Fixed issues found by fuzzer

Fixed issues found by fuzzer

Last week, the fuzzer found a few numerical issue with filters and I had written some fixes for them. Here are the fixes with some unit tests.

For senorblanco : So I figured out what was asserting when we'd get a 0 width "result" in SkBicubicImageFilter::onFilterImage(). Basically, if the "result" SkBitmap object calls SkBitmap::setConfig() with "width" and/or "height" set to 0, then the SkBitmap object will call SkBitmap::reset(), making the SkBitmap object's config invalid. At this point, calling SkBitmap::getAddr32() will assert, even without attempting to dereference the data pointer, because the SkBitmap's config is invalid. If height is valid, but width is 0, then this call to SkBitmap::getAddr32() happens directly in SkBicubicImageFilter::onFilterImage() a few lines lower and asserts right away.

BUG=

Committed: http://code.google.com/p/skia/source/detail?r=11249

[Stephen White, 2013-09-09 17:47:30]

LGTM

[commit-bot: I haz the power, 2013-09-10 13:39:55]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/sugoi@chromium.org/23533042/1

[commit-bot: I haz the power, 2013-09-10 13:39:59]

Presubmit check for 23533042-1 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')

[sugoi1, 2013-09-10 13:42:43]

Adding bsalomon@ for approval.

[bsalomon, 2013-09-10 13:46:02]

On 2013/09/10 13:42:43, sugoi1 wrote:
> Adding bsalomon@ for approval.

lgtm

[commit-bot: I haz the power, 2013-09-10 13:53:35]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/sugoi@chromium.org/23533042/1

[commit-bot: I haz the power, 2013-09-13 12:40:07]

Change committed as 11249