Accept SkFilterQuality in SkImageFilters::Shader

This is needed to help ease the migration from SkImageFilters::Paint,
until image shaders always force you to embed sampling options.

Change-Id: Id8dc8c3196a7935073677a5fbb8d35c3bd22f9ba
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/333757
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
2 files changed