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

chrome/browser/chromeos/login/existing_user_controller.cc

Index: chrome/browser/chromeos/login/existing_user_controller.cc
diff --git a/chrome/browser/chromeos/login/existing_user_controller.cc b/chrome/browser/chromeos/login/existing_user_controller.cc
index 59854dc7ca4cb6efc3cc590dc1cb9cd8b5cd113a..cc57fbaa5673902541bfaacc0f7118d4db407934 100644
--- a/chrome/browser/chromeos/login/existing_user_controller.cc
+++ b/chrome/browser/chromeos/login/existing_user_controller.cc
@@ -597,6 +597,10 @@ void ExistingUserController::ShowKioskAutolaunchScreen() {
   host_->StartWizard(OobeScreen::SCREEN_KIOSK_AUTOLAUNCH);
 }
 
+void ExistingUserController::ShowEncryptionMigrationScreen() {
+  host_->StartWizard(OobeScreen::SCREEN_ENCRYPTION_MIGRATION);
+}
+
 void ExistingUserController::ShowTPMError() {
   login_display_->SetUIEnabled(false);
   login_display_->ShowErrorScreen(LoginDisplay::TPM_ERROR);
@@ -825,6 +829,10 @@ void ExistingUserController::OnPasswordChangeDetected() {
   ShowPasswordChangedDialog();
 }
 
+void ExistingUserController::OnOldEncryptionDetected() {
+  ShowEncryptionMigrationScreen();
+}
+
 void ExistingUserController::WhiteListCheckFailed(const std::string& email) {
   PerformLoginFinishedActions(true /* start auto login timer */);