[Sync] Fixing easy lint violations.

components/sync/engine/cycle/sync_cycle_snapshot.h

 // Copyright 2012 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.
 
 #ifndef COMPONENTS_SYNC_ENGINE_CYCLE_SYNC_CYCLE_SNAPSHOT_H_
 #define COMPONENTS_SYNC_ENGINE_CYCLE_SYNC_CYCLE_SNAPSHOT_H_
 
 #include <stddef.h>
 
+#include <memory>
 #include <string>
 #include <vector>
 
 #include "base/time/time.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/base/progress_marker_map.h"
 #include "components/sync/engine/cycle/model_neutral_state.h"
 
 namespace base {
 class DictionaryValue;
@@ skipping 66 matching lines @@
   // now deprecated.  We continue to use it in the snapshot because there is
   // still some value in displaying it on the about:sync page.
   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource legacy_updates_source_;
 
   bool is_initialized_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_CYCLE_SYNC_CYCLE_SNAPSHOT_H_