Ensure the ExtensionSystem is ready before initializing an ExtensionAppModelBuilder

chrome/browser/ui/app_list/app_list_syncable_service.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 CHROME_BROWSER_UI_APP_LIST_APP_LIST_SYNCABLE_SERVICE_H_
 #define CHROME_BROWSER_UI_APP_LIST_APP_LIST_SYNCABLE_SERVICE_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "components/browser_context_keyed_service/browser_context_keyed_service.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 
 class ExtensionAppModelBuilder;
+class ExtensionService;
 class Profile;
 
 namespace app_list {
 
 class AppListModel;
 
-// Keyed Service that owns, stores, and syncs an AppListModel for a profile.
+// Keyed Service that owns, stores, and syncs an AppListModel for an
+// ExtensionSystem and corresponding profile.
 // TODO(stevenjb): Integrate with Sync. crbug.com/305024.
-class AppListSyncableService : public BrowserContextKeyedService {
+class AppListSyncableService : public BrowserContextKeyedService,
+                               public content::NotificationObserver {
  public:
-  explicit AppListSyncableService(Profile* profile);
+  // Create an empty model. Then, if |extension_service| is non-NULL and ready,
+  // populate it. Otherwise populate the model once extensions become ready.
+  AppListSyncableService(Profile* profile, ExtensionService* extension_service);
+
   virtual ~AppListSyncableService();
 
   AppListModel* model() { return model_.get(); }
 
  private:
+  void BuildModel();
+
+  // content::NotificationObserver:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
   Profile* profile_;
+  content::NotificationRegistrar registrar_;
   scoped_ptr<AppListModel> model_;
   scoped_ptr<ExtensionAppModelBuilder> apps_builder_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListSyncableService);
 };
 
 }  // namespace app_list
 
 #endif  // CHROME_BROWSER_UI_APP_LIST_APP_LIST_SYNCABLE_SERVICE_H_