[metacity] xrender: simplify process_property_notify

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 77af9bf109260addd4294f5fa0a2a20b13204a83
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Tue Jul 4 11:57:28 2017 +0300

    xrender: simplify process_property_notify

 src/compositor/meta-compositor-xrender.c |   29 +++++++++++++----------------
 1 files changed, 13 insertions(+), 16 deletions(-)
---
diff --git a/src/compositor/meta-compositor-xrender.c b/src/compositor/meta-compositor-xrender.c
index e2daec4..7e3766b 100644
--- a/src/compositor/meta-compositor-xrender.c
+++ b/src/compositor/meta-compositor-xrender.c
@@ -2169,25 +2169,22 @@ process_property_notify (MetaCompositorXRender *xrender,
   if (event->atom == display->atom__XROOTPMAP_ID ||
       event->atom == display->atom__XSETROOT_ID)
     {
-      screen = meta_display_screen_for_root (display, event->window);
-      if (screen)
-        {
-          Window xroot = meta_screen_get_xroot (screen);
-
-          if (xrender->root_tile)
-            {
-              XClearArea (xdisplay, xroot, 0, 0, 0, 0, TRUE);
-              XRenderFreePicture (xdisplay, xrender->root_tile);
-              xrender->root_tile = None;
+      screen = meta_display_get_screen (display);
 
-              /* Damage the whole screen as we may need to redraw the
-                 background ourselves */
-              damage_screen (xrender);
+      if (event->window == meta_screen_get_xroot (screen) &&
+          xrender->root_tile != None)
+        {
+          XClearArea (xdisplay, event->window, 0, 0, 0, 0, TRUE);
+          XRenderFreePicture (xdisplay, xrender->root_tile);
+          xrender->root_tile = None;
 
-              add_repair (xrender);
+          /* Damage the whole screen as we may need to redraw the
+           * background ourselves
+           */
+          damage_screen (xrender);
 
-              return;
-            }
+          add_repair (xrender);
+          return;
         }
     }