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Based on go/crostini-self-activate, we implement the wiring to allow
crostini windows to activate themselves. This involves:
 - Hooking the surface request up to the shell_surface
 - Building the exo::Permission framework suggested by oshima@
 - Building utilities to grant and revoke permissions
 - Hooking the shelf app controller up so it can grant and remove
   permissions.

This is a remake of crrev.com/c/1850690

Bug: 899587
Change-Id: Ib9c5af8a876fe190fc72be86b873170186c62c0d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935771
Commit-Queue: Nic Hollingum <hollingum@google.com>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721883}