Transform verts using nonsquare matrices in FPs.

IF THE CHROME ROLL BREAKS, ROLL BACK THIS CL!

This relands one portion of http://review.skia.org/403079, which was
rolled back due to a Chrome roll issue (a pixel-gap introduced in a form
rendering test).

Change-Id: I3d8f900c80c79f20e876ae360a93febe16a0a4bc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/406836
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
1 file changed