1830200 - Implement Capability Delegation

Status: ASSIGNED

(Core :: DOM: Core & HTML, enhancement)

Description

[Simon Pieters [:zcorpan]]

This feature allows delegating a capability that requires user activation to a child frame (possibly cross-origin), e.g. for requestFullscreen.

Spec: https://wicg.github.io/capability-delegation/spec.html
Explainer: https://github.com/WICG/capability-delegation
Mozilla standards-position: https://github.com/mozilla/standards-positions/issues/565

https://chromestatus.com/feature/5708770829139968 - shipping in Chrome 100.

The spec seems incomplete in that it doesn't cover all capabilities that require user activation, e.g. audio playback (depends on autoplay policy). Maybe not all capabilities make sense to delegate though? See https://developer.mozilla.org/en-US/docs/Web/Security/User_activation

This is needed to be able to use user activation-gated features across cross-origin same-site frames without document.domain (which is being removed in Chromium, see https://chromestatus.com/feature/5428079583297536 and for Gecko https://bugzilla.mozilla.org/show_bug.cgi?id=1817844). See https://twitter.com/mutherpluckinb/status/1538852415331500038 for a web dev request for this.

Comment 1

[Simon Pieters [:zcorpan]]

Removing 1817844 from "blocks" since Chrome deprecated document.domain without implementing this, and sites can opt out of origin agent clusters until this is implemented.

Comment 2

[Vincent Hilla [:vhilla]]

Attachment: Bug 1830200 - Part 1: Have window.postMessage(,,,) call postMessage(, options). r=#dom-core

Comment 3

[Vincent Hilla [:vhilla]]

Attachment: Bug 1830200 - Part 2: Implement basic framework for capability delegation. r=#dom-core

Depends on D204343

Comment 4

[Vincent Hilla [:vhilla]]

Attachment: Bug 1830200 - Part 3: Implement capability delegation for fullscreen request. r=#dom-core

Depends on D204344

Comment 5

[Vincent Hilla [:vhilla]]

Attachment: Bug 1830200 - Part 5: Implement capability delegation for screen capture API. r=#dom-core

Depends on D204345

Comment 6

[Vincent Hilla [:vhilla]]

Attachment: Bug 1830200 - Part 4: Remove fullscreen from capability delegation test file names. r=#dom-core

In part 5, we change these tests to be more general and test for both fullscreen and capability delegation. To preserve the file history and show changes, we rename the files in this separate commit.

Depends on D204345