Revert 177182 - ViewTest.ChangeNativeViewHierarchyFindRoots failure

ui/views/examples/content_client/examples_browser_main_parts.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/views/examples/content_client/examples_browser_main_parts.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/run_loop.h"
 #include "base/string_number_conversions.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/public/common/content_switches.h"
 #include "content/shell/shell_browser_context.h"
 #include "googleurl/src/gurl.h"
 #include "ui/views/examples/examples_window_with_content.h"
 #include "ui/views/focus/accelerator_handler.h"
 #include "ui/views/test/desktop_test_views_delegate.h"
 
 #if defined(USE_AURA)
 #include "ui/aura/env.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/desktop_aura/desktop_screen.h"
+#include "ui/views/widget/desktop_aura/desktop_stacking_client.h"
 #include "ui/views/widget/native_widget_aura.h"
 #endif
 
 namespace views {
 namespace examples {
 
 ExamplesBrowserMainParts::ExamplesBrowserMainParts(
     const content::MainFunctionParams& parameters) {
 }
 
 ExamplesBrowserMainParts::~ExamplesBrowserMainParts() {
 }
 
 void ExamplesBrowserMainParts::PreMainMessageLoopRun() {
   browser_context_.reset(new content::ShellBrowserContext(false));
 
 #if !defined(OS_CHROMEOS) && defined(USE_AURA)
+  stacking_client_.reset(new DesktopStackingClient);
+  aura::client::SetStackingClient(stacking_client_.get());
   gfx::Screen::SetScreenInstance(
       gfx::SCREEN_TYPE_NATIVE, CreateDesktopScreen());
 #endif
   views_delegate_.reset(new DesktopTestViewsDelegate);
 
   ShowExamplesWindowWithContent(QUIT_ON_CLOSE, browser_context_.get());
 }
 
 void ExamplesBrowserMainParts::PostMainMessageLoopRun() {
   browser_context_.reset();
   views_delegate_.reset();
 #if defined(USE_AURA)
+  stacking_client_.reset();
   aura::Env::DeleteInstance();
 #endif
 }
 
 bool ExamplesBrowserMainParts::MainMessageLoopRun(int* result_code) {
   // xxx: Hax here because this kills event handling.
 #if !defined(USE_AURA)
   AcceleratorHandler accelerator_handler;
   base::RunLoop run_loop(&accelerator_handler);
 #else
   base::RunLoop run_loop;
 #endif
   run_loop.Run();
   return true;
 }
 
 }  // namespace examples
 }  // namespace views