window/x11: Add flag to thaw commits after resize

To be able to thaw commits following a resize that might have frozen
commits, to keep freezes and thaws even, we need a way to tell whether
a repaint should also thaw commits.

Add a flag to `MetaWindowX11` and the appropriate functions to set and
query it.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/942

src/x11/window-x11-private.h

@@ -75,6 +75,9 @@ struct _MetaWindowX11Private
   MetaIconCache icon_cache;
   Pixmap wm_hints_pixmap;
   Pixmap wm_hints_mask;
+
+  /* Freeze/thaw on resize (for Xwayland) */
+  gboolean thaw_after_paint;
 };
 
 G_END_DECLS

src/x11/window-x11.c

@@ -4022,3 +4022,22 @@ meta_window_x11_thaw_commits (MetaWindow *window)
   MetaWindowX11 *window_x11 = META_WINDOW_X11 (window);
   META_WINDOW_X11_GET_CLASS (window_x11)->thaw_commits (window);
 }
+
+void
+meta_window_x11_set_thaw_after_paint (MetaWindow *window,
+                                      gboolean    thaw_after_paint)
+{
+  MetaWindowX11 *window_x11 = META_WINDOW_X11 (window);
+  MetaWindowX11Private *priv = meta_window_x11_get_instance_private (window_x11);
+
+  priv->thaw_after_paint = thaw_after_paint;
+}
+
+gboolean
+meta_window_x11_should_thaw_after_paint (MetaWindow *window)
+{
+  MetaWindowX11 *window_x11 = META_WINDOW_X11 (window);
+  MetaWindowX11Private *priv = meta_window_x11_get_instance_private (window_x11);
+
+  return priv->thaw_after_paint;
+}

src/x11/window-x11.h

@@ -84,4 +84,8 @@ Window   meta_window_x11_get_toplevel_xwindow    (MetaWindow *window);
 void     meta_window_x11_freeze_commits          (MetaWindow *window);
 void     meta_window_x11_thaw_commits            (MetaWindow *window);
 
+void     meta_window_x11_set_thaw_after_paint    (MetaWindow *window,
+                                                  gboolean    thaw_after_paint);
+gboolean meta_window_x11_should_thaw_after_paint (MetaWindow *window);
+
 #endif