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

webrtc/base/asyncudpsocket.h

 /*
  *  Copyright 2004 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.
  */
 
 #ifndef WEBRTC_BASE_ASYNCUDPSOCKET_H_
 #define WEBRTC_BASE_ASYNCUDPSOCKET_H_
 
 #include <memory>
 
 #include "webrtc/base/asyncpacketsocket.h"
 #include "webrtc/base/socketfactory.h"
 
 namespace rtc {
 
 // Provides the ability to receive packets asynchronously.  Sends are not
 // buffered since it is acceptable to drop packets under high load.
 class AsyncUDPSocket : public AsyncPacketSocket {
  public:
   // Binds |socket| and creates AsyncUDPSocket for it. Takes ownership
-  // of |socket|. Returns NULL if bind() fails (|socket| is destroyed
+  // of |socket|. Returns null if bind() fails (|socket| is destroyed
   // in that case).
   static AsyncUDPSocket* Create(AsyncSocket* socket,
                                 const SocketAddress& bind_address);
   // Creates a new socket for sending asynchronous UDP packets using an
   // asynchronous socket from the given factory.
   static AsyncUDPSocket* Create(SocketFactory* factory,
                                 const SocketAddress& bind_address);
   explicit AsyncUDPSocket(AsyncSocket* socket);
   ~AsyncUDPSocket() override;
 
@@ skipping 21 matching lines @@
   void OnWriteEvent(AsyncSocket* socket);
 
   std::unique_ptr<AsyncSocket> socket_;
   char* buf_;
   size_t size_;
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ASYNCUDPSOCKET_H_