more skcolorspace cleanup

This time with infinitely less stack usage.

Change-Id: Ic0b4662203eb2787fd9d793fee65ebcd592ad5f3
Reviewed-on: https://skia-review.googlesource.com/151420
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed