Reduce usage of MessageLoopProxy in base/

base/files/important_file_writer.cc

 // 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.
 
 #include "base/files/important_file_writer.h"
 
 #include <stdio.h>
 
 #include <string>
 
@@ skipping 70 matching lines @@
 
   if (!base::ReplaceFile(tmp_file_path, path, NULL)) {
     LogFailure(path, FAILED_RENAMING, "could not rename temporary file");
     base::DeleteFile(tmp_file_path, false);
     return false;
   }
 
   return true;
 }
 
-ImportantFileWriter::ImportantFileWriter(const FilePath& path,
-                                         base::SequencedTaskRunner* task_runner)
+ImportantFileWriter::ImportantFileWriter(
+    const FilePath& path,
+    const scoped_refptr<base::SequencedTaskRunner>& task_runner)
     : path_(path),
       task_runner_(task_runner),
       serializer_(NULL),
       commit_interval_(TimeDelta::FromMilliseconds(kDefaultCommitIntervalMs)),
       weak_factory_(this) {
   DCHECK(CalledOnValidThread());
   DCHECK(task_runner_.get());
 }
 
 ImportantFileWriter::~ImportantFileWriter() {
@@ skipping 82 matching lines @@
 
 void ImportantFileWriter::ForwardSuccessfulWrite(bool result) {
   DCHECK(CalledOnValidThread());
   if (result && !on_next_successful_write_.is_null()) {
     on_next_successful_write_.Run();
     on_next_successful_write_.Reset();
   }
 }
 
 }  // namespace base