Revert of Fast blurred rectangles on GPU

Revert of Fast blurred rectangles on GPU (https://codereview.chromium.org/119343003/)

Reason for revert:
Two problems:

1. broke compile on Build-Mac10.6-* bots
2. broke GM expectations on many bots

We'll need to examine the GM impact before re-landing.  I can work with you to do this on Tuesday if you like; just IM or email me.

Original issue's description:
> Perform the same analytic blur calculation on the GPU that we do on the CPU.  Results in significant performance gains when using Ganesh to render drop shadows in Chrome.
> 
> BUG=
> 
> Committed: http://code.google.com/p/skia/source/detail?r=13210

TBR=bsalomon@google.com,reed@google.com,humper@google.com
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: http://code.google.com/p/skia/source/detail?r=13213

[epoger, 2014-01-28 01:21:02]

Created Revert of Fast blurred rectangles on GPU

[commit-bot: I haz the power, 2014-01-28 01:21:12]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/epoger@google.com/140853008/1

[commit-bot: I haz the power, 2014-01-28 01:21:17]

Presubmit check for 140853008-1 failed and returned exit status 1.

Running presubmit commit checks ...

** Presubmit ERRORS **
Since the CL is editing public API, you must have an LGTM from one of:
('reed@chromium.org', 'reed@google.com', 'bsalomon@chromium.org',
'bsalomon@google.com')

[rmistry, 2014-01-28 01:51:33]

LGTM

[commit-bot: I haz the power, 2014-01-28 01:55:08]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/epoger@google.com/140853008/1

[commit-bot: I haz the power, 2014-01-28 01:55:30]

Change committed as 13213