WPT details: https://wpt.fyi/results/screen-capture/getdisplaymedia.https.html
Allowing getDisplayMedia() to be triggered without a user activation could be abused by malicious websites. To protect users, the spec was changed[1] to require user activation, and we are now following through in the Chromium implementation. [1] https://github.com/w3c/mediacapture-screen-share/pull/106