return val->QueryInterface(NS_GET_IID(nsIDOMCSSPrimitiveValue), (void **)&aValue);
return CallQueryInterface(val, &aValue);
nsComputedDOMStyle::GetBackgroundImage(nsIFrame *aFrame,                             nsIDOMCSSPrimitiveValue*& aValue){  nsROCSSPrimitiveValue* val=GetROCSSPrimitiveValue();  NS_ENSURE_TRUE(val, NS_ERROR_OUT_OF_MEMORY);  const nsStyleBackground* color=nsnull;  GetStyleData(eStyleStruct_Background, (const nsStyleStruct*&)color, aFrame);  if(color) {      val->SetString(color->mBackgroundImage);  }  else {    val->SetString("");  }  return val->QueryInterface(NS_GET_IID(nsIDOMCSSPrimitiveValue),                             (void **)&aValue);}