[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