Added SkSL Literal type

Previously kScalar was doing double-duty and standing in for both scalar
and literal types. This breaks it out into a separate enum value.

Change-Id: Ic975eeba87fb430d9fe183e284107f6aaff9b244
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/425180
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
1 file changed