Added bound computation to SkClipStack

http://codereview.appspot.com/6419048/

This will require re-baselining of complexclip* and filltypespersp



git-svn-id: http://skia.googlecode.com/svn/trunk@4730 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed