[Sync] Remove ModelError::IsSet() in favor of base::Optional.

components/sync/device_info/device_info_sync_bridge.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_DEVICE_INFO_DEVICE_INFO_SYNC_BRIDGE_H_
 #define COMPONENTS_SYNC_DEVICE_INFO_DEVICE_INFO_SYNC_BRIDGE_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "base/optional.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "components/sync/device_info/device_info_tracker.h"
 #include "components/sync/device_info/local_device_info_provider.h"
 #include "components/sync/model/model_error.h"
 #include "components/sync/model/model_type_store.h"
 #include "components/sync/model/model_type_sync_bridge.h"
 
 namespace sync_pb {
 class DeviceInfoSpecifics;
@@ skipping 10 matching lines @@
   typedef base::Callback<void(const ModelTypeStore::InitCallback& callback)>
       StoreFactoryFunction;
 
   DeviceInfoSyncBridge(LocalDeviceInfoProvider* local_device_info_provider,
                        const StoreFactoryFunction& callback,
                        const ChangeProcessorFactory& change_processor_factory);
   ~DeviceInfoSyncBridge() override;
 
   // ModelTypeSyncBridge implementation.
   std::unique_ptr<MetadataChangeList> CreateMetadataChangeList() override;
-  ModelError MergeSyncData(
+  base::Optional<ModelError> MergeSyncData(
       std::unique_ptr<MetadataChangeList> metadata_change_list,
       EntityDataMap entity_data_map) override;
-  ModelError ApplySyncChanges(
+  base::Optional<ModelError> ApplySyncChanges(
       std::unique_ptr<MetadataChangeList> metadata_change_list,
       EntityChangeList entity_changes) override;
   void GetData(StorageKeyList storage_keys, DataCallback callback) override;
   void GetAllData(DataCallback callback) override;
   std::string GetClientTag(const EntityData& entity_data) override;
   std::string GetStorageKey(const EntityData& entity_data) override;
   void DisableSync() override;
 
   // DeviceInfoTracker implementation.
   bool IsSyncing() const override;
@@ skipping 23 matching lines @@
   void NotifyObservers();
 
   // Used as callback given to LocalDeviceInfoProvider.
   void OnProviderInitialized();
 
   // Methods used as callbacks given to DataTypeStore.
   void OnStoreCreated(ModelTypeStore::Result result,
                       std::unique_ptr<ModelTypeStore> store);
   void OnReadAllData(ModelTypeStore::Result result,
                      std::unique_ptr<ModelTypeStore::RecordList> record_list);
-  void OnReadAllMetadata(ModelError error,
+  void OnReadAllMetadata(base::Optional<ModelError> error,
                          std::unique_ptr<MetadataBatch> metadata_batch);
   void OnCommit(ModelTypeStore::Result result);
 
   // Load metadata if the data is loaded and the provider is initialized.
   void LoadMetadataIfReady();
 
   // Performs reconciliation between the locally provided device info and the
   // stored device info data. If the sets of data differ, then we consider this
   // a local change and we send it to the processor.
   void ReconcileLocalAndStored();
@@ skipping 36 matching lines @@
 
   // Used to update our local device info once every pulse interval.
   base::OneShotTimer pulse_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceInfoSyncBridge);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DEVICE_INFO_DEVICE_INFO_SYNC_BRIDGE_H_