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This allows making default app customization based on user type. For
example make Youtube TV as default app on nocturne users only for
unmanaged apps.

This is implemeted similar to crrev.com/c/851338 that introduced the
same concept for crx default apps.

TEST=Locally (together with crrev.com/i/755690) + unit tests
BUG=902978

Change-Id: I78d5e3da4150d6d0e1f374261113d9cdfb80260a
Reviewed-on: https://chromium-review.googlesource.com/c/1391870
Commit-Queue: Yury Khmel <khmel@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619575}