anchor.diff:   * limitations under the License.
    */
   
  +import 'dart:async';
  +import 'dart:collection';
   import 'dart:html';
   
   typedef void Callback();
  
positive.code:   void _water(String zoneId) {
      window.console.log("Watering zone: ${zoneId}");
      AreaElement zone = document.query("#${zoneId}");
      int x = int.parse(zone.dataAttributes["center-x"]);
      int y = int.parse(zone.dataAttributes["center-y"]);
      int zoneNum = int.parse(zoneId.split("-")[1]);
      _repositionDroid(x, y, () {
        _droid.src = "/static/images/droid-watering-1.png";
  
negative.code:       _doAction(action);
        window.console.log("_waitingForTimer = true");
        _waitingForTimer = true;
        new Timer(new Duration(milliseconds: TIMER_INTERVAL),
                  _executeActionQueue);
      }
    }
  
  