Format::aspect should be a mask so that it is easier to iterate over
and test if an aspect is present.
This CL also re-exports wgpu's EnumClassBitMask helpers in dawn_native.
It also adds an EnumMaskIterator which wraps BitSetIterator to allow
iterating over the enums in an enum mask.
Bug: dawn:439
Change-Id: I08180a45b27c6031e2f80b0fa1801716677fd813
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/24682
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jiawei Shao <jiawei.shao@intel.com>
Commit-Queue: Austin Eng <enga@chromium.org>
