Have Document::accessSVGExtensions() return a reference

Source/core/svg/SVGFEImageElement.cpp

Index: Source/core/svg/SVGFEImageElement.cpp
diff --git a/Source/core/svg/SVGFEImageElement.cpp b/Source/core/svg/SVGFEImageElement.cpp
index 910af30fe176a5b0e4cefaee30852c43342567b1..93f9a1fe275a629920bfaa0e68ee5525135a4b03 100644
--- a/Source/core/svg/SVGFEImageElement.cpp
+++ b/Source/core/svg/SVGFEImageElement.cpp
@@ -75,7 +75,7 @@ void SVGFEImageElement::clearResourceReferences()
         m_cachedImage = 0;
     }
 
-    document().accessSVGExtensions()->removeAllTargetReferencesForElement(this);
+    document().accessSVGExtensions().removeAllTargetReferencesForElement(this);
 }
 
 void SVGFEImageElement::fetchImageResource()
@@ -99,13 +99,13 @@ void SVGFEImageElement::buildPendingResource()
         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();