Fix sky include guards to match Chromium style

sky/engine/core/dom/StyleSheetCandidate.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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-#ifndef StyleSheetCandidate_h
-#define StyleSheetCandidate_h
+#ifndef SKY_ENGINE_CORE_DOM_STYLESHEETCANDIDATE_H_
+#define SKY_ENGINE_CORE_DOM_STYLESHEETCANDIDATE_H_
 
 #include "sky/engine/platform/heap/Handle.h"
 #include "sky/engine/wtf/text/AtomicString.h"
 #include "sky/engine/wtf/text/WTFString.h"
 
 namespace blink {
 
 class Document;
 class Node;
 class StyleSheet;
@@ skipping 18 matching lines @@
     Node& node() const { return *m_node; }
 
     static Type typeOf(Node&);
 
     RawPtr<Node> m_node;
     Type m_type;
 };
 
 }
 
-#endif
+#endif  // SKY_ENGINE_CORE_DOM_STYLESHEETCANDIDATE_H_