Remove option to make GrCoordTransforms apply to device positions.

Remove option to make GrCoordTransforms apply to device positions.

Adds a device space texture decal effect to use for clipping.

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2870

Change-Id: Ifcc7617ea87f5a86e301995cba9dfc30a4b0e2c5
Reviewed-on: https://skia-review.googlesource.com/2870
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>