Implement a basic UI flow for cryptohome encryption migration.

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

 // 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.
 
 #include "chrome/browser/ui/webui/chromeos/login/encryption_migration_screen_handler.h"
 
+#include "chrome/browser/lifetime/application_lifetime.h"
+#include "chromeos/cryptohome/homedir_methods.h"
+#include "chromeos/dbus/cryptohome_client.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+
 namespace {
 
 constexpr char kJsScreenPath[] = "login.EncryptionMigrationScreen";
 
+// JS API callbacks names.
+constexpr char kJsApiStartMigration[] = "startMigration";
+constexpr char kJsApiRequestRestart[] = "requestRestart";
+
 }  // namespace
 
 namespace chromeos {
 
 EncryptionMigrationScreenHandler::EncryptionMigrationScreenHandler()
     : BaseScreenHandler(kScreenId) {
   set_call_js_prefix(kJsScreenPath);
 }
 
 EncryptionMigrationScreenHandler::~EncryptionMigrationScreenHandler() {
@@ skipping 12 matching lines @@
 void EncryptionMigrationScreenHandler::Hide() {
   show_on_init_ = false;
 }
 
 void EncryptionMigrationScreenHandler::SetDelegate(Delegate* delegate) {
   delegate_ = delegate;
   if (page_is_ready())
     Initialize();
 }
 
+void EncryptionMigrationScreenHandler::SetUserContext(
+    const UserContext& user_context) {
+  user_context_ = user_context;
+}
+
 void EncryptionMigrationScreenHandler::DeclareLocalizedValues(
     ::login::LocalizedValuesBuilder* builder) {}
 
 void EncryptionMigrationScreenHandler::Initialize() {
   if (!page_is_ready() || !delegate_)
     return;
 
   if (show_on_init_) {
     Show();
     show_on_init_ = false;
   }
 }
 
+void EncryptionMigrationScreenHandler::RegisterMessages() {
+  AddCallback(kJsApiStartMigration,
+              &EncryptionMigrationScreenHandler::HandleStartMigration);
+  AddCallback(kJsApiRequestRestart,
+              &EncryptionMigrationScreenHandler::HandleRequestRestart);
+}
+
+void EncryptionMigrationScreenHandler::HandleStartMigration() {
+  StartMigration();
+}
+
+void EncryptionMigrationScreenHandler::HandleRequestRestart() {
+  chrome::AttemptRestart();

[xiyuan, 2017/03/30 17:55:40]

IMHO, continuing signing in would be be better than restarting chrome and ask
user to sign in again if that is possible.

On chrome side, this can be done by somehow get the |delegate_| of
SigninScreenHandler and call its Login for existing user.

[fukino, 2017/03/31 02:29:52]

I agree with it.
I changed the button on the final screen from "Restart Now" to "Finish", and let
user log in using already-given user credential.
As the change is going to need a review, let me do it in a separate patch. (I
left a TODO comment.)

+}
+
+void EncryptionMigrationScreenHandler::UpdateUIState(UIState state) {
+  if (state == current_ui_state_)
+    return;
+
+  current_ui_state_ = state;
+  CallJS("setUIState", static_cast<int>(state));
+}
+
+void EncryptionMigrationScreenHandler::StartMigration() {
+  DBusThreadManager::Get()
+      ->GetCryptohomeClient()
+      ->SetDircryptoMigrationProgressHandler(
+          base::Bind(&EncryptionMigrationScreenHandler::OnMigrationProgress,
+                     base::Unretained(this)));
+
+  // |auth_key| is created in the same manner as CryptohomeAuthenticator.
+  const Key* key = user_context_.GetKey();
+  // If the |key| is a plain text password, crash rather than attempting to
+  // mount the cryptohome with a plain text password.
+  CHECK_NE(Key::KEY_TYPE_PASSWORD_PLAIN, key->GetKeyType());
+  // Set the authentication's key label to an empty string, which is a wildcard
+  // allowing any key to match. This is necessary because cryptohomes created by
+  // Chrome OS M38 and older will have a legacy key with no label while those
+  // created by Chrome OS M39 and newer will have a key with the label
+  // kCryptohomeGAIAKeyLabel.
+  const cryptohome::KeyDefinition auth_key(key->GetSecret(), std::string(),
+                                           cryptohome::PRIV_DEFAULT);
+  cryptohome::HomedirMethods::GetInstance()->MigrateToDircrypto(
+      cryptohome::Identification(user_context_.GetAccountId()),
+      cryptohome::Authorization(auth_key),
+      base::Bind(&EncryptionMigrationScreenHandler::OnMigrationRequested,
+                 base::Unretained(this)));

[xiyuan, 2017/03/30 17:55:40]

Let's use a WeakPtr instead of Unretained even though this should not happen.

[fukino, 2017/03/31 02:29:52]

Done.

+}
+
+void EncryptionMigrationScreenHandler::OnMigrationProgress(
+    cryptohome::DircryptoMigrationStatus status,
+    uint64_t current,
+    uint64_t total) {
+  switch (status) {
+    case cryptohome::DIRCRYPTO_MIGRATION_INITIALIZING:
+      UpdateUIState(UIState::MIGRATING);
+      break;
+    case cryptohome::DIRCRYPTO_MIGRATION_IN_PROGRESS:
+      UpdateUIState(UIState::MIGRATING);
+      CallJS("setMigrationProgress", static_cast<double>(current) / total);
+      break;
+    case cryptohome::DIRCRYPTO_MIGRATION_SUCCESS:
+    case cryptohome::DIRCRYPTO_MIGRATION_FAILED:
+      UpdateUIState(status == cryptohome::DIRCRYPTO_MIGRATION_SUCCESS
+                        ? UIState::MIGRATION_SUCCEEDED
+                        : UIState::MIGRATION_FAILED);
+      // Stop listening to the progress updates.
+      DBusThreadManager::Get()
+          ->GetCryptohomeClient()
+          ->SetDircryptoMigrationProgressHandler(
+              CryptohomeClient::DircryptoMigrationProgessHandler());
+      break;
+    default:
+      break;
+  }
+}
+
+void EncryptionMigrationScreenHandler::OnMigrationRequested(bool success) {
+  // This function is called when MigrateToDircrypto is correctly requested.
+  // It does not mean that the migration is completed. We should know the
+  // completion by DircryptoMigrationProgressHandler. success == false means a
+  // failure in DBus communication.
+  // TODO(fukino): Handle this case. Should we retry or restart?
+  DCHECK(success);
+}
+
 }  // namespace chromeos