Replace NULL with nullptr or null in webrtc/base/.

webrtc/base/asyncsocket.cc

 /*
  *  Copyright 2010 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/base/asyncsocket.h"
 #include "webrtc/base/checks.h"
 
 namespace rtc {
 
 AsyncSocket::AsyncSocket() {
 }
 
 AsyncSocket::~AsyncSocket() {
 }
 
-AsyncSocketAdapter::AsyncSocketAdapter(AsyncSocket* socket) : socket_(NULL) {
+AsyncSocketAdapter::AsyncSocketAdapter(AsyncSocket* socket) : socket_(nullptr) {
   Attach(socket);
 }
 
 AsyncSocketAdapter::~AsyncSocketAdapter() {
   delete socket_;
 }
 
 void AsyncSocketAdapter::Attach(AsyncSocket* socket) {
   RTC_DCHECK(!socket_);
   socket_ = socket;
@@ skipping 89 matching lines @@
 
 void AsyncSocketAdapter::OnWriteEvent(AsyncSocket* socket) {
   SignalWriteEvent(this);
 }
 
 void AsyncSocketAdapter::OnCloseEvent(AsyncSocket* socket, int err) {
   SignalCloseEvent(this, err);
 }
 
 }  // namespace rtc