replace NULL->nullptr in src/remoting.

remoting/host/host_main.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.
 //
 // This file implements the common entry point shared by all Chromoting Host
 // processes.
 
 #include "remoting/host/host_main.h"
 
 #include <string>
@@ skipping 117 matching lines @@
     return exit_code;
   }
 
   return kSuccessExitCode;
 }
 
 #endif  // !defined(OS_WIN)
 
 // Select the entry point corresponding to the process type.
 MainRoutineFn SelectMainRoutine(const std::string& process_type) {
-  MainRoutineFn main_routine = NULL;
+  MainRoutineFn main_routine = nullptr;
 
   if (process_type == kProcessTypeHost) {
     main_routine = &HostProcessMain;
 #if defined(OS_WIN)
   } else if (process_type == kProcessTypeDaemon) {
     main_routine = &DaemonProcessMain;
   } else if (process_type == kProcessTypeDesktop) {
     main_routine = &DesktopProcessMain;
   } else if (process_type == kProcessTypeController) {
     main_routine = &ElevatedControllerMain;
@@ skipping 89 matching lines @@
   return exit_code;
 }
 
 }  // namespace remoting
 
 #if !defined(OS_WIN)
 int main(int argc, char** argv) {
   return remoting::HostMain(argc, argv);
 }
 #endif  // !defined(OS_WIN)