Extend Xcb::Window wrapper to optionally not destroy window in dtor

We have windows which we don't want to destroy (e.g. the managed
clients) but still would like to be able to use the nicer API.

Therefore the not creating ctor and reset method have a second bool
arg to whether destroy the window or not. Default is to keep the
RAII functionality.

xcbutils.h

@@ -345,6 +345,9 @@ private:
  * will be freed when the instance gets destroyed.
  *
  * Furthermore the class provides wrappers around some xcb methods operating on an xcb_window_t.
+ *
+ * For the cases that one is more interested in wrapping the xcb methods the constructor which takes
+ * an existing window and the @link reset method allow to disable the RAII functionality.
  **/
 class Window
 {
@@ -352,9 +355,16 @@ public:
     /**
      * Takes over responsibility of @p window. If @p window is not provided an invalid Window is
      * created. Use @link create to set an xcb_window_t later on.
+     *
+     * If @p destroy is @c true the window will be destroyed together with this object, if @c false
+     * the window will be kept around. This is useful if you are not interested in the RAII capabilities
+     * but still want to use a window like an object.
+     *
      * @param window The window to manage.
+     * @param destroy Whether the window should be destroyed together with the object.
+     * @see reset
      **/
-    Window(xcb_window_t window = XCB_WINDOW_NONE);
+    Window(xcb_window_t window = XCB_WINDOW_NONE, bool destroy = true);
     /**
      * Creates an xcb_window_t and manages it. It's a convenient method to create a window with
      * depth, class and visual being copied from parent and border being @c 0.
@@ -402,8 +412,11 @@ public:
     void create(const QRect &geometry, uint16_t windowClass, uint32_t mask = 0, const uint32_t *values = NULL, xcb_window_t parent = rootWindow());
     /**
      * Frees the existing window and starts to manage the new @p window.
+     * If @p destroy is @c true the new managed window will be destroyed together with this
+     * object or when reset is called again. If @p destroy is @c false the window will not
+     * be destroyed. It is then the responsibility of the caller to destroy the window.
      **/
-    void reset(xcb_window_t window = XCB_WINDOW_NONE);
+    void reset(xcb_window_t window = XCB_WINDOW_NONE, bool destroy = true);
     /**
      * @returns @c true if a window is managed, @c false otherwise.
      **/
@@ -434,23 +447,27 @@ private:
     xcb_window_t doCreate(const QRect &geometry, uint16_t windowClass, uint32_t mask = 0, const uint32_t *values = NULL, xcb_window_t parent = rootWindow());
     void destroy();
     xcb_window_t m_window;
+    bool m_destroy;
 };
 
 inline
-Window::Window(xcb_window_t window)
+Window::Window(xcb_window_t window, bool destroy)
     : m_window(window)
+    , m_destroy(destroy)
 {
 }
 
 inline
 Window::Window(const QRect &geometry, uint32_t mask, const uint32_t *values, xcb_window_t parent)
     : m_window(doCreate(geometry, XCB_COPY_FROM_PARENT, mask, values, parent))
+    , m_destroy(true)
 {
 }
 
 inline
 Window::Window(const QRect &geometry, uint16_t windowClass, uint32_t mask, const uint32_t *values, xcb_window_t parent)
     : m_window(doCreate(geometry, windowClass, mask, values, parent))
+    , m_destroy(true)
 {
 }
 
@@ -463,7 +480,7 @@ Window::~Window()
 inline
 void Window::destroy()
 {
-    if (!isValid()) {
+    if (!isValid() || !m_destroy) {
         return;
     }
     xcb_destroy_window(connection(), m_window);
@@ -506,10 +523,11 @@ xcb_window_t Window::doCreate(const QRect &geometry, uint16_t windowClass, uint3
 }
 
 inline
-void Window::reset(xcb_window_t window)
+void Window::reset(xcb_window_t window, bool shouldDestroy)
 {
     destroy();
     m_window = window;
+    m_destroy = shouldDestroy;
 }
 
 inline