Have Document::accessSVGExtensions() return a reference

Source/core/svg/SVGFEImageElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2010 Dirk Schulze <krit@webkit.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.
  *
@@ skipping 57 matching lines @@
     return true;
 }
 
 void SVGFEImageElement::clearResourceReferences()
 {
     if (m_cachedImage) {
         m_cachedImage->removeClient(this);
         m_cachedImage = 0;
     }
 
-    document().accessSVGExtensions()->removeAllTargetReferencesForElement(this);
+    document().accessSVGExtensions().removeAllTargetReferencesForElement(this);
 }
 
 void SVGFEImageElement::fetchImageResource()
 {
     FetchRequest request(ResourceRequest(ownerDocument()->completeURL(hrefString())), localName());
     m_cachedImage = document().fetcher()->fetchImage(request);
 
     if (m_cachedImage)
         m_cachedImage->addClient(this);
 }
 
 void SVGFEImageElement::buildPendingResource()
 {
     clearResourceReferences();
     if (!inDocument())
         return;
 
     AtomicString id;
     Element* target = SVGURIReference::targetElementFromIRIString(hrefString(), document(), &id);
     if (!target) {
         if (id.isEmpty())
             fetchImageResource();
         else {
-            document().accessSVGExtensions()->addPendingResource(id, this);
+            document().accessSVGExtensions().addPendingResource(id, this);
             ASSERT(hasPendingResources());
         }
     } else if (target->isSVGElement()) {
         // Register us with the target in the dependencies map. Any change of hrefElement
         // that leads to relayout/repainting now informs us, so we can react to it.
-        document().accessSVGExtensions()->addElementReferencingTarget(this, toSVGElement(target));
+        document().accessSVGExtensions().addElementReferencingTarget(this, toSVGElement(target));
     }
 
     invalidate();
 }
 
 bool SVGFEImageElement::isSupportedAttribute(const QualifiedName& attrName)
 {
     DEFINE_STATIC_LOCAL(HashSet<QualifiedName>, supportedAttributes, ());
     if (supportedAttributes.isEmpty()) {
         SVGURIReference::addSupportedAttributes(supportedAttributes);
@@ skipping 73 matching lines @@
 }
 
 PassRefPtr<FilterEffect> SVGFEImageElement::build(SVGFilterBuilder*, Filter* filter)
 {
     if (m_cachedImage)
         return FEImage::createWithImage(filter, m_cachedImage->imageForRenderer(renderer()), m_preserveAspectRatio->currentValue());
     return FEImage::createWithIRIReference(filter, document(), hrefString(), m_preserveAspectRatio->currentValue());
 }
 
 }