I am trying to render Google Visualization API (google charts) on ExtJS 4 panel, but no luck.

Getting the following error :
1. Uncaught TypeError: Cannot set property 'GDataTableAdapter' of undefined
2. Uncaught TypeError: Cannot read property 'GVisualizationPanel' of undefined

I have included following files :
<link rel="stylesheet" type="text/css" href="/extjs/resources/css/ext-all.css">
<script type="text/javascript" src="/extjs/ext-debug.js"></script>
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript" src="/extjs/src/GVisualizationPanel.js"></script>

I had successfully implemented Google Charts with Extjs 3 but doesn't work with Extjs 4.

Any suggestions??