[mutter] meta-backend: Fix the max device calculation on removal

[Jasper St. Pierre <jstpierre src gnome org>]

commit 27d6b2645e46ff0050db9324d40a95d54950bd4c
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Sep 4 12:15:54 2014 -0700

    meta-backend: Fix the max device calculation on removal
    
    If we add device 2, then add device 254, then remove device 254, then
    the max device ID will be 253. Scan through all the devices again on
    removal to calculate a new max device ID.

 src/backends/meta-backend.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index efcca94..1b179cd 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -119,8 +119,16 @@ destroy_device_monitor (MetaBackend *backend,
                         int          device_id)
 {
   g_clear_object (&backend->device_monitors[device_id]);
+
   if (device_id == backend->device_id_max)
-    backend->device_id_max--;
+    {
+      /* Reset the max device ID */
+      int i, new_max = 0;
+      for (i = 0; i < backend->device_id_max; i++)
+        if (backend->device_monitors[i] != NULL)
+          new_max = i;
+      backend->device_id_max = new_max;
+    }
 }
 
 static void