anchor.diff:                  ),
                   new _ContactItem(
                     icon: Icons.message,
  +                  tooltip: 'Send message',
  +                  onPressed: () {
  +                    _scaffoldKey.currentState.showSnackBar(new SnackBar(
  +                      content: new Text('In this demo, this button doesn\'t do anything.')
  +                    ));
  +                  },
                     lines: <String>[
                       '(323) 555-6789',
                       'Work'
  
positive.code:     if (icon != null) {
        rowChildren.add(new SizedBox(
          width: 72.0,
          child: new Icon(icon: icon, color: Theme.of(context).disabledColor)
        ));
      }
      return new Padding(
  
negative.code:                   ]
                  ),
                  new _ContactItem(
                    icon: Icons.map,
                    tooltip: 'Open map',
                    onPressed: () {
                      _scaffoldKey.currentState.showSnackBar(new SnackBar(
                        content: new Text('This would show a map of Mountain View.')
                      ));
                    },
                    lines: <String>[
                      '1600 Amphitheater Parkway',
                      'Mountain View, CA',
  