stop calling legacy 255-biased colormatrix

... but keep the apis for now

Bug: skia:4872
Bug: skia:9012
Change-Id: I3a9b0c9194be6897c0e59b7edd972b7218168183
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/211343
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
22 files changed