views: Make view::Views::GetPreferredSize() const.

ui/views/controls/menu/menu_separator.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_VIEWS_CONTROLS_MENU_MENU_SEPARATOR_H_
 #define UI_VIEWS_CONTROLS_MENU_MENU_SEPARATOR_H_
 
 #include "base/compiler_specific.h"
 #include "ui/base/models/menu_separator_types.h"
 #include "ui/views/view.h"
 
 namespace views {
 
 class MenuItemView;
 
 class MenuSeparator : public View {
  public:
   MenuSeparator(MenuItemView* parent, ui::MenuSeparatorType type)
       : type_(type),
         parent_menu_item_(parent) {}
 
   // View overrides.
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
 
  private:
   void OnPaintAura(gfx::Canvas* canvas);
-  gfx::Size GetPreferredSizeAura();
+  gfx::Size GetPreferredSizeAura() const;
 
   // The type of the separator.
   const ui::MenuSeparatorType type_;
 
   // Our parent.
   MenuItemView* parent_menu_item_;
 
   DISALLOW_COPY_AND_ASSIGN(MenuSeparator);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_MENU_MENU_SEPARATOR_H_