Add RasterPipeline implementation for SkColorSpaceXform

This is initially turned on for Linux debug builds,
which allows us to start testing.

Chrome for Android is a really good candidate for
this (will appreciate the code size savings), but
I'd first like to run some tests to understand the
performance/size tradeoffs a little better.

BUG:660416

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD

Change-Id: I0fb2512216dfc0bda2e5388f9865318eec22291e
Reviewed-on: https://skia-review.googlesource.com/5348
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
4 files changed