Add support for matrix pre/postincrement in Metal.

The front end currently only allows scalar pre/post-increment,
so these changes can't be tested in this CL. Tests are in the
followup CL which loosens the frontend restrictions.

Change-Id: I97bb806854b6737a9ba605f66bbcaa26ab9fb466
Bug: b/40045109
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/846701
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
1 file changed