[gnome-system-monitor] application: use gtk_window_get_size not gtk_widget_get_size

[Alberts Muktupāvels <muktupavels src gnome org>]

commit cfe9e7399ab9efec79f6f56d66f16301a7392150
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Mon Feb 22 15:58:35 2016 +0200

    application: use gtk_window_get_size not gtk_widget_get_size
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762231

 src/application.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/application.cpp b/src/application.cpp
index fb22d38..3f8fb94 100644
--- a/src/application.cpp
+++ b/src/application.cpp
@@ -283,7 +283,7 @@ GsmApplication::save_config ()
     int width, height, xpos, ypos;
     gboolean maximized;
 
-    gtk_widget_get_size (main_window, &width, &height);
+    gtk_window_get_size (GTK_WINDOW (main_window), &width, &height);
     gtk_window_get_position (GTK_WINDOW (main_window), &xpos, &ypos);
 
     maximized = gdk_window_get_state (gtk_widget_get_window (main_window)) & GDK_WINDOW_STATE_MAXIMIZED;