Add fade to white animation when power button is pressed on Athena

athena/screen/public/screen_manager.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_SCREEN_PUBLIC_SCREEN_MANAGER_H_
 #define ATHENA_SCREEN_PUBLIC_SCREEN_MANAGER_H_
 
 #include <string>
 
 #include "athena/athena_export.h"
 
 namespace aura {
 class Window;
 }
 
 namespace gfx {
 class ImageSkia;
 }
 
+namespace ui {
+class LayerAnimator;
+}
+
 namespace wm {
 class FocusRules;
 }
 
 namespace athena {
 
 // Mananges basic UI components on the screen such as background, and provide
 // API for other UI components, such as window manager, home card, to
 // create and manage their windows on the screen.
 class ATHENA_EXPORT ScreenManager {
@@ skipping 27 matching lines @@
 
   // Creates the container window on the screen.
   virtual aura::Window* CreateContainer(const ContainerParams& params) = 0;
 
   // Return the context object to be used for widget creation.
   virtual aura::Window* GetContext() = 0;
 
   // Sets the background image.
   virtual void SetBackgroundImage(const gfx::ImageSkia& image) = 0;
 
+  // Returns the LayerAnimator to use to animate the entire screen (e.g. fade
+  // screen to white).
+  virtual ui::LayerAnimator* GetScreenAnimator() = 0;
+
   // Create a focus rules.
   // TODO(oshima): Make this virtual function.
   static wm::FocusRules* CreateFocusRules();
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_SCREEN_PUBLIC_SCREEN_MANAGER_H_