polymer smooth scroll

gistfile1.txt

<core-animation id="animation" duration="300" easing="ease-in-out" fill="forwards"></core-animation>

...

var start = scroller.scrollTop;
var end = section.offsetTop;
var delta = end - start;

this.$.animation.target = scroller;
this.$.animation.customEffect = function (timeFraction, target, animation) {
  target.scrollTop = start + delta * timeFraction;
};
this.$.animation.play();

awesome, thanks!