C++11 declares a type safe null pointer

content/common/gpu/gpu_memory_buffer_factory_x11.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.h"
 
 #include "base/logging.h"
 #include "content/common/gpu/gpu_memory_buffer_factory_x11_pixmap.h"
 #include "ui/gl/gl_image.h"
 #include "ui/gl/gl_image_shared_memory.h"
@@ skipping 33 matching lines @@
   virtual scoped_refptr<gfx::GLImage> CreateImageForGpuMemoryBuffer(
       const gfx::GpuMemoryBufferHandle& handle,
       const gfx::Size& size,
       unsigned internalformat,
       int client_id) override {
     switch (handle.type) {
       case gfx::SHARED_MEMORY_BUFFER: {
         scoped_refptr<gfx::GLImageSharedMemory> image(
             new gfx::GLImageSharedMemory(size, internalformat));
         if (!image->Initialize(handle))
-          return NULL;
+          return nullptr;
 
         return image;
       }
       case gfx::X11_PIXMAP_BUFFER:
         // Verify that client is the owner of the buffer we're about to use.
         if (handle.global_id.secondary_id != client_id)
           return scoped_refptr<gfx::GLImage>();
 
         return x11_pixmap_factory_.CreateImageForGpuMemoryBuffer(
             handle.global_id, size, internalformat);
       default:
         NOTREACHED();
         return scoped_refptr<gfx::GLImage>();
     }
   }
 
  private:
   GpuMemoryBufferFactoryX11Pixmap x11_pixmap_factory_;
 };
 
 }  // namespace
 
 // static
 scoped_ptr<GpuMemoryBufferFactory> GpuMemoryBufferFactory::Create() {
   return make_scoped_ptr<GpuMemoryBufferFactory>(
       new GpuMemoryBufferFactoryImpl);
 }
 
 }  // namespace content