systrace/catapult/third_party/polymer/components/iron-dropdown/demo/grow-height-animation.html

<!--
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->

<link rel="import" href="../../polymer/polymer.html">
<link rel="import" href="../../neon-animation/neon-animation-behavior.html">

<script>
  Polymer({
    is: 'expand-animation',

    behaviors: [
      Polymer.NeonAnimationBehavior
    ],

    configure: function(config) {
      var node = config.node;

      var height = node.getBoundingClientRect().height;

      this._effect = new KeyframeEffect(node, [{
        height: (height / 2) + 'px'
      }, {
        height: height + 'px'
      }], this.timingFromConfig(config));

      return this._effect;
    }
  });
</script>