[App Management] Link UI to backend permissions.

This CL updates the front end of the app management page to use the
real Permission struct, and links the UI components to the backend
SetPermission method, allowing the permissions of real apps to be
toggled from the UI.

Bug: 906508
Change-Id: Ia401df34e138893d8186c67413588aafdadafc19
Reviewed-on: https://chromium-review.googlesource.com/c/1404538
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Commit-Queue: Reka Norman <rekanorman@google.com>
Cr-Commit-Position: refs/heads/master@{#621917}
17 files changed