Properly measure usage for Node attributes removed from DOM4

Source/core/dom/Element.h

Index: Source/core/dom/Element.h
diff --git a/Source/core/dom/Element.h b/Source/core/dom/Element.h
index 01693744ad6bab37a79925eeea4b0bf9c479093c..9179307be83ab194b74d8433aa833bdf664ef395 100644
--- a/Source/core/dom/Element.h
+++ b/Source/core/dom/Element.h
@@ -643,6 +643,8 @@ public:
 
     InputMethodContext* inputMethodContext();
 
+    virtual void setPrefix(const AtomicString&, ExceptionState&) OVERRIDE FINAL;
+
 protected:
     Element(const QualifiedName& tagName, Document* document, ConstructionType type)
         : ContainerNode(document, type)
@@ -727,7 +729,6 @@ private:
 
     void scrollByUnits(int units, ScrollGranularity);
 
-    virtual void setPrefix(const AtomicString&, ExceptionState&) OVERRIDE FINAL;
     virtual NodeType nodeType() const OVERRIDE FINAL;
     virtual bool childTypeAllowed(NodeType) const OVERRIDE FINAL;