The actor emitted by ShellTrayManager is now ShellTrayIcon, a subclass
of ShellGtkEmbed which has several properties on it which are (or will
soon be) useful to the shell.
Part of the rearranging to use ShellTrayIcon means that we now show
the ShellEmbeddedWindow before creating its ShellGtkEmbed, which
requires a few modifications to ShellEmbeddedWindow (notably, telling
it at construct time what stage it will be drawn on, since it needs to
know that before it has a ShellGtkEmbed now).
https://bugzilla.gnome.org/show_bug.cgi?id=608869
* Rename ShellGtkWindowActor to ShellGtkEmbed, and make it require
a ShellEmbeddedWindow rather than a general GtkWindow.
* Add ShellEmbeddedWindow subclass of GtkWindow that bypasses most
of the GtkWindow complexity for size negotiation, and calls out
to a clutter actor instead; also automatically handle reparenting
the GtkWindow into the stage window.
* Use the reworked ShellGtkEmbed in ShellTrayManager, this simplifies
the code a bit, and more importantly results in the tray icons
having the correct size negotiation, rather than having a fixed
24x24 size.
http://bugzilla.gnome.org/show_bug.cgi?id=580047
