lib/html/dart2js/html_dart2js.dart

Index: lib/html/dart2js/html_dart2js.dart
diff --git a/lib/html/dart2js/html_dart2js.dart b/lib/html/dart2js/html_dart2js.dart
index 05f25274d56b78506ebef2fac3dd0fb520885900..fb25635e6fea3974bc00b37f09de9ebc576617ee 100644
--- a/lib/html/dart2js/html_dart2js.dart
+++ b/lib/html/dart2js/html_dart2js.dart
@@ -40601,7 +40601,7 @@ class _RemoteSendPortSync implements SendPortSync {
     var source = '$target-result';
     var result = null;
     var listener = (Event e) {
-      result = JSON.parse(e.detail);
+      result = JSON.parse(_getPortSyncEventData(e));
     };
     window.on[source].add(listener);
     _dispatchEvent(target, [source, message]);
@@ -40673,7 +40673,7 @@ class ReceivePortSync {
     _callback = callback;
     if (_listener === null) {
       _listener = (Event e) {
-        var data = JSON.parse(e.detail);
+        var data = JSON.parse(_getPortSyncEventData(e));
         var replyTo = data[0];
         var message = _deserialize(data[1]);
         var result = _callback(message);
@@ -40708,6 +40708,8 @@ void _dispatchEvent(String receiver, var message) {
   event.initCustomEvent(receiver, false, false, JSON.stringify(message));
   window.$dom_dispatchEvent(event);
 }
+
+String _getPortSyncEventData(CustomEvent event) => event.detail;
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.