Two questions:
If a layer has more than one legendInfos can we use the symbols in all the legendInfos to create AGSCompositeSymbol and then swatch? or AGSCompositeSymbol is different?
If there are different type of layers, what is common way for get Symbol, e.g. map have AGSArcGISMapImageLayer its legendInfos are 0. However when I use LegendViewController from one of your examples, it load the symbol.