Add Zone support for Timers.

tests/lib/async/catch_errors12_test.dart

 // Copyright (c) 2013, 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.
 
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'dart:isolate';
 
 main() {
   // We keep a ReceivePort open until all tests are done. This way the VM will
-  // time out if the callbacks are not invoked.
+  // hang if the callbacks are not invoked and the test will time out.
   var port = new ReceivePort();
   var events = [];
-  // Test that asynchronous errors are caught.
+  // Tests that errors that have been delayed by several milliseconds with
+  // Timers are still caught by `catchErrors`.
   catchErrors(() {
     events.add("catch error entry");
-    new Future.error("future error");
-    new Future.error("future error2");
-    new Future.value(499).then((x) => throw x);
+    Timer.run(() { throw "timer error"; });
+    new Timer(const Duration(milliseconds: 100), () { throw "timer2 error"; });
+    new Future.value(499).then((x) {
+      new Timer(const Duration(milliseconds: 200), () { throw x; });
+    });
     throw "catch error";
   }).listen((x) {
       events.add(x);
     },
     onDone: () {
       Expect.listEquals([
             "catch error entry",
             "main exit",
             "catch error",
-            "future error",
-            "future error2",
+            "timer error",
+            "timer2 error",
             499,
           ],
           events);
       port.close();
     });
   events.add("main exit");
 }