Fullscreen can't use the desktop as a parent in metro mode

ui/base/win/hwnd_util.h

 // 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.
 
 #ifndef UI_BASE_WIN_HWND_UTIL_H_
 #define UI_BASE_WIN_HWND_UTIL_H_
 #pragma once
 
 #include <windows.h>
 
@@ skipping 29 matching lines @@
                                    const gfx::Size& pref);
 
 // If |hwnd| is NULL logs various thing and CHECKs. Invoke right after calling
 // CreateWindow.
 UI_EXPORT void CheckWindowCreated(HWND hwnd);
 
 // Shows the system menu for |window| and sends the selected command (if the
 // user selected something.
 UI_EXPORT void ShowSystemMenu(HWND window, int screen_x, int screen_y);
 
+// Returns the window you can use to parent a top level window.
+// Note that in some cases we create child windows not parented to its final
+// container so in those cases you should pass true in |get_real_hwnd|.
+UI_EXPORT HWND GetWindowToParentTo(bool get_real_hwnd);
+
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_HWND_UTIL_H_