Fixed memory leak. Untangled confusing code with menu initialization and ownership.

ui/views/controls/button/button_dropdown.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 UI_VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_
 #define UI_VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_
 
 #include "base/memory/weak_ptr.h"
 #include "ui/views/controls/button/image_button.h"
 
@@ skipping 11 matching lines @@
 //
 // A button class that when pressed (and held) or pressed (and drag down) will
 // display a menu
 //
 ////////////////////////////////////////////////////////////////////////////////
 class VIEWS_EXPORT ButtonDropDown : public ImageButton {
  public:
   // The button's class name.
   static const char kViewClassName[];
 
+  // Takes ownership of the |model|.
   ButtonDropDown(ButtonListener* listener, ui::MenuModel* model);
   virtual ~ButtonDropDown();
 
   // If menu is currently pending for long press - stop it.
   void ClearPendingMenu();
 
   // Indicates if menu is currently showing.
   bool IsMenuShowing() const;
 
   // Overridden from views::View
@@ skipping 18 matching lines @@
   virtual bool ShouldEnterPushedState(const Event& event) OVERRIDE;
 
   // Returns if menu should be shown. Override this to change default behavior.
   virtual bool ShouldShowMenu();
 
   // Function to show the dropdown menu.
   virtual void ShowDropDownMenu();
 
  private:
   // The model that populates the attached menu.
-  ui::MenuModel* model_;
+  scoped_ptr<ui::MenuModel> model_;
 
   // Indicates if menu is currently showing.
   bool menu_showing_;
 
   // Y position of mouse when left mouse button is pressed
   int y_position_on_lbuttondown_;
 
   // Menu runner to display drop down menu.
   scoped_ptr<MenuRunner> menu_runner_;
 
   // A factory for tasks that show the dropdown context menu for the button.
   base::WeakPtrFactory<ButtonDropDown> show_menu_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ButtonDropDown);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_