Let's see what
Google[
^] says about your question.
Can I use charts offline?
Your users' computers must have access to
https://www.google.com/jsapi in order to use the interactive features of Google Charts. This is because the visualization libraries that your page requires are loaded dynamically before you use them. The code for loading the appropriate library is part of the included jsapi script, and is called when you invoke the google.load() method. Our terms of service do not allow you to download the google.load or google.visualization code to use offline.
-KR