add optional cull-rect to patheffects, so they can do less work if their results
lie outside of the current clip-bounds (the cull rect).
Review URL: https://codereview.appspot.com/7206044

git-svn-id: http://skia.googlecode.com/svn/trunk@7378 2bbb7eff-a529-9590-31e7-b0007b416f81
21 files changed