add friendly new ctor for xform steps

This isn't even used, so it definitely definitely
will have no perf impact.

Change-Id: I3e459bce440aef5e3e8fa2724dd2839b866920b6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/257656
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed