Add a non-blocking "OneShotEvent" class

chrome/browser/extensions/test_extension_service.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_TEST_EXTENSION_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 47 matching lines @@
       const syncer::SyncDataList& initial_sync_data,
       scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
       scoped_ptr<syncer::SyncErrorFactory> sync_error_factory) OVERRIDE;
   virtual void StopSyncing(syncer::ModelType type) OVERRIDE;
   virtual syncer::SyncDataList GetAllSyncData(
       syncer::ModelType type) const OVERRIDE;
   virtual syncer::SyncError ProcessSyncChanges(
       const tracked_objects::Location& from_here,
       const syncer::SyncChangeList& change_list) OVERRIDE;
 
-  virtual bool is_ready() OVERRIDE;
-
   virtual base::SequencedTaskRunner* GetFileTaskRunner() OVERRIDE;
 
   virtual void AddExtension(const extensions::Extension* extension) OVERRIDE;
   virtual void AddComponentExtension(
       const extensions::Extension* extension) OVERRIDE;
 
   virtual void UnloadExtension(
       const std::string& extension_id,
       extension_misc::UnloadedExtensionReason reason) OVERRIDE;
 
   virtual void SyncExtensionChangeIfNeeded(
       const extensions::Extension& extension) OVERRIDE;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_SERVICE_H_