fix: fullscreen crashing with roundedCorners: false

[codebytere]

Description of Change

Closes #35403.
Refs CL:1125099.

Fixes an issue where frameless windows with roundedCorners: false cannot enter fullscreen without crashing. This is happening because Chromium uses a custom NativeWidgetMacNSWindowBorderlessFrame when the NSWindow has a NSWindowStyleMaskBorderless style mask, which is itself a subclass of NSNextStepFrame. NSNextStepFrame does not implement any of the public or private methods required for fullscreen, and so it would crash with errors like:

-[NativeWidgetMacNSWindowBorderlessFrame _surrenderToolbarViewForFullScreenWindow:]: unrecognized selector sent to instance

The cleanest solution for this would be to document this case in the roundedCorners option, and prevent the window from going fullscreen.

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: Fixed an issue where frameless windows with roundedCorners: false couldn't enter fullscreen without crashing.

[sircharlo]

Hey there! Quick question: wouldn't it be better to remove the offending roundedCorners attribute before entering fullscreen, and then re-adding it after exiting fullscreen?

[codebytere]

@sircharlo i wish, but it's not just an attribute that can be removed. It's an option that defines how the window and its frame are constructed from the outset, and which can't really be changed without destroying and recreating the underlying NSWindow.

[sircharlo]

Well, that sucks. I'll have to rethink that part of my app. I was hoping a behavior similar to other apps like VLC that manage this situation, but I guess this is a Chromium quirk.

[codebytere]

@sircharlo there's potential for overriding that behavior in Electron and allowing for fullscreen, but it'd be a bigger refactor and for now i'd just like to prevent it crashing. I can have a stab at the more complex fix but it might take a while

[codebytere]

Unrelated failure - merging.

[release-clerk]

Release Notes Persisted

Fixed an issue where frameless windows with roundedCorners: false couldn't enter fullscreen without crashing.

[trop]

I have automatically backported this PR to "21-x-y", please check out #35454

[trop]

I have automatically backported this PR to "20-x-y", please check out #35455

[trop]

I have automatically backported this PR to "19-x-y", please check out #35456