x-list.html

<dom-module id="x-list">
  <template>
    <iron-list item-height="_getItemHeight"></iron-list>
  </template>
  <script>
    Polymer({
      is: 'x-list',
      _getItemHeight: function(node) {
        if (node.hasTimeGap) {
          return 116;
        }
        if (node.isCardEnd) {
          return 72;
        }
        return 44;
      }
    });
</script>
</dom-module>