arc: Add splash screen for ARC++ Kiosk startup

chrome/browser/chromeos/app_mode/arc/arc_kiosk_app_launcher.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_CHROMEOS_APP_MODE_ARC_ARC_KIOSK_APP_LAUNCHER_H_
 #define CHROME_BROWSER_CHROMEOS_APP_MODE_ARC_ARC_KIOSK_APP_LAUNCHER_H_
 
 #include "chrome/browser/ui/app_list/arc/arc_app_list_prefs.h"
 #include "ui/aura/env_observer.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 
 namespace chromeos {
 
 // Starts Android app in kiosk mode.
 // Keeps track of start progress and pins app window
 // when it's finally opened.
 class ArcKioskAppLauncher : public ArcAppListPrefs::Observer,
                             public aura::EnvObserver,
                             public aura::WindowObserver {
  public:
+  class Delegate {
+   public:
+    Delegate() = default;
+    virtual void OnAppWindowLaunched() = 0;
+
+   protected:
+    virtual ~Delegate() = default;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Delegate);
+  };
+
   ArcKioskAppLauncher(content::BrowserContext* context,
                       ArcAppListPrefs* prefs,
-                      const std::string& app_id);
+                      const std::string& app_id,
+                      Delegate* delegate);
 
   ~ArcKioskAppLauncher() override;
 
   // ArcAppListPrefs::Observer overrides.
   void OnTaskCreated(int32_t task_id,
                      const std::string& package_name,
                      const std::string& activity,
                      const std::string& intent) override;
 
   // aura::EnvObserver overrides.
   void OnWindowInitialized(aura::Window* window) override;
 
   // aura::WindowObserver overrides.
   void OnWindowPropertyChanged(aura::Window* window,
                                const void* key,
                                intptr_t old) override;
   void OnWindowDestroying(aura::Window* window) override;
 
  private:
   // Check whether it's the app's window and pins it.
   bool CheckAndPinWindow(aura::Window* const window);
   void StopObserving();
 
   const std::string app_id_;
   ArcAppListPrefs* const prefs_;
   int task_id_ = -1;
   std::set<aura::Window*> windows_;
+  // Not owning the delegate, delegate owns this class.
+  Delegate* const delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcKioskAppLauncher);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_APP_MODE_ARC_ARC_KIOSK_APP_LAUNCHER_H_