A ground overlay is an image that is fixed to a map. A ground overlay
has the following properties:
The amount that the image should be rotated in a clockwise direction. The center of the rotation will be the image's anchor. This
is optional and the default bearing is 0, i.e., the image is aligned
so that up is north.
GoogleMap map = ...; // get a map.
BitmapDescriptor image = ...; // get an image.
LatLngBounds bounds = ...; // get a bounds
// Adds a ground overlay with 50% transparency.
GroundOverlay groundOverlay = map.addGroundOverlay(new GroundOverlayOptions()