Have Document::accessSVGExtensions() return a reference

Source/core/svg/SVGAnimateElement.cpp

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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 188 matching lines @@
     ShouldApplyAnimation shouldApply = shouldApplyAnimation(targetElement, attributeName);
 
     if (shouldApply == DontApplyAnimation)
         return;
 
     if (shouldApply == ApplyXMLAnimation) {
         // SVG DOM animVal animation code-path.
         m_animatedProperties = animator->findAnimatedPropertiesForAttributeName(targetElement, attributeName);
         SVGElementAnimatedPropertyList::const_iterator end = m_animatedProperties.end();
         for (SVGElementAnimatedPropertyList::const_iterator it = m_animatedProperties.begin(); it != end; ++it)
-            document().accessSVGExtensions()->addElementReferencingTarget(this, it->element);
+            document().accessSVGExtensions().addElementReferencingTarget(this, it->element);
 
         ASSERT(!m_animatedProperties.isEmpty());
 
         ASSERT(propertyTypesAreConsistent(m_animatedPropertyType, m_animatedProperties));
         if (!m_animatedType)
             m_animatedType = animator->startAnimValAnimation(m_animatedProperties);
         else {
             animator->resetAnimValToBaseVal(m_animatedProperties, m_animatedType.get());
             animator->animValDidChange(m_animatedProperties);
         }
@@ skipping 205 matching lines @@
 
 SVGAnimatedTypeAnimator* SVGAnimateElement::ensureAnimator()
 {
     if (!m_animator)
         m_animator = SVGAnimatorFactory::create(this, targetElement(), m_animatedPropertyType);
     ASSERT(m_animatedPropertyType == m_animator->type());
     return m_animator.get();
 }
 
 }