Fix sky include guards to match Chromium style

sky/engine/core/css/CSSMarkup.h

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 - 2010  Torch Mobile (Beijing) Co. Ltd. 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 CSSMarkup_h
-#define CSSMarkup_h
+#ifndef SKY_ENGINE_CORE_CSS_CSSMARKUP_H_
+#define SKY_ENGINE_CORE_CSS_CSSMARKUP_H_
 
 #include "sky/engine/wtf/text/WTFString.h"
 
 // Helper functions for converting from CSSValues to text.
 // FIXME: This file has a similar purpose to
 // CSSOMUtils.h. Perhaps the two should be combined?
 
 namespace blink {
 
 String quoteCSSString(const String&);
 String quoteCSSStringIfNeeded(const String&);
 String quoteCSSURLIfNeeded(const String&);
 
 } // namespace blink
 
-#endif // CSSMarkup_h
+#endif  // SKY_ENGINE_CORE_CSS_CSSMARKUP_H_