result = parentContent->ChildAt(offset, *getter_AddRefs(childContent));
result = parentContent->ChildAt(offset, getter_AddRefs(childContent));
nsSelection::GetFirstCellNodeInRange(nsIDOMRange *aRange, nsIDOMNode **aCellNode){  if (!aRange || !aCellNode) return NS_ERROR_NULL_POINTER;  *aCellNode = nsnull;  nsCOMPtr<nsIDOMNode> startParent;  nsresult result = aRange->GetStartContainer(getter_AddRefs(startParent));  if (NS_FAILED(result)) return result;  if (!startParent) return NS_ERROR_FAILURE;  PRInt32 offset;  result = aRange->GetStartOffset(&offset);  if (NS_FAILED(result)) return result;  nsCOMPtr<nsIContent> parentContent = do_QueryInterface(startParent);  nsCOMPtr<nsIContent> childContent;  result = parentContent->ChildAt(offset, *getter_AddRefs(childContent));  if (NS_FAILED(result)) return result;  if (!childContent) return NS_ERROR_NULL_POINTER;  // Don't return node if not a cell  if (!IsCell(childContent)) return NS_OK;  nsCOMPtr<nsIDOMNode> childNode = do_QueryInterface(childContent);  if (childNode)  {    *aCellNode = childNode;    NS_ADDREF(*aCellNode);  }  return NS_OK;}