!HTMLElement} row
     * @protected
     */
    _updateFirstAndLastColumnForRow(row) {
      Array.from(row.querySelectorAll('[part~="cell"]:not([part~="details-cell"])'))
        .sort((a, b) => {
          return a._column._order - b._column._order;
        }).forEach((cell, cellIndex, children) => {
          this._toggleAttribute('first-column', cellIndex === 0, cell);
          this._toggleAttribute('last-column', cellIndex === children.length - 1, cell);
        });
    }

    /**
     * @param {!Node