[App Management] Add permissions to fake backend.

This CL adds a permissions map to the app struct used by the fake
backend, and allows these permissions to be toggled in the PWA
permission view.

Bug: 906508
Change-Id: I292671d5f4fa9034fac10eba421380aaef8367ad
Reviewed-on: https://chromium-review.googlesource.com/c/1388128
Reviewed-by: calamity <calamity@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Reka Norman <rekanorman@google.com>
Cr-Commit-Position: refs/heads/master@{#619596}
21 files changed