Make the minimized home card not overlap activities on Athena

athena/main/athena_launcher.h

 // Copyright 2014 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 ATHENA_MAIN_ATHENA_LAUNCHER_H_
 #define ATHENA_MAIN_ATHENA_LAUNCHER_H_
 
 namespace aura {
 class Window;
 }
 
 namespace content {
 class BrowserContext;
 }
 
 namespace athena {
 class ActivityFactory;
 class AppModelBuilder;
+class ScreenManagerDelegate;
 
 // Starts/shuts down the athena shell environment.
-void StartAthenaEnv(aura::Window* root_window);
+void StartAthenaEnv(aura::Window* root_window,
+                    ScreenManagerDelegate* screen_manager_delegate);
 
 void StartAthenaSessionWithContext(content::BrowserContext* context);
 
 // Starts/shuts down the athena shell environment.
 void StartAthenaSession(ActivityFactory* activity_factory,
                         AppModelBuilder* app_model_builder);
 
 void ShutdownAthena();
 
 }  // namespace athena
 
 #endif  // ATHENA_MAIN_ATHENA_LAUNCHER_H_