FXC has trouble dealing with these.
This was originally added to handle returning arrays as structures.
HLSL supports typedefs, which is a much simpiler solution, and doesn't upset FXC.
Bug: tint:848
Bug: tint:904
Change-Id: Ie841c9c454461a885a35c41476fd4d05d3f34cbf
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/56774
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>