C++11 declares a type safe null pointer

content/common/gpu/client/command_buffer_proxy_impl.h

 // 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.
 
 #ifndef CONTENT_COMMON_GPU_CLIENT_COMMAND_BUFFER_PROXY_IMPL_H_
 #define CONTENT_COMMON_GPU_CLIENT_COMMAND_BUFFER_PROXY_IMPL_H_
 
 #include <map>
 #include <queue>
 #include <string>
@@ skipping 48 matching lines @@
   };
 
   typedef base::Callback<void(
       const std::string& msg, int id)> GpuConsoleMessageCallback;
 
   CommandBufferProxyImpl(GpuChannelHost* channel, int route_id);
   virtual ~CommandBufferProxyImpl();
 
   // Sends an IPC message to create a GpuVideoDecodeAccelerator. Creates and
   // returns it as an owned pointer to a media::VideoDecodeAccelerator.  Returns
-  // NULL on failure to create the GpuVideoDecodeAcceleratorHost.
+  // nullptr on failure to create the GpuVideoDecodeAcceleratorHost.
   // Note that the GpuVideoDecodeAccelerator may still fail to be created in
-  // the GPU process, even if this returns non-NULL. In this case the VDA client
-  // is notified of an error later, after Initialize().
+  // the GPU process, even if this returns non-nullptr.
+  // In this case the VDA clienta is notified of an error later,
+  // after Initialize().
   scoped_ptr<media::VideoDecodeAccelerator> CreateVideoDecoder();
 
   // Sends an IPC message to create a GpuVideoEncodeAccelerator. Creates and
   // returns it as an owned pointer to a media::VideoEncodeAccelerator.  Returns
-  // NULL on failure to create the GpuVideoEncodeAcceleratorHost.
+  // nullptr on failure to create the GpuVideoEncodeAcceleratorHost.
   // Note that the GpuVideoEncodeAccelerator may still fail to be created in
-  // the GPU process, even if this returns non-NULL. In this case the VEA client
+  // the GPU process, even if this returns non-nullptr.
+  // In this case the VEA client
   // is notified of an error later, after Initialize();
   scoped_ptr<media::VideoEncodeAccelerator> CreateVideoEncoder();
 
   // IPC::Listener implementation:
   virtual bool OnMessageReceived(const IPC::Message& message) override;
   virtual void OnChannelError() override;
 
   // CommandBuffer implementation:
   virtual bool Initialize() override;
   virtual State GetLastState() override;
@@ skipping 117 matching lines @@
   std::vector<ui::LatencyInfo> latency_info_;
 
   SwapBuffersCompletionCallback swap_buffers_completion_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CommandBufferProxyImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_COMMAND_BUFFER_PROXY_IMPL_H_