Delete Tracked, and move Location to its own file.

base/threading/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_WORKER_POOL_H_
 #define BASE_THREADING_WORKER_POOL_H_
 #pragma once
 
 #include "base/base_export.h"
 #include "base/callback.h"
-#include "base/tracked.h"
 
 class Task;
 
+namespace tracked_objects {
+class Location;
+}  // namespace tracked_objects
+
 namespace base {
 
 // This is a facility that runs tasks that don't require a specific thread or
 // a message loop.
 //
 // WARNING: This shouldn't be used unless absolutely necessary. We don't wait
 // for the worker pool threads to finish on shutdown, so the tasks running
 // inside the pool must be extremely careful about other objects they access
 // (MessageLoops, Singletons, etc). During shutdown these object may no longer
 // exist.
 class BASE_EXPORT WorkerPool {
  public:
   // This function posts |task| to run on a worker thread.  |task_is_slow|
   // should be used for tasks that will take a long time to execute.  Returns
   // false if |task| could not be posted to a worker thread.  Regardless of
   // return value, ownership of |task| is transferred to the worker pool.
   //
   // TODO(ajwong): Remove the Task* based overload once we've finishsed the
   // Task -> Closure migration.
   static bool PostTask(const tracked_objects::Location& from_here,
                        Task* task, bool task_is_slow);
   static bool PostTask(const tracked_objects::Location& from_here,
                        const base::Closure& task, bool task_is_slow);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_WORKER_POOL_H_