replace NULL->nullptr in src/remoting.

remoting/host/clipboard_x11.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.
 
 #include "remoting/host/clipboard.h"
 
 #include <X11/Xlib.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 34 matching lines @@
   // and owned by this class.
   Display* display_;
 
   // Watcher used to handle X11 events from |display_|.
   base::MessageLoopForIO::FileDescriptorWatcher x_connection_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(ClipboardX11);
 };
 
 ClipboardX11::ClipboardX11()
-    : display_(NULL) {
+    : display_(nullptr) {
 }
 
 ClipboardX11::~ClipboardX11() {
   Stop();
 }
 
 void ClipboardX11::Start(
     scoped_ptr<protocol::ClipboardStub> client_clipboard) {
   // TODO(lambroslambrou): Share the X connection with InputInjector.
-  display_ = XOpenDisplay(NULL);
+  display_ = XOpenDisplay(nullptr);
   if (!display_) {
     LOG(ERROR) << "Couldn't open X display";
     return;
   }
   client_clipboard_.swap(client_clipboard);
 
   x_server_clipboard_.Init(display_,
                            base::Bind(&ClipboardX11::OnClipboardChanged,
                                       base::Unretained(this)));
 
@@ skipping 10 matching lines @@
     const protocol::ClipboardEvent& event) {
   x_server_clipboard_.SetClipboard(event.mime_type(), event.data());
 }
 
 void ClipboardX11::Stop() {
   client_clipboard_.reset();
   x_connection_watcher_.StopWatchingFileDescriptor();
 
   if (display_) {
     XCloseDisplay(display_);
-    display_ = NULL;
+    display_ = nullptr;
   }
 }
 
 void ClipboardX11::OnFileCanReadWithoutBlocking(int fd) {
   PumpXEvents();
 }
 
 void ClipboardX11::OnFileCanWriteWithoutBlocking(int fd) {
 }
 
@@ skipping 16 matching lines @@
     XNextEvent(display_, &event);
     x_server_clipboard_.ProcessXEvent(&event);
   }
 }
 
 scoped_ptr<Clipboard> Clipboard::Create() {
   return make_scoped_ptr(new ClipboardX11());
 }
 
 }  // namespace remoting