use (temp) gpu-imagefilter-cache for applyFilter

use (temp) gpu-imagefilter-cache for applyFilter

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/13ccbf8a681d69e4685849d9dedeabea0fea7773

[reed1, 2015-10-20 16:39:35]

reed@google.com changed reviewers:
+ bsalomon@google.com, mtklein@google.com

[reed1, 2015-10-20 16:39:36]

ptal

this should fix the valgrind memory leak, since now we explicitly tear-down the
"cache" after each usage (as we already to in the drawing case.)

[reed1, 2015-10-20 16:39:44]

The CQ bit was checked by reed@google.com

[commit-bot: I haz the power, 2015-10-20 16:39:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1414653003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1414653003/1

[commit-bot: I haz the power, 2015-10-20 16:39:47]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-10-20 22:39 UTC

[bsalomon, 2015-10-20 16:41:50]

lgtm

[mtklein, 2015-10-20 16:50:18]

lgtm

[commit-bot: I haz the power, 2015-10-20 16:56:55]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/13ccbf8a681d69e4685849d9dedeabea0fea7773