Added DSL modifiers declarations

Change-Id: I97a7c5cfb3ce3f430074092616a3256422c8ad5e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/444979
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
4 files changed