Chrome Version       : 65.0.3325.181
OS Version: OS X 10.13.3
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari: OK
    Firefox: FAIL
    IE/Edge: don't know

What steps will reproduce the problem?
1. Run `new Date().getTimezoneOffset()` in console, note offset
2. Change timezone to some other one
3. Re-run `new Date().getTimezoneOffset()`. Note how it returns 0 until you restart Chrome, no matter what timezone you set.

What is the expected result?
It returns the new timezone offset.

What happens instead of that?
It returns 0 independent of timezone until Chrome is restarted.

UserAgentString: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36