I record google chart and find it will be local if you change several keywords in the two load.js. I upload it here but dont use it in your application because it is out of the license of google chart.
Replace "https://www.gstatic.com" to "." . Change current version from "46" to "offlineSaving" . Replace "https://www.gstatic.com" to "." . Save Other resource in offlinesaving/js or /css folder.