C++11 declares a type safe null pointer

content/common/gpu/gpu_memory_buffer_factory_io_surface.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 "content/common/gpu/gpu_memory_buffer_factory_io_surface.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 
 #include "content/common/gpu/client/gpu_memory_buffer_impl_io_surface.h"
 #include "ui/gl/gl_image_io_surface.h"
 
 namespace content {
 namespace {
 
 void AddBooleanValue(CFMutableDictionaryRef dictionary,
                      const CFStringRef key,
                      bool value) {
   CFDictionaryAddValue(
       dictionary, key, value ? kCFBooleanTrue : kCFBooleanFalse);
 }
 
 void AddIntegerValue(CFMutableDictionaryRef dictionary,
                      const CFStringRef key,
                      int32 value) {
   base::ScopedCFTypeRef<CFNumberRef> number(
-      CFNumberCreate(NULL, kCFNumberSInt32Type, &value));
+      CFNumberCreate(nullptr, kCFNumberSInt32Type, &value));
   CFDictionaryAddValue(dictionary, key, number.get());
 }
 
 }  // namespace
 
 GpuMemoryBufferFactoryIOSurface::GpuMemoryBufferFactoryIOSurface() {
 }
 
 GpuMemoryBufferFactoryIOSurface::~GpuMemoryBufferFactoryIOSurface() {
 }
@@ skipping 54 matching lines @@
     return scoped_refptr<gfx::GLImage>();
 
   scoped_refptr<gfx::GLImageIOSurface> image(new gfx::GLImageIOSurface(size));
   if (!image->Initialize(it->second.get()))
     return scoped_refptr<gfx::GLImage>();
 
   return image;
 }
 
 }  // namespace content