[gtk+] Stop passing root window to gdk_device_query_state

[Matthias Clasen <matthiasc src gnome org>]

commit 127922cf44b941c26e158ef68b9117cdeed3da37
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Aug 8 19:49:29 2017 -0400

    Stop passing root window to gdk_device_query_state
    
    The backends do the right thing now.

 gdk/gdkdevice.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdkdevice.c b/gdk/gdkdevice.c
index 62ee1cf..9c84e0c 100644
--- a/gdk/gdkdevice.c
+++ b/gdk/gdkdevice.c
@@ -598,7 +598,7 @@ gdk_device_get_position_double (GdkDevice        *device,
   default_screen = gdk_display_get_default_screen (display);
 
   _gdk_device_query_state (device,
-                           gdk_screen_get_root_window (default_screen),
+                           NULL,
                            NULL,
                            &tmp_x, &tmp_y,
                            NULL, NULL, NULL);