Extension Settings API: make it so that when changes received from Sync fail to

chrome/browser/extensions/settings/settings_backend.h

 // Copyright (c) 2011 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_SETTINGS_SETTINGS_BACKEND_H_
 #define CHROME_BROWSER_EXTENSIONS_SETTINGS_SETTINGS_BACKEND_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/file_path.h"
@@ skipping 20 matching lines @@
   explicit SettingsBackend(
       // Ownership NOT taken.
       SettingsStorageFactory* storage_factory,
       const FilePath& base_path,
       const scoped_refptr<SettingsObserverList>& observers);
 
   virtual ~SettingsBackend();
 
   // Gets a weak reference to the storage area for a given extension.
   // Must be run on the FILE thread.
-  //
-  // By default this will be an SettingsLeveldbStorage, but on
-  // failure to create a leveldb instance will fall back to
-  // InMemorySettingsStorage.
-  SettingsStorage* GetStorage(
-      const std::string& extension_id) const;
+  SettingsStorage* GetStorage(const std::string& extension_id) const;
 
   // Deletes all setting data for an extension.  Call on the FILE thread.
   void DeleteStorage(const std::string& extension_id);
 
   // SyncableService implementation.
   virtual SyncDataList GetAllSyncData(syncable::ModelType type) const OVERRIDE;
   virtual SyncError MergeDataAndStartSyncing(
       syncable::ModelType type,
       const SyncDataList& initial_sync_data,
       SyncChangeProcessor* sync_processor) OVERRIDE;
   virtual SyncError ProcessSyncChanges(
       const tracked_objects::Location& from_here,
       const SyncChangeList& change_list) OVERRIDE;
   virtual void StopSyncing(syncable::ModelType type) OVERRIDE;
 
  private:
   // Gets a weak reference to the storage area for a given extension,
   // initializing sync with some initial data if sync enabled.
   //
   // By default this will be of a cached LEVELDB storage, but on failure to
   // create a leveldb instance will fall back to cached NOOP storage.
   SyncableSettingsStorage* GetOrCreateStorageWithSyncData(
       const std::string& extension_id, const DictionaryValue& sync_data) const;
 
   // Gets all extension IDs known to extension settings.  This may not be all
   // installed extensions.
   std::set<std::string> GetKnownExtensionIDs() const;
 
+  // Disable the syncing of the storage area for |extension_id|.
+  void DisableSyncForExtension(const std::string& extension_id) const;
+
   // The Factory to use for creating leveldb storage areas.  Not owned.
   SettingsStorageFactory* const storage_factory_;
 
   // The base file path to create any leveldb databases at.
   const FilePath base_path_;
 
   // The list of observers to settings changes.
   const scoped_refptr<SettingsObserverList> observers_;
 
   // A cache of SettingsStorage objects that have already been created.
   // Ensure that there is only ever one created per extension.
   typedef std::map<std::string, linked_ptr<SyncableSettingsStorage> >
       StorageObjMap;
   mutable StorageObjMap storage_objs_;
 
   // Current sync model type.  Will be UNSPECIFIED if sync hasn't been enabled
   // yet, and either SETTINGS or APP_SETTINGS if it has been.
   syncable::ModelType sync_type_;
 
   // Current sync processor, if any.
   SyncChangeProcessor* sync_processor_;
 
   DISALLOW_COPY_AND_ASSIGN(SettingsBackend);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_SETTINGS_SETTINGS_BACKEND_H_