Fixed typo

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 9fded73d91e239bf4dfe7eb6159a0fe321e32ccc..c71369730771571a53885ac0f1bdc5b76d5db191 100644
--- a/lib/html/dart2js/html_dart2js.dart
+++ b/lib/html/dart2js/html_dart2js.dart
@@ -39660,7 +39660,7 @@ EventTarget _convertNativeToDart_EventTarget(e) {
   // from a different frame - without a patched prototype - so we cannot
   // rely on Dart type checking.
   if (JS('bool', r'"setInterval" in #', e))
-    return _DOMWindowCrossFrameImpl._createSafe(event);
+    return _DOMWindowCrossFrameImpl._createSafe(e);
   else
     return e;
 }