core: Make "adding ignored serials" private API

This sounds unnecessary from shell code, and possibly even harmful.
Make this API private and move it into the X11 parts where it belongs.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2828>

src/core/display.c

@@ -1287,38 +1287,6 @@ meta_display_get_current_time_roundtrip (MetaDisplay *display)
     return meta_x11_display_get_current_time_roundtrip (display->x11_display);
 }
 
-/**
- * meta_display_add_ignored_crossing_serial:
- * @display: a #MetaDisplay
- * @serial: the serial to ignore
- *
- * Save the specified serial and ignore crossing events with that
- * serial for the purpose of focus-follows-mouse. This can be used
- * for certain changes to the window hierarchy that we don't want
- * to change the focus window, even if they cause the pointer to
- * end up in a new window.
- */
-void
-meta_display_add_ignored_crossing_serial (MetaDisplay  *display,
-                                          unsigned long serial)
-{
-  int i;
-
-  /* don't add the same serial more than once */
-  if (display->ignored_crossing_serials[N_IGNORED_CROSSING_SERIALS-1] == serial)
-    return;
-
-  /* shift serials to the left */
-  i = 0;
-  while (i < (N_IGNORED_CROSSING_SERIALS - 1))
-    {
-      display->ignored_crossing_serials[i] = display->ignored_crossing_serials[i+1];
-      ++i;
-    }
-  /* put new one on the end */
-  display->ignored_crossing_serials[i] = serial;
-}
-
 static gboolean
 window_raise_with_delay_callback (void *data)
 {

src/meta/display.h

@@ -168,10 +168,6 @@ META_EXPORT
 GSList *meta_display_sort_windows_by_stacking (MetaDisplay *display,
                                                GSList      *windows);
 
-META_EXPORT
-void meta_display_add_ignored_crossing_serial (MetaDisplay  *display,
-                                               unsigned long serial);
-
 META_EXPORT
 void meta_display_clear_mouse_mode (MetaDisplay *display);
 

src/x11/meta-x11-display.c

@@ -2381,6 +2381,31 @@ meta_x11_display_focus_sentinel_clear (MetaX11Display *x11_display)
   return (x11_display->sentinel_counter == 0);
 }
 
+
+static void
+meta_x11_display_add_ignored_crossing_serial (MetaX11Display *x11_display,
+                                              unsigned long   serial)
+{
+  MetaDisplay *display = x11_display->display;
+  int i;
+
+  /* don't add the same serial more than once */
+  if (serial ==
+      display->ignored_crossing_serials[N_IGNORED_CROSSING_SERIALS - 1])
+    return;
+
+  /* shift serials to the left */
+  i = 0;
+  while (i < (N_IGNORED_CROSSING_SERIALS - 1))
+    {
+      display->ignored_crossing_serials[i] =
+        display->ignored_crossing_serials[i + 1];
+      ++i;
+    }
+  /* put new one on the end */
+  display->ignored_crossing_serials[i] = serial;
+}
+
 void
 meta_x11_display_set_stage_input_region (MetaX11Display *x11_display,
                                          XserverRegion   region)
@@ -2402,7 +2427,7 @@ meta_x11_display_set_stage_input_region (MetaX11Display *x11_display,
    * focus-follows-mouse focus - it's not the user doing something, it's the
    * environment changing under the user.
    */
-  meta_display_add_ignored_crossing_serial (x11_display->display,
+  meta_x11_display_add_ignored_crossing_serial (x11_display,
                                                 XNextRequest (xdisplay));
   XFixesSetWindowShapeRegion (xdisplay,
                               x11_display->composite_overlay_window,