replace NULL->nullptr in src/remoting.

remoting/host/installer/mac/uninstaller/remoting_uninstaller_app.mm

 // 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.
 
 #include "remoting/host/installer/mac/uninstaller/remoting_uninstaller_app.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "remoting/host/installer/mac/uninstaller/remoting_uninstaller.h"
 
@@ skipping 22 matching lines @@
   @try {
     NSLog(@"Chrome Remote Desktop uninstall starting.");
 
     RemotingUninstaller* uninstaller =
         [[[RemotingUninstaller alloc] init] autorelease];
     OSStatus status = [uninstaller remotingUninstall];
 
     NSLog(@"Chrome Remote Desktop Host uninstall complete.");
 
     bool success = false;
-    NSString* message = NULL;
+    NSString* message = nullptr;
     if (status == errAuthorizationSuccess) {
       success = true;
       message = @"Chrome Remote Desktop Host successfully uninstalled.";
     } else if (status == errAuthorizationCanceled) {
       message = @"Chrome Remote Desktop Host uninstall canceled.";
     } else if (status == errAuthorizationDenied) {
       message = @"Chrome Remote Desktop Host uninstall authorization denied.";
     } else {
       [NSException raise:@"AuthorizationCopyRights Failure"
                   format:@"Error during AuthorizationCopyRights status=%d",
                              static_cast<int>(status)];
     }
-    if (message != NULL) {
+    if (message != nullptr) {
       NSLog(@"Uninstall %s: %@", success ? "succeeded" : "failed", message);
       [self showSuccess:success withMessage:message];
     }
   }
   @catch (NSException* exception) {
     NSLog(@"Exception %@ %@", [exception name], [exception reason]);
     NSString* message =
         @"Error! Unable to uninstall Chrome Remote Desktop Host.";
     [self showSuccess:false withMessage:message];
   }
@@ skipping 27 matching lines @@
 
       NSLog(@"Chrome Remote Desktop Host uninstall complete.");
       NSLog(@"Status = %d", static_cast<int>(status));
       return status != errAuthorizationSuccess;
     }
   } else {
     return NSApplicationMain(argc, (const char**)argv);
   }
 }