The two parts were mapping windows to applications, and
recording application usage statistics. The latter part
(now called ShellAppUsage) is much more naturally built on top of
the former (now called ShellWindowTracker).
ShellWindowTracker retains the startup-notification handling.
ShellWindowTracker also gains a focus-app property, which is
what most things in the shell UI are interested in (instead of
window focus).
ShellAppSystem moves to exporting ShellApp from more of its
public API, rather than ShellAppInfo. ShellAppSystem also
ensures that ShellApp instances are unique by holding
a hash on the ids.
ShellApp's private API is split off into a shell-app-private.h,
so shell-app.h can be included in shell-app-system.h.
Favorites handling is removed from ShellAppSystem, now inside
appFavorites.js.
Port all of the JavaScript for these changes.
https://bugzilla.gnome.org/show_bug.cgi?id=598646
Previously, we had ShellAppInfo, which contains fundamental
information about an application, and methods on ShellAppMonitor
to retrieve "live" information like the window list.
AppIcon ended up being used as the "App" class which was painful
for various reasons; among them that we need to handle window
list changes, and some consumers weren't ready for that.
Clean things up a bit by introducing a new ShellApp class in C,
which currently wraps a ShellAppInfo.
AppIcon then is more like the display actor for a ShellApp. Notably,
the ".windows" property moves out of it. The altTab code which
won't handle dynamic changes instead is changed to maintain a
cached version.
ShellAppMonitor gains some more methods related to ShellApp now.
In the future, we might consider changing ShellApp to be a GInterface,
which could be implemented by ShellDesktopFileApp, ShellWindowApp.
Then we could axe ShellAppInfo from the "public" API and it would
return to being an internal loss mitigation layer for GMenu.
https://bugzilla.gnome.org/show_bug.cgi?id=598227
