centralize internal headers into skcms_internal.h

This is the first of many refactors, roughly:

  1) centralize internal headers into skcms_internal.h
  2) centralize implementation into skcms.c
  3) trim down skcms_internal.h where possible
  4) convert skcms.c to skcms.cc
  5) update impl of transform to not need Transform_inl.h hack
  6) finally start on F16 transforms

In the end we should be left with skcms.h and skcms.cc,
and skcms_internal.h and all our existing test tools.

Change-Id: Ifce1325f0b35e9a7958ee156e3e02e9cdef340e4
Reviewed-on: https://skia-review.googlesource.com/138928
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@chromium.org>
21 files changed