ccpr: Don't do coverage count transformations on literal coverage atlases

Previously we would just run coverage count transformations on
everything, including cached literal coverage atlases. This was
wasteful since it isn't necessary if the atlas already has literal
coverage. MSAA mode will introduce even more atlases that don't need
coverage count transformations, so it's definitely time to clean this
up.

Bug: skia:
Change-Id: Ifc72eaa7cbd4ab5e4ef4acb5610117ae9f54e4c1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/227144
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
5 files changed