<apex:page StandardController="Account" extensions="AccountHierarchyChartController" sidebar="false" showHeader="false">

<script type='text/javascript' src='https://www.google.com/jsapi'></script>
<script type='text/javascript'>
    google.load('visualization', '1', {packages:['orgchart']});
    google.setOnLoadCallback(drawChart);
    function drawChart() {
        var data = new google.visualization.DataTable();
        data.addColumn('string', 'Name');
        data.addColumn('string', 'Manager');
        data.addColumn('string', 'ToolTip');
        
            data.addRows([         
                  {!ContactData}
            ]);
        var chart = new google.visualization.OrgChart(document.getElementById('chart_div'));
        chart.draw(data, {allowHtml:true});
    }
</script>
    <div id='chart_div' style="font-size:18px;"></div>
</apex:page>