Add a DirectContextID to GrDirectContexts

Bug: skia:11728
Change-Id: I80ab54f2cfa0bbc69f688e1e598eeeb4bde1a1a4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/383023
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
3 files changed