[Background Sync] Remove out-of-date layout test

[Background Sync] Remove out-of-date layout test

Uncontrolled window clients should now be allowed to register one-shot
background sync events, as long as they have a registered service worker.
This patch removes the old test (which expected exactly the opposite
behaviour.) Part 3 changes the behaviour in Chromium, and a new layout test for
the correct behaviour is added in part 4.

This is part 2 of a now-four-part blink-chromium-blink dance.
Part 1: https://codereview.chromium.org/1309393003
Part 2: https://codereview.chromium.org/1324903002 (this patch)
Part 3: https://codereview.chromium.org/1316743002
Part 4: https://codereview.chromium.org/1314453003

BUG=5188884
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201561

[iclelland, 2015-09-01 14:17:05]

iclelland@chromium.org changed reviewers:
+ jkarlin@chromium.org, mlamouri@chromium.org

[iclelland, 2015-09-01 14:20:05]

jkarlin: FYI; hopefully no action required :)
mlamouri: Can you take a quick look? The test for the correct behaviour is now
being added in the fourth CL in the series, to land after the Chromium CL is
committed.
Thanks.

[mlamouri (slow - plz ping), 2015-09-01 14:27:00]

The CQ bit was checked by mlamouri@chromium.org

[mlamouri (slow - plz ping), 2015-09-01 14:27:00]

lgtm

[commit-bot: I haz the power, 2015-09-01 14:27:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1324903002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1324903002/20001

[commit-bot: I haz the power, 2015-09-01 15:27:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-01 15:27:36]

Try jobs failed on following builders:
  linux_chromium_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[iclelland, 2015-09-01 15:29:40]

The CQ bit was checked by iclelland@chromium.org

[commit-bot: I haz the power, 2015-09-01 15:29:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1324903002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1324903002/20001

[commit-bot: I haz the power, 2015-09-01 16:11:10]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201561