test.js

   <script type="text/javascript">
google.load('visualization', '1', {packages: ['corechart']});

  //pass the infowindow as argument, we need it later
function drawVisualization(infowindow) {
  var queryText = encodeURIComponent("SELECT Year, Austria, Bulgaria, \
                                      Denmark, Greece FROM 641716");

    /*note:      we don't need the ContainerId here, 
                 we use the node-reference with draw
     *also note: we use ChartWrapper here, because we need 
                 the ready-event of the chart to redraw the infowindow
    */
  var chart=new google.visualization.ChartWrapper({
    "dataSourceUrl": 'https://www.google.com/fusiontables/gvizdata?tq=',
    "query":"SELECT Year, Austria, Bulgaria, Denmark, Greece FROM 641716",
    "refreshInterval": 5,
    "chartType": "PieChart",
    "options": {
      "title":"Yearly Coffee Consumption by Country",
      "vAxis": {"title": "Year"},
      "hAxis": {"title": "Cups"}
    }
  });


  var ready=google.visualization.events.addListener(chart, 'ready', function(){
      //re-assign the map-property to redraw the 
      //infowindow when the chart has been drawn
    infowindow.setMap(infowindow.getMap());
      //remove the ready-listener
    google.visualization.events.removeListener(ready);
   });

    //draw the chart
  chart.draw(infowindow.getContent().lastChild);

}

function initialize() {
    map = new google.maps.Map(document.getElementById('map-canvas'), {
      center: new google.maps.LatLng(29.296435107347698, -29.54822280000008),
      zoom: 2,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });

    var layer = new google.maps.FusionTablesLayer({
      query: {
        select: 'col0',
        from: '1PoUAVtdJKOKnJT_ZYkoM7yDpGw-wNJMHXakPeC0'
      },
      map: map,
        //don't use the infowindows of the FTLayer
      suppressInfoWindows:true
    });
      //a custom infowindow
    infowindow=new google.maps.InfoWindow();


    google.maps.event.addListener(layer, 'click', function(e) {
      //call drawVisualization when the infowindow is ready
      google.maps.event.addListenerOnce(infowindow,'domready',function(){
        drawVisualization(infowindow);
      });
        //create the content for the infowindow
      var node=document.createElement('div');
      node.innerHTML=e.infoWindowHtml;
        //create the node where the chart will be drawn
      node.appendChild(document.createElement('div'));
        //open the infowindow
      infowindow.setOptions({position:e.latLng,content:node,map:map});
     });
  }

  google.maps.event.addDomListener(window, 'load', initialize);

</script>