restore arrow function bind this workaround

lib/runtime/dart/isolate.js

Index: lib/runtime/dart/isolate.js
diff --git a/lib/runtime/dart/isolate.js b/lib/runtime/dart/isolate.js
index d625ecb66afead486c0f6e13793f8eafa852c029..48c5c74ce167a8d43dafab82eef216831641a3ce 100644
--- a/lib/runtime/dart/isolate.js
+++ b/lib/runtime/dart/isolate.js
@@ -147,14 +147,14 @@ dart_library.library('dart/isolate', null, /* Imports */[
         controller.addError(error, error.stackTrace);
       }
       dart.fn(handleError, dart.void, [dart.dynamic]);
-      controller = async.StreamController.broadcast({sync: true, onListen: dart.fn(() => {
+      controller = async.StreamController.broadcast({sync: true, onListen: dart.fn((() => {
           port = RawReceivePort.new(handleError);
           this.addErrorListener(port.sendPort);
-        }), onCancel: dart.fn(() => {
+        }).bind(this)), onCancel: dart.fn((() => {
           this.removeErrorListener(port.sendPort);
           port.close();
           port = null;
-        })});
+        }).bind(this))});
       return controller.stream;
     }
   }