With this extension, it is possible to import Vulkan images into ANGLE
(similar to EXT_external_objects) while specifying the Vulkan create and
usage flags used to create that image.  This can be used by the
application to drop usage flags it does not need to improve performance,
or add create flags as it requires.

Bug: angleproject:4912
Bug: fuchsia:52759
Change-Id: Ia568973b19670999dd0e69f6ac5548e8ef0c3eec
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2335020
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>