anchor.diff:  
   export 'interop/database_interop.dart' show ServerValue;
   
  -/// Log debugging information to the console.
  +/// Logs debugging information to the console.
  +/// If [persistent], it remembers the logging state between page refreshes.
   ///
   /// See: <https://firebase.google.com/docs/reference/js/firebase.database#.enableLogging>.
   void enableLogging([logger, bool persistent = false]) =>
       database_interop.enableLogging(jsify(logger), persistent);
   
  -/// The Firebase Database service class.
  +/// Firebase realtime database service class.
   ///
   /// See: <https://firebase.google.com/docs/reference/js/firebase.database>.
   class Database extends JsObjectWrapper<database_interop.DatabaseJsImpl> {
     App _app;
  +
  +  /// App for this instance of database service.
     App get app {
       if (_app != null) {
         _app.jsObject = jsObject.app;
  
positive.code:     return _app;
    }
  
    Database.fromJsObject(database_interop.DatabaseJsImpl jsObject)
        : super.fromJsObject(jsObject);
  
    void goOffline() => jsObject.goOffline();
  
    void goOnline() => jsObject.goOnline();
  
    DatabaseReference ref([String path]) =>
        new DatabaseReference.fromJsObject(jsObject.ref(path));
  
    DatabaseReference refFromURL(String url) =>
        new DatabaseReference.fromJsObject(jsObject.refFromURL(url));
  }
  
  /// A Reference represents a specific location in your database and
  /// can be used for reading or writing data to that database location.
  ///
  /// See: <https://firebase.google.com/docs/reference/js/firebase.database.Reference>.
  class DatabaseReference<T extends database_interop.ReferenceJsImpl>
      extends Query<T> {
    String get key => jsObject.key;
  
    DatabaseReference _parent;
    DatabaseReference get parent {
      if (jsObject.parent != null) {
        if (_parent != null) {
  
negative.code:     return c.future;
    }
  
    /// Updates data with [values] at actual database location.
    Future update(values) => handleThenable(jsObject.update(jsify(values)));
  }
  
  