Generalize migration code in WebDatabase.

chrome/browser/webdata/token_service_table.h

 // Copyright (c) 2011 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_WEBDATA_TOKEN_SERVICE_TABLE_H_
 #define CHROME_BROWSER_WEBDATA_TOKEN_SERVICE_TABLE_H_
 
 #include <map>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "chrome/browser/webdata/web_database_table.h"
 
 class TokenServiceTable : public WebDatabaseTable {
  public:
   TokenServiceTable(sql::Connection* db, sql::MetaTable* meta_table)
       : WebDatabaseTable(db, meta_table) {}
   virtual ~TokenServiceTable() {}
   virtual bool Init() OVERRIDE;
   virtual bool IsSyncable() OVERRIDE;
+  virtual bool MigrateToVersion(int version,
+                                const std::string& app_locale,
+                                bool* update_compatible_version) OVERRIDE;
 
   // Remove all tokens previously set with SetTokenForService.
   bool RemoveAllTokens();
 
   // Retrieves all tokens previously set with SetTokenForService.
   // Returns true if there were tokens and we decrypted them,
   // false if there was a failure somehow
   bool GetAllTokens(std::map<std::string, std::string>* tokens);
 
   // Store a token in the token_service table. Stored encrypted. May cause
   // a mac keychain popup.
   // True if we encrypted a token and stored it, false otherwise.
   bool SetTokenForService(const std::string& service,
                           const std::string& token);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TokenServiceTable);
 };
 
 #endif  // CHROME_BROWSER_WEBDATA_TOKEN_SERVICE_TABLE_H_