Custom gnome session

Lightdm looks for

/usr/share/xsessions/cairo-dock-xmonad.desktop

[Desktop Entry]
Name=Cairo-Dock-Xmonad (GNOME)
Comment=This session logs you into GNOME with Cairo-Dock and Xmonad
Exec=gnome-session --session=cairo-dock-xmonad
TryExec=cairo-dock-session
Icon=
Type=Application

The session required components are given in
/usr/share/gnome-session/sessions/cairo-dock-xmonad.session

[GNOME Session]
Name=Cairo-Dock-Xmonad
RequiredComponents=gnome-settings-daemon;xmonad-xcomp;cairo-dock;
DesktopName=Unity

the component is defined in
/usr/share/applications/xmonad-xcomp.desktop

[Desktop Entry]
Type=Application
Name=Xmonad-Xcomp
Exec=xm
NoDisplay=true
X-GNOME-WMName=Xmonad
X-GNOME-Autostart-Phase=WindowManager
X-GNOME-Provides=windowmanager
X-GNOME-Autostart-Notify=true

where xm is the /usr/local/bin script

#!/bin/bash

# Check if xmonad is running
if pgrep "xmonad-x86_64" > /dev/null
then
    echo "xmonad Running"
else
    xmonad --replace&
fi
xcompmgr -C &
wallpaperScript&