Don't allow quota requests without an infobar service

Don't allow quota requests without an infobar service

For legacy reasons, extensions can only request quota if there is an
infobar service. In practice, this means that extension background pages
are excluded. We should keep this same constraint to avoid changing
callback behavior with permission bubbles.

BUG=

Committed: https://crrev.com/51f26d1f718456f09fe9f79eeb491da90e0c5ddf
Cr-Commit-Position: refs/heads/master@{#319834}

[felt, 2015-03-10 01:55:32]

felt@chromium.org changed reviewers:
+ kinuko@chromium.org, thestig@chromium.org

[felt, 2015-03-10 01:55:43]

kinuko, thestig, PTAL

[kinuko, 2015-03-10 02:46:48]

lgtm

[Lei Zhang, 2015-03-10 03:04:11]

The CQ bit was checked by thestig@chromium.org

[Lei Zhang, 2015-03-10 03:04:12]

lgtm

[commit-bot: I haz the power, 2015-03-10 03:04:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/989363003/1

[commit-bot: I haz the power, 2015-03-10 04:09:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-10 04:10:18]

Patchset 1 (id:??) landed as
https://crrev.com/51f26d1f718456f09fe9f79eeb491da90e0c5ddf
Cr-Commit-Position: refs/heads/master@{#319834}