DomStorage commit task sequencing.

webkit/dom_storage/dom_storage_task_runner.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 WEBKIT_DOM_STORAGE_DOM_STORAGE_TASK_RUNNER_
 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_TASK_RUNNER_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/time.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace dom_storage {
 
 // Tasks must run serially with respect to one another, but may
-// execute on different OS threads. The base class is implemented
-// in terms of a MessageLoopProxy.
+// execute on different OS threads.
 class DomStorageTaskRunner : public base::SequencedTaskRunner {
  public:
-  explicit DomStorageTaskRunner(base::MessageLoopProxy* message_loop);
   virtual ~DomStorageTaskRunner();
 
   // The PostTask() method, defined by TaskRunner, schedules a task
   // to run immediately.
 
   // Schedules a task to be run after a delay.
   virtual bool PostDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       base::TimeDelta delay) OVERRIDE;
@@ skipping 13 matching lines @@
   // terms of PostDelayedTask and the latter is similarly deprecated.
   virtual bool PostNonNestableDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       base::TimeDelta delay) OVERRIDE;
   virtual bool PostNonNestableDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       int64 delay_ms) OVERRIDE;
 
+  virtual bool PostShutdownBlockingTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) = 0;
+
+  virtual bool PostShutdownBlockingCommitTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) = 0;
+
  protected:
+  explicit DomStorageTaskRunner(base::MessageLoopProxy* message_loop);
+
   const scoped_refptr<base::MessageLoopProxy> message_loop_;
 };
 
 // A derived class that utlizes the SequenceWorkerPool under a
-// dom_storage specific SequenceToken. The MessageLoopProxy
+// dom_storage specific SequenceTokens. The MessageLoopProxy
 // is used to delay scheduling on the worker pool.
 class DomStorageWorkerPoolTaskRunner : public DomStorageTaskRunner {
  public:
   DomStorageWorkerPoolTaskRunner(
       base::SequencedWorkerPool* sequenced_worker_pool,
       base::SequencedWorkerPool::SequenceToken sequence_token,
       base::MessageLoopProxy* delayed_task_loop);
   virtual ~DomStorageWorkerPoolTaskRunner();
 
   // Schedules a sequenced worker task to be run after a delay.
   virtual bool PostDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       base::TimeDelta delay) OVERRIDE;
 
   base::SequencedWorkerPool::SequenceToken sequence_token() const;
 
+  virtual bool PostShutdownBlockingTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) OVERRIDE;
+
+  virtual bool PostShutdownBlockingCommitTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) OVERRIDE;
+
  private:
   const scoped_refptr<base::SequencedWorkerPool> sequenced_worker_pool_;
   base::SequencedWorkerPool::SequenceToken sequence_token_;
+  base::SequencedWorkerPool::SequenceToken commit_sequence_token_;
 };
 
 // A derived class used in unit tests that causes us to ignore the
 // delay in PostDelayedTask so we don't need to block in unit tests
 // for the timeout to expire.
 class MockDomStorageTaskRunner : public DomStorageTaskRunner {
  public:
   explicit MockDomStorageTaskRunner(base::MessageLoopProxy* message_loop);
   virtual ~MockDomStorageTaskRunner() {}
 
   virtual bool PostDelayedTask(
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       base::TimeDelta delay) OVERRIDE;
+
+  virtual bool PostShutdownBlockingTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) OVERRIDE;
+
+  virtual bool PostShutdownBlockingCommitTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) OVERRIDE;
 };
 
 }  // namespace dom_storage
 
 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_TASK_RUNNER_