GitLab

Restores the arc app notification badging on shelf icons by re-wiring
ArcNotificationManager get app id code path through mojo.

- Change ArcNotificationManager to handle get app id asynchronously;
- Add GetArcAppIdByPackageName to AshMessageCenterClient mojo interface;
- ArcNotificationManager use the mojo call to get app id;

Bug: 768439
Change-Id: I199636b374d539677d93e35be1fd4f7b9b900bca
Reviewed-on: https://chromium-review.googlesource.com/1012123Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553603}