encode F16Norm as rec2020

Just a debugging aid to help diffing against esrgb.

Change-Id: I5e4991f598a7b00a0d903fddcf3a05a396c0536d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/198221
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed