GrRRectBlurEffect uses child for nine patch

Bug: skia:10139

Change-Id: Ic306775bb8d1f5d8b29cc38c116d0f8c3e0d55a2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297193
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
3 files changed