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

Source/core/rendering/RenderTableCell.cpp

Index: Source/core/rendering/RenderTableCell.cpp
diff --git a/Source/core/rendering/RenderTableCell.cpp b/Source/core/rendering/RenderTableCell.cpp
index b1badb2eeca2a7f4cf77b4162504647825f3732b..048e66af9124334398ed777250bdc533bbb54122 100644
--- a/Source/core/rendering/RenderTableCell.cpp
+++ b/Source/core/rendering/RenderTableCell.cpp
@@ -1260,7 +1260,7 @@ RenderTableCell* RenderTableCell::createAnonymous(Document* document)
 
 RenderTableCell* RenderTableCell::createAnonymousWithParentRenderer(const RenderObject* parent)
 {
-    RenderTableCell* newCell = RenderTableCell::createAnonymous(parent->document());
+    RenderTableCell* newCell = RenderTableCell::createAnonymous(&parent->document());
     RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(parent->style(), TABLE_CELL);
     newCell->setStyle(newStyle.release());
     return newCell;