explore always using SkRasterPipeline for color space transforms

On my trashcan, bench times change: mostly slowdowns, some speedups.
On the other hand, this cuts about 270K of code out of Skia.

Change-Id: Ib1069792508ced361c11ea809b0b8187f5e28a5c
Reviewed-on: https://skia-review.googlesource.com/19744
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
1 file changed