have SkConvertPixels use SkColorSpaceXformSteps

This ought to allow the fast paths in more cases, e.g. memcpy() when
both src and dst are the same format.  Today if we tag a dst color space
at all, we'll think we need to fall back to the general case pipeline.

Some refactoring too, but no big functional change beyond using steps.

Change-Id: I8fa01025229e3b9418e7f43241a2f03628a97288
Reviewed-on: https://skia-review.googlesource.com/155640
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
1 file changed