Did a small test and it is easy to draw the on the map. Here my test code.
<dmx-google-maps id="maps1" onready="drawPath(this)" width="800" zoom="3" latitude="0" longitude="-180" maptype="terrain"></dmx-google-maps>
<script>
function drawPath(component) {
var map = component.map;
var flightPlanCoordinates = [
{lat: 37.772, lng: -122.214},
{lat: 21.291, lng: -157.821},
{lat: -18.142, lng: 178.431},
{lat: -27.467, lng: 153.027}
];
var flightPath = new google.maps.Polyline({
path: flightPlanCoordinates,
geodesic: true,
strokeColor: '#FF0000',
strokeOpacity: 1.0,
strokeWeight: 2
});
flightPath.setMap(map);
}
</script>