Clean up condition variable usage in SequencedWorkerPool

base/threading/sequenced_worker_pool.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_H_
 #define BASE_THREADING_SEQUENCED_WORKER_POOL_H_
 #pragma once
 
 #include <cstddef>
 #include <string>
@@ skipping 196 matching lines @@
                                const Closure& task,
                                TimeDelta delay) OVERRIDE;
   virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
 
   // 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 calling this will not prevent other threads from posting work to
   // 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
+  // this doesn't come up since in a test, all the work is being posted from
   // the main thread.
   void FlushForTesting();
 
+  // Spuriously signal that there is work to be done.
+  void TriggerSpuriousWorkSignalForTesting();
+
+  // Get the number of times the work signal has been triggered.
+  int GetWorkSignalCountForTesting() const;
+
   // 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.
+  //
+  // Must be called from the same thread this object was constructed on.
   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);
 
  protected:
   virtual ~SequencedWorkerPool();
 
   virtual void OnDestruct() const OVERRIDE;
@@ skipping 10 matching lines @@
   // Avoid pulling in too many headers by putting (almost) everything
   // into |inner_|.
   const scoped_ptr<Inner> inner_;
 
   DISALLOW_COPY_AND_ASSIGN(SequencedWorkerPool);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_SEQUENCED_WORKER_POOL_H_