HashTraits<RefPtr<P> >::peek should consider empty value

Source/wtf/HashTraits.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012 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 134 matching lines @@
         }
 
         typedef PassRefPtr<P> PassInType;
         static void store(PassRefPtr<P> value, RefPtr<P>& storage) { storage = value; }
 
         typedef PassRefPtr<P> PassOutType;
         static PassRefPtr<P> passOut(RefPtr<P>& value) { return value.release(); }
 
         typedef P* PeekType;
         static PeekType peek(const RefPtr<P>& value) { return value.get(); }
+        static PeekType peek(P* value) { return value; }
     };
 
     template<> struct HashTraits<String> : SimpleClassHashTraits<String> {
         static const bool hasIsEmptyValueFunction = true;
         static bool isEmptyValue(const String&);
     };
 
     // This struct template is an implementation detail of the isHashTraitsEmptyValue function,
     // which selects either the emptyValue function or the isEmptyValue function to check for empty values.
     template<typename Traits, bool hasEmptyValueFunction> struct HashTraitsEmptyValueChecker;
@@ skipping 82 matching lines @@
     };
 
 } // namespace WTF
 
 using WTF::HashTraits;
 using WTF::PairHashTraits;
 using WTF::NullableHashTraits;
 using WTF::SimpleClassHashTraits;
 
 #endif // WTF_HashTraits_h