sync: deferred initialization support for app/extension settings

chrome/browser/extensions/api/storage/settings_backend.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_SETTINGS_BACKEND_H_
 #define CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_BACKEND_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 22 matching lines @@
 // Lives entirely on the FILE thread.
 class SettingsBackend : public syncer::SyncableService {
  public:
   // |storage_factory| is use to create leveldb storage areas.
   // |base_path| is the base of the extension settings directory, so the
   // databases will be at base_path/extension_id.
   // |observers| is the list of observers to settings changes.
   SettingsBackend(
       const scoped_refptr<SettingsStorageFactory>& storage_factory,
       const base::FilePath& base_path,
+      syncer::ModelType sync_type,
       const SettingsStorageQuotaEnforcer::Limits& quota,
       const scoped_refptr<SettingsObserverList>& observers);
 
   virtual ~SettingsBackend();
 
   // Gets a weak reference to the storage area for |extension_id|.
   // Must be run on the FILE thread.
   ValueStore* 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);
 
   // syncer::SyncableService implementation.
   virtual syncer::SyncDataList GetAllSyncData(
       syncer::ModelType type) const OVERRIDE;
   virtual syncer::SyncMergeResult MergeDataAndStartSyncing(
       syncer::ModelType type,
       const syncer::SyncDataList& initial_sync_data,
       scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
       scoped_ptr<syncer::SyncErrorFactory> sync_error_factory) OVERRIDE;
   virtual syncer::SyncError ProcessSyncChanges(
       const tracked_objects::Location& from_here,
       const syncer::SyncChangeList& change_list) OVERRIDE;
   virtual void StopSyncing(syncer::ModelType type) OVERRIDE;
 
+  // Provides a StartSyncFlare to the SyncableService. See
+  // sync_start_util for more.
+  void InjectStartSyncFlare(
+      const syncer::SyncableService::StartSyncFlare& flare);
+
  private:
   // Gets a weak reference to the storage area for a given extension,
   // initializing sync with some initial data if sync enabled.
   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;
@@ skipping 13 matching lines @@
 
   // The list of observers to settings changes.
   const scoped_refptr<SettingsObserverList> observers_;
 
   // A cache of ValueStore 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.
+  // Current sync model type. Either EXTENSION_SETTINGS or APP_SETTINGS.
   syncer::ModelType sync_type_;
 
   // Current sync processor, if any.
   scoped_ptr<syncer::SyncChangeProcessor> sync_processor_;
 
   // Current sync error handler if any.
   scoped_ptr<syncer::SyncErrorFactory> sync_error_factory_;
 
+  syncer::SyncableService::StartSyncFlare flare_;
+
   DISALLOW_COPY_AND_ASSIGN(SettingsBackend);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_BACKEND_H_