GPU version of onMakeColorSpace

New fragment processor that implements end-to-end
color space conversion, with nonlinear blending.

BUG=skia:6242

Change-Id: Ied86170fc28537a2bc209d57530d3ded48b467a9
Reviewed-on: https://skia-review.googlesource.com/9543
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
6 files changed