Gtk3: Fix separator color on Gtk3.20

chrome/browser/ui/libgtkui/gtk_util.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_LIBGTKUI_GTK_UTIL_H_
 #define CHROME_BROWSER_UI_LIBGTKUI_GTK_UTIL_H_
 
 #include <gtk/gtk.h>
 #include <string>
 
@@ skipping 50 matching lines @@
 // it above |parent|. Do nothing if |parent| is NULL.
 void SetGtkTransientForAura(GtkWidget* dialog, aura::Window* parent);
 
 // Gets the transient parent aura window for |dialog|.
 aura::Window* GetAuraTransientParent(GtkWidget* dialog);
 
 // Clears the transient parent for |dialog|.
 void ClearAuraTransientParent(GtkWidget* dialog);
 
 #if GTK_MAJOR_VERSION > 2
+// Returns true iff the runtime version of Gtk used meets
+// |major|.|minor|.|micro|.
+bool GtkVersionCheck(int major, int minor = 0, int micro = 0);
+
 template <typename T>
 class ScopedGObject {
  public:
   explicit ScopedGObject(T* obj) : obj_(obj) {
     // Increase the reference count of |obj_|, removing the floating
     // reference if it has one.
     g_object_ref_sink(obj_);
   }
 
   ScopedGObject(const ScopedGObject<T>& other) : obj_(other.obj_) {
@@ skipping 50 matching lines @@
 
 // If there is a border, renders the border from the style context
 // created by GetStyleContextFromCss(|css_selector|) into a single
 // pixel and returns the color.  Otherwise returns kInvalidColor.
 SkColor GetBorderColor(const char* css_selector);
 #endif
 
 }  // namespace libgtkui
 
 #endif  // CHROME_BROWSER_UI_LIBGTKUI_GTK_UTIL_H_