Move DOMActivate event from UI Events to HTML

[zcorpan]

What is the issue with the HTML Standard?

See w3c/uievents#411 (comment)

Related: #10431

cc @plehegar @vinhill @smaug----

[smaug----]

FWIW, I believe there are no WPTs for DOMActivate.

[zcorpan]

Chromium copies the click event's bubbles when creating the DOMActivate event. WebKit and Gecko seemingly always set bubbles to true.

https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/dom/node.cc;l=3280-3285

https://software.hixie.ch/utilities/js/live-dom-viewer/saved/14515

Other things to test:

• cancelling
• default action handling
  • differences between el.dispatchEvent(new MouseEvent("click")), el.dispatchEvent(new Event("DOMActivate")), el.click() (see this comment)
  • transient user activation for things that open a picker
• legacy-pre-activation behavior and legacy-canceled-activation behavior for <input type=checkbox> and radio
• behavior for disabled form controls
• Gecko: ShouldPreventDOMActivateDispatch() special-cases <input type=file> internal button
• guard against re-entrant/double DOMActivate
• trusted when the click event has trusted = false
• composed
• event path if the node is disconnected or crosses shadow boundary
• command/commandfor
• popover