added SkSLNodeArrayWrapper

Not yet used as of this CL.

Change-Id: Ic82ab5e2e2ca17fb11c16e22cfa6b7ad5ff74c77
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/328657
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
3 files changed