Remove GrTextureContext.

This change mostly just removes GrTextureContext and switches users to
directly creating GrSurfaceContexts. Outside of updating types, the factory
functions for creating Gr*Contexts have not been updated in this but will
be done in a followup.

Change-Id: I55257568d4c096c5fb48c5e38bfa2c01b824e7b5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/260289
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
26 files changed