Unify SVG parent checks for LayoutObject construction using always the light tree parent.

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2009, 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 217 matching lines @@
   void childrenChanged(const ChildrenChange&) override;
 
   static CSSPropertyID cssPropertyIdForSVGAttributeName(const QualifiedName&);
   void updateRelativeLengthsInformation() {
     updateRelativeLengthsInformation(selfHasRelativeLengths(), this);
   }
   void updateRelativeLengthsInformation(bool hasRelativeLengths, SVGElement*);
   static void markForLayoutAndParentResourceInvalidation(LayoutObject*);
 
   virtual bool selfHasRelativeLengths() const { return false; }
+  bool isInSVGSubtree() const;
+  bool isValidAndInSVGSubtree() const;
 
   SVGElementRareData* ensureSVGRareData();
   inline bool hasSVGRareData() const { return m_SVGRareData; }
   inline SVGElementRareData* svgRareData() const {
     ASSERT(m_SVGRareData);
     return m_SVGRareData.get();
   }
 
   void reportAttributeParsingError(SVGParsingError,
                                    const QualifiedName&,
@@ skipping 87 matching lines @@
   inline bool isElementOfType<const thisType>(const SVGElement& element) { \
     return is##thisType(element);                                          \
   }                                                                        \
   DEFINE_ELEMENT_TYPE_CASTS_WITH_FUNCTION(thisType)
 
 }  // namespace blink
 
 #include "core/SVGElementTypeHelpers.h"
 
 #endif  // SVGElement_h