Clamp ambient blur radius

Bug: skia:8078
Change-Id: I8a45ce49b236ae0ad4c2176be71011c372c316ce
Reviewed-on: https://skia-review.googlesource.com/135861
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed