scripting: Add desktops property to AbstractClient

With the new virtual desktops model, a window can be on several virtual
desktops. Currently, scripts have no any way to get the list of desktops
the window is on. This change addresses that.

src/abstract_client.h

@@ -75,9 +75,16 @@ class KWIN_EXPORT AbstractClient : public Toplevel
     /**
      * The desktop this Client is on. If the Client is on all desktops the property has value -1.
      * This is a legacy property, use x11DesktopIds instead
+     *
+     * @deprecated Use the desktops property instead.
      */
     Q_PROPERTY(int desktop READ desktop WRITE setDesktop NOTIFY desktopChanged)
 
+    /**
+     * The virtual desktops this client is on. If it's on all desktops, the list is empty.
+     */
+    Q_PROPERTY(QVector<KWin::VirtualDesktop *> desktops READ desktops WRITE setDesktops NOTIFY desktopChanged)
+
     /**
      * Whether the Client is on all desktops. That is desktop is -1.
      */
@@ -90,6 +97,8 @@ class KWIN_EXPORT AbstractClient : public Toplevel
 
     /**
      * The x11 ids for all desktops this client is in. On X11 this list will always have a length of 1
+     *
+     * @deprecated prefer using apis that use VirtualDesktop objects
      */
     Q_PROPERTY(QVector<uint> x11DesktopIds READ x11DesktopIds NOTIFY x11DesktopIdsChanged)
 

src/scripting/scripting.cpp

@@ -24,6 +24,7 @@
 #include "input.h"
 #include "options.h"
 #include "screenedge.h"
+#include "virtualdesktops.h"
 #include "workspace.h"
 #include "x11client.h"
 // KDE
@@ -656,6 +657,7 @@ void KWin::Scripting::init()
     });
 
     qmlRegisterType<KWin::AbstractClient>();
+    qmlRegisterType<KWin::VirtualDesktop>();
     qmlRegisterType<KWin::X11Client>();
     qmlRegisterType<QAbstractItemModel>();