Extract shell methods from ApplicationImpl into a base class, and pass this to Initialize() instead.

mash/shelf/shelf_model.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 MASH_SHELF_SHELF_MODEL_H_
 #define MASH_SHELF_SHELF_MODEL_H_
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "mash/shelf/shelf_item_types.h"
 #include "mash/wm/public/interfaces/user_window_controller.mojom.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 namespace mojo {
-class ApplicationImpl;
+class Shell;
 }
 
 namespace mash {
 namespace shelf {
 
 class ShelfModelObserver;
 
 // Model used by ShelfView.
 class ShelfModel : public mash::wm::mojom::UserWindowObserver {
  public:
   enum Status {
     STATUS_NORMAL,
     // A status that indicates apps are syncing/loading.
     STATUS_LOADING,
   };
 
-  explicit ShelfModel(mojo::ApplicationImpl* app);
+  explicit ShelfModel(mojo::Shell* shell);
   ~ShelfModel() override;
 
   // Adds a new item to the model. Returns the resulting index.
   int Add(const ShelfItem& item);
 
   // Adds the item. |index| is the requested insertion index, which may be
   // modified to meet type-based ordering. Returns the actual insertion index.
   int AddAt(int index, const ShelfItem& item);
 
   // Removes the item at |index|.
@@ skipping 76 matching lines @@
   mash::wm::mojom::UserWindowControllerPtr user_window_controller_;
   mojo::Binding<mash::wm::mojom::UserWindowObserver> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfModel);
 };
 
 }  // namespace shelf
 }  // namespace mash
 
 #endif  // MASH_SHELF_SHELF_MODEL_H_