aBinding->GetBindingURI(impl->mClassName);
aBinding->BindingURI()->GetSpec(impl->mClassName);
NS_NewXBLProtoImpl(nsXBLPrototypeBinding* aBinding,                    const PRUnichar* aClassName,                    nsXBLProtoImpl** aResult){  nsXBLProtoImpl* impl = new nsXBLProtoImpl();  if (!impl)    return NS_ERROR_OUT_OF_MEMORY;  if (aClassName)    impl->mClassName.AssignWithConversion(aClassName);  else    aBinding->GetBindingURI(impl->mClassName);  aBinding->SetImplementation(impl);  *aResult = impl;  return NS_OK;}