fix: add support for --ozone-platform-hint flag on Linux

[vially]

Description of Change

Add support for the --ozone-platform-hint flag in order to make it easier for users to switch between the X11 and Wayland platforms (e.g.: by using --ozone-platform-hint=auto).

Implementation details

This was implemented by reusing the same logic from upstream, but it required implementing chrome::SessionEnding() which is a bit hacky. This was necessary due to this call from ChromeBrowserMainExtraPartsOzone::PostCreateMainMessageLoop().

Another option would have been to either patch that method or copy the logic from ChromeBrowserMainExtraPartsOzone and ChromeBrowserMainExtraPartsLinux inside Electron. If Electron maintainers think that's a more reasonable approach I'll update this pull-request accordingly.

EDIT: This description is no longer relevant because the implementation has been reworked with feedback from Electron maintainers.

Fixes #33810

Checklist

• PR description included and stakeholders cc'd (@deepak1556 @ckerr @MarshallOfSound)
• npm test passes
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Added support for --ozone-platform-hint flag on Linux

[deepak1556]

Can you copy the logic to support this flag into ElectronBrowserMainParts

electron/shell/browser/electron_browser_main_parts.cc

Line 214 in f1746c8

int ElectronBrowserMainParts::PreEarlyInitialization() {

Electron has its own shutdown logic and bringing in ChromeBrowserMainExtraParts overrides this, also it is not necessary to support this flag.

[vially]

@deepak1556 I've copied the logic from ChromeBrowserMainExtraPartsLinux into ElectronBrowserMainParts, as you've suggested (unless I've misunderstood).

However, it is a bit verbose so it may be worth moving it someplace else in order to keep ElectronBrowserMainParts a bit cleaner. Let me know what you think and whether you have any suggestions for refactoring it to make it slightly cleaner.

[deepak1556]

Thanks!

[release-clerk]

Release Notes Persisted

Added support for --ozone-platform-hint flag on Linux

[trop]

I have automatically backported this PR to "18-x-y", please check out #35013

[trop]

I have automatically backported this PR to "20-x-y", please check out #35014

[trop]

I have automatically backported this PR to "19-x-y", please check out #35015