[mutter/wayland] mutter-wl: Support setting NULL surface regions.

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

commit 237d990dea5baa8769f541a294f64852332fdcd4
Author: Andreas Heider <andreas heider io>
Date:   Wed Nov 6 00:00:48 2013 +0100

    mutter-wl: Support setting NULL surface regions.
    
    According to the wayland spec (A.14.1.5. wl_surface::set_opaque_region),
    setting a NULL opaque region is possible and should cause the pending
    opaque region to be set to empty. This implements the required
    behavoir.
    
    Also fixes set_input_region, which suffered from an analogous bug.
    
    Previously the weston-simple-egl demo client caused mutter-wayland to
    crash with a segfault in meta_wayland_surface_set_opaque_region, with
    this patch it works as intended.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711518

 src/wayland/meta-wayland-surface.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)
---
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index f77f9cb..5f00ce3 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -199,14 +199,17 @@ meta_wayland_surface_set_opaque_region (struct wl_client *client,
                                         struct wl_resource *region_resource)
 {
   MetaWaylandSurface *surface = wl_resource_get_user_data (surface_resource);
-  MetaWaylandRegion *region = wl_resource_get_user_data (region_resource);
 
   /* X11 unmanaged window */
   if (!surface)
     return;
 
   g_clear_pointer (&surface->pending.opaque_region, cairo_region_destroy);
-  surface->pending.opaque_region = cairo_region_copy (region->region);
+  if (region_resource)
+    {
+      MetaWaylandRegion *region = wl_resource_get_user_data (region_resource);
+      surface->pending.opaque_region = cairo_region_copy (region->region);
+    }
 }
 
 static void
@@ -215,14 +218,17 @@ meta_wayland_surface_set_input_region (struct wl_client *client,
                                        struct wl_resource *region_resource)
 {
   MetaWaylandSurface *surface = wl_resource_get_user_data (surface_resource);
-  MetaWaylandRegion *region = wl_resource_get_user_data (region_resource);
 
   /* X11 unmanaged window */
   if (!surface)
     return;
 
   g_clear_pointer (&surface->pending.input_region, cairo_region_destroy);
-  surface->pending.input_region = cairo_region_copy (region->region);
+  if (region_resource)
+    {
+      MetaWaylandRegion *region = wl_resource_get_user_data (region_resource);
+      surface->pending.input_region = cairo_region_copy (region->region);
+    }
 }
 
 static void