ash: Move ShelfWidget ownership to WmShelf and refactor access to it

ash/common/shelf/wm_shelf.h

 // Copyright 2016 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 ASH_COMMON_SHELF_WM_SHELF_H_
 #define ASH_COMMON_SHELF_WM_SHELF_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 21 matching lines @@
 class WmWindow;
 
 // Controller for the shelf state. Exists for the lifetime of each root window
 // controller. Note that the shelf widget may not be created until after login.
 class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
  public:
   // Returns the shelf for the display that |window| is on. Note that the shelf
   // widget may not exist, or the shelf may not be visible.
   static WmShelf* ForWindow(WmWindow* window);
 
-  // TODO(jamescook): Create the ShelfLayoutManager in this class.
-  virtual void SetShelfLayoutManager(ShelfLayoutManager* manager);
+  virtual void CreateShelfWidget(WmWindow* root);

[James Cook, 2016/08/31 22:18:08]

Ugly, but at least it makes the steps explicit.

+  void ShutdownShelfWidget();
+  void DestroyShelfWidget();
+
   ShelfLayoutManager* shelf_layout_manager() const {
     return shelf_layout_manager_;
   }
 
-  ShelfWidget* shelf_widget() { return shelf_widget_; }
+  ShelfWidget* shelf_widget() { return shelf_widget_.get(); }
 
   // Creates the shelf view.
   void InitializeShelf();
   void ShutdownShelf();
 
   // True after the ShelfView has been created (e.g. after login).
   bool IsShelfInitialized() const;
 
   // Returns the window showing the shelf.
   WmWindow* GetWindow();
@@ skipping 89 matching lines @@
   void WillChangeVisibilityState(ShelfVisibilityState new_state) override;
   void OnAutoHideStateChanged(ShelfAutoHideState new_state) override;
   void OnBackgroundUpdated(ShelfBackgroundType background_type,
                            BackgroundAnimatorChangeType change_type) override;
 
  private:
   // Layout manager for the shelf container window. Instances are constructed by
   // ShelfWidget and lifetimes are managed by the container windows themselves.
   ShelfLayoutManager* shelf_layout_manager_ = nullptr;
 
-  // TODO(jamescook): Move ShelfWidget ownership here.
-  ShelfWidget* shelf_widget_ = nullptr;
+  std::unique_ptr<ShelfWidget> shelf_widget_;
 
   // Internal implementation detail. Do not expose externally. Owned by views
   // hierarchy. Null before login and in secondary display init.
   ShelfView* shelf_view_ = nullptr;
 
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM_LOCKED;
 
   // Sets shelf alignment to bottom during login and screen lock.
   std::unique_ptr<ShelfLockingManager> shelf_locking_manager_;
 
   ShelfAutoHideBehavior auto_hide_behavior_ = SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
 
   base::ObserverList<WmShelfObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(WmShelf);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_WM_SHELF_H_