Implement submit API to GrContext.

Change-Id: Ib813d42abb5f63e2ecdbf245d416658143853288
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/289033
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
14 files changed