Use SkSwizzler to convert from CMYK

Move convert_CMYK_to_RGBA into two functions in SkSwizzler: one for 565
and one for 8888.

For simplicity, when converting to 8888, we no longer convert in place.

BUG=skia:4476

Review URL: https://codereview.chromium.org/1411083009
4 files changed