[Sync] Add ability to save/restore Nigori to SyncEncryptionHandlerImpl

sync/internal_api/debug_info_event_listener.h

Index: sync/internal_api/debug_info_event_listener.h
diff --git a/sync/internal_api/debug_info_event_listener.h b/sync/internal_api/debug_info_event_listener.h
index ba556500af50714c80e17549ddacfda88660eae5..f84eece9a1384ae6b7490d3b8f10af42f06d77a4 100644
--- a/sync/internal_api/debug_info_event_listener.h
+++ b/sync/internal_api/debug_info_event_listener.h
@@ -65,6 +65,8 @@ class SYNC_EXPORT_PRIVATE DebugInfoEventListener
   void OnCryptographerStateChanged(Cryptographer* cryptographer) override;
   void OnPassphraseTypeChanged(PassphraseType type,
                                base::Time explicit_passphrase_time) override;
+  void OnLocalSetCustomPassphrase(
+      const SyncEncryptionHandler::NigoriState& nigori_state) override;
 
   // Sync manager events.
   void OnNudgeFromDatatype(ModelType datatype);