Revert the merge. Mac build is mysteriously broken.

third_party/WebKit/JavaScriptCore/wtf/HashTraits.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef WTF_HashTraits_h
 #define WTF_HashTraits_h
 
+#include "Assertions.h"
 #include "HashFunctions.h"
 #include "TypeTraits.h"
 #include <utility>
 #include <limits>
 
 namespace WTF {
 
     using std::pair;
     using std::make_pair;
 
@@ skipping 72 matching lines @@
 
     template<typename First, typename Second>
     struct HashTraits<pair<First, Second> > : public PairHashTraits<HashTraits<First>, HashTraits<Second> > { };
 
 } // namespace WTF
 
 using WTF::HashTraits;
 using WTF::PairHashTraits;
 
 #endif // WTF_HashTraits_h