Refactor LoginDatabase migration

components/password_manager/core/browser/login_database.h

 // Copyright 2014 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 COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_LOGIN_DATABASE_H_
 #define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_LOGIN_DATABASE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 152 matching lines @@
   static EncryptionResult EncryptedString(const base::string16& plain_text,
                                           std::string* cipher_text);
 
   // Decrypts cipher_text, setting the value of plain_text and returning true if
   // successful, or returning false and leaving plain_text unchanged if
   // decryption fails (e.g., if the underlying OS encryption system is
   // temporarily unavailable).
   static EncryptionResult DecryptedString(const std::string& cipher_text,
                                           base::string16* plain_text);
 
-  bool InitLoginsTable();
-  bool MigrateOldVersionsAsNeeded();
-
   // Fills |form| from the values in the given statement (which is assumed to
   // be of the form used by the Get*Logins methods).
   // Returns the EncryptionResult from decrypting the password in |s|; if not
   // ENCRYPTION_RESULT_SUCCESS, |form| is not filled.
   static EncryptionResult InitPasswordFormFromStatement(
       autofill::PasswordForm* form,
       sql::Statement* s);
 
   // Gets all blacklisted or all non-blacklisted (depending on |blacklisted|)
   // credentials. On success returns true and overwrites |forms| with the
@@ skipping 14 matching lines @@
   sql::MetaTable meta_table_;
   StatisticsTable stats_table_;
 
   // If set to 'true', then the password values are cleared before encrypting
   // and storing in the database. At the same time AddLogin/UpdateLogin return
   // PasswordStoreChangeList containing the real password.
   // This is a temporary measure for migration the Keychain on Mac.
   // crbug.com/466638
   bool clear_password_values_;
 
+  // These cached strings are used to build SQL statements.
+  std::string add_statement_;
+  std::string add_replace_statement_;
+  std::string update_statement_;
+  std::string delete_statement_;
+  std::string autosignin_statement_;
+  std::string get_statement_;
+  std::string get_statement_psl_;
+  std::string get_statement_federated_;
+  std::string get_statement_psl_federated_;
+  std::string created_statement_;
+  std::string synced_statement_;
+  std::string blacklisted_statement_;
+  std::string encrypted_statement_;
+
   DISALLOW_COPY_AND_ASSIGN(LoginDatabase);
 };
 
 }  // namespace password_manager
 
 #endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_LOGIN_DATABASE_H_