Make reducedShaderMode a shader cap

Allows GrProcessors to change behavior based on cap.

Bug: skia:11844
Change-Id: I4378c47c50a9bf33fa7461c6b9c522413e932bcd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/395717
Commit-Queue: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Auto-Submit: Brian Salomon <bsalomon@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
4 files changed