Add a screen to migrate filesystem encryption from eCryptfs to ext4 crypto.

chrome/browser/ui/webui/chromeos/login/encryption_migration_screen_handler.h

Index: chrome/browser/ui/webui/chromeos/login/encryption_migration_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/encryption_migration_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/encryption_migration_screen_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..4ae2a93a032d00d45fd7be6c265a580912642cd3
--- /dev/null
+++ b/chrome/browser/ui/webui/chromeos/login/encryption_migration_screen_handler.h
@@ -0,0 +1,40 @@
+// Copyright 2017 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_WEBUI_CHROMEOS_LOGIN_ENCRYPTION_MIGRATION_SCREEN_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_ENCRYPTION_MIGRATION_SCREEN_HANDLER_H_
+
+#include "base/macros.h"
+#include "chrome/browser/chromeos/login/screens/encryption_migration_screen_view.h"
+#include "chrome/browser/ui/webui/chromeos/login/base_screen_handler.h"
+
+namespace chromeos {
+
+// WebUI implementation of EncryptionMigrationScreenView
+class EncryptionMigrationScreenHandler : public EncryptionMigrationScreenView,
+                                         public BaseScreenHandler {
+ public:
+  EncryptionMigrationScreenHandler();
+  ~EncryptionMigrationScreenHandler() override;
+
+  // EncryptionMigrationScreenView:
+  void Show() override;
+  void Hide() override;
+  void SetDelegate(Delegate* delegate) override;
+
+  // BaseScreenHandler:
+  void DeclareLocalizedValues(
+      ::login::LocalizedValuesBuilder* builder) override;
+  void Initialize() override;
+
+ private:
+  Delegate* delegate_ = nullptr;
+  bool show_on_init_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(EncryptionMigrationScreenHandler);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_ENCRYPTION_MIGRATION_SCREEN_HANDLER_H_