Reland "Revert "Initial land of SkSL DSL.""

This reverts commit a3b8ac76e506dd4f1d25697f6a4255f991d48447.

Reason for revert: Need to revert again, red tree.

Original change's description:
> Revert "Revert "Initial land of SkSL DSL.""
>
> This reverts commit dd213e9d46f9542aadb5658edb430c95f476d57e.
>
> Change-Id: I43be020dd1b07dc13862150a9d95493f8c48b3b1
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/342622
> Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: John Stiles <johnstiles@google.com>
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

TBR=brianosman@google.com,ethannicholas@google.com,johnstiles@google.com

# Not skipping CQ checks because this is a reland.

No-Presubmit: true
No-Try: true
Change-Id: I8e967ef8ecb7f01dc578d38264e2600b04e9b62d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/342917
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
34 files changed