Add SkMeshSpecification::findChild accessor.

This will allow users to find their child indices more easily,
and matches the existing findUniform/etc. accessors.

Bug: b/40045302
Change-Id: I3e092431443754eb6cfbeb853d2740ae8a2c3848
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/760097
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
3 files changed