SkQP:  add slack to model

Change-Id: Id14e5d4d6c5d517c29cd09b815ede1b52604d96a
Reviewed-on: https://skia-review.googlesource.com/99322
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
1 file changed