// carlos canto // 09/26/14
// https://forums.adobe.com/thread/287812
var idoc = app.activeDocument;
var ilayer = idoc.activeLayer;
for (i=0; i<ilayer.layers.length; i++) {
   var sublayer = ilayer.layers[i];
   sublayer.name = sublayer.pageItems[0].name || sublayer.pageItems[0].contents;
}