https://techcrunch.com/2018/06/12/google-puts-an-end-to-chrome-extension-installs-from-third-party-sites/

Google today announced a major change to its Chrome Web Store policy that aims to shield users from websites that try to fool them into installing their Chome extensions. Until now, developers who publish their apps in the Web Store, could also initiate app and extension installs from their own websites. Too often, though, developers combined these so-called ‘inline installs‘ with deceptive information on their sites to get users to install them. Unsurprisingly, that’s not quite the experience Google had in mind when it enabled this feature back in 2011, so now it’s shutting it down.

Starting today, inline installation will be unavailable to all newly published extensions. Developers who use the standard method for calling for an install from their site will see that their users will get redirected to the Chrome Web Store to complete the installation.