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

Source/core/svg/SVGTextPathElement.cpp

Index: Source/core/svg/SVGTextPathElement.cpp
diff --git a/Source/core/svg/SVGTextPathElement.cpp b/Source/core/svg/SVGTextPathElement.cpp
index dbba6197c8ebc113a3c44b7f7c558af5dedd051e..c4d66e28e51c248beae38157f6078f048e359469 100644
--- a/Source/core/svg/SVGTextPathElement.cpp
+++ b/Source/core/svg/SVGTextPathElement.cpp
@@ -68,8 +68,7 @@ SVGTextPathElement::~SVGTextPathElement()
 
 void SVGTextPathElement::clearResourceReferences()
 {
-    ASSERT(document());
-    document()->accessSVGExtensions()->removeAllTargetReferencesForElement(this);
+    document().accessSVGExtensions()->removeAllTargetReferencesForElement(this);
 }
 
 bool SVGTextPathElement::isSupportedAttribute(const QualifiedName& attrName)
@@ -161,20 +160,20 @@ void SVGTextPathElement::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->hasTagName(SVGNames::pathTag)) {
         // 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));
     }
 }