Fix sky include guards to match Chromium style

sky/engine/core/dom/StyleElement.h

 /*
  * Copyright (C) 2006, 2007 Rob Buis
  *
  * 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 StyleElement_h
-#define StyleElement_h
+#ifndef SKY_ENGINE_CORE_DOM_STYLEELEMENT_H_
+#define SKY_ENGINE_CORE_DOM_STYLEELEMENT_H_
 
 #include "sky/engine/core/css/CSSStyleSheet.h"
 #include "sky/engine/wtf/text/TextPosition.h"
 
 namespace blink {
 
 class ContainerNode;
 class Document;
 class Element;
 class TreeScope;
@@ skipping 24 matching lines @@
     void clearSheet(Element* ownerElement = 0);
 
     bool m_createdByParser : 1;
     bool m_loading : 1;
     bool m_registeredAsCandidate : 1;
     TextPosition m_startPosition;
 };
 
 }
 
-#endif
+#endif  // SKY_ENGINE_CORE_DOM_STYLEELEMENT_H_