Note: works for well-formed poly-to-poly (perspective) transforms, but
doesn't support AE's degenerate corners semantics (concave/inverted
polys) at this point.
Bug: skia:10100
Change-Id: I5b3492b008302495b616867c139c6e5ad6dc57df
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281595
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
