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

ui/base/win/hwnd_util.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 "ui/base/win/hwnd_util.h"
 
 #include "base/i18n/rtl.h"
 #include "base/string_util.h"
+#include "base/win/metro.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 namespace ui {
 
 namespace {
 
 // Adjust the window to fit.
 void AdjustWindowToFit(HWND hwnd, const RECT& bounds, bool fit_to_monitor) {
   if (fit_to_monitor) {
@@ skipping 155 matching lines @@
   UINT flags = TPM_LEFTBUTTON | TPM_RIGHTBUTTON | TPM_RETURNCMD;
   if (base::i18n::IsRTL())
     flags |= TPM_RIGHTALIGN;
   HMENU system_menu = GetSystemMenu(window, FALSE);
   int command = TrackPopupMenu(system_menu, flags, screen_x, screen_y, 0,
                                window, NULL);
   if (command)
     SendMessage(window, WM_SYSCOMMAND, command, 0);
 }
 
+extern "C" {
+  typedef HWND (*RootWindow)();
+}
+
+HWND GetWindowToParentTo(bool get_real_hwnd) {
+  HMODULE metro = base::win::GetMetroModule();
+  if (!metro)
+    return get_real_hwnd ? ::GetDesktopWindow() : HWND_DESKTOP;
+  // In windows 8 metro-mode the root window is not the desktop.
+  RootWindow root_window =
+      reinterpret_cast<RootWindow>(::GetProcAddress(metro, "GetRootWindow"));
+  return root_window();
+}
+
 }  // namespace ui