Revert "Revert 193798 "Revert r192949 "Disable shader disk cache by defa...""

Revert "Revert 193798 "Revert r192949 "Disable shader disk cache by defa...""

The automation_proxy don't appear in the build run where this was committed.
Doesn't seem like this is the root cause of the issues.

> Revert 193798 "Revert r192949 "Disable shader disk cache by defa..."
>
> Reverting seems to fix memory_test test locally on linux.
>
> BUG=230085
>
> > Revert r192949 "Disable shader disk cache by default."
> >
> > This reverts commit r192949. The disable has been merged into
> > M27 so re-enabling on trunk.
> >
> > BUG=228989
> >
> > Review URL: https://chromiumcodereview.appspot.com/13872012
>
> TBR=dsinclair@chromium.org
>
> Review URL: https://codereview.chromium.org/13924005

TBR=tonyg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=195083

[commit-bot: I haz the power, 2013-04-18 19:57:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dsinclair@chromium.org/14119009/1

[commit-bot: I haz the power, 2013-04-18 23:52:14]

Retried try job too often on win7_aura for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win7_aura&...

[commit-bot: I haz the power, 2013-04-19 00:43:36]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dsinclair@chromium.org/14119009/1

[commit-bot: I haz the power, 2013-04-19 03:51:02]

Change committed as 195083

[groby-ooo-7-16, 2013-05-08 20:23:24]

This brought the memory issues back, WebKit Valgrind only. 

See e.g.
http://build.chromium.org/p/chromium.memory.fyi/builders/Webkit%20Linux%20%28...

Will file bug & suppression, just a heads-up