anchor.diff:       }]);
        return c.future;
      }
  +
  +   /**
  +    * Resolve a future, given an error and result.
  +    */
  +   void _resolveFuture(Completer c, var err, var res) {
  +     if (err != null) {
  +       c.completeError(err);
  +     } else {
  +       c.complete(res);
  +     }
  +   }
   }
  
positive.code:   }
  }
  
  class Firebase extends Query {
    /**
     * Resolve a future, given an error and result.
     */
  
negative.code:    * Construct a new Firebase reference from a JsObject.
     */
    Firebase.fromJsObject(JsObject obj) : super.fromJsObject(obj);
  
    /**
     * Getter for onDisconnect.
     */
    Disconnect get onDisconnect {
      if (this._onDisconnect != null) {
        return this._onDisconnect;
      }
      this._onDisconnect = new Disconnect(this._fb.callMethod('onDisconnect'));
      return this._onDisconnect;
    }
  
    /**
     * Authenticates a Firebase client using a provided Authentication token.
  