[ServiceWorkerCache] Serialize ServiceWorkerCacheStorage operations

content/browser/service_worker/service_worker_cache_scheduler.h

+// Copyright 2015 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_CACHE_SCHEDULER_H_
+#define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_SCHEDULER_H_
+
+#include <list>
+
+#include "base/callback.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class CONTENT_EXPORT ServiceWorkerCacheScheduler {
+ public:
+  ServiceWorkerCacheScheduler();
+  virtual ~ServiceWorkerCacheScheduler();
+
+  // Adds the operation to the tail of the queue and starts it if the scheduler
+  // is idle.
+  void ScheduleOperation(const base::Closure& closure);
+
+  // Call this after each operation completes. It cleans up the current
+  // operation and starts the next.
+  void CompleteOperationAndRunNext();
+
+  bool Empty() const;
+
+ private:
+  void RunOperationIfIdle();
+
+  // The list of operations waiting on initialization.
+  std::list<base::Closure> pending_operations_;
+  bool operation_running_;
+
+  DISALLOW_COPY_AND_ASSIGN(ServiceWorkerCacheScheduler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_SCHEDULER_H_