Polymer.dart: Programmatically add template bindings

CountNotifier.dart

class CountNotifier extends ChangeNotifier {
  int _count = 0;
  int get count => _count;
  set count(int count) {
    _count = notifyPropertyChange(#count, _count, count);
  }
}

main.dart

CountNotifier counter = new CountNotifier();
TemplateElement count_template = new TemplateElement();
count_template.attributes["bind"] = "";
count_template.content.appendHtml("You have clicked {{count}} times.");

templateBind(count_template)
    ..model = counter;

document.body.children.add(count_template);

document.body.onKeyPress.listen((KeyboardEvent event) {
  if(event.keyCode == KeyCode.ENTER) {
    counter.count++;
  }
});