[Sync] Removing duplicated includes between cc and h files.

components/sync/engine/cycle/sync_cycle_snapshot.cc

 // Copyright (c) 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.
 
 #include "components/sync/engine/cycle/sync_cycle_snapshot.h"
 
-#include <stddef.h>
-
 #include <memory>
 #include <utility>
 
 #include "base/json/json_writer.h"
 #include "base/values.h"
 #include "components/sync/protocol/proto_enum_conversions.h"
 
 namespace syncer {
 
 SyncCycleSnapshot::SyncCycleSnapshot()
@@ skipping 141 matching lines @@
     const {
   return num_to_delete_entries_by_type_;
 }
 
 sync_pb::GetUpdatesCallerInfo::GetUpdatesSource
 SyncCycleSnapshot::legacy_updates_source() const {
   return legacy_updates_source_;
 }
 
 }  // namespace syncer