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

Source/core/rendering/RenderMarquee.cpp

Index: Source/core/rendering/RenderMarquee.cpp
diff --git a/Source/core/rendering/RenderMarquee.cpp b/Source/core/rendering/RenderMarquee.cpp
index ecfff0d0ae59dc498887824fc35d06c6de7c3d45..9540f0b3a6c1464c36a76e110dba431ce2dbe549 100644
--- a/Source/core/rendering/RenderMarquee.cpp
+++ b/Source/core/rendering/RenderMarquee.cpp
@@ -72,7 +72,7 @@ RenderMarquee::RenderMarquee(Element* element)
     , m_stopped(false)
     , m_direction(MAUTO)
 {
-    UseCounter::count(document(), UseCounter::HTMLMarqueeElement);
+    UseCounter::count(&document(), UseCounter::HTMLMarqueeElement);
 }
 
 RenderMarquee::~RenderMarquee()
@@ -167,7 +167,7 @@ void RenderMarquee::start()
 
     // We may end up propagating a scroll event. It is important that we suspend events until
     // the end of the function since they could delete the layer, including the marquee.
-    FrameView* frameView = document()->view();
+    FrameView* frameView = document().view();
     if (frameView)
         frameView->pauseScheduledEvents();