[fullscreen] Time to dispatch the fullscreenchange event (#5)

In the current spec, the `fullscreenchange` event is dispatched synchronously inside the loop of changing the document state, which means the event handler may reach an incomplete state of style. For `requestFullscreen`, the state of the child document isn't flipped. For `exitFullscreen`, the state of the parent document isn't flipped.

As far as I can see, it doesn't match any of the current impl. Gecko, Blink (assuming WebKit shares the same code), Trident (including Edge which is shipping the unprefixed Fullscreen API) dispatch all `fullscreenchange` events with a complete state.

Personally I don't have a strong opinion about which is better. But given all impls agree with the same way, and I don't see reaching incomplete state makes much sense, I propose we change the spec to match the impls.

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/fullscreen/issues/5