Revert of Add BW masks to random scaler context (patchset #1 id:1 of https://codereview.chromium.org/1270793003/)

Reason for revert:
breaks mac

Original issue's description:
> Add BW masks to random scaler context
>
> TBR=bsalomon@google.com
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/a4a530614e9ba856aac3f16c29683e6a2a9153d9

TBR=joshualitt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1264843003
2 files changed