ow.scrollTo :
      function scrollTo(scrollLeft, scrollTop) {
        target.scrollLeft = scrollLeft;
        target.scrollTop = scrollTop;
      };

    if (options.behavior === 'smooth') {

      if (hasNativeScrollBehavior) {

        target.scroll(options);

      } else {

        var timingFn = Polymer.AppLayout.scrollTimingFunction;
        var startTime = Date.now();
        var currentScrollTop = target === docEl ? window.pageYOffset : target.scrollTop;
        var currentScrollLeft = target === d