replace NULL->nullptr in src/remoting.

remoting/host/desktop_process_main.cc

 // Copyright (c) 2012 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.
 //
 // This file implements the Windows service controlling Me2Me host processes
 // running within user sessions.
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
@@ skipping 49 matching lines @@
   desktop_environment_factory.reset(new Me2MeDesktopEnvironmentFactory(
       ui_task_runner,
       input_task_runner,
       ui_task_runner));
 #endif  // !defined(OS_WIN)
 
   if (!desktop_process.Start(desktop_environment_factory.Pass()))
     return kInitializationFailed;
 
   // Run the UI message loop.
-  ui_task_runner = NULL;
+  ui_task_runner = nullptr;
   run_loop.Run();
 
   return kSuccessExitCode;
 }
 
 }  // namespace remoting
 
 #if !defined(OS_WIN)
 int main(int argc, char** argv) {
   return remoting::HostMain(argc, argv);
 }
 #endif  // !defined(OS_WIN)