Move Node/ContainerNode's traverseToChildAt() to NodeTraversal

Source/core/dom/ContainerNode.cpp

Index: Source/core/dom/ContainerNode.cpp
diff --git a/Source/core/dom/ContainerNode.cpp b/Source/core/dom/ContainerNode.cpp
index 8c20d806aca347a6e5ae6344e7aec2aeadda5aa2..28f42740ee236b5f0afd430b4286c872a7ca1cc8 100644
--- a/Source/core/dom/ContainerNode.cpp
+++ b/Source/core/dom/ContainerNode.cpp
@@ -1105,15 +1105,6 @@ unsigned ContainerNode::countChildren() const
     return count;
 }
 
-Node* ContainerNode::traverseToChildAt(unsigned index) const
-{
-    unsigned i;
-    Node *n = firstChild();
-    for (i = 0; n != 0 && i < index; i++)
-        n = n->nextSibling();
-    return n;
-}
-
 PassRefPtrWillBeRawPtr<Element> ContainerNode::querySelector(const AtomicString& selectors, ExceptionState& exceptionState)
 {
     if (selectors.isEmpty()) {