Revert of Use approximate scratch textures for image filters.

Revert of Use approximate scratch textures for image filters. (patchset #1 id:1 of https://codereview.chromium.org/679113004/)

Reason for revert:
Images change on some machines. Mostly look OK but not sure about imagefiltersbase on N5.

Old"
http://chromium-skia-gm.commondatastorage.googleapis.com/gm/bitmap-64bitMD5/imagefiltersbase/11449357083048653160.png

New:
http://chromium-skia-gm.commondatastorage.googleapis.com/gm/bitmap-64bitMD5/imagefiltersbase/14279906119350384263.png

Original issue's description:
> Use approximate scratch textures for image filters.
> 
> Committed: https://skia.googlesource.com/skia/+/96c60686eef6fc514feba6136f1b475f71dbf3ec

TBR=senorblanco@google.com,senorblanco@chromium.org
NOTREECHECKS=true
NOTRY=true

Committed: https://skia.googlesource.com/skia/+/a9a80e5f427e02efe7289f3784cf047d12a0b5bd

[bsalomon, 2014-10-27 19:58:30]

Created Revert of Use approximate scratch textures for image filters.

[commit-bot: I haz the power, 2014-10-27 19:58:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/664823003/1

[commit-bot: I haz the power, 2014-10-27 19:59:08]

Committed patchset #1 (id:1) as a9a80e5f427e02efe7289f3784cf047d12a0b5bd