Move GrOpFlushState out of GrDrawingManager and onto the stack

Change-Id: If1b3481af7637bfed8a73d75be41c6422319951f
Reviewed-on: https://skia-review.googlesource.com/96540
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
10 files changed