arc-app-launcher: Minimal support for ARC app launcher.

chrome/browser/ui/app_list/app_list_model_builder.h

+// Copyright 2015 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_MODEL_BUILDER_H_
+#define CHROME_BROWSER_UI_APP_LIST_APP_LIST_MODEL_BUILDER_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "chrome/browser/ui/app_list/app_list_syncable_service.h"
+#include "ui/app_list/app_list_item_list_observer.h"
+#include "ui/app_list/app_list_model.h"
+
+class AppListControllerDelegate;
+class Profile;
+
+// This abstract class populates and maintains the given |model| with
+// information from |profile| for the specific item type.
+class AppListModelBuilder : public app_list::AppListItemListObserver {
+ public:
+  explicit AppListModelBuilder(AppListControllerDelegate* controller,

[jochen (gone - plz use gerrit), 2015/12/03 10:25:39]

no explicit, can you clarify whether it takes ownership of controller, why is
item_type not a std::string?

[khmel1, 2015/12/03 12:34:49]

Removed explicit (left from legacy code with one param).

AppListItem::GetItemType returns const char*. 
Type is is declared for example:
in header:
class ExtensionAppItem ...
  static const char kItemType[];
in cc
const char ExtensionAppItem::kItemType[] = "ExtensionAppItem";
This constant is returned at GetItemType

Legacy code checks in many places like this:
if (item->GetItemType() == ExtensionAppItem::kItemType)

So, I just followed legacy code design.

+                               const char* item_type);
+   ~AppListModelBuilder() override;
+
+  // Initialize to use app-list sync and sets |service_| to |service|.

[jochen (gone - plz use gerrit), 2015/12/03 10:25:39]

this comment should tell whether it takes ownership of service and model

[khmel1, 2015/12/03 12:34:49]

Done.

+  void InitializeWithService(app_list::AppListSyncableService* service,
+                             app_list::AppListModel* model);
+
+  // Initialize to use extension sync and sets |service_| to NULL. Used in

[jochen (gone - plz use gerrit), 2015/12/03 10:25:39]

nullptr

[khmel1, 2015/12/03 12:34:49]

Done.

+  // tests and when AppList sync is not enabled.
+  void InitializeWithProfile(Profile* profile, app_list::AppListModel* model);
+
+ protected:
+  // Builds the model with the current profile.
+  virtual void BuildModel() = 0;
+
+  app_list::AppListSyncableService* service() { return service_; }
+
+  Profile* profile() { return profile_; }
+
+  AppListControllerDelegate* controller() { return controller_; }
+
+  app_list::AppListModel* model() { return model_; }
+
+  // Inserts an app based on app ordinal prefs.
+  void InsertApp(scoped_ptr<app_list::AppListItem> app);
+
+  const app_list::AppListSyncableService::SyncItem* GetSyncItem(
+      const std::string& id);
+
+  // Returns app instance matching |id| or NULL.
+  app_list::AppListItem* GetAppItem(const std::string& id);
+
+ private:
+  // Unowned pointers to the service that owns this and associated profile.
+  app_list::AppListSyncableService* service_ = nullptr;
+  Profile* profile_ = nullptr;
+
+  // Unowned pointer to the app list controller.
+  AppListControllerDelegate* controller_;
+
+  // Unowned pointer to the app list model.
+  app_list::AppListModel* model_ = nullptr;
+
+  // Global constant defined for each item type.
+  const char* item_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(AppListModelBuilder);
+};
+
+#endif  // CHROME_BROWSER_UI_APP_LIST_APP_LIST_MODEL_BUILDER_H_