API addition: animation.attrKeyframes for element attributes

[clyfe]

It's a shame to have to write all that code [1] to make a custom animation just to animate scrollTop.
How about having an array of hashes similar animation.keyframes but instead css attributes, it would have element attributes like scrollTop, and it would yield a customEffect function:

var animation = new CoreAnimation();
animation.duration = 500;
animation.target = document.getElementById('el');
animation.attrKeyframes = [
  {scrollTop: animation.target.scrollTop},
  {scrollTop: 500}
];
animation.play();

[1] http://stackoverflow.com/a/26852482/283608