mPseudo = aPseudoElt;
if (!DOMStringIsNull(aPseudoElt) && !aPseudoElt.IsEmpty()) { mPseudo = do_GetAtom(aPseudoElt); NS_ENSURE_TRUE(mPseudo, NS_ERROR_OUT_OF_MEMORY); }
nsComputedDOMStyle::Init(nsIDOMElement *aElement, const nsString& aPseudoElt,                         nsIPresShell *aPresShell){  NS_ENSURE_ARG_POINTER(aElement);  NS_ENSURE_ARG_POINTER(aPresShell);  mPresShell = aPresShell;  mContent = do_QueryInterface(aElement);  if (!mContent) {    // This should not happen, all our elements support nsIContent!    return NS_ERROR_FAILURE;  }  mPseudo = aPseudoElt;  nsCOMPtr<nsIPresContext> presCtx;  mPresShell->GetPresContext(getter_AddRefs(presCtx));  NS_ENSURE_TRUE(presCtx, NS_ERROR_FAILURE);  presCtx->GetTwipsToPixels(&mT2P);  return NS_OK;}