[Sync] Persist keystore key across restarts

sync/internal_api/sync_manager.h

 // Copyright (c) 2012 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 SYNC_INTERNAL_API_SYNC_MANAGER_H_
 #define SYNC_INTERNAL_API_SYNC_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 441 matching lines @@
             HttpPostProviderFactory* post_factory,
             const browser_sync::ModelSafeRoutingInfo& model_safe_routing_info,
             const std::vector<browser_sync::ModelSafeWorker*>& workers,
             browser_sync::ExtensionsActivityMonitor*
                 extensions_activity_monitor,
             ChangeDelegate* change_delegate,
             const std::string& user_agent,
             const SyncCredentials& credentials,
             sync_notifier::SyncNotifier* sync_notifier,
             const std::string& restored_key_for_bootstrapping,
+            const std::string& restored_keystore_key_for_bootstrapping,
             bool keystore_encryption_enabled,
             TestingMode testing_mode,
             browser_sync::Encryptor* encryptor,
             browser_sync::UnrecoverableErrorHandler*
                 unrecoverable_error_handler,
             browser_sync::ReportUnrecoverableErrorFunction
                 report_unrecoverable_error_function);
 
   // Throw an unrecoverable error from a transaction (mostly used for
   // testing).
@@ skipping 57 matching lines @@
   // potentially dereference garbage.
   void RemoveObserver(Observer* observer);
 
   // Status-related getter.  May be called on any thread.
   Status GetDetailedStatus() const;
 
   // Whether or not the Nigori node is encrypted using an explicit passphrase.
   // May be called on any thread.
   bool IsUsingExplicitPassphrase();
 
+  // Extracts the keystore encryption bootstrap token if a keystore key existed.
+  // Returns true if bootstrap token successfully extracted, false otherwise.
+  bool GetKeystoreKeyBootstrapToken(std::string* token);
+
   // Call periodically from a database-safe thread to persist recent changes
   // to the syncapi model.
   void SaveChanges();
 
   // Initiates shutdown of various components in the sync engine.  Must be
   // called from the main thread to allow preempting ongoing tasks on the sync
   // loop (that may be blocked on I/O).  The semantics of |callback| are the
   // same as with StartConfigurationMode. If provided and a scheduler / sync
   // loop exists, it will be invoked from the sync loop by the scheduler to
   // notify that all work has been flushed + cancelled, and it is idle.
@@ skipping 90 matching lines @@
     sync_api::UserShare* share);
 
 const char* ConnectionStatusToString(ConnectionStatus status);
 
 // Returns the string representation of a PassphraseRequiredReason value.
 const char* PassphraseRequiredReasonToString(PassphraseRequiredReason reason);
 
 }  // namespace sync_api
 
 #endif  // SYNC_INTERNAL_API_SYNC_MANAGER_H_