Hook up the SequencedWorkerPool to the browser thread.

base/threading/sequenced_worker_pool.h

 // Copyright (c) 2011 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_H_
 #define BASE_THREADING_SEQUENCED_WORKER_POOL_H_
 #pragma once
 
 #include <string>
 
@@ skipping 154 matching lines @@
   //
   // The task will be guaranteed to run to completion before shutdown
   // (BLOCK_SHUTDOWN semantics).
   //
   // Returns true if the task was posted successfully. This may fail during
   // shutdown regardless of the specified ShutdownBehavior.
   bool PostSequencedWorkerTask(SequenceToken sequence_token,
                                const tracked_objects::Location& from_here,
                                const base::Closure& task);
 
+  // Like PostSequencedWorkerTask above, but allows you to specify a named
+  // token, which saves an extra call to GetNamedSequenceToken.
+  bool PostNamedSequencedWorkerTask(const std::string& token_name,
+                                    const tracked_objects::Location& from_here,
+                                    const base::Closure& task);
+
   // Same as PostSequencedWorkerTask but allows specification of the shutdown
   // behavior.
   bool PostSequencedWorkerTaskWithShutdownBehavior(
       SequenceToken sequence_token,
       const tracked_objects::Location& from_here,
       const base::Closure& task,
       WorkerShutdown shutdown_behavior);
 
+  // Blocks until all pending tasks are complete. This should only be called in
+  // unit tests when you want to validate something that should have happened.
+  //
+  // Note that callin this will not prevent other threads from posting work to

[jam, 2012/01/08 23:04:23]

nit: calling

+  // the queue while the calling thread is waiting on Flush(). In this case,
+  // Flush will return only when there's no more work in the queue. Normally,
+  // this doesn't come up sine in a test, all the work is being posted from
+  // the main thread.
+  void Flush();

[jam, 2012/01/08 23:04:23]

if this is only for testing, can we call this FlushForTesting

+
   // Implements the worker pool shutdown. This should be called during app
   // shutdown, and will discard/join with appropriate tasks before returning.
   // After this call, subsequent calls to post tasks will fail.
   void Shutdown();
 
   // Called by tests to set the testing observer. This is NULL by default
   // and ownership of the pointer is kept with the caller.
   void SetTestingObserver(TestingObserver* observer);
 
  private:
   class Inner;
   class Worker;
 
   friend class Inner;
   friend class Worker;
 
   scoped_refptr<Inner> inner_;
 
   DISALLOW_COPY_AND_ASSIGN(SequencedWorkerPool);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_SEQUENCED_WORKER_POOL_H_