[gtk+] Revert "range: move GtkColorScale special case to GtkColorScale"

[Cosimo Cecchi <cosimoc src gnome org>]

commit 8b87eca11eae37a1e3357982b4ea7b6204b3d10d
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Mon Feb 22 18:54:24 2016 -0800

    Revert "range: move GtkColorScale special case to GtkColorScale"
    
    This reverts commit d93d266ed9e3e26e382a4f6d4b5d4ea19eff3bcf.

 gtk/gtkcolorscale.c |    5 -----
 gtk/gtkrange.c      |    8 +++++++-
 2 files changed, 7 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkcolorscale.c b/gtk/gtkcolorscale.c
index bafcf1b..5509c9c 100644
--- a/gtk/gtkcolorscale.c
+++ b/gtk/gtkcolorscale.c
@@ -23,7 +23,6 @@
 #include "gtkgesturelongpress.h"
 #include "gtkcolorutils.h"
 #include "gtkorientable.h"
-#include "gtkrangeprivate.h"
 #include "gtkstylecontext.h"
 #include "gtkaccessible.h"
 #include "gtkprivate.h"
@@ -256,7 +255,6 @@ scale_draw (GtkWidget *widget,
 static void
 gtk_color_scale_init (GtkColorScale *scale)
 {
-  GtkCssNode *trough_node;
   GtkStyleContext *context;
 
   scale->priv = gtk_color_scale_get_instance_private (scale);
@@ -271,9 +269,6 @@ gtk_color_scale_init (GtkColorScale *scale)
 
   context = gtk_widget_get_style_context (GTK_WIDGET (scale));
   gtk_style_context_add_class (context, "color");
-
-  trough_node = gtk_range_get_trough_node (GTK_RANGE (scale));
-  gtk_css_node_set_visible (trough_node, FALSE);
 }
 
 static void
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 3dcd634..2591a44 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2268,8 +2268,14 @@ gtk_range_draw (GtkWidget *widget,
 {
   GtkRange *range = GTK_RANGE (widget);
   GtkRangePrivate *priv = range->priv;
+  gboolean draw_trough = TRUE;
+
+  if (GTK_IS_COLOR_SCALE (widget))
+      draw_trough = FALSE;
+
+  if (draw_trough)
+    gtk_css_gadget_draw (priv->trough_gadget, cr);
 
-  gtk_css_gadget_draw (priv->trough_gadget, cr);
   gtk_css_gadget_draw (priv->slider_gadget, cr);
 
   if (priv->stepper_a_gadget)