app_list: Add sync animation.

ui/app_list/app_list_model.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_APP_LIST_APP_LIST_MODEL_H_
 #define UI_APP_LIST_APP_LIST_MODEL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/base/models/list_model.h"
 
 namespace app_list {
 
 class AppListItemModel;
+class AppListModelObserver;
 class SearchBoxModel;
 class SearchResult;
 
 // Master model of app list that consists of three sub models: Apps,
 // SearchBoxModel and SearchResults. The Apps sub model owns a list of
 // AppListItemModel and is displayed in the grid view. SearchBoxModel is
 // the model for SearchBoxView. SearchResults owns a list of SearchResult.
 class APP_LIST_EXPORT AppListModel {
  public:
+  enum Status {
+    STATUS_NORMAL,
+    STATUS_SYNCING,  // Syncing apps or installing synced apps.
+  };
+
   typedef ui::ListModel<AppListItemModel> Apps;
   typedef ui::ListModel<SearchResult> SearchResults;
 
   AppListModel();
   ~AppListModel();
 
+  void AddObserver(AppListModelObserver* observer);
+  void RemoveObserver(AppListModelObserver* observer);
+
+  void SetStatus(Status status);
+
   Apps* apps() { return apps_.get(); }
   SearchBoxModel* search_box() { return search_box_.get(); }
   SearchResults* results() { return results_.get(); }
+  Status status() const { return status_; }
 
  private:
   scoped_ptr<Apps> apps_;
 
   scoped_ptr<SearchBoxModel> search_box_;
   scoped_ptr<SearchResults> results_;
 
+  Status status_;
+  ObserverList<AppListModelObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(AppListModel);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_MODEL_H_