Revert of Fire notifications when reboot is requested, not scheduled

Revert of Fire notifications when reboot is requested, not scheduled (patchset #5 id:80001 of https://codereview.chromium.org/727363002/)

Reason for revert:
This seems to have caused crashes on a couple of browser tests on the chromeos bots. See https://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/34145/steps/browser_tests for details.

Original issue's description:
> Fire notifications when reboot is requested, not scheduled
>
> This CL fixes two bugs in the original implementation of the
> runtime.onRestartRequired() notification:
>
> 1) Fire a notification when a reboot is requested, not scheduled.
> 2) Fix race at start-up, ensuring that reboots scheduled before
>    observer registration are not missed.
>
> BUG=433811
> TEST=Updated and extended unit and browser tests
>
> Committed: https://crrev.com/2bdfb49a86c46ac3a8a953a1e2f4e8e1bb41dc02
> Cr-Commit-Position: refs/heads/master@{#304624}

TBR=xiyuan@chromium.org,bartfab@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=433811
Committed: https://crrev.com/3e9ab1e27aafb0995e38a9401d1fd35c3adce967
Cr-Commit-Position: refs/heads/master@{#304638}

[sky, 2014-11-18 17:58:33]

Created Revert of Fire notifications when reboot is requested, not scheduled

[commit-bot: I haz the power, 2014-11-18 17:59:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/741473002/1

[commit-bot: I haz the power, 2014-11-18 18:00:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-18 18:01:35]

Patchset 1 (id:??) landed as
https://crrev.com/3e9ab1e27aafb0995e38a9401d1fd35c3adce967
Cr-Commit-Position: refs/heads/master@{#304638}

[bartfab (slow), 2014-11-18 18:52:46]

lgtm