Push API: Fix registration failing because app handler is missing

Push API: Fix registration failing because app handler is missing

A regression was introduced by https://codereview.chromium.org/823993003
whereby the first push registration only works if the user is signed in,
and hence an AppHandler happens to be added by sync. Instead Push should
add AppHandlers for pending registrations so there is always an app
handler while we are trying to register.

BUG=456054
Committed: https://crrev.com/126aba183c8281e3ba2351ed595b53bd1b2f3d6f
Cr-Commit-Position: refs/heads/master@{#315019}

[johnme, 2015-02-06 11:52:28]

johnme@chromium.org changed reviewers:
+ mvanouwerkerk@chromium.org

[Michael van Ouwerkerk, 2015-02-06 12:02:07]

lgtm

Nice way of also handling multiple pending registration attempts.

[johnme, 2015-02-06 12:30:32]

New patchsets have been uploaded after l-g-t-m from mvanouwerkerk@chromium.org

[johnme, 2015-02-06 12:31:11]

The CQ bit was checked by johnme@chromium.org

[commit-bot: I haz the power, 2015-02-06 12:31:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/905713002/20001

[commit-bot: I haz the power, 2015-02-06 13:22:57]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-06 13:24:07]

Patchset 2 (id:??) landed as
https://crrev.com/126aba183c8281e3ba2351ed595b53bd1b2f3d6f
Cr-Commit-Position: refs/heads/master@{#315019}