Revert of base: Fix/add header #ifndef guards.

base/pending_task.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_PENDING_TASK_H_
-#define BASE_PENDING_TASK_H_
+#ifndef PENDING_TASK_H_
+#define PENDING_TASK_H_
 
 #include <queue>
 
 #include "base/base_export.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/time/time.h"
 #include "base/tracking_info.h"
 
 namespace base {
@@ skipping 33 matching lines @@
 class BASE_EXPORT TaskQueue : public std::queue<PendingTask> {
  public:
   void Swap(TaskQueue* queue);
 };
 
 // PendingTasks are sorted by their |delayed_run_time| property.
 typedef std::priority_queue<base::PendingTask> DelayedTaskQueue;
 
 }  // namespace base
 
-#endif  // BASE_PENDING_TASK_H_
+#endif  // PENDING_TASK_H_