Add Caps bit to enable WGSL code generator.

This flag will allow us to transition from SPIR-V to WGSL for
Graphite Dawn.

Bug: b/40044196
Change-Id: Ib1ffea063dc57527bfbdb06ea6a620a8762be668
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/745061
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
4 files changed