[mutter/wayland] screen: use stack tracker for initial window query

[Daniel Drake <dsd src gnome org>]

commit 39d26be94159f5c03ebdeeb27006f9b69f3867dd
Author: Daniel Drake <drake endlessm com>
Date:   Mon Dec 30 14:26:10 2013 -0600

    screen: use stack tracker for initial window query
    
    In meta_screen_manage_all_windows() we can use our own stack
    tracker to get the list of windows - no need to query X again.
    
    A copy is needed because the stack gets modified as part of the loop.
    Specifically, meta_stack_tracker_get_stack() at this time returns the
    predicted stack, and meta_window_new() performs a few operations
    (e.g. framing) which cause immediate changes to the predicted stack.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=721345

 src/core/screen.c |   18 ++++++++----------
 1 files changed, 8 insertions(+), 10 deletions(-)
---
diff --git a/src/core/screen.c b/src/core/screen.c
index d006b43..2fc9bfe 100644
--- a/src/core/screen.c
+++ b/src/core/screen.c
@@ -883,9 +883,9 @@ meta_screen_free (MetaScreen *screen,
 void
 meta_screen_manage_all_windows (MetaScreen *screen)
 {
-  Window ignored1, ignored2;
-  Window *children;
-  guint n_children, i;
+  MetaStackWindow *_children;
+  MetaStackWindow *children;
+  int n_children, i;
 
   meta_display_grab (screen->display);
 
@@ -894,20 +894,18 @@ meta_screen_manage_all_windows (MetaScreen *screen)
       meta_screen_create_guard_window (screen->display->xdisplay, screen);
 
   meta_stack_freeze (screen->stack);
+  meta_stack_tracker_get_stack (screen->stack_tracker, &_children, &n_children);
 
-  XQueryTree (screen->display->xdisplay,
-              screen->xroot,
-              &ignored1, &ignored2, &children, &n_children);
+  /* Copy the stack as it will be modified as part of the loop */
+  children = g_memdup (_children, sizeof (MetaStackWindow) * n_children);
 
   for (i = 0; i < n_children; ++i)
     {
-      meta_window_new (screen->display, children[i], TRUE,
+      meta_window_new (screen->display, children[i].x11.xwindow, TRUE,
                        META_COMP_EFFECT_NONE);
     }
 
-  if (children)
-    XFree (children);
-
+  g_free (children);
   meta_stack_thaw (screen->stack);
 
   meta_display_ungrab (screen->display);