Add LogOut method to GaiaCookieManagerService::Observer.

Add LogOut method to GaiaCookieManagerService::Observer.

This allows GMCS observers to be notified whenever a logout operation
finished.

BUG=

Committed: https://crrev.com/eb45c1381249694ef750bf5e5eceab7577c5bb6b
Cr-Commit-Position: refs/heads/master@{#423845}

[bzanotti, 2016-10-06 19:18:16]

The CQ bit was checked by bzanotti@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-06 19:18:58]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[bzanotti, 2016-10-06 19:42:03]

bzanotti@chromium.org changed reviewers:
+ rogerta@chromium.org

[bzanotti, 2016-10-06 19:42:03]

Please take a look.

Main reason for adding this is to use it in integration tests downstream to
ensure Mirror is fully working. This is especially important for us on iOS since
our implementation is more brittle due to technical limitations.

[commit-bot: I haz the power, 2016-10-06 20:13:01]

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

[commit-bot: I haz the power, 2016-10-06 20:13:02]

Dry run: This issue passed the CQ dry run.

[Roger Tawa OOO till Jul 10th, 2016-10-07 13:17:17]

lgtm

[bzanotti, 2016-10-07 13:18:39]

The CQ bit was checked by bzanotti@chromium.org

[commit-bot: I haz the power, 2016-10-07 13:18:52]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-07 13:24:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-07 13:26:55]

Description was changed from

==========
Add LogOut method to GaiaCookieManagerService::Observer.

This allows GMCS observers to be notified whenever a logout operation
finished.

BUG=
==========

to

==========
Add LogOut method to GaiaCookieManagerService::Observer.

This allows GMCS observers to be notified whenever a logout operation
finished.

BUG=

Committed: https://crrev.com/eb45c1381249694ef750bf5e5eceab7577c5bb6b
Cr-Commit-Position: refs/heads/master@{#423845}
==========

[commit-bot: I haz the power, 2016-10-07 13:26:55]

Patchset 1 (id:??) landed as
https://crrev.com/eb45c1381249694ef750bf5e5eceab7577c5bb6b
Cr-Commit-Position: refs/heads/master@{#423845}