Aura: Build on the linux desktop, plus add USE_ASH.

chrome/browser/ui/views/select_file_dialog_aura.cc

 // Copyright (c) 2011 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/ui/select_file_dialog.h"
 
 #include "chrome/browser/ui/views/select_file_dialog_extension.h"
 #include "content/public/browser/browser_thread.h"
 
 using content::BrowserThread;
 
 // static
 SelectFileDialog* SelectFileDialog::Create(Listener* listener) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-#if defined(OS_WIN)
+#if defined(USE_ASH) && defined(FILE_MANAGER_EXTENSION)
+  return SelectFileDialogExtension::Create(listener);
+#else
   return NULL;
-#else
-  return new SelectFileDialogExtension(listener);
 #endif
 }