Made it private and accessible internally via SkCanvasPriv.
Update SkGpuDevice methods/variables after rename of GrDrawSurfaceContext.
Cq-Include-Trybots: luci.skia.skia.primary:Canary-G3,Canary-Flutter,Canary-Android
Change-Id: I3da64cee1de03c201243ee6c7ccd4b4c44cad8c9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/346498
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>