Remove dead code from childIndex optimization

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 74d0a787394dc19cf9639ad37db3d880cbf950f6..a07a2a859e3d9f2cb2cb1af34f65c5c2f0c717be 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -2419,20 +2419,6 @@ RenderStyle* Element::computedStyle(PseudoId pseudoElementSpecifier)
     return pseudoElementSpecifier ? rareData.computedStyle()->getCachedPseudoStyle(pseudoElementSpecifier) : rareData.computedStyle();
 }
 
-void Element::setChildIndex(unsigned index)
-{
-    ElementRareData& rareData = ensureElementRareData();
-    if (RenderStyle* style = renderStyle())
-        style->setUnique();
-    rareData.setChildIndex(index);
-}
-
-unsigned Element::rareDataChildIndex() const
-{
-    ASSERT(hasRareData());
-    return elementRareData()->childIndex();
-}
-
 AtomicString Element::computeInheritedLanguage() const
 {
     const Node* n = this;