Centralize SkColorInfo in SkSpecialImage base class (take 2)

This is a bit of a reversal of:
https://skia-review.googlesource.com/c/skia/+/572247 (Update SkSpecialImage_Gpu to use GrColorInfo)

but I believe it makes the SkSpecialImage class a bit less cumbersome.

Bug: b/241427862
Change-Id: I3f53521751859596b244a9f58068bbfe0c01b287
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/574696
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
3 files changed