Only allow one shadowRoot.

sky/engine/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 191 matching lines @@
     void recalcStyle(StyleRecalcChange, Text* nextTextSibling = 0);
     void setAnimationStyleChange(bool);
     void setNeedsAnimationStyleRecalc();
 
     void setNeedsCompositingUpdate();
 
     bool supportsStyleSharing() const;
 
     ElementShadow* shadow() const;
     ElementShadow& ensureShadow();
-    PassRefPtr<ShadowRoot> createShadowRoot(ExceptionState&);
+    PassRefPtr<ShadowRoot> ensureShadowRoot(ExceptionState&);
     ShadowRoot* shadowRoot() const;
-    ShadowRoot* youngestShadowRoot() const;
 
     bool hasAuthorShadowRoot() const { return shadowRoot(); }
 
     RenderStyle* computedStyle(PseudoId = NOPSEUDO);
 
     bool isUpgradedCustomElement() { return customElementState() == Upgraded; }
     bool isUnresolvedCustomElement() { return customElementState() == WaitingForUpgrade; }
 
     AtomicString computeInheritedLanguage() const;
 
@@ skipping 315 matching lines @@
 
 inline void Node::removedFrom(ContainerNode* insertionPoint)
 {
     ASSERT(insertionPoint->inDocument() || isContainerNode());
     if (insertionPoint->inDocument())
         clearFlag(InDocumentFlag);
     if (isInShadowTree() && !treeScope().rootNode().isShadowRoot())
         clearFlag(IsInShadowTreeFlag);
 }
 
+inline ShadowRoot* Node::shadowRoot() const
+{
+    if (!isElementNode())
+        return 0;
+    return toElement(this)->shadowRoot();
+}
+
 inline void Element::invalidateStyleAttribute()
 {
     ASSERT(elementData());
     elementData()->m_styleAttributeIsDirty = true;
 }
 
 inline bool isShadowHost(const Node* node)
 {
     return node && node->isElementNode() && toElement(node)->shadow();
 }
@@ skipping 25 matching lines @@
     static PassRefPtr<T> create(const QualifiedName&, Document&)
 #define DEFINE_ELEMENT_FACTORY_WITH_TAGNAME(T) \
     PassRefPtr<T> T::create(const QualifiedName& tagName, Document& document) \
     { \
         return adoptRef(new T(tagName, document)); \
     }
 
 } // namespace
 
 #endif  // SKY_ENGINE_CORE_DOM_ELEMENT_H_