code: function (origin) {
              if (origin == null) {
                  return;
              }
              var /** @type {?} */ dir = this._getLayoutDirection();
              if ((dir == 'ltr' && origin <= 0) || (dir == 'rtl' && origin > 0)) {
                  this._origin = 'left';
              }
              else {
                  this._origin = 'right';
              }
          }
docs: The origin position from which this tab should appear when it is centered into view.
  @param {?} origin
  @return {?}