Add second argument to Future error handlers.

tests/lib/async/stack_trace12_test.dart

Index: tests/lib/async/stack_trace12_test.dart
diff --git a/tests/lib/async/zone_root_bind_test.dart b/tests/lib/async/stack_trace12_test.dart
similarity index 59%
copy from tests/lib/async/zone_root_bind_test.dart
copy to tests/lib/async/stack_trace12_test.dart
index 7b73f9851514f2a7bab8e72825cb6d4626bb15b5..1d1e8af3fedcf99d36bed6111f77a05552c03465 100644
--- a/tests/lib/async/zone_root_bind_test.dart
+++ b/tests/lib/async/stack_trace12_test.dart
@@ -7,12 +7,13 @@ import 'package:async_helper/async_helper.dart';
 import 'dart:async';
 
 main() {
-  Expect.identical(Zone.ROOT, Zone.current);
-  Zone forked = Zone.current.fork();
-  var f = Zone.current.bindCallback(() {
-    Expect.identical(Zone.ROOT, Zone.current);
-  }, runGuarded: false);
-  forked.run(() {
-    f();
-  });
-}
+  StackTrace trace;
+  asyncStart();
+  var f = new Future(() { throw "foo"; });
+  f.then((_) { throw "Unreachable"; },
+    onError: (e, st) {
+      Expect.equals("foo", e);
+      Expect.isNotNull(st);
+      asyncEnd();
+    });
+}