Add SkNamedGamut::kXYZ (ie, the identity matrix)

Sometimes useful when setting up transforms. And we didn't have a simple
way to reference/create an identity skcms_Matrix3x3 yet.

Bug: skia:
Change-Id: Ic35045f38e9c9a75133bf9167f165fcc6790bd69
Reviewed-on: https://skia-review.googlesource.com/c/181662
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed