The design calls for the curtain to appear in the gdm greeter too.
Implement this by having the screenshield manage the login dialog
(delegating its creation to SessionMode).
https://bugzilla.gnome.org/show_bug.cgi?id=619955
When the screenshield is deactivated, instead of going back to the
session immediately, prompt the user for authentication.
This essentially reinstates what used to be provided by gnome-screensaver.
https://bugzilla.gnome.org/show_bug.cgi?id=619955
We now drop all status icons that are not explicitly enabled, which
breaks the ibus icon. Add it to the list of allowed icons until we
merge it with the keyboard one.
https://bugzilla.gnome.org/show_bug.cgi?id=677058
Add a sessionMode.allowKeybindingsWhenModal property, which determines
whether keybindings should still be handled while a modal dialog is
up or not.
https://bugzilla.gnome.org/show_bug.cgi?id=676156
Instead of falling back to a set of default values or crashing the
window manager when an invalid mode is specified, check the value
of the ShellGlobal:session-mode property before taking over as WM
and make a clean exit if it cannot be resolved to an existent mode.
https://bugzilla.gnome.org/show_bug.cgi?id=676156
Rather than accessing global.session_type / global.session_mode
all over the place, delegate mode information to a dedicated
sessionMode object. While not very useful for now, we will replace
checks for a particular mode with checks for particular properties
that sessionMode defines based on global.session_mode.
https://bugzilla.gnome.org/show_bug.cgi?id=676156
