Initialize GC mixin bases only when leftmost vtable has been initialized.

Source/core/svg/SVGFilterElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010. 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 15 matching lines @@
 #include "core/svg/SVGFilterElement.h"
 
 #include "core/XLinkNames.h"
 #include "core/rendering/svg/RenderSVGResourceFilter.h"
 #include "core/svg/SVGParserUtilities.h"
 
 namespace blink {
 
 inline SVGFilterElement::SVGFilterElement(Document& document)
     : SVGElement(SVGNames::filterTag, document)
-    , SVGURIReference(this)
     , m_x(SVGAnimatedLength::create(this, SVGNames::xAttr, SVGLength::create(LengthModeWidth), AllowNegativeLengths))
     , m_y(SVGAnimatedLength::create(this, SVGNames::yAttr, SVGLength::create(LengthModeHeight), AllowNegativeLengths))
     , m_width(SVGAnimatedLength::create(this, SVGNames::widthAttr, SVGLength::create(LengthModeWidth), ForbidNegativeLengths))
     , m_height(SVGAnimatedLength::create(this, SVGNames::heightAttr, SVGLength::create(LengthModeHeight), ForbidNegativeLengths))
     , m_filterUnits(SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>::create(this, SVGNames::filterUnitsAttr, SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX))
     , m_primitiveUnits(SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>::create(this, SVGNames::primitiveUnitsAttr, SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE))
     , m_filterRes(SVGAnimatedIntegerOptionalInteger::create(this, SVGNames::filterResAttr))
 {
+    SVGURIReference::initialize(this);
+
     // Spec: If the x/y attribute is not specified, the effect is as if a value of "-10%" were specified.
     // Spec: If the width/height attribute is not specified, the effect is as if a value of "120%" were specified.
     m_x->setDefaultValueAsString("-10%");
     m_y->setDefaultValueAsString("-10%");
     m_width->setDefaultValueAsString("120%");
     m_height->setDefaultValueAsString("120%");
 
     addToPropertyMap(m_x);
     addToPropertyMap(m_y);
     addToPropertyMap(m_width);
@@ skipping 107 matching lines @@
     m_clientsToAdd.add(client);
 }
 
 void SVGFilterElement::removeClient(Node* client)
 {
     ASSERT(client);
     m_clientsToAdd.remove(client);
 }
 
 } // namespace blink