Added DSL support for static if & switch statements

Change-Id: If11443997ae29266bf46da77c1e4f9583fa3f5a5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/402577
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
6 files changed