Add choke point for modifying non-AA rect draws (e.g., applying clipping)

NOTREECHECKS=true
NOPRESUBMIT=true

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2125333002

Committed: https://skia.googlesource.com/skia/+/e5e3a7a5203f256083d015c923cc9c662877aba9
Review-Url: https://codereview.chromium.org/2125333002
6 files changed