Shave some yaks in RenderLayerStackingNode

Source/core/rendering/RenderLayerStackingNode.h

Index: Source/core/rendering/RenderLayerStackingNode.h
diff --git a/Source/core/rendering/RenderLayerStackingNode.h b/Source/core/rendering/RenderLayerStackingNode.h
index f808161f37c260c9099a244a14dcaeed9fe6114e..901bd46d22a3f755c9a70f53a275281c81d8e4e2 100644
--- a/Source/core/rendering/RenderLayerStackingNode.h
+++ b/Source/core/rendering/RenderLayerStackingNode.h
@@ -88,7 +88,6 @@ public:
     void updateStackingNodesAfterStyleChange(const RenderStyle* oldStyle);
 
     RenderLayerStackingNode* ancestorStackingContextNode() const;
-    RenderLayerStackingNode* ancestorStackingNode() const;
 
     // Gets the enclosing stacking context for this node, possibly the node
     // itself, if it is a stacking context.
@@ -149,15 +148,14 @@ private:
 
     RenderLayer* m_layer;
 
-    // For stacking contexts, m_posZOrderList holds a sorted list of all the
-    // descendant nodes within the stacking context that have z-indices of 0 or greater
-    // (auto will count as 0). m_negZOrderList holds descendants within our stacking context with negative
-    // z-indices.
+    // m_posZOrderList holds a sorted list of all the descendant nodes within
+    // that have z-indices of 0 or greater (auto will count as 0).
+    // m_negZOrderList holds descendants within our stacking context with
+    // negative z-indices.
     OwnPtr<Vector<RenderLayerStackingNode*> > m_posZOrderList;
     OwnPtr<Vector<RenderLayerStackingNode*> > m_negZOrderList;
 
-    // This list contains child nodes that cannot create stacking contexts. For now it is just
-    // overflow layers, but that may change in the future.
+    // This list contains child nodes that cannot create stacking contexts.
     OwnPtr<Vector<RenderLayerStackingNode*> > m_normalFlowList;
 
     unsigned m_zOrderListsDirty : 1;