[google_maps_flutter] FlutterMain has been deprecated #70923

  private static BitmapDescriptor toBitmapDescriptor(Object o) {
    final List<?> data = toList(o);
    switch (toString(data.get(0))) {
      case "defaultMarker":
        if (data.size() == 1) {
          return BitmapDescriptorFactory.defaultMarker();
        } else {
          return BitmapDescriptorFactory.defaultMarker(toFloat(data.get(1)));
        }
      case "fromAsset":
        if (data.size() == 2) {
          return BitmapDescriptorFactory.fromAsset(
              FlutterMain.getLookupKeyForAsset(toString(data.get(1))));
        } else {
          return BitmapDescriptorFactory.fromAsset(
              FlutterMain.getLookupKeyForAsset(toString(data.get(1)), toString(data.get(2))));
        }
      case "fromAssetImage":
        if (data.size() == 3) {
          return BitmapDescriptorFactory.fromAsset(
              FlutterMain.getLookupKeyForAsset(toString(data.get(1))));
        } else {
          throw new IllegalArgumentException(
              "'fromAssetImage' Expected exactly 3 arguments, got: " + data.size());
        }
      case "fromBytes":
        return getBitmapFromBytes(data);
      default:
        throw new IllegalArgumentException("Cannot interpret " + o + " as BitmapDescriptor");
    }
  }