Fix sky include guards to match Chromium style

sky/engine/wtf/HashSet.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2011 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_HashSet_h
-#define WTF_HashSet_h
+#ifndef SKY_ENGINE_WTF_HASHSET_H_
+#define SKY_ENGINE_WTF_HASHSET_H_
 
 #include "sky/engine/wtf/DefaultAllocator.h"
 #include "sky/engine/wtf/HashTable.h"
 
 namespace WTF {
 
     struct IdentityExtractor;
 
     // Note: empty or deleted values are not allowed, using them may lead to undefined behavior.
     // For pointer valuess this means that null pointers are not allowed unless you supply custom traits.
@@ skipping 234 matching lines @@
         iterator it = collection.begin();
         iterator end = collection.end();
         for (unsigned i = 0; it != end; ++it, ++i)
             vector[i] = *it;
     }
 
 } // namespace WTF
 
 using WTF::HashSet;
 
-#endif /* WTF_HashSet_h */
+#endif  // SKY_ENGINE_WTF_HASHSET_H_