add operator-> to Color and HSLA

Change-Id: I0819a89feea5576bd914f47fcb7a84c440ab46bb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/280982
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
1 file changed