Revert of [fsp] Add an initial AsyncFileUtil.

chrome/browser/chromeos/file_system_provider/fileapi/backend_delegate.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 "chrome/browser/chromeos/file_system_provider/fileapi/backend_delegate.h"
-
-#include "base/memory/scoped_ptr.h"
-#include "chrome/browser/chromeos/file_system_provider/fileapi/provider_async_file_util.h"
-#include "content/public/browser/browser_thread.h"
-#include "webkit/browser/blob/file_stream_reader.h"
-#include "webkit/browser/fileapi/file_stream_writer.h"
-#include "webkit/browser/fileapi/file_system_url.h"
-
-using content::BrowserThread;
-
-namespace chromeos {
-namespace file_system_provider {
-
-BackendDelegate::BackendDelegate()
-    : async_file_util_(new internal::ProviderAsyncFileUtil) {}
-
-BackendDelegate::~BackendDelegate() {}
-
-fileapi::AsyncFileUtil* BackendDelegate::GetAsyncFileUtil(
-    fileapi::FileSystemType type) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK_EQ(fileapi::kFileSystemTypeProvided, type);
-  return async_file_util_.get();
-}
-
-scoped_ptr<webkit_blob::FileStreamReader>
-BackendDelegate::CreateFileStreamReader(
-    const fileapi::FileSystemURL& url,
-    int64 offset,
-    const base::Time& expected_modification_time,
-    fileapi::FileSystemContext* context) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK_EQ(fileapi::kFileSystemTypeProvided, url.type());
-  NOTIMPLEMENTED();
-  return scoped_ptr<webkit_blob::FileStreamReader>();
-}
-
-scoped_ptr<fileapi::FileStreamWriter> BackendDelegate::CreateFileStreamWriter(
-    const fileapi::FileSystemURL& url,
-    int64 offset,
-    fileapi::FileSystemContext* context) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK_EQ(fileapi::kFileSystemTypeProvided, url.type());
-  NOTIMPLEMENTED();
-  return scoped_ptr<fileapi::FileStreamWriter>();
-}
-
-}  // namespace file_system_provider
-}  // namespace chromeos