Make UnityLauncherAPI work

[JakobDev]

This allows showing the download progress in the Window Icon.

It requires libunity, as you can see here.

While this API is also supported outside Unity/KDE, Chromium does check if it's running on Unity/KDE, we may need to set XDG_CURRENT_DESKTOP=KDE to make it work on other Desktops too.

[flathubbot]

Started test build 97366

[flathubbot]

Build 97366 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/80141/org.chromium.Chromium.flatpakref

[flathubbot]

Started test build 97428

[rany2]

Can this be added to the BaseApp first?

[JakobDev]

You mean libunity? I can do it, but 'm not sure if any other Browser makes use of it.

[flathubbot]

Build 97428 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/80204/org.chromium.Chromium.flatpakref