nsCOMPtr<nsIContent> content; aFrame->GetContent(getter_AddRefs(content));
static PRBool CheckBooleanAttr(nsIFrame* aFrame, nsIAtom* aAtom){  if (!aFrame)    return PR_FALSE;  nsCOMPtr<nsIContent> content;  aFrame->GetContent(getter_AddRefs(content));  nsAutoString attr;  nsresult res = content->GetAttr(kNameSpaceID_None, aAtom, attr);  if (res == NS_CONTENT_ATTR_NO_VALUE ||      (res != NS_CONTENT_ATTR_NOT_THERE && attr.IsEmpty()))    return PR_TRUE; // This handles the HTML case (an attr with no value is like a true val)  return attr.EqualsIgnoreCase("true"); // This handles the XUL case.}