Make FileStream::Seek async and add FileStream::SeekSync for sync operation

net/base/file_stream.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 "net/base/file_stream.h"
 
 namespace net {
 
 FileStream::FileStream(net::NetLog* net_log)
     : impl_(net_log) {
@@ skipping 21 matching lines @@
 }
 
 int FileStream::OpenSync(const FilePath& path, int open_flags) {
   return impl_.OpenSync(path, open_flags);
 }
 
 bool FileStream::IsOpen() const {
   return impl_.IsOpen();
 }
 
-int64 FileStream::Seek(Whence whence, int64 offset) {
-  return impl_.Seek(whence, offset);
+int FileStream::Seek(Whence whence, int64 offset,
+                     const Int64CompletionCallback& callback) {
+  return impl_.Seek(whence, offset, callback);
+}
+
+int64 FileStream::SeekSync(Whence whence, int64 offset) {
+  return impl_.SeekSync(whence, offset);
 }
 
 int64 FileStream::Available() {
   return impl_.Available();
 }
 
 int FileStream::Read(
     IOBuffer* in_buf, int buf_len, const CompletionCallback& callback) {
   return impl_.Read(in_buf, buf_len, callback);
 }
@@ skipping 30 matching lines @@
 void FileStream::SetBoundNetLogSource(
     const net::BoundNetLog& owner_bound_net_log) {
   impl_.SetBoundNetLogSource(owner_bound_net_log);
 }
 
 base::PlatformFile FileStream::GetPlatformFileForTesting() {
   return impl_.GetPlatformFileForTesting();
 }
 
 }  // namespace net