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

Source/core/rendering/AutoTableLayout.cpp

Index: Source/core/rendering/AutoTableLayout.cpp
diff --git a/Source/core/rendering/AutoTableLayout.cpp b/Source/core/rendering/AutoTableLayout.cpp
index fbccbaa5bb4fbb6b4ff702aeabaec6209176dabc..2c290c68fb1c95350ffcc691d330998ed13a4263 100644
--- a/Source/core/rendering/AutoTableLayout.cpp
+++ b/Source/core/rendering/AutoTableLayout.cpp
@@ -126,7 +126,7 @@ void AutoTableLayout::recalcColumn(unsigned effCol)
 
     // Nav/IE weirdness
     if (columnLayout.logicalWidth.isFixed()) {
-        if (m_table->document()->inQuirksMode() && columnLayout.maxLogicalWidth > columnLayout.logicalWidth.value() && fixedContributor != maxContributor) {
+        if (m_table->document().inQuirksMode() && columnLayout.maxLogicalWidth > columnLayout.logicalWidth.value() && fixedContributor != maxContributor) {
             columnLayout.logicalWidth = Length();
             fixedContributor = 0;
         }