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

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 5930cccd8a5dc4753ae79d3e05d8f1061ffa06a5..7f105314de0b63e1d196c7af53fd0fa6d20183b5 100644
--- a/Source/core/svg/SVGMPathElement.cpp
+++ b/Source/core/svg/SVGMPathElement.cpp
@@ -64,20 +64,20 @@ void SVGMPathElement::buildPendingResource()
         return;
 
     String id;
-    Element* target = SVGURIReference::targetElementFromIRIString(hrefCurrentValue(), document(), &id);
+    Element* target = SVGURIReference::targetElementFromIRIString(hrefCurrentValue(), &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();
@@ -85,8 +85,7 @@ void SVGMPathElement::buildPendingResource()
 
 void SVGMPathElement::clearResourceReferences()
 {
-    ASSERT(document());
-    document()->accessSVGExtensions()->removeAllTargetReferencesForElement(this);
+    document().accessSVGExtensions()->removeAllTargetReferencesForElement(this);
 }
 
 Node::InsertionNotificationRequest SVGMPathElement::insertedInto(ContainerNode* rootParent)
@@ -152,7 +151,7 @@ void SVGMPathElement::svgAttributeChanged(const QualifiedName& attrName)
 
 SVGPathElement* SVGMPathElement::pathElement()
 {
-    Element* target = targetElementFromIRIString(hrefCurrentValue(), document());
+    Element* target = targetElementFromIRIString(hrefCurrentValue(), &document());
     if (target && target->hasTagName(SVGNames::pathTag))
         return toSVGPathElement(target);
     return 0;