Update GrFragmentProcessor handling in Make methods in SkSL

Change-Id: I89ec73049126f3b5ff695a31a94e4816d4639fcd
Reviewed-on: https://skia-review.googlesource.com/68901
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2 files changed