anchor.diff:      }
   
       if (props_exist) {
  -      print('Found JavaScript property ${prop_string}');
  +      _log.finest('Found JavaScript property ${prop_string}');
         completer.complete(obj);
       } else {
         new Timer(PROPERTY_POLL_INTERVAL, completeIfJsAttrExists);
  
positive.code: //
  // The future returns the JsObject corresponding to the property.
  Future<JsObject> whenJsPropExists(String prop_string) {
    const Duration PROPERTY_POLL_INTERVAL = const Duration(milliseconds: 25);
    final List<String> props = prop_string.split('.');
  
  
negative.code:     void onLoad(Map responseJson),
      {void onError(HttpRequest request, ProgressEvent e),
       String method: 'POST'}) {
    final Logger _log = new Logger('postJson');
    HttpRequest httpRequest = new HttpRequest();
    httpRequest.open(method, url);
    httpRequest.setRequestHeader(
  