Update 2019-01-09: Please see answer below as there is a way to fix this with CUPS 2.2.8.
Update 2020-10-17: Upgrading from 18.04 LTS to 20.04 LTS will fix it as it upgrades the version of CUPS from 2.2.7 (which contains the bug) to version 2.3.1 which does not have the bug. Since some users may not be able to upgrade to 20.04 LTS right now this is still very valid for the 18.04 LTS users.
I have Ubuntu 18.04 LTS installed clean on this system. When I try to add a printer through CUPS 2.2.7 address of http://localhost:631 in the Chrome browser, I can't add the printer as I keep getting Unauthorized. It never asks for a login. How do I add my printer through CUPS using Google Chrome?
BTW, Firefox, Chromium and other browsers so far seem to work fine for adding a printer in CUPS 2.2.7. It appears to be a bug between CUPS 2.2.7 and Google Chrome.