Stop passing the root node to node lists traversal functions

Source/core/dom/ChildNodeList.h

Index: Source/core/dom/ChildNodeList.h
diff --git a/Source/core/dom/ChildNodeList.h b/Source/core/dom/ChildNodeList.h
index c91a04354003b674386b9777669f070b09303a18..517935893900396714ca3b5ad80badd518a49999 100644
--- a/Source/core/dom/ChildNodeList.h
+++ b/Source/core/dom/ChildNodeList.h
@@ -52,8 +52,8 @@ public:
     ContainerNode& rootNode() const { return ownerNode(); }
     bool canTraverseBackward() const { return true; }
     Node* itemBefore(const Node* previousItem) const;
-    Node* traverseToFirstElement(const ContainerNode& root) const { return root.firstChild(); }
-    Node* traverseForwardToOffset(unsigned offset, Node& currentNode, unsigned& currentOffset, const ContainerNode& root) const;
+    Node* traverseToFirstElement() const { return rootNode().firstChild(); }
+    Node* traverseForwardToOffset(unsigned offset, Node& currentNode, unsigned& currentOffset) const;
 
 private:
     explicit ChildNodeList(ContainerNode& rootNode);