anchor.diff:        var setSize = 100;
         var phrase = 'It works!';
         list.items = buildDataSet(setSize);
  +      // TODO(jakemac): Update once we resolve
  +      // https://github.com/dart-lang/polymer_interop/issues/6
         list.jsElement.callMethod('set', ['items.0.index', phrase]);
         return new Future(() {}).then((_) {
           expect(getFirstItemFromList(list).text, phrase);
  
positive.code:       var setSize = 45;
        var phrase = 'It works!';
        list.items = buildDataSet(setSize);
        list.jsElement.callMethod(
            'splice', ['items', 0, setSize, buildItem(phrase)]);
        return new Future(() {}).then((_) {
  
negative.code:           'contribution': 100,
            'target': setSize*rowHeight
          }, ([_]) {
            // TODO(jakemac): Update once we resolve
            // https://github.com/dart-lang/polymer_interop/issues/6
            list.jsElement.callMethod('set', ['items.0.index', phrase]);
            new Future(() {}).then(scrollBackUp);
          });
  