base: Fix/add header #ifndef guards.

base/sequenced_task_runner.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_SEQUENCED_TASKRUNNER_H_
-#define BASE_SEQUENCED_TASKRUNNER_H_
+#ifndef BASE_SEQUENCED_TASK_RUNNER_H_
+#define BASE_SEQUENCED_TASK_RUNNER_H_
 
 #include "base/base_export.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "base/task_runner.h"
 
 namespace base {
 
 // A SequencedTaskRunner is a subclass of TaskRunner that provides
 // additional guarantees on the order that tasks are started, as well
 // as guarantees on when tasks are in sequence, i.e. one task finishes
@@ skipping 132 matching lines @@
                           void(*deleter)(const void*),
                           const void* object);
 
   bool ReleaseSoonInternal(const tracked_objects::Location& from_here,
                            void(*releaser)(const void*),
                            const void* object);
 };
 
 }  // namespace base
 
-#endif  // BASE_SEQUENCED_TASKRUNNER_H_
+#endif  // BASE_SEQUENCED_TASK_RUNNER_H_