Function getRootElement_

src/error-reporting.js:708–711

* @param {!Window} win * @return {!Element} * @private

(win)

 * @private
 */
function getRootElement_(win) {
  const root = Services.ampdocServiceFor(win).getSingleDoc().getRootNode();
  return dev().assertElement(root.documentElement || root.body || root);
}