Revert "[graphite] SurfaceDrawContext -> DrawContext"

This reverts commit a525fd141bbde7c226f98c223d4b59d064189220.

Reason for revert: missed updating sdc->dc in one spot

Original change's description:
> [graphite] SurfaceDrawContext -> DrawContext
>
> Bug: skia:12466
> Change-Id: If4a06bc0ab8befab8a155276c316ba9378b90a48
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/455658
> Commit-Queue: Michael Ludwig <michaelludwig@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

Bug: skia:12466
Change-Id: I60e316225d44d7046bc82c80fe42345d8941f99e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/455662
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
8 files changed