Revert 198844 "Move sequenced_task_runner to base/task"

trunk/src/base/sequence_checker_impl.cc

 // 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.
 
 #include "base/sequence_checker_impl.h"
 
-#include "base/task/sequenced_task_runner.h"
+#include "base/sequenced_task_runner.h"
 
 namespace base {
 
 SequenceCheckerImpl::SequenceCheckerImpl(
     const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner)
     : sequenced_task_runner_(sequenced_task_runner) {}
 
 SequenceCheckerImpl::~SequenceCheckerImpl() {}
 
 bool SequenceCheckerImpl::CalledOnValidSequence() const {
   AutoLock auto_lock(lock_);
   return sequenced_task_runner_.get() ?
       sequenced_task_runner_->RunsTasksOnCurrentThread() :
       thread_checker_.CalledOnValidThread();
 }
 
 void SequenceCheckerImpl::ChangeSequence(
     const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner) {
   AutoLock auto_lock(lock_);
   sequenced_task_runner_ = sequenced_task_runner;
   thread_checker_.DetachFromThread();
 }
 
 }  // namespace base