This is a quick implementation which supports only one backing Image
and one type of ImageView at a time, for 2D texture only.

It also implements a helper class for finding compatible memory pools.
It's possible we can keep a cache of memory pool indexes given the
guarantees the Vulkan spec has on compatible memory types (see the
documentation for VkMemoryRequirements).

BUG=angleproject:2167

Change-Id: I1d7a8eaec90f240273ad75194e23430d6d4c5dc1
Reviewed-on: https://chromium-review.googlesource.com/680000
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Frank Henigman <fjhenigman@chromium.org>