Could be added to gaLayers. Right now, this service is map agnostic.

Also, I think this new component will need to take care of other things as well. We have different kinds of layers: background, cataloglayers* (wms, wmts, aggregate), kml import layers*, wms import layers*, preview layers (in search, catalogtree, wms import), feature layers for redlining, feature layers for measurements, etc. Those denoted with * are part of the layer list. For all of these, order needs to be managed and maintained by this service.