Fix object ownership in ui/base/models.

ui/views/examples/tree_view_example.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_EXAMPLES_TREE_VIEW_EXAMPLE_H_
 #define UI_VIEWS_EXAMPLES_TREE_VIEW_EXAMPLE_H_
 
 #include "base/macros.h"
 #include "ui/base/models/simple_menu_model.h"
 #include "ui/base/models/tree_node_model.h"
@@ skipping 52 matching lines @@
   void ShowContextMenuForView(View* source,
                               const gfx::Point& point,
                               ui::MenuSourceType source_type) override;
 
   // SimpleMenuModel::Delegate:
   bool IsCommandIdChecked(int command_id) const override;
   bool IsCommandIdEnabled(int command_id) const override;
   void ExecuteCommand(int command_id, int event_flags) override;
 
   // The tree view to be tested.
-  TreeView* tree_view_;
+  std::unique_ptr<TreeView> tree_view_;
 
   // Control buttons to modify the model.
   LabelButton* add_;
   LabelButton* remove_;
   LabelButton* change_title_;
 
   typedef ui::TreeNodeWithValue<int> NodeType;
 
   ui::TreeNodeModel<NodeType> model_;
 
   std::unique_ptr<ui::SimpleMenuModel> context_menu_model_;
   std::unique_ptr<MenuRunner> context_menu_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(TreeViewExample);
 };
 
 }  // namespace examples
 }  // namespace views
 
 #endif  // UI_VIEWS_EXAMPLES_TREE_VIEW_EXAMPLE_H_