GitLab

This CL adds the AppLaunchHandler class to call FullRestoreReadHandler
to read the full restore data from the full restore data file on a
background task runner, and restore apps and web pages based on the
user preference or the user's choice.

The apps can be re-launched for the restoration when:
1. There is the restore data for the app.
2. The user preference sets always restore or the user selects 'Restore'
from the notification dialog.
3. The app is ready.

If one of the above 3 conditions is not ready, wait until all of them
are ready.

BUG=1146900

Change-Id: I0ac76e856458d762cbda1606432e26f8bf08447d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2599646Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Nancy Wang <nancylingwang@chromium.org>
Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841282}