This patch fixes the "apps vanish from alt-TAB bug".
If a "package system" rips away and possibly replaces .desktop files
at some random time, we have historically used inotify to detect this
and reread state (in a racy way, but...). In GNOME 2, this was
generally not too problematic because the menu widget was totally
separate from the list of windows - and the data they operate on was
disjoint as well.
In GNOME 3 we unify these, and this creates architectural problems
because the windows are tied to the app.
What this patch tries to do is, when rereading the application state,
if we have a running application, we keep that app around instead of
making a new instance. This ensures we preserve any state such as the
set of open windows.
This requires moving the running state into ShellAppSystem. Adjust
callers as necessary, and while we're at it drop the unused "contexts"
stuff.
This is just a somewhat quick band-aid; a REAL fix would require us
having low-level control over application installation. As long as
we're on top of random broken tar+wget wrappers, it will be gross.
A slight future improvement to this patch would add an explicit
"merge" between the old and new data. I think probably we always keep
around the ShellApp corresponding to a given ID, but replace its
GMenuTreeEntry.
https://bugzilla.gnome.org/show_bug.cgi?id=657990
In some situations we might need to look up an application from
a process identifier, such as the notification system where we
will determine application from the message sender.
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
