il.preventer || detail.sourceEvent;
        if (preventer && preventer.preventDefault) {
          preventer.preventDefault();
        }
      }
    },

    /**
     * Prevents the dispatch and default action of the given event name.
     *
     * @memberof Polymer.Gestures
     * @param {string} evName Event name.
     */
    prevent: function(evName) {
      let recognizer = this._findRecognizerByEvent(evName);
      if (recognizer.info) {
        recognizer.info.prevent = true;
      }
    },

    /**
  