Add mouse*, drag* and touch* events to Window and Document events stream helper extensions

[fsw]

According to MDN mouse* and drag* events bubble up to Document and Window:

https://developer.mozilla.org/en-US/docs/Web/API/Window#bubbled_events
https://developer.mozilla.org/en-US/docs/Web/API/Document#bubbled_events

Also code like this was working with dart:html:

document.onMouseMove.listen(handler);
document.onDragEnd.listen(handler);

I am not sure about the touch* events. MDN does not list those events for Document and Window but on the other hand they do bubble (at least in Firefox 145.0.* and Chrome 142.0.*). Also onTouchMove was already added in WindowEventGetters and those events were also working with dart:html. So maybe those should be added but to WindowCustomEvents and DocumentCustomEvents extensions instead?

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• I’ve reviewed the contributor guide and applied the relevant portions to this PR.

[kevmoo]

Thoughts @srujzs

At a minimum @fsw we'll want a changelog entry here!

[srujzs]

Sorry for the delay! LGTM % my comments.

[srujzs]

I believe this and onTouchLeave didn't exist on Window before, so perhaps remove?

[srujzs]

This and onTouchLeave also didn't exist on Document before, perhaps remove?

[srujzs]

I am not sure about the touch* events. MDN does not list those events for Document and Window but on the other hand they do bubble (at least in Firefox 145.0.* and Chrome 142.0.*). Also onTouchMove was already added in WindowEventGetters and those events were also working with dart:html. So maybe those should be added but to WindowCustomEvents and DocumentCustomEvents extensions instead?

Yeah, some of the touch events don't really exist afaict (e.g. touchleave). It's possible they were removed at some point from the spec, but for parity with dart:html, keeping those is reasonable. WindowCustomEvents was really meant for the events that required some additional, custom checks. That doesn't apply here, so putting the added events in WindowEventGetters and DocumentEventGetters is fine.