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

webrtc/base/win32socketserver.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.
  */
 
@@ skipping 125 matching lines @@
 // Win32Thread. Automatically pumps Windows messages.
 ///////////////////////////////////////////////////////////////////////////////
 
 class Win32Thread : public Thread {
  public:
   Win32Thread() : ss_(this), id_(0) {
     set_socketserver(&ss_);
   }
   virtual ~Win32Thread() {
     Stop();
-    set_socketserver(NULL);
+    set_socketserver(nullptr);
   }
   virtual void Run() {
     id_ = GetCurrentThreadId();
     Thread::Run();
     id_ = 0;
   }
   virtual void Quit() {
     PostThreadMessage(id_, WM_QUIT, 0, 0);
   }
  private:
   Win32SocketServer ss_;
   DWORD id_;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 }  // namespace rtc
 
 #endif  // WEBRTC_WIN
 
 #endif  // WEBRTC_BASE_WIN32SOCKETSERVER_H_