Simplify DSLVar assignment.

It can live in the base class instead of having matching implementations
in each subclass. Also, there didn't seem to be a reason to have a
templated and non-templated version which did the same thing.

Change-Id: I312af9e71561d847580430000fbfae6fa99fe837
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/542140
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed