arc: Implement proper Arc window activation for task moving to front.

chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.h

 // Copyright 2016 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_ASH_LAUNCHER_ARC_APP_WINDOW_LAUNCHER_CONTROLLER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_WINDOW_LAUNCHER_CONTROLLER_H_
 
 #include <map>
 #include <memory>
 #include <vector>
@@ skipping 61 matching lines @@
   void OnMaximizeModeEnded() override;
 
   // ArcAppListPrefs::Observer:
   void OnAppReadyChanged(const std::string& app_id, bool ready) override;
   void OnAppRemoved(const std::string& app_id) override;
   void OnTaskCreated(int task_id,
                      const std::string& package_name,
                      const std::string& activity) override;
   void OnTaskDestroyed(int task_id) override;
   void OnTaskSetActive(int32_t task_id) override;
+  void OnTaskMovedToFront(int32_t task_id) override;
   void OnTaskOrientationLockRequested(
       int32_t task_id,
       const arc::mojom::OrientationLock orientation_lock) override;
 
  private:
   class AppWindow;
 
   using TaskIdToAppWindow = std::map<int, std::unique_ptr<AppWindow>>;
   using AppControllerMap =
       std::map<std::string, ArcAppWindowLauncherItemController*>;
@@ skipping 20 matching lines @@
   TaskIdToAppWindow task_id_to_app_window_;
   AppControllerMap app_controller_map_;
   std::vector<aura::Window*> observed_windows_;
   Profile* observed_profile_ = nullptr;
   bool observing_shell_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(ArcAppWindowLauncherController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_WINDOW_LAUNCHER_CONTROLLER_H_