NS_IMETHOD GetAttributeNS(const nsString& aNamespaceURI, const nsString& aLocalName, nsString& aReturn) {
NS_IMETHOD GetAttributeNS(const nsAReadableString& aNamespaceURI, const nsAReadableString& aLocalName, nsAWritableString& aReturn) {
  NS_IMETHOD GetAttributeNS(const nsString& aNamespaceURI,                            const nsString& aLocalName, nsString& aReturn) {    return mInner.GetAttributeNS(aNamespaceURI, aLocalName, aReturn);  }