[Sync] Fixing easy lint violations.

components/sync/device_info/device_info.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_DEVICE_INFO_DEVICE_INFO_H_
 #define COMPONENTS_SYNC_DEVICE_INFO_DEVICE_INFO_H_
 
+#include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "components/sync/protocol/sync.pb.h"
 
 namespace base {
 class DictionaryValue;
 }
 
@@ skipping 74 matching lines @@
   // ids in that the same device will have different id for different apps
   // and they are also reset when app/extension is uninstalled.
   std::string public_id_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceInfo);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DEVICE_INFO_DEVICE_INFO_H_