OwnPtr, OwnArrayPtr: Use copy/move-and-swap for assignment operators

Source/wtf/OwnPtr.h

 /*
  *  Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Library General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 119 matching lines @@
 
     template<typename T> inline typename OwnPtr<T>::PtrType OwnPtr<T>::leakPtr()
     {
         PtrType ptr = m_ptr;
         m_ptr = 0;
         return ptr;
     }
 
     template<typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<T>& o)
     {
-        PtrType ptr = m_ptr;
-        m_ptr = o.leakPtr();
-        ASSERT(!ptr || m_ptr != ptr);
-        deleteOwnedPtr(ptr);
+        ASSERT(!o || o != m_ptr);
+        OwnPtr ptr = o;
+        swap(ptr);
         return *this;
     }
 
     template<typename T> template<typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<U>& o)
     {
-        PtrType ptr = m_ptr;
-        m_ptr = o.leakPtr();
-        ASSERT(!ptr || m_ptr != ptr);
-        deleteOwnedPtr(ptr);
+        ASSERT(!o || o != m_ptr);
+        OwnPtr ptr = o;
+        swap(ptr);
         return *this;
     }
 
 #if COMPILER_SUPPORTS(CXX_RVALUE_REFERENCES)
     template<typename T> inline OwnPtr<T>::OwnPtr(OwnPtr<T>&& o)
         : m_ptr(o.leakPtr())
     {
     }
 
     template<typename T> template<typename U> inline OwnPtr<T>::OwnPtr(OwnPtr<U>&& o)
@@ skipping 50 matching lines @@
     template<typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)
     {
         return p.get();
     }
 
 } // namespace WTF
 
 using WTF::OwnPtr;
 
 #endif // WTF_OwnPtr_h