[Extensions] Don't run unload listeners when an extension is removed

chrome/test/data/extensions/unload_listener/page.js

Index: chrome/test/data/extensions/unload_listener/page.js
diff --git a/chrome/test/data/extensions/unload_listener/page.js b/chrome/test/data/extensions/unload_listener/page.js
new file mode 100644
index 0000000000000000000000000000000000000000..205375e6711c40f612a0622abdf4cbf0619f7a79
--- /dev/null
+++ b/chrome/test/data/extensions/unload_listener/page.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.
+
+function onUnload() {
+  var xhr = new XMLHttpRequest();
+  xhr.open('GET', 'https://www.example.com/', true);
+  xhr.send();
+}
+
+window.onbeforeunload = onUnload;

[Charlie Reis, 2016/09/21 18:29:33]

I'd suggest leaving this line out, since beforeunload is different.  (I could
see testing both separately if we're concerned about it, but that may not be
necessary.)

[Devlin, 2016/09/22 00:35:21]

Is there any harm?  Neither one of these should change the outcome of removing
the tabs synchronously, which I think is what we want to ensure, right?

[Charlie Reis, 2016/09/22 20:37:47]

I suppose it would matter more if it were possible for a beforeunload-only fix
to make the test pass, while unload is still broken.  But you're right the test
will only pass if neither beforeunload nor unload kick off an async close.  I'm
fine with leaving it.

+window.onunload = onUnload;