Cleaning up SkColorSpaceXform a bit

Remove SkColorSpaceXform_base from the inheritance chain. Move some
enums only used within XYZ to be class scoped. Eliminate redundant
context structs, and just use the SkJumper types directly.

SkColorSpaceXform_Base still exists, but just to hold a couple static
functions. Trying to untangle the dst gamma table mess next.

Bug: skia:
Change-Id: I6d2b7807c33e61a0d7df74e334356567d8a2c0e0
Reviewed-on: https://skia-review.googlesource.com/112601
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
8 files changed