GTK: A first *very* rough cut at a global menu.

ui/base/models/accelerator_gtk.h

 // Copyright (c) 2011 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 UI_BASE_MODELS_ACCELERATOR_GTK_H_
 #define UI_BASE_MODELS_ACCELERATOR_GTK_H_
 #pragma once
 
 #include <gdk/gdk.h>
 
@@ skipping 27 matching lines @@
   AcceleratorGtk() : gdk_keyval_(0) { }
   virtual ~AcceleratorGtk() { }
 
   guint GetGdkKeyCode() const {
     return gdk_keyval_ > 0 ?
            // The second parameter is false because accelerator keys are
            // expressed in terms of the non-shift-modified key.
            gdk_keyval_ : ui::GdkKeyCodeForWindowsKeyCode(key_code_, false);
   }
 
-  GdkModifierType gdk_modifier_type() {
+  GdkModifierType gdk_modifier_type() const {
     return static_cast<GdkModifierType>(modifiers());
   }
 
  private:
   // The GDK keycode.
   guint gdk_keyval_;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_MODELS_ACCELERATOR_GTK_H_