This allows us to write SkSL shaders which are valid both for use as
Runtime Effect, and for compilation with skslc targeting Metal.
Change-Id: I74e125d81865d4092e657a7d9948d2e72054bda5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/357777
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
97d18174d6