[Sync] Rely on directory to decide which types need to be purged

sync/test/engine/test_syncable_utils.h

Index: sync/test/engine/test_syncable_utils.h
diff --git a/sync/test/engine/test_syncable_utils.h b/sync/test/engine/test_syncable_utils.h
index 7f162f70fc0badd97d7356e00cc5611cc0dbd352..5975e1228ca5eb9293206ae5ab3f7ef407596eb5 100644
--- a/sync/test/engine/test_syncable_utils.h
+++ b/sync/test/engine/test_syncable_utils.h
@@ -11,6 +11,7 @@
 #include <string>
 
 #include "sync/internal_api/public/base/model_type.h"
+#include "sync/protocol/sync.pb.h"
 
 namespace syncer {
 namespace syncable {
@@ -42,6 +43,8 @@ void CreateTypeRoot(WriteTransaction* trans,
                     syncable::Directory *dir,
                     ModelType type);
 
+sync_pb::DataTypeProgressMarker BuildProgress(ModelType type);
+
 }  // namespace syncable
 }  // namespace syncer