Add default allowed value of Ask for Push Notifications.

Add default allowed value of Ask for Push Notifications.

Push Notifications not only support Ask already, it is the default value, so this should match that reality.

BUG=425698
Committed: https://crrev.com/6a6414165fd098d1df8d4c5e5ddf74d2648282dc
Cr-Commit-Position: refs/heads/master@{#302136}

[Finnur, 2014-10-30 14:41:21]

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

[Bernhard Bauer, 2014-10-30 16:44:32]

lgtm

[Finnur, 2014-10-30 18:44:51]

The CQ bit was checked by finnur@chromium.org

[commit-bot: I haz the power, 2014-10-30 18:45:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/689993002/1

[commit-bot: I haz the power, 2014-10-30 19:54:40]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-30 19:56:04]

Patchset 1 (id:??) landed as
https://crrev.com/6a6414165fd098d1df8d4c5e5ddf74d2648282dc
Cr-Commit-Position: refs/heads/master@{#302136}