Add debug trap to track down crash.

Original CL by arthurhsu: http://codereview.appspot.com/5144046/

BUG=CR 94421

Review URL: http://codereview.appspot.com/5132051

git-svn-id: http://skia.googlecode.com/svn/trunk@2344 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed