ARC CUPS API IPP request (oop)Validation service

This service will serve the ARC CUPS API by accepting an IPP request via
mojom calls, validate its format in a heavily restricted/jailed process,
and return the result.

This change just contains the scaffolding for the service,
validation/jailing to follow soon.

Test: WIP
Bug: chromium:831913
Change-Id: I5cd88b82746d999743e3ebddfc6aef15e408506d
Reviewed-on: https://chromium-review.googlesource.com/1121108
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Commit-Queue: Luum Habtemariam <luum@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575877}
19 files changed