[mutter] MetaBackground: fix getting stuck in a bad state after monitor changes

[Owen Taylor <otaylor src gnome org>]

commit 458953268b61290e47915ba4c915985670829515
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Fri Sep 12 14:47:18 2014 -0400

    MetaBackground: fix getting stuck in a bad state after monitor changes
    
    After the ::monitors-changed signal, set the dirty flag on each new
    monitor information struct so the per-monitor resources will be
    recreated.

 src/compositor/meta-background.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/src/compositor/meta-background.c b/src/compositor/meta-background.c
index 0fb784a..0370f55 100644
--- a/src/compositor/meta-background.c
+++ b/src/compositor/meta-background.c
@@ -133,8 +133,13 @@ on_monitors_changed (MetaScreen     *screen,
 
   if (priv->screen)
     {
+      int i;
+
       priv->n_monitors = meta_screen_get_n_monitors (screen);
       priv->monitors = g_new0 (MetaBackgroundMonitor, priv->n_monitors);
+
+      for (i = 0; i < priv->n_monitors; i++)
+        priv->monitors[i].dirty = TRUE;
     }
 }