Simplify SkSL::Setting code dramatically

These values are always bool, so we can eliminate several levels of
indirection.

Change-Id: I074e9bd7a8f984776f4c710f640d761dee4258c2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/546862
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed