Add Context factories to GrDirectContext

In order to stage the transition from GrContext to GrDirectContext, both
of them will have to have the factories for a while.

This CL also removes all internal uses of the old (GrContext) factories.

Change-Id: Ibe1edd0818ea23a0d54257c55f35f12526047ef3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302263
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Adlai Holler <adlai@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
36 files changed