replace NULL->nullptr in src/remoting.

remoting/host/shaped_desktop_capturer.cc

 // Copyright 2014 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/shaped_desktop_capturer.h"
 
 #include "base/logging.h"
 #include "remoting/host/desktop_shape_tracker.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
 
 namespace remoting {
 
 ShapedDesktopCapturer::ShapedDesktopCapturer(
     scoped_ptr<webrtc::DesktopCapturer> desktop_capturer,
     scoped_ptr<DesktopShapeTracker> shape_tracker)
     : desktop_capturer_(desktop_capturer.Pass()),
       shape_tracker_(shape_tracker.Pass()),
-      callback_(NULL) {
+      callback_(nullptr) {
 }
 
 ShapedDesktopCapturer::~ShapedDesktopCapturer() {}
 
 void ShapedDesktopCapturer::Start(webrtc::DesktopCapturer::Callback* callback) {
   callback_ = callback;
   desktop_capturer_->Start(this);
 }
 
 void ShapedDesktopCapturer::Capture(const webrtc::DesktopRegion& region) {
   desktop_capturer_->Capture(region);
 }
 
 webrtc::SharedMemory* ShapedDesktopCapturer::CreateSharedMemory(size_t size) {
   return callback_->CreateSharedMemory(size);
 }
 
 void ShapedDesktopCapturer::OnCaptureCompleted(webrtc::DesktopFrame* frame) {
   shape_tracker_->RefreshDesktopShape();
   frame->set_shape(new webrtc::DesktopRegion(shape_tracker_->desktop_shape()));
   callback_->OnCaptureCompleted(frame);
 }
 
 }  // namespace remoting