Align browsers on user activation for extension API: allow `auxclick` and `contextmenu` DOM events

[tophf]

Chrome: mousedown, keydown, auxclick, contextmenu.
Firefox: mousedown, keydown.

[carlosjeurissen]

Did you test other events and on mobile as well? The HTML spec mentions pointerdown on desktop while on mobile, pointerdown is not enough and pointerup is required.

[tophf]

No, I don't have a mobile device for the time being.

[tophf]

pointerdown and pointerup keep activation in Firefox (and Chrome) on desktop - probably because they are internally similar to mousexxxx.

[tophf]

Looks like this is where Firefox limits the events: https://searchfox.org/firefox-main/source/dom/base/UserActivation.cpp#86

[Rob--W]

The issue here is really sparse, and not even including a test case or a description of impact. So what we discussed so far is the literal question here: whether auxclick and contextmenu events should count towards user activation.

As noted in today's meeting, user activation is the realm of the web platform, not extensions.

The relevant spec at https://html.spec.whatwg.org/multipage/interaction.html#activation-triggering-input-event specifies the following events that ought trigger activation:

An activation triggering input event is any event whose isTrusted attribute is true and whose type is one of:

• "keydown", provided the key is neither the Esc key nor a shortcut key reserved by the user agent;
• "mousedown";
• "pointerdown", provided the event's pointerType is "mouse";
• "pointerup", provided the event's pointerType is not "mouse"; or
• "touchend".

The auxclick and contextmenu events are not listed here.
However, these events are typically preceded by the "mousedown" events, which is listed as a qualifying event. This suggests that you should get the expected behavior - user activation ought be enabled when auxclick or contextmenu events fire.

In the context of extensions, this may not be enough to enable the use of extension APIs that are tied to the more strictly scoped user gesture requirement (which expire when an event dispatch ends, rather than carrying on for a limited time like user activation). Support for user activation in extension APIs is tracked at #918.

[tophf]

The issue here is really sparse, and not even including a test case

Not sure why a test case is necessary but hopefully this should suffice:

window.onauxclick = window.oncontextmenu = () => browser.sidebarAction.open()

or a description of impact

I guess "impact" means that these events won't work in Firefox with any extension API that requires a user gesture.