Add a lock screen example.

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"
 #include "ui/aura_shell/shell_window_ids.h"
@@ skipping 19 matching lines @@
       new aura::internal::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_consumes_events(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);
 }
 
 void InitDesktopWindow() {
   aura::Window::Windows containers;
@@ skipping 25 matching lines @@
       internal::kShellWindowId_StatusContainer)->AddChild(
           status_area->GetNativeView());
 
   desktop_layout->set_background_widget(desktop_background);
   desktop_layout->set_launcher_widget(launcher);
   desktop_layout->set_status_area_widget(status_area);
 }
 
 }  // namespace aura_shell