Introduce ServiceWorkerHandle for tracking WebServiceWorkerImpl reference

content/browser/service_worker/service_worker_storage.h

 // Copyright 2013 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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_STORAGE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_STORAGE_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 54 matching lines @@
   void DeleteRegistration(const GURL& pattern,
                           const StatusCallback& callback);
 
   // Returns new IDs which are guaranteed to be unique in the storage.
   int64 NewRegistrationId();
   int64 NewVersionId();
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerStorageTest, PatternMatches);
 
+  // TODO(michaeln,kinuko): Make this not own ServiceWorkerRegistration.
   typedef std::map<GURL, scoped_refptr<ServiceWorkerRegistration> >
       PatternToRegistrationMap;
 
   static bool PatternMatches(const GURL& pattern, const GURL& script_url);
 
   // This is the in-memory registration. Eventually the registration will be
   // persisted to disk.
   PatternToRegistrationMap registration_by_pattern_;
 
   int last_registration_id_;
   int last_version_id_;
 
   scoped_refptr<quota::QuotaManagerProxy> quota_manager_proxy_;
   base::FilePath path_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerStorage);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_STORAGE_H_