change the way windows are parented when their parent is set to NULL.

ui/aura_shell/shell.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_shell/shell.h"
+
+#include "ui/aura/desktop.h"
+#include "ui/aura/toplevel_window_container.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_types.h"
+#include "ui/aura_shell/desktop_layout_manager.h"
+#include "ui/aura_shell/shell_factory.h"
+#include "ui/aura_shell/shell_window_ids.h"
+#include "views/widget/widget.h"
+
+namespace aura_shell {
+
+namespace {
+// Creates each of the special window containers that holds windows of various
+// types in the shell UI. They are added to |containers| from back to front in
+// the z-index.
+void CreateSpecialContainers(aura::Window::Windows* containers) {
+  aura::Window* background_container = new aura::Window(NULL);
+  background_container->set_id(
+      internal::kShellWindowId_DesktopBackgroundContainer);
+  containers->push_back(background_container);
+
+  aura::Window* default_container = new aura::ToplevelWindowContainer;
+  default_container->set_id(internal::kShellWindowId_DefaultContainer);
+  containers->push_back(default_container);
+
+  aura::Window* always_on_top_container = new aura::ToplevelWindowContainer;
+  always_on_top_container->set_id(
+      internal::kShellWindowId_AlwaysOnTopContainer);
+  containers->push_back(always_on_top_container);
+
+  aura::Window* launcher_container = new aura::Window(NULL);
+  launcher_container->set_id(internal::kShellWindowId_LauncherContainer);
+  containers->push_back(launcher_container);
+
+  aura::Window* lock_container = new aura::Window(NULL);
+  lock_container->set_stops_event_propagation(true);
+  lock_container->set_id(internal::kShellWindowId_LockScreenContainer);
+  containers->push_back(lock_container);
+
+  aura::Window* status_container = new aura::Window(NULL);
+  status_container->set_id(internal::kShellWindowId_StatusContainer);
+  containers->push_back(status_container);
+
+  aura::Window* menu_container = new aura::Window(NULL);
+  menu_container->set_id(internal::kShellWindowId_MenusAndTooltipsContainer);
+  containers->push_back(menu_container);
+}
+}  // namespace
+
+Shell::Shell() {
+}
+
+Shell::~Shell() {
+}
+
+void Shell::Init() {
+  aura::Desktop::GetInstance()->set_delegate(this);
+  aura::Window::Windows containers;
+  CreateSpecialContainers(&containers);
+  aura::Window::Windows::const_iterator i;
+  for (i = containers.begin(); i != containers.end(); ++i) {
+    (*i)->Init();
+    aura::Desktop::GetInstance()->window()->AddChild(*i);
+    (*i)->Show();
+  }
+
+  aura::Window* root_window = aura::Desktop::GetInstance()->window();
+  internal::DesktopLayoutManager* desktop_layout =
+      new internal::DesktopLayoutManager(root_window);
+  root_window->SetLayoutManager(desktop_layout);
+
+  desktop_layout->set_background_widget(internal::CreateDesktopBackground());
+  desktop_layout->set_launcher_widget(internal::CreateLauncher());
+  desktop_layout->set_status_area_widget(internal::CreateStatusArea());
+}
+
+aura::Window* Shell::GetContainer(int container_id) {
+  return const_cast<aura::Window*>(
+      const_cast<const aura_shell::Shell*>(this)->GetContainer(container_id));
+}
+
+const aura::Window* Shell::GetContainer(int container_id) const {
+  return aura::Desktop::GetInstance()->window()->GetChildById(container_id);
+}
+
+void Shell::AddChildToDefaultParent(aura::Window* window) {
+  aura::Window* parent = NULL;
+  switch (window->type()) {
+    case aura::kWindowType_Toplevel:
+      parent = GetContainer(internal::kShellWindowId_DefaultContainer);
+      break;
+    case aura::kWindowType_Menu:
+    case aura::kWindowType_Tooltip:
+      parent = GetContainer(internal::kShellWindowId_MenusAndTooltipsContainer);
+      break;
+    default:
+      // This will crash for controls, since they can't be parented to anything.
+      break;
+  }
+  parent->AddChild(window);
+}
+
+aura::Window* Shell::GetTopmostWindowToActivate(aura::Window* ignore) const {
+  const aura::ToplevelWindowContainer* container =
+      GetContainer(internal::kShellWindowId_DefaultContainer)->
+          AsToplevelWindowContainer();
+  return container->GetTopmostWindowToActivate(ignore);
+}
+
+}  // namespace aura_shell