Use std::unique_ptr to transfer base::Value ownership in extensions::ValueStoreChange

chrome/browser/extensions/api/storage/syncable_settings_storage.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 CHROME_BROWSER_EXTENSIONS_API_STORAGE_SYNCABLE_SETTINGS_STORAGE_H_
 #define CHROME_BROWSER_EXTENSIONS_API_STORAGE_SYNCABLE_SETTINGS_STORAGE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 80 matching lines @@
   // Returns any error when trying to sync, or an empty error on success.
   syncer::SyncError SendLocalSettingsToSync(
       std::unique_ptr<base::DictionaryValue> local_state);
 
   // Overwrites local state with sync state.
   // Returns any error when trying to sync, or an empty error on success.
   syncer::SyncError OverwriteLocalSettingsWithSync(
       std::unique_ptr<base::DictionaryValue> sync_state,
       std::unique_ptr<base::DictionaryValue> local_state);
 
-  // Called when an Add/Update/Remove comes from sync. Ownership of Value*s
-  // are taken.
-  syncer::SyncError OnSyncAdd(
-      const std::string& key,
-      base::Value* new_value,
-      ValueStoreChangeList* changes);
-  syncer::SyncError OnSyncUpdate(
-      const std::string& key,
-      base::Value* old_value,
-      base::Value* new_value,
-      ValueStoreChangeList* changes);
-  syncer::SyncError OnSyncDelete(
-      const std::string& key,
-      base::Value* old_value,
-      ValueStoreChangeList* changes);
+  // Called when an Add/Update/Remove comes from sync.
+  syncer::SyncError OnSyncAdd(const std::string& key,
+                              std::unique_ptr<base::Value> new_value,
+                              ValueStoreChangeList* changes);
+  syncer::SyncError OnSyncUpdate(const std::string& key,
+                                 std::unique_ptr<base::Value> old_value,
+                                 std::unique_ptr<base::Value> new_value,
+                                 ValueStoreChangeList* changes);
+  syncer::SyncError OnSyncDelete(const std::string& key,
+                                 std::unique_ptr<base::Value> old_value,
+                                 ValueStoreChangeList* changes);
 
   // List of observers to settings changes.
   const scoped_refptr<SettingsObserverList> observers_;
 
   // Id of the extension these settings are for.
   std::string const extension_id_;
 
   // Storage area to sync.
   const std::unique_ptr<ValueStore> delegate_;
 
   // Object which sends changes to sync.
   std::unique_ptr<SettingsSyncProcessor> sync_processor_;
 
   const syncer::ModelType sync_type_;
   const syncer::SyncableService::StartSyncFlare flare_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncableSettingsStorage);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_STORAGE_SYNCABLE_SETTINGS_STORAGE_H_