The Bing and Google support was written for two specific Leaflet plugins, so if you want to use them with this BasemapBar control you should use those same ones.
new L.Control.BasemapBar({ layers:basemap_listing }).addTo(map);
Constructor Options
* _layers_ -- A list of layer descriptions, comprising the basemap choices available. See _Layer Types_ below for details on supported layer types.
* _position_ -- The usual L.Control positioning for the control; defaults to 'topright'
Layer Types
The _layers_ parameter is a list of object literals, each one describing a basemap option.
All basemap options must have a _type_ attribute and a _label_ attribute. Depending on the type, additional options are required.
The _label_ attribute must be unique as it is both the visible label for the basemap option, and also the unique identifier for the layer instance.
* An ordinary L.TileLayer
* type:'xyz' * label -- The unique name, and also and visible label, of this basemap option.
* tooltip -- A tooltip displayed when the mouse hovers over the button for this layer. Optional, default to "".
* url -- The URL template for this L.TileLayer. Passed to L.TileLayer as-is.
* tileLayerOptions -- An object of other options to be passed to the L.TileLayer as-given, e.g. subdomains and attributions.
* A Bing basemap option
* type:'bing' * label -- The unique name, and also and visible label, of this basemap option.
* url -- Which Bing basemap offering? Valid values are: _street_ _aerial_ _aerialwithlabels_
* A Google basemap option
* type:'google' * label -- The unique name, and also and visible label, of this basemap option.
* url -- Which Google basemap offering? Valid values are: _streets_ _satellite_ _hybrid_ _terrain_