Check the available storage size before starting encryption migration.

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

 // 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"
 #include "chromeos/login/auth/user_context.h"
 #include "third_party/cros_system_api/dbus/cryptohome/dbus-constants.h"
 
 namespace chromeos {
 
 // WebUI implementation of EncryptionMigrationScreenView
 class EncryptionMigrationScreenHandler : public EncryptionMigrationScreenView,
                                          public BaseScreenHandler {
  public:
   EncryptionMigrationScreenHandler();
   ~EncryptionMigrationScreenHandler() override;
 
   // EncryptionMigrationScreenView implementation:
   void Show() override;
   void Hide() override;
   void SetDelegate(Delegate* delegate) override;
   void SetUserContext(const UserContext& user_context) override;
   void SetShouldResume(bool should_resume) override;
   void SetContinueLoginCallback(ContinueLoginCallback callback) override;
+  void SetupInitialView() override;
 
   // BaseScreenHandler implementation:
   void DeclareLocalizedValues(
       ::login::LocalizedValuesBuilder* builder) override;
   void Initialize() override;
 
  private:
   // Enumeration for the migration state. These values must be kept in sync with
   // EncryptionMigrationUIState in JS code.
   enum UIState {
     INITIAL = 0,
-    MIGRATING = 1,
-    MIGRATION_SUCCEEDED = 2,
-    MIGRATION_FAILED = 3
+    READY = 1,
+    MIGRATING = 2,
+    MIGRATION_SUCCEEDED = 3,
+    MIGRATION_FAILED = 4,
+    NOT_ENOUGH_STORAGE = 5,
   };
 
   // WebUIMessageHandler implementation:
   void RegisterMessages() override;
 
   // Handlers for JS API callbacks.
   void HandleStartMigration();
   void HandleSkipMigration();
   void HandleRequestRestart();
 
   // Updates UI state.
   void UpdateUIState(UIState state);
 
   // Requests cryptohome to start encryption migration.
+  void CheckAvailableStorage();
+  void OnGetAvailableStorage(int64_t size);
   void StartMigration();
 
   // Handlers for cryptohome API callbacks.
   void OnMigrationProgress(cryptohome::DircryptoMigrationStatus status,
                            uint64_t current,
                            uint64_t total);
   void OnMigrationRequested(bool success);
 
   Delegate* delegate_ = nullptr;
   bool show_on_init_ = false;
 
   // The current UI state which should be refrected in the web UI.
   UIState current_ui_state_ = INITIAL;
 
   // The current user's UserContext, which is used to request the migration to
   // cryptohome.
   UserContext user_context_;
 
   // The callback which is used to log in to the session from the migration UI.
   ContinueLoginCallback continue_login_callback_;
 
+  // True if the system should resume the previous incomplete migration.
+  bool should_resume_ = false;
+
   base::WeakPtrFactory<EncryptionMigrationScreenHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EncryptionMigrationScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_ENCRYPTION_MIGRATION_SCREEN_HANDLER_H_