Fix ServiceWorkerPushMessagingTest.OnPush.

Fix ServiceWorkerPushMessagingTest.OnPush.

r394194 exposed some race. It seems that waiting for a push message to
be handled by push_service() is the right thing to do.

BUG=612840, 612673
Test=On Chromeos and windows, the test now always pass locally.

Committed: https://crrev.com/d429e25851e808a426a8a692525987f3da008559
Cr-Commit-Position: refs/heads/master@{#395153}

[lazyboy, 2016-05-18 22:52:22]

lazyboy@chromium.org changed reviewers:
+ rdevlin.cronin@chromium.org

[Devlin, 2016-05-20 17:30:15]

lgtm

[lazyboy, 2016-05-20 20:13:08]

The CQ bit was checked by lazyboy@chromium.org

[lazyboy, 2016-05-20 20:13:08]

The patchset sent to the CQ was uploaded after l-g-t-m from
rdevlin.cronin@chromium.org
Link to the patchset: https://codereview.chromium.org/1987393003/#ps20001
(title: "enable test")

[commit-bot: I haz the power, 2016-05-20 20:13:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1987393003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1987393003/20001

[commit-bot: I haz the power, 2016-05-20 20:19:09]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-05-20 20:20:54]

Description was changed from

==========
Fix ServiceWorkerPushMessagingTest.OnPush.

r394194 exposed some race. It seems that waiting for a push message to
be handled by push_service() is the right thing to do.

BUG=612840,612673
Test=On Chromeos and windows, the test now always pass locally.
==========

to

==========
Fix ServiceWorkerPushMessagingTest.OnPush.

r394194 exposed some race. It seems that waiting for a push message to
be handled by push_service() is the right thing to do.

BUG=612840,612673
Test=On Chromeos and windows, the test now always pass locally.

Committed: https://crrev.com/d429e25851e808a426a8a692525987f3da008559
Cr-Commit-Position: refs/heads/master@{#395153}
==========

[commit-bot: I haz the power, 2016-05-20 20:20:55]

Patchset 2 (id:??) landed as
https://crrev.com/d429e25851e808a426a8a692525987f3da008559
Cr-Commit-Position: refs/heads/master@{#395153}