[Sync] Fixing easy lint violations.

components/sync/core/model_type_store_backend_unittest.cc

 // Copyright 2015 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 "components/sync/core/model_type_store_backend.h"
 
+#include <utility>
+
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/leveldatabase/src/include/leveldb/env.h"
 #include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
 
 namespace syncer {
 
 class ModelTypeStoreBackendTest : public testing::Test {
  public:
   scoped_refptr<ModelTypeStoreBackend> GetOrCreateBackend() {
     std::string path = "/test_db";
@@ skipping 164 matching lines @@
   ASSERT_TRUE(backend_second->HasOneRef());
   ASSERT_FALSE(BackendExistsForPath(path));
 
   // delete another backend.
   backend_second = nullptr;
   ASSERT_FALSE(backend_second.get());
   ASSERT_FALSE(BackendExistsForPath("/test_db2"));
 }
 
 }  // namespace syncer