Add SVGUseElement::createInstanceTree helper

third_party/WebKit/Source/core/svg/SVGUseElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  *
  * 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,
@@ skipping 73 matching lines @@
 
     void scheduleShadowTreeRecreation();
     void cancelShadowTreeRecreation();
     bool haveLoadedRequiredResources() override { return !isStructurallyExternal() || m_haveFiredLoadEvent; }
 
     bool selfHasRelativeLengths() const override;
 
     // Instance tree handling
     void buildShadowAndInstanceTree(SVGElement& target);
     void clearInstanceRoot();
+    PassRefPtrWillBeRawPtr<Element> createInstanceTree(SVGElement& targetRoot) const;
     void clearShadowTree();
     bool hasCycleUseReferencing(const SVGUseElement&, const ContainerNode& targetInstance, SVGElement*& newTarget) const;
     bool expandUseElementsInShadowTree();
     void expandSymbolElementsInShadowTree();
     void cloneNonMarkupEventListeners();
     void addReferencesToFirstDegreeNestedUseElements(SVGElement& target);
 
     void invalidateDependentShadowTrees();
 
     bool resourceIsStillLoading() const;
@@ skipping 11 matching lines @@
 
     bool m_haveFiredLoadEvent;
     bool m_needsShadowTreeRecreation;
     RefPtrWillBeMember<SVGElement> m_targetElementInstance;
     RefPtrWillBeMember<DocumentResource> m_resource;
 };
 
 } // namespace blink
 
 #endif // SVGUseElement_h