Web-Facing Change PSA: User accepting getDisplayMedia() dialog will confer activation
Elad Alon
Contact emails
Specification
https://www.w3.org/TR/screen-capture/
Summary
When a Web application calls getDisplayMedia(), Chromium returns a promise and shows the user a dialog. The dialog prompts the user to select a tab, window or screen to capture. After the user finishes interacting with that dialog, Chromium either resolves or rejects the promise, depending on whether the user chose a tab/window/screen to share (resolve) or rejected the dialog (reject).
Starting with Chromium m139, when the user clicks the “share” button, transient activation will be conferred on the document right before the promise is resolved.
One exciting new way this can be used is:
A Web-based video-conferencing app prompts the user to share a tab, window or screen.
If the user chooses a window, that window is brought to the foreground and gains focus.
The Web app can now trigger PiP, allowing the user to still see other people, without the need for the user to first navigate back to the Web app and click again.
The change matches a recent change to the Screen Capture specification.
Risks
Interoperability and Compatibility
Gecko: No signal (Discussed and agreed in the WebRTC WG meeting of May 2025 and subsequent editor’s meeting)
WebKit: No signal (Discussed and agreed in the WebRTC WG meeting of May 2025 and subsequent editor’s meeting)
Flag name on about://flags
chrome://flags/#get-display-media-confers-activation
Finch feature name
GetDisplayMediaConfersActivation
Sample links
https://gdm-transient-activation.glitch.me/