Don't apply blur to zero-sized circles

Bug: skia:7452
Change-Id: I7aac621cba8519174d306d9d304aa72a07947f46
Reviewed-on: https://skia-review.googlesource.com/91444
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed