[Sync] Refactor passphrase state handling

sync/internal_api/sync_encryption_handler_impl.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_ENCRYPTION_HANDLER_IMPL_H_
 #define SYNC_INTERNAL_API_SYNC_ENCRYPTION_HANDLER_IMPL_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 39 matching lines @@
 
   // SyncEncryptionHandler implementation.
   virtual void AddObserver(Observer* observer) OVERRIDE;
   virtual void RemoveObserver(Observer* observer) OVERRIDE;
   virtual void Init() OVERRIDE;
   virtual void SetEncryptionPassphrase(const std::string& passphrase,
                                        bool is_explicit) OVERRIDE;
   virtual void SetDecryptionPassphrase(const std::string& passphrase) OVERRIDE;
   virtual void EnableEncryptEverything() OVERRIDE;
   virtual bool EncryptEverythingEnabled() const OVERRIDE;
-  // Can be called from any thread.
-  // TODO(zea): enforce this is only called on sync thread.
-  virtual bool IsUsingExplicitPassphrase() const OVERRIDE;
+  virtual PassphraseState GetPassphraseState() const OVERRIDE;
 
   // NigoriHandler implementation.
   // Note: all methods are invoked while the caller holds a transaction.
   virtual void ApplyNigoriUpdate(
       const sync_pb::NigoriSpecifics& nigori,
       syncable::BaseTransaction* const trans) OVERRIDE;
   virtual void UpdateNigoriFromEncryptedTypes(
       sync_pb::NigoriSpecifics* nigori,
       syncable::BaseTransaction* const trans) const OVERRIDE;
   // Can be called from any thread.
@@ skipping 100 matching lines @@
 
   // Container for all data that can be accessed from multiple threads. Do not
   // access this object directly. Instead access it via UnlockVault(..) and
   // UnlockVaultMutable(..).
   Vault vault_unsafe_;
 
   // Sync encryption state that is only modified and accessed from the sync
   // thread.
   // Whether all current and future types should be encrypted.
   bool encrypt_everything_;
-  // Whether the user is using a custom passphrase for encryption.
-  bool explicit_passphrase_;
+  // The current state of the passphrase required to decrypt the encryption
+  // keys stored in the nigori node.
+  PassphraseState passphrase_state_;
 
   // The number of times we've automatically (i.e. not via SetPassphrase or
   // conflict resolver) updated the nigori's encryption keys in this chrome
   // instantiation.
   int nigori_overwrite_count_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncEncryptionHandlerImpl);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_SYNC_ENCRYPTION_HANDLER_IMPL_H_