IssueTracker

Have you looked at using the Asynchronous Loading method https://developers.google.com/maps/documentation/javascript/tutorial#Loading_the_Maps_API ?

Example 1. Just trying to attach your gmaps script.
If you open the developer console, you will see that gmaps init script is loaded, but "getScript("https://maps.gstatic.com/intl/en_us/mapfiles/api-3/9/8/main.js");" line isn't working, there is no new script in the document after document.write.

Example 2. Trying to use callback parameter. Init is loaded, main javascript file is loaded too. But not working, exception screenshot is in attach.

For example 2 - your code:

...
    lf.main = function(a) {
        eval(a);   // <-- Uncaught Error: Code generation from strings disallowed for this context
    };
...

Just to poke this bug, using the asynchronous loading method has no effect on this.  The only workaround is to roll back to manifest version 1 which is actively being phased out.

Switched to Yandex Maps, it works well.
Thank you!

As manifest version 1 won't be accepted by the Chrome Webstore starting in mid August, we really do need a workaround/fix.