Revert of Incrementally flush GrDrawTarget (patchset #8 id:130001 of https://codereview.chromium.org/1386463004/ )

Reason for revert:
breaking bots

Original issue's description:
> Incrementally flush GrDrawTarget
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/a7e878064509ef96b54d5507dab0b50def66dc13

TBR=robertphillips@google.com,bsalomon@google.com,joshualitt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1386683002
2 files changed