Revert "have SkConvertPixels use SkColorSpaceXformSteps"

This reverts commit 6d0e566e941b09f5f9fb9f5a95c123459409c4ad.

Reason for revert: broke flutter post-roll, apparently

Original change's description:
> 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>

TBR=mtklein@google.com,brianosman@google.com

Change-Id: Ie32c763bb637f959696c4458826a02919938a578
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/156008
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
1 file changed