anchor.diff:                        List<Widget> children = <Widget>[];
                         children.add(new Text(
                           message,
  -                        style: new TextStyle(fontSize: 24.0),
  +                        style: const TextStyle(fontSize: 24.0),
                           textAlign: TextAlign.center
                         ));
                         if (progressMax >= 0.0) {
  -                        children.add(new SizedBox(height: 18.0));
  +                        children.add(const SizedBox(height: 18.0));
                           children.add(new Center(child: new CircularProgressIndicator(value: progressMax > 0 ? progress / progressMax : null)));
                         }
                         return new Block(children: children);
  
positive.code:                 ),
                  new Expanded(
                    child: new Block(
                      padding: new EdgeInsets.symmetric(horizontal: 24.0),
                      children: <Widget>[ new Text(explanation, textAlign: TextAlign.center) ]
                    ),
                  ),
  
negative.code:               children: <Widget>[
                  new Expanded(
                    child: new Center(
                      child: const FlutterLogo(size: 100.0),
                    ),
                  ),
                  new Expanded(
  