[canvaskit] Add flexibility to setColor API

Change-Id: Ib0946bb05bc5cbf485a6687e46c7e61312bcd24c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/293344
Reviewed-by: Yegor Jbanov <yjbanov@google.com>
Reviewed-by: Nathaniel Nifong <nifong@google.com>
8 files changed