Declaring constructors as methods is strange

[domenic]

In https://privacycg.github.io/saa-non-cookie-storage/#storageaccesshandle the members BroadcastChannel and SharedWorker are presumably supposed to be sort of namespaced versions of the global BroadcastChannel and SharedWorker constructors.

However, since they are declared as Web IDL operations, they end up as JavaScript methods, not constructors.

This has several observable differences, notably around how they don't require new, and fail various IsConstructor tests. E.g. they cannot be subclassed.

Ideally we would define these as constructors. Doing so would probably require new Web IDL infrastructure, however...

[annevk]

@johannhof I think this issue needs addressing. I think the easiest path forward here is to define these as createBroadcastChannel() or some such. I wouldn't be opposed to a more complicated story that also allows for subclassing, but these weird class-like-looking methods we should not enshrine in the platform.

[johannhof]

@annevk yeah, I agree with this feedback. We can prioritize proposing an alternative API surface. I think we can make this mostly backwards compatible for existing Chrome deployments, too.

cc @cfredric