Make toolbar compile on linux.

views/controls/button/button_dropdown.h

 // Copyright (c) 2006-2008 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 VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_
 #define VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_
 
 #include "base/task.h"
 #include "views/controls/button/image_button.h"
 #include "views/controls/menu/menu.h"
@@ skipping 25 matching lines @@
   virtual bool OnMouseDragged(const MouseEvent& e);
 
   // Overridden from View. Used to display the right-click menu, as triggered
   // by the keyboard, for instance. Using the member function ShowDropDownMenu
   // for the actual display.
   virtual void ShowContextMenu(int x,
                                int y,
                                bool is_mouse_gesture);
 
   // Internal function to show the dropdown menu
-  void ShowDropDownMenu(HWND window);
+  void ShowDropDownMenu(gfx::NativeView window);
 
   // Specifies who to delegate populating the menu
   Menu::Delegate* menu_delegate_;
 
   // Y position of mouse when left mouse button is pressed
   int y_position_on_lbuttondown_;
 
   // A factory for tasks that show the dropdown context menu for the button.
   ScopedRunnableMethodFactory<ButtonDropDown> show_menu_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ButtonDropDown);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_