Use viz::ResourceID instead of unsigned

BUG=788439

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I47143c9c80e8f53082420ff32a08fc64114ee08c
Reviewed-on: https://chromium-review.googlesource.com/1053094
Commit-Queue: Justin Novosad <junov@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557527}
4 files changed