Gnome-Window-Applets is a Gnome panel applets that substitute maximized window title and buttons.Window Title and Window Buttons are essentially controls for windows that are placed on the Panel instead of a window. By default they only control maximized windows, but can be configured to control any focused window.

Download and install Gnome-Window-Applets
Select to download appropriate deb package and double click to install:
gnome-window-applets_0.2.5-2~ppa1_amd64.deb
gnome-window-applets_0.2.5-2~ppa1_i386.deb
Or download from gnome-look.org
Add applets to panel and hide the window decorations on maximized windows

Right click on gnome panel and select “Add to Panel”,in following screen add “Window Buttons”,”Window Title”,then choose a right position by right-clicking on them and select “Move”.

gnome-window-applets1

Right-click the Window Buttons on panel gnome-window-applets3,select Preferences.Check “Hide Compiz decorations for maximized window” in Behavior tab.(you need to be using Compiz)

gnome-window-applets2

See the effect:
gnome-window-applet