kFileSystemTypeIsolated should be only used in the URL exposed to renderer

chrome/browser/extensions/api/file_system/file_system_api.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 "chrome/browser/extensions/api/file_system/file_system_api.h"
 
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 240 matching lines @@
 void FileSystemEntryFunction::RegisterFileSystemAndSendResponse(
     const FilePath& path, EntryType entry_type) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
   fileapi::IsolatedContext* isolated_context =
       fileapi::IsolatedContext::GetInstance();
   DCHECK(isolated_context);
 
   std::string registered_name;
   std::string filesystem_id = isolated_context->RegisterFileSystemForPath(
-      fileapi::kFileSystemTypeIsolated, path, &registered_name);
+      fileapi::kFileSystemTypeNativeLocal, path, &registered_name);
 
   content::ChildProcessSecurityPolicy* policy =
       content::ChildProcessSecurityPolicy::GetInstance();
   int renderer_id = render_view_host_->GetProcess()->GetID();
   if (entry_type == WRITABLE)
     policy->GrantReadWriteFileSystem(renderer_id, filesystem_id);
   else
     policy->GrantReadFileSystem(renderer_id, filesystem_id);
 
   // We only need file level access for reading FileEntries. Saving FileEntries
@@ skipping 281 matching lines @@
 
   if (entry_type == WRITABLE && !HasFileSystemWritePermission()) {
     error_ = kRequiresFileSystemWriteError;
     return false;
   }
 
   return ShowPicker(suggested_name, file_type_info, picker_type, entry_type);
 }
 
 }  // namespace extensions