Fix for thin filled and hairline roundrects.

Fix for thin filled and hairline roundrects.

The roundrect renderer was dropping into the
ConvexPathRenderer when it didn't need to -- if a stroke is 
just on the edge of being acceptable it will now use the 
roundrect renderer.

BUG=Skia:1802
Committed: http://code.google.com/p/skia/source/detail?r=12168

[robertphillips, 2013-11-06 16:13:25]

lgtm short term but don't we still have a problem with the convex path renderer?

[jvanverth1, 2013-11-06 16:23:34]

On 2013/11/06 16:13:25, robertphillips wrote:
> lgtm short term but don't we still have a problem with the convex path
renderer?

Yes, I'm going to look at that next. I believe rrects narrower than their
half-stroke may still fail.

[commit-bot: I haz the power, 2013-11-06 16:34:43]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/jvanverth@google.com/59903005/1

[commit-bot: I haz the power, 2013-11-07 16:34:40]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/jvanverth@google.com/59903005/1

[commit-bot: I haz the power, 2013-11-07 16:34:56]

Change committed as 12168