C++11 declares a type safe null pointer

content/common/gpu/client/webgraphicscontext3d_command_buffer_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_WEBGRAPHICSCONTEXT3D_COMMAND_BUFFER_IMPL_H_
 #define CONTENT_COMMON_GPU_CLIENT_WEBGRAPHICSCONTEXT3D_COMMAND_BUFFER_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 50 matching lines @@
   class ShareGroup : public base::RefCountedThreadSafe<ShareGroup> {
    public:
     ShareGroup();
 
     WebGraphicsContext3DCommandBufferImpl* GetAnyContextLocked() {
       // In order to ensure that the context returned is not removed while
       // in use, the share group's lock should be aquired before calling this
       // function.
       lock_.AssertAcquired();
       if (contexts_.empty())
-        return NULL;
+        return nullptr;
       return contexts_.front();
     }
 
     void AddContextLocked(WebGraphicsContext3DCommandBufferImpl* context) {
       lock_.AssertAcquired();
       contexts_.push_back(context);
     }
 
     void RemoveContext(WebGraphicsContext3DCommandBufferImpl* context) {
       base::AutoLock auto_lock(lock_);
@@ skipping 38 matching lines @@
   CONTENT_EXPORT gpu::ContextSupport* GetContextSupport();
 
   gpu::gles2::GLES2Implementation* GetImplementation() {
     return real_gl_.get();
   }
 
   // Return true if GPU process reported context lost or there was a
   // problem communicating with the GPU process.
   bool IsCommandBufferContextLost();
 
-  // Create & initialize a WebGraphicsContext3DCommandBufferImpl.  Return NULL
-  // on any failure.
+  // Create & initialize a WebGraphicsContext3DCommandBufferImpl.
+  // Return nullptr on any failure.
   static CONTENT_EXPORT WebGraphicsContext3DCommandBufferImpl*
       CreateOffscreenContext(
           GpuChannelHost* host,
           const WebGraphicsContext3D::Attributes& attributes,
           bool lose_context_when_out_of_memory,
           const GURL& active_url,
           const SharedMemoryLimits& limits,
           WebGraphicsContext3DCommandBufferImpl* share_context);
 
   size_t GetMappedMemoryLimit() {
@@ skipping 67 matching lines @@
 
   // Member variables should appear before the WeakPtrFactory, to ensure
   // that any WeakPtrs to Controller are invalidated before its members
   // variable's destructors are executed, rendering them invalid.
   base::WeakPtrFactory<WebGraphicsContext3DCommandBufferImpl> weak_ptr_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_WEBGRAPHICSCONTEXT3D_COMMAND_BUFFER_IMPL_H_