chore: remove deprecated 'new-window' event

[miniak]

Description of Change

It has been deprecated since Electron 13. Warning was added in Electron 20 (#34528).

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation is changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: The deprecated new-window event has been removed.

[nornagon]

i'm worried about removing this without any machinery to explode when people try to do things the old way. we used to recommend new-window listeners for security reasons, and i bet a lot of apps still use it. removing it without an error/warning seems dangerous.

i suggest a 2-version deprecate/delete cycle:

1. in version X, add a warning when an app registers a new-window listener.
2. in version X+1, remove the event and throw an error when the app registers a new-window listener.

[miniak]

@nornagon can we still add the warning in Electron 20 to be able to land the removal in Electron 21?

[nornagon]

@miniak I'm not necessarily against that, but it's been deprecated for over a year now so I'm not sure waiting one more version to delete it is that bad? Is there any rush?

[miniak]

@nornagon no rush actually. I can add the warning only to main and wait with this one. What do others in the @electron/wg-api think?

[samuelmaddock]

Adding a deprecation log and waiting seems like the correct approach. We may not be considering a certain use case and users can voice their concern prior to removal if they notice the deprecation.

If we can afford it, maybe waiting 2 versions would be worthwhile since not everyone upgrades to the latest version.

[miniak]

@samuelmaddock the question was mainly whether to do warning in E21 and then remove in E22, or already warn in E20 and remove in E21. We can also warn in E20 and remove in E22.

[samuelmaddock]

We can also warn in E20 and remove in E22.

This sounds best to me to give folks upgrading ample time.

[jkleinsc]

API LGTM

[nornagon]

API LGTM

[zcbenz]

API LGTM

[release-clerk]

Release Notes Persisted

The deprecated new-window event has been removed.