send 3D masks through raster pipeline blitter

This makes the emboss mask filter work correctly with anything that's
SkRasterPipeline-only, like color filters or color spaces.

PS5 implements lowp too.

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ic2bf4d37a0f85670f47ec875e692e5b4cdc02271
Reviewed-on: https://skia-review.googlesource.com/c/168620
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
5 files changed