feat: add new nativeTheme API

[MarshallOfSound]

This adds a new nativeTheme API which extracts APIs from systemPreferences (which was becoming a bit of a dumping ground) and consolidates them all to be backed by Chromium's NativeTheme module which is better implemented, more resilient and means we don't have to maintain the theme code 👍

It also allows us to easily implement the updated event.

Notes: Added new nativeTheme API to read and respond to changes in the OS's theme and color scheme

[deermichel]

Now we're talking 🎉

[deermichel]

Lots of nits 😆 - super sorry. Additionally:

• Did you miss module-keys.js or isn't it used anymore?
• nativeTheme.shouldUseInvertedColorScheme doesn't work on macOS for me (always false), but update event gets fired when I toggle it
• Afaik, the nativeTheme methods on Linux aren't implemented and default to some value - we should state that
• Oh and we have some fake tests for the sysPref methods - do we wanna move them to a new nativeThemeSpec?

[MarshallOfSound]

Did you miss module-keys.js or isn't it used anymore?

module-keys.js is only used for browser APIs. These APIs are in common.

nativeTheme.shouldUseInvertedColorScheme doesn't work on macOS for me (always false), but update event gets fired when I toggle it

This API is only implemented on Windows inside Chromium, it's a one liner to implement on macOS so I'll do that here as well.

Afaik, the nativeTheme methods on Linux aren't implemented and default to some value - we should state that

Potentially, will have to review which APIs are implemented for linux 👍

Oh and we have some fake tests for the sysPref methods - do we wanna move them to a new nativeThemeSpec?

New tests should be added here that the APIs "work"

[deermichel]

LGTM 🚢

[release-clerk]

Release Notes Persisted

Added new nativeTheme API to read and respond to changes in the OS's theme and color scheme

[trop]

I have automatically backported this PR to "7-0-x", please check out #19758

[damienallen]

Just updated today and didn't even know this was coming, awesome 🙌