Sync: fix for the code that checks whether the initial download has completed

sync/test/engine/mock_connection_manager.h

Index: sync/test/engine/mock_connection_manager.h
diff --git a/sync/test/engine/mock_connection_manager.h b/sync/test/engine/mock_connection_manager.h
index c09cf87df3cc9935beeb20f74ba4ac935ca0aa4a..8bcc5c2d9c5a12ec32833150d0d71e09ef138bb5 100644
--- a/sync/test/engine/mock_connection_manager.h
+++ b/sync/test/engine/mock_connection_manager.h
@@ -269,6 +269,9 @@ class MockConnectionManager : public ServerConnectionManager {
   // Locate the most recent update message for purpose of alteration.
   sync_pb::SyncEntity* GetMutableLastUpdate();
 
+  // Adds a new progress marker to the last update.
+  sync_pb::DataTypeProgressMarker* AddUpdateProgressMarker();
+
  private:
   sync_pb::SyncEntity* AddUpdateFull(syncable::Id id,
                                      syncable::Id parentid,