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 5574a8c60ce531be47546db2496c1169b53d1462..2997c8cdec8009d83369771f469fd855db6461b0 100644
--- a/sync/notifier/invalidation_util.cc
+++ b/sync/notifier/invalidation_util.cc
@@ -36,6 +36,33 @@ bool ObjectIdToRealModelType(const invalidation::ObjectId& object_id,
           object_id.name(), model_type);
 }
 
+ObjectIdSet ModelTypeSetToObjectIdSet(const ModelTypeSet& model_types) {
+  ObjectIdSet ids;
+  for (ModelTypeSet::Iterator iter = model_types.First(); iter.Good();
+       iter.Inc()) {
+    invalidation::ObjectId model_type_as_id;
+    if (!RealModelTypeToObjectId(iter.Get(), &model_type_as_id)) {
+      DLOG(WARNING) << "Invalid model type " << iter.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;