Better Z-index support.

ui/aura_shell/desktop_window.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 "ui/aura/desktop.h"
+#include "ui/aura/toplevel_window_container.h"
+#include "ui/aura/window.h"
+#include "ui/aura_shell/desktop_layout_manager.h"
+#include "ui/aura_shell/shell_factory.h"
+
+namespace aura_shell {
+
+namespace internal {
+
+aura::Window* CreateToplevelWindowContainer() {
+  aura::Window* container = new aura::internal::ToplevelWindowContainer;
+  container->Init();
+  container->SetBounds(gfx::Rect(0, 0, 1024, 768), 0);
+  container->SetVisibility(aura::Window::VISIBILITY_SHOWN);
+  container->SetParent(aura::Desktop::GetInstance()->window());
+  aura::Desktop::GetInstance()->set_toplevel_window_container(container);
+  return container;
+}
+
+}  // namespace internal
+
+void InitDesktopWindow() {
+  aura::Window* desktop_window = aura::Desktop::GetInstance()->window();
+  internal::DesktopLayoutManager* desktop_layout =
+      new internal::DesktopLayoutManager(desktop_window);
+  desktop_window->SetLayoutManager(desktop_layout);
+
+  // The order of creation here is important to establish the z-index:
+  desktop_layout->set_background_widget(internal::CreateDesktopBackground());
+  desktop_layout->set_toplevel_window_container(
+      internal::CreateToplevelWindowContainer());
+  desktop_layout->set_launcher_widget(internal::CreateLauncher());
+  desktop_layout->set_status_area_widget(internal::CreateStatusArea());
+}
+
+}  // namespace aura_shell
+