Try out refFoo pattern on GrRenderTargetContext

Change-Id: Ifae5618f30c2202b9083f479b58556709ff6126a
Reviewed-on: https://skia-review.googlesource.com/6990
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
10 files changed