Implementation of SequencedTaskRunner based on SequencedWorkerPool.

base/threading/sequenced_worker_pool_unittest.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 BASE_THREADING_SEQUENCED_WORKER_POOL_UNITTEST_H_
+#define BASE_THREADING_SEQUENCED_WORKER_POOL_UNITTEST_H_
+
+#include "base/callback.h"
+#include "base/threading/sequenced_worker_pool.h"
+
+class MessageLoop;
+
+namespace base {
+
+// Wrapper around SequencedWorkerPool that blocks destruction until
+// the pool is actually destroyed.  This is so that a
+// SequencedWorkerPool from one test doesn't outlive its test and
+// cause strange races with other tests that touch global stuff (like
+// histograms and logging).  However, this requires that nothing else
+// on this thread holds a ref to the pool when the
+// SequencedWorkerPoolOwner is destroyed.
+class SequencedWorkerPoolOwner : public SequencedWorkerPool::TestingObserver {
+ public:
+  SequencedWorkerPoolOwner(size_t max_threads,
+                           const std::string& thread_name_prefix);
+
+  virtual ~SequencedWorkerPoolOwner();
+
+  // Don't change the return pool's testing observer.
+  const scoped_refptr<SequencedWorkerPool>& pool();
+
+  // The given callback will be called on WillWaitForShutdown().
+  void SetWillWaitForShutdownCallback(const Closure& callback);
+
+ private:
+  // SequencedWorkerPool::TestingObserver implementation.
+  virtual void WillWaitForShutdown() OVERRIDE;
+  virtual void OnDestruct() OVERRIDE;
+
+  MessageLoop* const constructor_message_loop_;
+  scoped_refptr<SequencedWorkerPool> pool_;
+  // TODO(francoisk777@gmail.com) Make this a scoped_ptr and forward-declare?
+  // Perhaps not worth the trouble as this header will only be included in a
+  // few places.
+  Closure will_wait_for_shutdown_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(SequencedWorkerPoolOwner);
+};
+
+}  // namespace base
+
+#endif  // BASE_THREADING_SEQUENCED_WORKER_POOL_UNITTEST_H_