Add write and read/write support to FileStream (renamed from FileInputStream)...

net/url_request/url_request_file_job.cc

 // Copyright (c) 2006-2008 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.
 
 // For loading files, we make use of overlapped i/o to ensure that reading from
 // the filesystem (e.g., a network filesystem) does not block the calling
 // thread.  An alternative approach would be to use a background thread or pool
 // of threads, but it seems better to leverage the operating system's ability
 // to do background file reads for us.
 //
@@ skipping 159 matching lines @@
   // We may have been orphaned...
   if (!request_)
     return;
 
   is_directory_ = file_info.is_directory;
 
   int rv = net::OK;
   if (!exists) {
     rv = net::ERR_FILE_NOT_FOUND;
   } else if (!is_directory_) {
-    rv = stream_.Open(file_path_, true);
+    int flags = base::PLATFORM_FILE_OPEN | 
+                base::PLATFORM_FILE_READ |
+                base::PLATFORM_FILE_ASYNC;
+    rv = stream_.Open(file_path_, flags);
   }
 
   if (rv == net::OK) {
     set_expected_content_size(file_info.size);
     NotifyHeadersComplete();
   } else {
     NotifyDone(URLRequestStatus(URLRequestStatus::FAILED, rv));
   }
 }
 
@@ skipping 42 matching lines @@
     return false;
 
   *location = net::FilePathToFileURL(new_path);
   *http_status_code = 301;
   return true;
 #else
   return false;
 #endif
 }