Add PrePreparedDesc to GrTextureOp

This centralizes the information we are preparing and reduces duplicate computation (e.g., of the VertexSpec).

Change-Id: Iac2c4d0890389e641ee9a7453dace31c0a4ca965
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249983
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
2 files changed