Add effect for ellipse clipping.

BUG=skia:2181
R=jvanverth@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/218583013

git-svn-id: http://skia.googlecode.com/svn/trunk@14024 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed