Revert of Turn SkTaskGroups back on. (patchset #1 id:1 of https://codereview.chromium.org/687263007/)

Reason for revert:
precautionary revert.  may have caused WinXP crashes on Chrome tree: https://code.google.com/p/chromium/issues/detail?id=429207

Original issue's description:
> Turn SkTaskGroups back on.
>
> Revert "Disable SkTaskGroup in SkMultiPictureDraw temporarily."
> Revert "Revert harder, removing SkTaskGroup.cpp from core temporarily."
>
> NOTREECHECKS=true
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/2100c5ed7a5e5470a04e7af7309d8bd3fc4249f7

TBR=reed@google.com,mtklein@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/693993002
GrContext no longer ever draws on Gpu

BUG=skia:

Review URL: https://codereview.chromium.org/683733005
Revert of GrContext no longer ever draws on Gpu (patchset #7 id:120001 of https://codereview.chromium.org/683733005/)

Reason for revert:
breaks some android bots

Original issue's description:
> GrContext no longer ever draws on Gpu
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/7a75e5230872732e71ea99058d9afe5d4b6758b0

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

Review URL: https://codereview.chromium.org/694983002