Revert of some cleanup around GrGpu/GrDrawTarget copySurface (patchset #3 id:40001 of https://codereview.chromium.org/749903003/)

Reason for revert:
likely causing es rendering errors.

Original issue's description:
> some cleanup around GrGpu/GrDrawTarget copySurface
>
> Committed: https://skia.googlesource.com/skia/+/e9aa5dc4d5906788eaf691d7c69f1494928f401d

TBR=joshualitt@google.com
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/763593002