Hide filter-quality from imagefilter::shader

Bug: skia:7650
Change-Id: Ia16f169efdb6be2ce381b9ab3b7f6fcecda26312
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/363799
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed