This simplifies life when revising the swizzle logic.
Change-Id: I7fc63c0cc845c4741c17c82b3078040264b61ba0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/317379
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
