Simplify SkSL::Setting code dramatically
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 <f4fcf42d3bb5924557f1eeb3be66747535e585da@google.com>
Commit-Queue: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>

google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia