Revert "Revert "Initial checkin of SkSL lexical analyzer generator (not actually in use yet).""

This reverts commit 3ed4781ee1bd5af9b3ee2623e5356e86ce36e812.

Bug: skia:
Change-Id: If0de7ca17c4da8000d3526a73b71be6ee34ce060
Reviewed-on: https://skia-review.googlesource.com/43561
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
15 files changed