[graphite] Be explicit about pending draws on DrawContext destruction

Bug: skia:12466
Change-Id: I266ee1ae865e85f778191c7812b690e203bb4df4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/471096
Auto-Submit: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
1 file changed