GitLab

Cleanup born from move of printing::ColorModel enum into mojom in
r799398.  Reduce the number of static_cast<int> in the code by updating
the API to accept printing::mojom::ColorModel in as many places as
possible.

Bug: 809738
Change-Id: Ib1d0024a94e21b9bf982174d99e85b04616f1009
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2368082Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Alan Screen <awscreen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802847}