if (NS_FAILED(content->ChildAt(aOffset, *getter_AddRefs(cChild))))
if (NS_FAILED(content->ChildAt(aOffset, getter_AddRefs(cChild))))
nsHTMLCopyEncoder::GetChildAt(nsIDOMNode *aParent, PRInt32 aOffset){  nsCOMPtr<nsIDOMNode> resultNode;    if (!aParent)     return resultNode;    nsCOMPtr<nsIContent> content = do_QueryInterface(aParent);  nsCOMPtr<nsIContent> cChild;  NS_PRECONDITION(content, "null content in nsHTMLCopyEncoder::GetChildAt");    if (NS_FAILED(content->ChildAt(aOffset, *getter_AddRefs(cChild))))    return resultNode;    resultNode = do_QueryInterface(cChild);  return resultNode;}