Fix sky include guards to match Chromium style

sky/engine/core/dom/RenderTreeBuilder.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google 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 RenderTreeBuilder_h
-#define RenderTreeBuilder_h
+#ifndef SKY_ENGINE_CORE_DOM_RENDERTREEBUILDER_H_
+#define SKY_ENGINE_CORE_DOM_RENDERTREEBUILDER_H_
 
 #include "sky/engine/core/dom/Document.h"
 #include "sky/engine/core/dom/Node.h"
 #include "sky/engine/core/dom/NodeRenderingTraversal.h"
 #include "sky/engine/wtf/RefPtr.h"
 
 namespace blink {
 
 class ContainerNode;
 class RenderObject;
@@ skipping 30 matching lines @@
     RenderStyle& style() const;
 
     RawPtr<Node> m_node;
     RawPtr<ContainerNode> m_renderingParent;
     NodeRenderingTraversal::ParentDetails m_parentDetails;
     mutable RefPtr<RenderStyle> m_style;
 };
 
 } // namespace blink
 
-#endif
+#endif  // SKY_ENGINE_CORE_DOM_RENDERTREEBUILDER_H_