code: function (event, extraData) {
              if (!this.__validateNbTouches(event)) {
                  return null;
              }
              this._disconnectTouchEvents();
              this.startData = {
                  positions : ariaTouchEvent.getPositions(event),
                  time : (new Date()).getTime()
              };
              this.currentData = null;
              this._connectAdditionalTouchEvents();
              if (this._getFakeEventsMap().start) {
                  return this._raiseFakeEvent(event, this._getFakeEventsMap().start, extraData);
              } else {
                  return (event.returnValue != null) ? event.returnValue : !event.defaultPrevented;
              }
          }
docs: Generic start point for a gesture: unregisters initial listeners, registers additional listeners, set initial
  data, optional fake event raised
  @param {Object} event the original event
  @protected
  @return {Boolean} false if preventDefault is true