[css-view-transitions-1] Skip ViewTransitions in detached iframes

[khushalsagar]

If startViewTransition is called on an iframe which is detached from the tree, or the iframe becomes detached during the transition, should we skip the transition? It seems similar to how we handle document visibility here.

@nt1m @noamr

[nt1m]

Is there a tangible benefit into doing so?

[khushalsagar]

If the iframe is detached we'll never render any frames for it and will be stuck at the step here, waiting for the next frame to capture the old state. Seems better to skip and invoke the update callback to show the new DOM directly. Same reasoning as the visibility case IMO.

[nt1m]

Ah right, I don't see a reason not to then.

[noamr]

A detached iframe is always hidden, and becomes hidden when it is detached from the tree, so this should already be the case.

[khushalsagar]

^ cool. Leaving this open to drop a note in the spec.