Fix memory leak in Sync FakeServerEntity

sync/test/fake_server/tombstone_entity.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/test/fake_server/tombstone_entity.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "sync/internal_api/public/base/model_type.h"
@@ skipping 14 matching lines @@
 }
 
 TombstoneEntity::TombstoneEntity(const string& id,
                                  const ModelType& model_type)
     : FakeServerEntity(id, model_type, 0, string()) { }
 
 string TombstoneEntity::GetParentId() const {
   return string();
 }
 
-sync_pb::SyncEntity* TombstoneEntity::SerializeAsProto() {
-  sync_pb::SyncEntity* sync_entity = new sync_pb::SyncEntity();
-  FakeServerEntity::SerializeBaseProtoFields(sync_entity);
+void TombstoneEntity::SerializeAsProto(sync_pb::SyncEntity* proto) {
+  FakeServerEntity::SerializeBaseProtoFields(proto);
 
-  sync_pb::EntitySpecifics* specifics = sync_entity->mutable_specifics();
+  sync_pb::EntitySpecifics* specifics = proto->mutable_specifics();
   AddDefaultFieldValue(FakeServerEntity::GetModelType(), specifics);
-
-  return sync_entity;
 }
 
 bool TombstoneEntity::IsDeleted() const {
   return true;
 }
 
 bool TombstoneEntity::IsFolder() const {
   return false;
 }
 
 }  // namespace fake_server