Have Node::document() return a reference instead of a pointer

Source/core/svg/SVGPolyElement.cpp

Index: Source/core/svg/SVGPolyElement.cpp
diff --git a/Source/core/svg/SVGPolyElement.cpp b/Source/core/svg/SVGPolyElement.cpp
index 78c95aa56a8bb948385941d751a411c2af4ca010..d57e59e08ac8397e8f501e79453a966bb1efa602 100644
--- a/Source/core/svg/SVGPolyElement.cpp
+++ b/Source/core/svg/SVGPolyElement.cpp
@@ -82,7 +82,7 @@ void SVGPolyElement::parseAttribute(const QualifiedName& name, const AtomicStrin
     if (name == SVGNames::pointsAttr) {
         SVGPointList newList;
         if (!pointsListFromSVGData(newList, value))
-            document()->accessSVGExtensions()->reportError("Problem parsing points=\"" + value + "\"");
+            document().accessSVGExtensions()->reportError("Problem parsing points=\"" + value + "\"");
 
         if (SVGAnimatedProperty* wrapper = SVGAnimatedProperty::lookupWrapper<SVGPolyElement, SVGAnimatedPointList>(this, pointsPropertyInfo()))
             static_cast<SVGAnimatedPointList*>(wrapper)->detachListWrappers(newList.size());