Set a bit on Custom Elements on creation to simplify wrapping

Source/bindings/v8/CustomElementHelpers.cpp

Index: Source/bindings/v8/CustomElementHelpers.cpp
diff --git a/Source/bindings/v8/CustomElementHelpers.cpp b/Source/bindings/v8/CustomElementHelpers.cpp
index 7ad874e5b5062e78c1d2d018001f17f0b3ce1f5e..886de9de965c1db42dc51a326c1fc9699b4a78ce 100644
--- a/Source/bindings/v8/CustomElementHelpers.cpp
+++ b/Source/bindings/v8/CustomElementHelpers.cpp
@@ -244,13 +244,6 @@ const QualifiedName* CustomElementHelpers::findLocalName(v8::Handle<v8::Object>
     return 0;
 }
 
-bool CustomElementHelpers::isCustomElement(Element* element)
-{
-    // FIXME: This dynamically consults the "is" attribute; instead a
-    // bit should be marked on elements that are Custom Elements
-    return CustomElementRegistry::isCustomTagName(element->localName()) || CustomElementRegistry::isCustomTagName(element->getAttribute(HTMLNames::isAttr));
-}
-
 void CustomElementHelpers::invokeReadyCallbackIfNeeded(Element* element, v8::Handle<v8::Context> context)
 {
     v8::Handle<v8::Value> wrapperValue = toV8(element, context->Global(), context->GetIsolate());