GitLab

This enables initializing vulkan and offscreen rendering but not
presentation.

Bug: 851997
Test: ozone_demo gets past vulkan instance creation on
  eve build with vulkan support

Change-Id: I14f56fb4e22c0cdc275aaead3e734f59e18722a9
Reviewed-on: https://chromium-review.googlesource.com/1104862
Commit-Queue: Michael Spang <spang@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569976}