Revert of base: Remove use of MessageLoopProxy

base/files/file_proxy.cc

 // Copyright 2014 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/file_proxy.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
+#include "base/message_loop/message_loop_proxy.h"
 #include "base/task_runner.h"
 #include "base/task_runner_util.h"
 
 namespace {
 
 void FileDeleter(base::File file) {
 }
 
 }  // namespace
 
@@ skipping 327 matching lines @@
 bool FileProxy::Flush(const StatusCallback& callback) {
   DCHECK(file_.IsValid());
   GenericFileHelper* helper = new GenericFileHelper(this, file_.Pass());
   return task_runner_->PostTaskAndReply(
       FROM_HERE,
       Bind(&GenericFileHelper::Flush, Unretained(helper)),
       Bind(&GenericFileHelper::Reply, Owned(helper), callback));
 }
 
 }  // namespace base