Expose aaType in simple mesh draw op helper

Ops that use the SimpleMeshDrawHelper but also need to make decisions on
the aa type need access to the aa type that the helper stores.

Bug: skia:
Change-Id: I52dfbd89ead550de68fea96078dd6600620ad6cf
Reviewed-on: https://skia-review.googlesource.com/c/167389
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
1 file changed