anchor.diff:  import 'package:polymer/polymer.dart';
   import 'package:js_wrapping/js_wrapping.dart';
   
  +export 'Events/MouseEvent.dart';
   export 'leafletjs_js_bindings/geo.dart';
   export 'leafletjs_js_bindings/Icon.dart';
   
  
positive.code:         notifyPropertyChange(#Center, Center, newCenter);
          Center = newCenter;
        }
        notifyChanges();
      });
    }
    
  
negative.code: import 'leafletjs_js_bindings/Icon.dart' as L;
  import 'leafletjs_js_bindings/geo.dart' as L;
  import 'leafletjs_js_bindings/Util.dart' as L;
  import 'Events/MouseEvent.dart' as L;
  
  JsObject toJs(var obj){
   if (obj is JsInterface) return asJsObject(obj);
  