Make CaptureController an EventTarget

[fred-wang]

See https://dom.spec.whatwg.org/#eventtarget

The extension in the spec is:

partial interface CaptureController {
  attribute EventHandler oncapturedmousechange;
};

I see interfaces with similar interfaces with similar onsomething EventHandler attribute derive from EventTarget but not sure whether that's something that is a requirement or even just that we consider interesting here.

[eladalon1983]

Are you aware of precedents of an extension spec introducing inheritance?

[fred-wang]

Are you aware of precedents of an extension spec introducing inheritance?

That does not seem possible:

"Note: A partial interface definition cannot specify that the interface inherits from another interface. Inheritance is to be specified on the original interface definition."

https://webidl.spec.whatwg.org/#dfn-partial-interface

[fred-wang]

@eladalon1983 For now the solutions I have in mind are:

1. Get this inheritance change accepted in the Screen Capture directly.
2. Introduce a separate class deriving from EventTarget and exposing on* events. This class would be exposed as a new attribute of CaptureController, or alternatively it could inherit from CaptureController and passed as an option to getDisplayMedia (but not sure this would work).

[eladalon1983]

Short-term, let's redefine CaptureController in our spec as inheriting from EventTarget. (That is, not use partial, but say that we're redefining it outright.) Will you send a PR to that effect?

Long-term, let's try to get this accepted in the Screen Capture spec. I'll start the discussion. (Edit: I've filed w3c/mediacapture-screen-share/issues/268 and w3c/mediacapture-screen-share/issues/269 and asked for a time slot to discuss this during the June interim of the WebRTC WG, which manages the spec where CaptureController is defined.)

[fred-wang]

@eladalon1983 OK, I submitted a first PR here: #10 ; will work on the constructor stuff in a separate PR

[eladalon1983]

Frédéric, do you mind if I close this issue now?

[fred-wang]

@eladalon1983 OK when #10 is merged :-) and then we can close issue #1 too

[fred-wang]

Oh nevermind, we actually don't need to specify inheritance on partial interfaces. I already had removed that from PR #10...