[gtk+] Revert "gtktrayicon-x11: Stop using set_double_buffered"

[Matthias Clasen <matthiasc src gnome org>]

commit 15af0e789be3ee7fb9729ec3aff45681002d7341
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Oct 15 14:37:25 2014 -0400

    Revert "gtktrayicon-x11: Stop using set_double_buffered"
    
    This reverts commit 4a72563c7b801052f4291a4757bd1011946677b9.
    
    It turns out that this commit broke statusicons under Xfce when
    not using a compositor.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=737986

 gtk/deprecated/gtktrayicon-x11.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)
---
diff --git a/gtk/deprecated/gtktrayicon-x11.c b/gtk/deprecated/gtktrayicon-x11.c
index 2f696f0..2ef872e 100644
--- a/gtk/deprecated/gtktrayicon-x11.c
+++ b/gtk/deprecated/gtktrayicon-x11.c
@@ -356,6 +356,27 @@ gtk_tray_icon_draw (GtkWidget *widget,
       cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
       cairo_paint (cr);
     }
+  else
+    {
+      GdkRectangle clip;
+
+      if (gdk_cairo_get_clip_rectangle (cr, &clip))
+        {
+          /* Clear to parent-relative pixmap
+           * We need to use direct X access here because GDK doesn't know about
+           * the parent realtive pixmap. */
+          cairo_surface_flush (target);
+
+          XClearArea (GDK_WINDOW_XDISPLAY (window),
+                      GDK_WINDOW_XID (window),
+                      clip.x, clip.y,
+                      clip.width, clip.height,
+                      False);
+          cairo_surface_mark_dirty_rectangle (target, 
+                                              clip.x, clip.y,
+                                              clip.width, clip.height);
+        }
+    }
 
   if (GTK_WIDGET_CLASS (gtk_tray_icon_parent_class)->draw)
     retval = GTK_WIDGET_CLASS (gtk_tray_icon_parent_class)->draw (widget, cr);
@@ -481,6 +502,11 @@ gtk_tray_icon_get_visual_property (GtkTrayIcon *icon)
       icon->priv->manager_visual_rgba = FALSE;
     }
 
+  /* For the background-relative hack we use when we aren't
+   * using a real RGBA visual, we can't be double-buffered
+   */
+  gtk_widget_set_double_buffered (GTK_WIDGET (icon), icon->priv->manager_visual_rgba);
+
   if (type != None)
     XFree (prop.prop);
 }