In order be able to modify panel information statically,
we need to have access to the CcShellModel from static
functions. CcApplication, thus, is a better place for the
model to live, since we can access it outside any scope
using g_application_get_default().
It also makes sense from the modeling point of view, since
the model is not tied to the shell anymore.
There is no overview anymore -- Settings is always
visualizing a panel at any given time.
I just noticed that the Alt+Left shortcut was always
broken too. This will be fixed in a following commit.
These were only used by CcApplication, and at this level
of the program we don't need to use any wrapper functions,
since we're certain that the CcWindow is a GtkWindow subclass.
This commit updates the code to use the recently
introduced API. The new functions improve the
legibility and maintainability of the code, and
makes it easier to work on new features.
https://bugzilla.gnome.org/show_bug.cgi?id=766922
