fix fiddle with blur

Docs-Preview: https://skia.org/?cl=114018
NOTRY=true
R=caryclark@google.com
Bug: skia:6898
Change-Id: Ied96a0b8479a9b359299ba24ecfa55022046beb0
Reviewed-on: https://skia-review.googlesource.com/114018
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@skia.org>
3 files changed