SPIR-V geometry shader support

Bug: skia:
Change-Id: Ie6808eae3fb534257f79b63307c3d65391b60965
Reviewed-on: https://skia-review.googlesource.com/23141
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Chris Dalton <csmartdalton@google.com>
2 files changed