[extension SW]: Support event listener registration and event dispatching.

chrome/test/data/extensions/api_test/service_worker/events/on_updated.js

Index: chrome/test/data/extensions/api_test/service_worker/events/on_updated.js
diff --git a/chrome/test/data/extensions/api_test/service_worker/events/on_updated.js b/chrome/test/data/extensions/api_test/service_worker/events/on_updated.js
new file mode 100644
index 0000000000000000000000000000000000000000..5ce2a6178e8152d67abf52a4571924a7cadbe553
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/service_worker/events/on_updated.js
@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+window.onload = function() {
+  setTimeout(function() {
+    document.title = 'foo';
+    setTimeout(function() {
+      document.title = 'bar';
+    }, 0);
+  }, 0);
+}
+