[SyncFS] Make ExtensionService usage of SyncWorker asynchronous

chrome/browser/sync_file_system/drive_backend/sync_worker.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 CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_WORKER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_WORKER_H_
 
 #include <set>
 #include <string>
 
@@ skipping 49 matching lines @@
     virtual void UpdateServiceState(RemoteServiceState state,
                                     const std::string& description) = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
   static scoped_ptr<SyncWorker> CreateOnWorker(
       const base::FilePath& base_dir,
       Observer* observer,
-      ExtensionServiceInterface* extension_service,
+      const base::WeakPtr<ExtensionServiceInterface>& extension_service,
       scoped_ptr<SyncEngineContext> sync_engine_context,
       leveldb::Env* env_override);
 
   virtual ~SyncWorker();
 
   void Initialize();
 
   // SyncTaskManager::Client overrides
   virtual void MaybeScheduleNextTask() OVERRIDE;
   virtual void NotifyLastOperationStatus(
@@ skipping 41 matching lines @@
   drive::DriveUploaderInterface* GetDriveUploader();
   MetadataDatabase* GetMetadataDatabase();
   SyncTaskManager* GetSyncTaskManager();
 
   void AddObserver(Observer* observer);
 
  private:
   friend class DriveBackendSyncTest;
   friend class SyncEngineTest;
 
+  enum AppStatus {

[peria, 2014/04/24 02:38:21]

(optional) I recommend to move this enum to extensin_service_interface.h

[tzik, 2014/04/24 06:56:55]

ExtensionRegistry has similar but fine grained, which is not needed for us.
So, I think its owners don't want to put this in.

+    APP_STATUS_ENABLED,
+    APP_STATUS_DISABLED,
+    APP_STATUS_UNINSTALLED,
+  };
+
+  typedef base::hash_map<std::string, AppStatus> AppStatusMap;
+
   SyncWorker(const base::FilePath& base_dir,
-             ExtensionServiceInterface* extension_service,
+             const base::WeakPtr<ExtensionServiceInterface>& extension_service,
              scoped_ptr<SyncEngineContext> sync_engine_context,
              leveldb::Env* env_override);
 
   void DoDisableApp(const std::string& app_id,
                     const SyncStatusCallback& callback);
   void DoEnableApp(const std::string& app_id,
                    const SyncStatusCallback& callback);
 
   void PostInitializeTask();
   void DidInitialize(SyncEngineInitializer* initializer,
                      SyncStatusCode status);
   void UpdateRegisteredApp();
+  static void QueryAppStatusOnUIThread(
+      const base::WeakPtr<ExtensionServiceInterface>& extension_service_ptr,
+      const std::vector<std::string>* apps,
+      AppStatusMap* status,
+      const base::Closure& callback);
+  void DidQueryAppStatus(const AppStatusMap* app_status);
   void DidProcessRemoteChange(RemoteToLocalSyncer* syncer,
                               const SyncFileCallback& callback,
                               SyncStatusCode status);
   void DidApplyLocalChange(LocalToRemoteSyncer* syncer,
                            const SyncStatusCallback& callback,
                            SyncStatusCode status);
 
   void MaybeStartFetchChanges();
   void DidResolveConflict(SyncStatusCode status);
   void DidFetchChanges(SyncStatusCode status);
@@ skipping 15 matching lines @@
   bool should_check_remote_change_;
   bool listing_remote_changes_;
   base::TimeTicks time_to_check_changes_;
 
   bool sync_enabled_;
   ConflictResolutionPolicy default_conflict_resolution_policy_;
   bool network_available_;
 
   scoped_ptr<SyncTaskManager> task_manager_;
 
-  // TODO(tzik): Add a proxy class for ExtensionServiceInterface to cross
-  // thread, and hold its instance as WeakPtr here.
-  ExtensionServiceInterface* extension_service_;
+  base::WeakPtr<ExtensionServiceInterface> extension_service_;
 
   scoped_ptr<SyncEngineContext> context_;
   ObserverList<Observer> observers_;
 
   base::WeakPtrFactory<SyncWorker> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(SyncWorker);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_WORKER_H_