Clean up code duplication of isAtShadowBoundary()

Source/core/dom/Element.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003-2011, 2013, 2014 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
@@ skipping 824 matching lines @@
 inline bool isShadowHost(const Node* node)
 {
     return node && node->isElementNode() && toElement(node)->shadow();
 }
 
 inline bool isShadowHost(const Element* element)
 {
     return element && element->shadow();
 }
 
+inline bool isAtShadowBoundary(const Element* element)
+{
+    if (!element)
+        return false;
+    ContainerNode* parentNode = element->parentNode();
+    return parentNode && parentNode->isShadowRoot();
+}
+
 // These macros do the same as their NODE equivalents but additionally provide a template specialization
 // for isElementOfType<>() so that the Traversal<> API works for these Element types.
 #define DEFINE_ELEMENT_TYPE_CASTS(thisType, predicate) \
     template <> inline bool isElementOfType<const thisType>(const Node& node) { return node.predicate; } \
     DEFINE_NODE_TYPE_CASTS(thisType, predicate)
 
 #define DEFINE_ELEMENT_TYPE_CASTS_WITH_FUNCTION(thisType) \
     template <> inline bool isElementOfType<const thisType>(const Node& node) { return is##thisType(node); } \
     DEFINE_NODE_TYPE_CASTS_WITH_FUNCTION(thisType)
 
 #define DECLARE_ELEMENT_FACTORY_WITH_TAGNAME(T) \
     static PassRefPtrWillBeRawPtr<T> create(const QualifiedName&, Document&)
 #define DEFINE_ELEMENT_FACTORY_WITH_TAGNAME(T) \
     PassRefPtrWillBeRawPtr<T> T::create(const QualifiedName& tagName, Document& document) \
     { \
         return adoptRefWillBeNoop(new T(tagName, document)); \
     }
 
 } // namespace
 
 #endif