Disable protected content button in Guest mode settings

Disable protected content button in Guest mode settings

UIAccountTweaks disables the "manage protected content exceptions"
button in guest mode, but the ContentSettingsHandler re-enables it.

BUG=417103
R=stevenjb@chromium.org

Committed: https://crrev.com/e83e359eb0ae40d1d479eb0f281f0b21d713919b
Cr-Commit-Position: refs/heads/master@{#296531}

[michaelpg, 2014-09-24 00:45:34]

Minor fix for guest mode settings

[stevenjb, 2014-09-24 16:16:11]

lgtm

[michaelpg, 2014-09-24 21:00:11]

The CQ bit was checked by michaelpg@chromium.org

[commit-bot: I haz the power, 2014-09-24 21:01:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/601633002/1

[commit-bot: I haz the power, 2014-09-24 21:48:30]

Committed patchset #1 (id:1) as ff3c4ecd39b2a38dfede78e2a805742dce7c5f45

[commit-bot: I haz the power, 2014-09-24 21:49:28]

Patchset 1 (id:??) landed as
https://crrev.com/e83e359eb0ae40d1d479eb0f281f0b21d713919b
Cr-Commit-Position: refs/heads/master@{#296531}