Move definition of PasswordType enum to a separate header.

components/sync/core_impl/sync_encryption_handler_impl.cc

Index: components/sync/core_impl/sync_encryption_handler_impl.cc
diff --git a/components/sync/core_impl/sync_encryption_handler_impl.cc b/components/sync/core_impl/sync_encryption_handler_impl.cc
index 95c24e351c227ce7a181fbc505a89e9843d1bfa7..1f0b234a10cdcd48a698e360f5f1a46ba748909f 100644
--- a/components/sync/core_impl/sync_encryption_handler_impl.cc
+++ b/components/sync/core_impl/sync_encryption_handler_impl.cc
@@ -23,6 +23,7 @@
 #include "components/sync/base/cryptographer.h"
 #include "components/sync/base/encryptor.h"
 #include "components/sync/base/experiments.h"
+#include "components/sync/base/passphrase_type.h"
 #include "components/sync/base/time.h"
 #include "components/sync/core/read_node.h"
 #include "components/sync/core/read_transaction.h"
@@ -127,11 +128,6 @@ sync_pb::NigoriSpecifics::PassphraseType EnumPassphraseTypeToProto(
   }
 }
 
-bool IsExplicitPassphrase(PassphraseType type) {
-  return type == PassphraseType::CUSTOM_PASSPHRASE ||
-         type == PassphraseType::FROZEN_IMPLICIT_PASSPHRASE;
-}
-
 // Keystore Bootstrap Token helper methods.
 // The bootstrap is a base64 encoded, encrypted, ListValue of keystore key
 // strings, with the current keystore key as the last value in the list.