anchor.diff:                    ]
                   ),
                   new _ContactItem(
  +                  icon: Icons.map,
  +                  tooltip: 'Open map',
  +                  onPressed: () {
  +                    _scaffoldKey.currentState.showSnackBar(new SnackBar(
  +                      content: new Text('This would also show a map, if this was not a demo.')
  +                    ));
  +                  },
                     lines: <String>[
                       '126 Severyns Ave',
                       'Mountain View, CA',
  
positive.code: }
  
  class _ContactItem extends StatelessWidget {
    _ContactItem({ Key key, this.icon, this.lines }) : super(key: key) {
      assert(lines.length > 1);
    }
  
    final IconData icon;
    final List<String> lines;
  
    @override
    Widget build(BuildContext context) {
  
negative.code:           actions: <Widget>[
              new IconButton(
                icon: Icons.create,
                tooltip: 'Edit',
                onPressed: () {
                  _scaffoldKey.currentState.showSnackBar(new SnackBar(
                    content: new Text('This is actually just a demo. Editing isn\'t supported.')
                  ));
                }
              ),
  