mash: Move WmShelfAura ownership to RootWindowController and init it earlier

ash/shelf/shelf.h

 // Copyright 2013 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_SHELF_SHELF_H_
 #define ASH_SHELF_SHELF_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 22 matching lines @@
 
 namespace views {
 class View;
 }
 
 namespace ash {
 class FocusCycler;
 class ShelfDelegate;
 class ShelfIconObserver;
 class ShelfModel;
-class WmShelfAura;
 
 namespace test {
 class ShelfTestAPI;
 }
 
 // Controller for shelf state. All access to state (visibility, auto-hide, etc.)
 // should occur via this class.
 class ASH_EXPORT Shelf {
  public:
   static const char kNativeViewName[];
@@ skipping 94 matching lines @@
     return shelf_widget_->shelf_layout_manager();
   }
 
   // Returns rectangle bounding all visible shelf items. Used screen coordinate
   // system.
   gfx::Rect GetVisibleItemsBoundsInScreen() const;
 
   // Returns ApplicationDragAndDropHost for this shelf.
   app_list::ApplicationDragAndDropHost* GetDragAndDropHostForAppList();
 
-  WmShelfAura* wm_shelf() { return wm_shelf_.get(); }
-
  private:
   friend class test::ShelfTestAPI;
 
-  std::unique_ptr<WmShelfAura> wm_shelf_;
   ShelfDelegate* delegate_;
   ShelfWidget* shelf_widget_;
   ShelfView* shelf_view_;
   ShelfLockingManager shelf_locking_manager_;
 
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM;
   ShelfAutoHideBehavior auto_hide_behavior_ = SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
 
   DISALLOW_COPY_AND_ASSIGN(Shelf);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_H_