Move all typecasting code to individual screens.

chrome/browser/chromeos/login/screen_manager.h

Index: chrome/browser/chromeos/login/screen_manager.h
diff --git a/chrome/browser/chromeos/login/screen_manager.h b/chrome/browser/chromeos/login/screen_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..b897180b43d2aa05e6bb0991b7b4f75936e1d8f5
--- /dev/null
+++ b/chrome/browser/chromeos/login/screen_manager.h
@@ -0,0 +1,40 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[ygorshenin1, 2014/09/03 12:58:46]

s/(c) 2012/2014/

[Denis Kuznetsov (DE-MUC), 2014/09/03 13:16:06]

Acknowledged.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_LOGIN_SCREEN_MANAGER_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_SCREEN_MANAGER_H_
+
+#include <map>
+#include <string>
+
+#include "base/compiler_specific.h"

[ygorshenin1, 2014/09/03 12:58:46]

You don't need compiler_specific.h. Also you don't need hash_tables.h. Add
inclusion of "base/macros.h" for DISALLOW_COPY_AND_ASSIGN().

[Denis Kuznetsov (DE-MUC), 2014/09/03 13:16:06]

Done.

+#include "base/containers/hash_tables.h"
+#include "base/memory/linked_ptr.h"
+#include "chrome/browser/chromeos/login/screens/wizard_screen.h"
+
+namespace chromeos {
+
+// Class that manages creation and ownership of screens.
+class ScreenManager {
+ public:
+  ScreenManager();
+  virtual ~ScreenManager();
+
+  // Getter for screen with lazy initialization.
+  WizardScreen* GetScreen(const std::string& screen_name);
+
+  // Factory for screen instances.
+  virtual WizardScreen* CreateScreen(const std::string& screen_name) = 0;
+
+ private:
+  // Screens.
+  typedef std::map<std::string, linked_ptr<WizardScreen> > ScreenMap;
+  ScreenMap screens_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScreenManager);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREEN_MANAGER_H_