Replace NULL with nullptr in all C++ files.

webrtc/voice_engine/test/channel_transport/udp_socket_wrapper_unittest.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 35 matching lines @@
 };
 
 // Creates a socket using the static constructor method and verifies that
 // it's added to the socket manager.
 TEST(UdpSocketWrapper, CreateSocket) {
   int32_t id = 42;
   // We can't test deletion of sockets without a socket manager.
   uint8_t threads = 1;
   UdpSocketManager* mgr = UdpSocketManager::Create(id, threads);
   UdpSocketWrapper* socket =
-      UdpSocketWrapper::CreateSocket(id,
-                                     mgr,
-                                     NULL,  // CallbackObj
-                                     NULL,  // IncomingSocketCallback
-                                     false,  // ipV6Enable
-                                     false);  // disableGQOS
+      UdpSocketWrapper::CreateSocket(id, mgr,
+                                     nullptr,  // CallbackObj
+                                     nullptr,  // IncomingSocketCallback
+                                     false,    // ipV6Enable
+                                     false);   // disableGQOS
   socket->CloseBlocking();
   UdpSocketManager::Return();
 }
 
 }  // namespace test
 }  // namespace webrtc