Revert of Merge duplicate code in invalidation helper.

sync/tools/invalidation_helper.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sync/tools/invalidation_helper.h"
+
+#include "google/cacheinvalidation/types.pb.h"
+
+namespace syncer {
+
+bool RealModelTypeToObjectId(ModelType model_type,
+                             invalidation::ObjectId* object_id) {
+  std::string notification_type;
+  if (!RealModelTypeToNotificationType(model_type, &notification_type)) {
+    return false;
+  }
+  object_id->Init(ipc::invalidation::ObjectSource::CHROME_SYNC,
+                  notification_type);
+  return true;
+}
+
+ObjectIdSet ModelTypeSetToObjectIdSet(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;
+}
+
+}  // namespace syncer