[Sync] Add a sanity integration test for USS.

components/sync/test/fake_server/unique_client_entity.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_TEST_FAKE_SERVER_UNIQUE_CLIENT_ENTITY_H_
 #define COMPONENTS_SYNC_TEST_FAKE_SERVER_UNIQUE_CLIENT_ENTITY_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 10 matching lines @@
 namespace fake_server {
 
 // An entity that is unique per client account.
 //
 // TODO(pvalenzuela): Reconsider the naming of this class. In some cases, this
 // type is used to represent entities where the unique client tag is irrelevant
 // (e.g., Autofill Wallet).
 class UniqueClientEntity : public FakeServerEntity {
  public:
   UniqueClientEntity(const std::string& id,
+                     const std::string& client_defined_unique_tag,
                      syncer::ModelType model_type,
                      int64_t version,
                      const std::string& name,
-                     const std::string& client_defined_unique_tag,
                      const sync_pb::EntitySpecifics& specifics,
                      int64_t creation_time,
                      int64_t last_modified_time);
 
   ~UniqueClientEntity() override;
 
   // Factory function for creating a UniqueClientEntity.
   static std::unique_ptr<FakeServerEntity> Create(
       const sync_pb::SyncEntity& client_entity);
 
   // Factory function for creating a UniqueClientEntity for use in the
   // FakeServer injection API.
   static std::unique_ptr<FakeServerEntity> CreateForInjection(
       const std::string& name,
       const sync_pb::EntitySpecifics& entity_specifics);
 
   // Derives an ID from a unique client tagged entity.
   static std::string EffectiveIdForClientTaggedEntity(
       const sync_pb::SyncEntity& entity);
 
   // FakeServerEntity implementation.
   bool RequiresParentId() const override;
   std::string GetParentId() const override;
   void SerializeAsProto(sync_pb::SyncEntity* proto) const override;
 
  private:
   // These member values have equivalent fields in SyncEntity.
-  std::string client_defined_unique_tag_;
   int64_t creation_time_;
   int64_t last_modified_time_;
 };
 
 }  // namespace fake_server
 
 #endif  // COMPONENTS_SYNC_TEST_FAKE_SERVER_UNIQUE_CLIENT_ENTITY_H_