Supervised users: Add a cmdline flag and about:flags entry to enable the host blacklist

Supervised users: Add a cmdline flag and about:flags entry to enable the host blacklist

BUG=410824
Committed: https://crrev.com/fd04f1559164601a5a7a52118d0cb2612d41c83e
Cr-Commit-Position: refs/heads/master@{#293740}

[Marc Treib, 2014-09-05 14:56:09]

treib@chromium.org changed reviewers:
+ bauerb@chromium.org

[Marc Treib, 2014-09-05 14:56:10]

PTAL!

[Bernhard Bauer, 2014-09-05 15:28:03]

lgtm

[Marc Treib, 2014-09-05 15:28:52]

The CQ bit was checked by treib@chromium.org

[commit-bot: I haz the power, 2014-09-05 15:29:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/treib@chromium.org/545193003/1

[commit-bot: I haz the power, 2014-09-05 16:38:10]

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

[commit-bot: I haz the power, 2014-09-05 16:38:10]

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

[Marc Treib, 2014-09-08 08:06:06]

treib@chromium.org changed reviewers:
+ asvitkine@chromium.org

[Marc Treib, 2014-09-08 08:06:06]

+asvitkine

Alexei, can you please review my trivial update in histograms.xml? Thanks!

[Alexei Svitkine (slow), 2014-09-08 15:01:21]

lgtm

[Marc Treib, 2014-09-08 15:13:47]

The CQ bit was checked by treib@chromium.org

[commit-bot: I haz the power, 2014-09-08 15:17:15]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/treib@chromium.org/545193003/20001

[commit-bot: I haz the power, 2014-09-08 16:34:16]

Committed patchset #2 (id:20001) as 7504129b41b4a9966272e7181039112c8f115c0f

[commit-bot: I haz the power, 2014-09-10 03:46:45]

Patchset 2 (id:??) landed as
https://crrev.com/fd04f1559164601a5a7a52118d0cb2612d41c83e
Cr-Commit-Position: refs/heads/master@{#293740}