[Sync] Replacing NULL with nullptr in code and null in comments for components/sync/

components/sync/tools/testserver/run_sync_testserver.cc

 // Copyright 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 <stdint.h>
 #include <stdio.h>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 39 matching lines @@
   if (!base::LaunchProcess(python_command, base::LaunchOptions()).IsValid()) {
     LOG(ERROR) << "Failed to launch test script " << sync_test_script_name;
     return false;
   }
   return true;
 }
 
 // Gets a port value from the switch with name |switch_name| and writes it to
 // |port|. Returns true if a port was provided and false otherwise.
 static bool GetPortFromSwitch(const std::string& switch_name, uint16_t* port) {
-  DCHECK(port != NULL) << "|port| is NULL";
+  DCHECK(port != nullptr) << "|port| is null";
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   int port_int = 0;
   if (command_line->HasSwitch(switch_name)) {
     std::string port_str = command_line->GetSwitchValueASCII(switch_name);
     if (!base::StringToInt(port_str, &port_int)) {
       return false;
     }
   }
   *port = static_cast<uint16_t>(port_int);
   return true;
@@ skipping 42 matching lines @@
     printf("Error: failed to start python sync test server. Exiting.\n");
     return -1;
   }
 
   printf("Python sync test server running at %s (type ctrl+c to exit)\n",
          test_server->host_port_pair().ToString().c_str());
 
   base::RunLoop().Run();
   return 0;
 }