DomStorage commit task sequencing.

webkit/dom_storage/dom_storage_task_runner.h

Index: webkit/dom_storage/dom_storage_task_runner.h
===================================================================
--- webkit/dom_storage/dom_storage_task_runner.h	(revision 127221)
+++ webkit/dom_storage/dom_storage_task_runner.h	(working copy)
@@ -18,11 +18,9 @@
 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
@@ -56,12 +54,22 @@
       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:
@@ -79,9 +87,18 @@
 
   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
@@ -96,6 +113,14 @@
       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