Uncached memory is an optimal memory type for resources with
write-only access from the CPU since it avoids polluting CPU caches
with data the CPU will never use.

Bug: angleproject:2162
Change-Id: I33d0d91830979990bcdcca3bd9eedde0345fb5a6
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2131880
Commit-Queue: Mohan Maiya <m.maiya@samsung.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>