- Add an extension test which throws from native code.

tests/standalone/io/test_extension_fail_tester.dart

Index: tests/standalone/io/test_extension_fail_tester.dart
===================================================================
--- tests/standalone/io/test_extension_fail_tester.dart	(revision 0)
+++ tests/standalone/io/test_extension_fail_tester.dart	(revision 0)
@@ -0,0 +1,20 @@
+// 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.
+
+#library("test_extension_test");
+
+#import("dart:isolate");
+#import('test_extension.dart');
+
+main() {
+  try {
+    Cat.throwMeTheBall("ball");
+  } on String catch (e) {
+    Expect.equals("ball", e);
+  }
+  // Make sure the exception is thrown out to the event handler from C++ code.
+  // The harness expects the string "ball" to be thrown and the process to
+  // end with an unhandled exception.
+  new Timer(0, (_) => Cat.throwMeTheBall("ball"));
+}