Move definition of PasswordType enum to a separate header.

components/sync/core/sync_encryption_handler.h

 // Copyright 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 COMPONENTS_SYNC_CORE_SYNC_ENCRYPTION_HANDLER_H_
 #define COMPONENTS_SYNC_CORE_SYNC_ENCRYPTION_HANDLER_H_
 
 #include <string>
 
 #include "base/time/time.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/protocol/sync.pb.h"
 
 namespace syncer {
 
 class Cryptographer;
+enum class PassphraseType;
 
 // Reasons due to which Cryptographer might require a passphrase.
 enum PassphraseRequiredReason {
   REASON_PASSPHRASE_NOT_REQUIRED = 0,  // Initial value.
   REASON_ENCRYPTION = 1,               // The cryptographer requires a
                                        // passphrase for its first attempt at
                                        // encryption. Happens only during
                                        // migration or upgrade.
   REASON_DECRYPTION = 2,               // The cryptographer requires a
                                        // passphrase for its first attempt at
                                        // decryption.
 };
 
-// The different states for the encryption passphrase. These control if and how
-// the user should be prompted for a decryption passphrase.
-// Do not re-order or delete these entries; they are used in a UMA histogram.
-// Please edit SyncPassphraseType in histograms.xml if a value is added.
-enum class PassphraseType {
-  IMPLICIT_PASSPHRASE = 0,         // GAIA-based passphrase (deprecated).
-  KEYSTORE_PASSPHRASE = 1,         // Keystore passphrase.
-  FROZEN_IMPLICIT_PASSPHRASE = 2,  // Frozen GAIA passphrase.
-  CUSTOM_PASSPHRASE = 3,           // User-provided passphrase.
-  PASSPHRASE_TYPE_SIZE,            // The size of this enum; keep last.
-};
-
 // Enum used to distinguish which bootstrap encryption token is being updated.
 enum BootstrapTokenType {
   PASSPHRASE_BOOTSTRAP_TOKEN,
   KEYSTORE_BOOTSTRAP_TOKEN
 };
 
 // Sync's encryption handler. Handles tracking encrypted types, ensuring the
 // cryptographer encrypts with the proper key and has the most recent keybag,
 // and keeps the nigori node up to date.
 // Implementations of this class must be assumed to be non-thread-safe. All
@@ skipping 129 matching lines @@
   // bag of encryption keys in the nigori node.
   virtual PassphraseType GetPassphraseType() const = 0;
 
   // The set of types that are always encrypted.
   static ModelTypeSet SensitiveTypes();
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_CORE_SYNC_ENCRYPTION_HANDLER_H_