Refactor sync-specific parts out of SyncNotifier/SyncNotifierObserver

sync/notifier/invalidation_util.cc

Index: sync/notifier/invalidation_util.cc
diff --git a/sync/notifier/invalidation_util.cc b/sync/notifier/invalidation_util.cc
index 0065b50e2b99d1a990eb042d588b84c1e7726806..5b18d66f3ae8ed207ca5eb4a4f02f5f90c34c632 100644
--- a/sync/notifier/invalidation_util.cc
+++ b/sync/notifier/invalidation_util.cc
@@ -33,6 +33,32 @@ bool ObjectIdToRealModelType(const invalidation::ObjectId& object_id,
   return NotificationTypeToRealModelType(object_id.name(), model_type);
 }
 
+ObjectIdSet ModelTypeSetToObjectIdSet(const ModelTypeSet& model_types) {
+  ObjectIdSet ids;
+  for (ModelTypeSet::Iterator it = model_types.First(); it.Good(); it.Inc()) {
+    invalidation::ObjectId model_type_as_id;
+    if (!RealModelTypeToObjectId(it.Get(), &model_type_as_id)) {
+      DLOG(WARNING) << "Invalid model type " << it.Get();
+      continue;
+    }
+    ids.insert(model_type_as_id);
+  }
+  return ids;
+}
+
+ModelTypeSet ObjectIdSetToModelTypeSet(const ObjectIdSet& ids) {
+  ModelTypeSet model_types;
+  for (ObjectIdSet::const_iterator it = ids.begin(); it != ids.end(); ++it) {
+    ModelType model_type;
+    if (!ObjectIdToRealModelType(*it, &model_type)) {
+      DLOG(WARNING) << "Invalid object ID " << ObjectIdToString(*it);
+      continue;
+    }
+    model_types.Put(model_type);
+  }
+  return model_types;
+}
+
 std::string ObjectIdToString(
     const invalidation::ObjectId& object_id) {
   std::stringstream ss;