Rewrite some SkWuffsCodec designated initializers

This should have been part of 48aa221 "Update Wuffs version", but was
missed.

Bug: skia:8235
Bug: skia:8764
Change-Id: I3d73ca71872431955ad66d67de4166bdda0a1071
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/206141
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
1 file changed