInterface* LossDetectionInterface::Create(
     LossDetectionType loss_type) {
   switch (loss_type) {
     case kNack:
       return new TCPLossAlgorithm();
     case kTime:
       return new TimeLossAlgorithm();
   }
   LOG(DFATAL) << "Unknown loss detection algorithm:" << loss_type;
-  return NULL;
+  return nullptr;
 }
 
 }  // namespace net