Add quad type and persp/aa utilities to GrQuad

This refactor makes some of the quad logic in GrTextureOp available for
use with other quad GrOps.

Bug: skia:
Change-Id: I1c173cfdf61b33c8422ddd8b91406a970a1c8e5d
Reviewed-on: https://skia-review.googlesource.com/c/163253
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
3 files changed