Use canonical colors for luminance color

We tried an experiment using the full color to see if there were
any performance problems. There were some perf regressions caused by creating
more cached strikes because the keys were created using full
color instead of a canonical color. Change back to using
canonical color.

BUG=chromium:929858

Change-Id: Ief8fb9dc21e118547fcac958d63498b22cc79b95
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/193376
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
2 files changed