 Create the element's ripple effect via creating a `<paper-ripple>`.
     * Override this method to customize the ripple element.
     * @return {!PaperRippleElement} Returns a `<paper-ripple>` element.
     */
    _createRipple: function() {
      return /** @type {!PaperRippleElement} */ (
          document.createElement('paper-ripple'));
    },

    _noinkChanged: function(noink) {
      if (this.hasRipple()) {
        this._ripple.noink = noink;
      }
    }
  };
</script>
