}
};
updater.addSource(rootScope, resultValue);
updater.addConsumer(rootScope, resultValue);
updater.addDependency(resultValue, prefixValue);
updater.addDependency(resultValue, containerFactoryButtonValue);
// Represents controller that updates state of OK button and error messages.
final OkButtonControl<Result> okButtonControl =
new OkButtonControl<Result>(resultValue, warningSources, elements);
updater.addConsumer(rootScope, okButtonControl);