Prevent a service worker from keeping itself alive by self postMessage.

content/test/data/service_worker/worker_message_to_self.js

Index: content/test/data/service_worker/worker_message_to_self.js
diff --git a/content/test/data/service_worker/worker_message_to_self.js b/content/test/data/service_worker/worker_message_to_self.js
new file mode 100644
index 0000000000000000000000000000000000000000..1de40704d9969eb48e5f5c9f7797467ad21530d2
--- /dev/null
+++ b/content/test/data/service_worker/worker_message_to_self.js
@@ -0,0 +1,12 @@
+// Copyright 2016 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.
+
+this.onactivate = function(event) {
+    self.registration.active.postMessage('foo');
+};
+
+this.onmessage = function(event) {
+    console.log("MESSAGE");
+    self.registration.active.postMessage('foo');
+};