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

Source/core/rendering/RenderListItem.cpp

Index: Source/core/rendering/RenderListItem.cpp
diff --git a/Source/core/rendering/RenderListItem.cpp b/Source/core/rendering/RenderListItem.cpp
index 62df763cf60e065f73fb602d424e8b3d995a56b6..4beebbeb16383b1602b3aedcb6c5931458398cf9 100644
--- a/Source/core/rendering/RenderListItem.cpp
+++ b/Source/core/rendering/RenderListItem.cpp
@@ -221,7 +221,7 @@ static RenderObject* getParentOfFirstLineBox(RenderBlock* curr, RenderObject* ma
     if (!firstChild)
         return 0;
 
-    bool inQuirksMode = curr->document()->inQuirksMode();
+    bool inQuirksMode = curr->document().inQuirksMode();
     for (RenderObject* currChild = firstChild; currChild; currChild = currChild->nextSibling()) {
         if (currChild == marker)
             continue;