Add some SkASSERT's, to try to track down a reliability issue in Chrome.

http://codereview.appspot.com/105075
http://crbug.com/17569



git-svn-id: http://skia.googlecode.com/svn/trunk@317 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed