window: Add function to calculate current bounds

This will later be used to tell Wayland clients about a size they
shouldn't exceed.

If the window doesn't have a main monitor, this function does nothing
and returns FALSE.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2167>

src/core/window-private.h

@@ -912,4 +912,8 @@ void meta_window_clear_queued (MetaWindow *window);
 
 void meta_window_update_layout (MetaWindow *window);
 
+gboolean meta_window_calculate_bounds (MetaWindow *window,
+                                       int        *bounds_width,
+                                       int        *bounds_height);
+
 #endif

src/core/window.c

@@ -8555,3 +8555,29 @@ meta_window_get_alive (MetaWindow *window)
 {
   return window->is_alive;
 }
+
+gboolean
+meta_window_calculate_bounds (MetaWindow *window,
+                              int        *bounds_width,
+                              int        *bounds_height)
+{
+  MetaLogicalMonitor *main_monitor;
+
+  main_monitor = meta_window_get_main_logical_monitor (window);
+  if (main_monitor)
+    {
+      MetaRectangle work_area;
+
+      meta_window_get_work_area_for_logical_monitor (window,
+                                                     main_monitor,
+                                                     &work_area);
+
+      *bounds_width = work_area.width;
+      *bounds_height = work_area.height;
+      return TRUE;
+    }
+  else
+    {
+      return FALSE;
+    }
+}