mash: Support ShelfModel access in Chrome.

ash/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 ASH_SHELF_SHELF_MODEL_H_
 #define ASH_SHELF_SHELF_MODEL_H_
 
 #include <map>
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/public/cpp/shelf_item.h"
 #include "ash/public/interfaces/shelf.mojom.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 
 namespace ash {
 
 class ShelfItemDelegate;
 class ShelfModelObserver;
 
+// An id for the AppList item, which is added in the ShelfModel constructor.
+// Generated as crx_file::id_util::GenerateId("org.chromium.applist")
+ASH_EXPORT extern const char kAppListId[];
+
 // Model used for shelf items. Owns ShelfItemDelegates but does not create them.
+// TODO(msw): Move this to ash/public/cpp and use ASH_PUBLIC_EXPORT.
 class ASH_EXPORT ShelfModel {
  public:
   ShelfModel();
   ~ShelfModel();
 
   // Pins an app with |app_id| to shelf. A running instance will get pinned.
-  // In case there is no running instance a new shelf item is created and
-  // pinned.
+  // If there is no running instance, a new shelf item is created and pinned.
   void PinAppWithID(const std::string& app_id);
 
   // Check if the app with |app_id_| is pinned to the shelf.
   bool IsAppPinned(const std::string& app_id);
 
   // Unpins app item with |app_id|.
   void UnpinAppWithID(const std::string& app_id);
 
   // Cleans up the ShelfItemDelegates.
   void DestroyItemDelegates();
@@ skipping 59 matching lines @@
 
   std::map<ShelfID, std::unique_ptr<ShelfItemDelegate>>
       id_to_item_delegate_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfModel);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_MODEL_H_