Have Document::accessSVGExtensions() return a reference

Source/core/svg/SVGMPathElement.cpp

Index: Source/core/svg/SVGMPathElement.cpp
diff --git a/Source/core/svg/SVGMPathElement.cpp b/Source/core/svg/SVGMPathElement.cpp
index 61a1bb5304bfad868b5813f51c318ecd775df407..eb2c22afa203efea1d76e8f29be91d88d0f85fdd 100644
--- a/Source/core/svg/SVGMPathElement.cpp
+++ b/Source/core/svg/SVGMPathElement.cpp
@@ -63,17 +63,17 @@ void SVGMPathElement::buildPendingResource()
     Element* target = SVGURIReference::targetElementFromIRIString(hrefString(), document(), &id);
     if (!target) {
         // Do not register as pending if we are already pending this resource.
-        if (document().accessSVGExtensions()->isElementPendingResource(this, id))
+        if (document().accessSVGExtensions().isElementPendingResource(this, id))
             return;
 
         if (!id.isEmpty()) {
-            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));
     }
 
     targetPathChanged();
@@ -81,7 +81,7 @@ void SVGMPathElement::buildPendingResource()
 
 void SVGMPathElement::clearResourceReferences()
 {
-    document().accessSVGExtensions()->removeAllTargetReferencesForElement(this);
+    document().accessSVGExtensions().removeAllTargetReferencesForElement(this);
 }
 
 Node::InsertionNotificationRequest SVGMPathElement::insertedInto(ContainerNode* rootParent)