replace NULL->nullptr in src/remoting.

remoting/host/win/entry_point.cc

 // Copyright (c) 2013 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 <windows.h>
 
 #include "remoting/host/host_main.h"
 
 // The common entry point for remoting_host.exe and remoting_desktop.exe. In
 // order to be really small the app doesn't link against the CRT.
 void HostEntryPoint() {
   // CommandLine::Init() ignores the passed parameters on Windows, so it is safe
-  // to pass NULL here.
-  int exit_code = remoting::HostMain(0, NULL);
+  // to pass nullptr here.
+  int exit_code = remoting::HostMain(0, nullptr);
   ExitProcess(exit_code);
 }