Using eval() function in a Chrome Extension requires 'unsafe-eval' permission to be declared in the manifest.json, regardless the presence of the Goole Javascript Client Library inside that extension.
Evaluated JavaScript. The policy against eval() and its relatives like setTimeout(String), setInterval(String), and new Function(String)
can be relaxed by adding 'unsafe-eval' to your policy:
"content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'"
However, we strongly recommend against doing this. These functions are
notorious XSS attack vectors.
See the official Google Documentation for more information about
Content Security Policy.