Disallow C++11 compilers from constructing OwnPtrs from 0

Source/wtf/PassOwnPtr.h

 /*
  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 
 namespace WTF {
 
     // Unlike most of our smart pointers, PassOwnPtr can take either the pointer type or the pointed-to type.
 
     template<typename T> class OwnPtr;
     template<typename T> class PassOwnPtr;
     template<typename T> PassOwnPtr<T> adoptPtr(T*);
 
     template<typename T> class PassOwnPtr {
+        WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(PassOwnPtr);
     public:
         typedef typename RemovePointer<T>::Type ValueType;
         typedef ValueType* PtrType;
 
         PassOwnPtr() : m_ptr(0) { }
         PassOwnPtr(std::nullptr_t) : m_ptr(0) { }
 
         // It somewhat breaks the type system to allow transfer of ownership out of
         // a const PassOwnPtr. However, it makes it much easier to work with PassOwnPtr
         // temporaries, and we don't have a need to use real const PassOwnPtrs anyway.
@@ skipping 110 matching lines @@
     }
 
 } // namespace WTF
 
 using WTF::PassOwnPtr;
 using WTF::adoptPtr;
 using WTF::const_pointer_cast;
 using WTF::static_pointer_cast;
 
 #endif // WTF_PassOwnPtr_h