Add abs support to RP builder.

Change-Id: Ib362fea3e09f68e58b9366b4b87e9a9fa4cf07ff
Bug: skia:13676
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/626239
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
2 files changed