[gnome-system-monitor] Do not use deprecated gtk_style_context_get_font

[Robert Roth <robertroth src gnome org>]

commit a2d7fc1ad3f14bee627356128401b39b108ae892
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Jul 11 00:08:06 2013 +0300

    Do not use deprecated gtk_style_context_get_font

 src/load-graph.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/load-graph.cpp b/src/load-graph.cpp
index d313f76..4bbac9d 100644
--- a/src/load-graph.cpp
+++ b/src/load-graph.cpp
@@ -100,7 +100,7 @@ void draw_background(LoadGraph *graph) {
     cairo_paint (cr);
 
     layout = pango_cairo_create_layout (cr);
-    font_desc = pango_font_description_copy (gtk_style_context_get_font (context, GTK_STATE_FLAG_NORMAL));
+    gtk_style_context_get (context, GTK_STATE_FLAG_NORMAL, GTK_STYLE_PROPERTY_FONT, &font_desc, NULL);
     pango_font_description_set_size (font_desc, 0.8 * graph->fontsize * PANGO_SCALE);
     pango_layout_set_font_description (layout, font_desc);
     pango_font_description_free (font_desc);