Sync: Don't set/use Parent ID for non-hierarchical sync data types.

sync/engine/syncer_util.cc

Index: sync/engine/syncer_util.cc
diff --git a/sync/engine/syncer_util.cc b/sync/engine/syncer_util.cc
index 3a8870017c554dad472e42ab26ca04564faaa10e..5577e0b8f225a2a0c8fe6c6b36266dd795589655 100644
--- a/sync/engine/syncer_util.cc
+++ b/sync/engine/syncer_util.cc
@@ -406,7 +406,11 @@ void UpdateServerFieldsFromUpdate(
 
   DCHECK_EQ(target->GetId(), SyncableIdFromProto(update.id_string()))
       << "ID Changing not supported here";
-  target->PutServerParentId(SyncableIdFromProto(update.parent_id_string()));
+  if (SyncerProtoUtil::ShouldMaintainHierarchy(update)) {
+    target->PutServerParentId(SyncableIdFromProto(update.parent_id_string()));
+  } else {
+    target->PutServerParentId(syncable::Id());
+  }
   target->PutServerNonUniqueName(name);
   target->PutServerVersion(update.version());
   target->PutServerCtime(ProtoTimeToTime(update.ctime()));