Remove calls to deprecated MessageLoop methods in headless.

Remove calls to deprecated MessageLoop methods in headless.

This CL (hopefully) removes all calls to these methods in headless:
- MessageLoop::PostTask
- MessageLoop::PostDelayedTask
- MessageLoop::DeleteSoon
- MessageLoop::ReleaseSoon
- MessageLoop::Run
- MessageLoop::RunUntilIdle

BUG=616447
R=skyostil@chromium.org

Committed: https://crrev.com/caf5d18c1f0719b5d6c572f82debab1ad33db204
Cr-Commit-Position: refs/heads/master@{#416897}

[fdoray, 2016-09-06 20:25:59]

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

[commit-bot: I haz the power, 2016-09-06 20:26:46]

Dry run: 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, 2016-09-06 21:18:08]

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

[commit-bot: I haz the power, 2016-09-06 21:18:09]

Dry run: This issue passed the CQ dry run.

[fdoray, 2016-09-06 21:56:40]

PTAL

[Sami, 2016-09-07 10:03:53]

lgtm, thank you!

[Sami, 2016-09-07 10:04:00]

The CQ bit was checked by skyostil@chromium.org

[commit-bot: I haz the power, 2016-09-07 10:04:22]

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, 2016-09-07 10:09:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-07 10:11:08]

Description was changed from

==========
Remove calls to deprecated MessageLoop methods in headless.

This CL (hopefully) removes all calls to these methods in headless:
- MessageLoop::PostTask
- MessageLoop::PostDelayedTask
- MessageLoop::DeleteSoon
- MessageLoop::ReleaseSoon
- MessageLoop::Run
- MessageLoop::RunUntilIdle

BUG=616447
R=skyostil@chromium.org
==========

to

==========
Remove calls to deprecated MessageLoop methods in headless.

This CL (hopefully) removes all calls to these methods in headless:
- MessageLoop::PostTask
- MessageLoop::PostDelayedTask
- MessageLoop::DeleteSoon
- MessageLoop::ReleaseSoon
- MessageLoop::Run
- MessageLoop::RunUntilIdle

BUG=616447
R=skyostil@chromium.org

Committed: https://crrev.com/caf5d18c1f0719b5d6c572f82debab1ad33db204
Cr-Commit-Position: refs/heads/master@{#416897}
==========

[commit-bot: I haz the power, 2016-09-07 10:11:09]

Patchset 1 (id:??) landed as
https://crrev.com/caf5d18c1f0719b5d6c572f82debab1ad33db204
Cr-Commit-Position: refs/heads/master@{#416897}