GitLab

1. Implemented Vulkan backed skia representation of
SharedImageBackingAHB.
2. Added synchronisation between gl backed and Vk backed
representations.

Bug: 891060
Change-Id: I46ba32dea62569cd67d6f3b24559f4ef28307168
Reviewed-on: https://chromium-review.googlesource.com/c/1370471Reviewed-by: Eric Karl <ericrk@chromium.org>
Commit-Queue: vikas soni <vikassoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618320}