make StackingClient dispatch to either ash or desktop

chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.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 "chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.h"
 
 #include "chrome/browser/chrome_browser_main.h"
 #include "chrome/browser/toolkit_extra_parts.h"
+#include "chrome/browser/ui/aura/stacking_client_aura.h"
 #include "ui/aura/desktop/desktop_screen.h"
 #include "ui/aura/desktop/desktop_stacking_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/single_display_manager.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/native_widget_aura.h"
 
 #if defined(OS_LINUX)
 #include "chrome/browser/ui/libgtk2ui/gtk2_ui.h"
 #include "ui/base/linux_ui.h"
+#else
 #endif
 
 #if defined(USE_ASH)
 #include "chrome/browser/ui/ash/ash_init.h"
 #endif
 
 ChromeBrowserMainExtraPartsAura::ChromeBrowserMainExtraPartsAura() {
 }
 
 ChromeBrowserMainExtraPartsAura::~ChromeBrowserMainExtraPartsAura() {
 }
 
 void ChromeBrowserMainExtraPartsAura::PreProfileInit() {
 #if !defined(OS_CHROMEOS)
 #if defined(USE_ASH)
   if (!chrome::ShouldOpenAshOnStartup())
 #endif
   {
     gfx::Screen::SetScreenInstance(
         gfx::SCREEN_TYPE_NATIVE, aura::CreateDesktopScreen());
     aura::Env::GetInstance()->SetDisplayManager(new aura::SingleDisplayManager);
-    stacking_client_.reset(new aura::DesktopStackingClient);
+    stacking_client_.reset(new StackingClientAura);
+    aura::client::SetStackingClient(stacking_client_.get());
   }
 #endif
 
 #if !defined(USE_ASH) && defined(OS_LINUX)
   // TODO(erg): Refactor this into a dlopen call when we add a GTK3 port.
   ui::LinuxUI::SetInstance(BuildGtk2UI());
 #endif
 }
 
 void ChromeBrowserMainExtraPartsAura::PostMainMessageLoopRun() {
   stacking_client_.reset();
 
   // aura::Env instance is deleted in BrowserProcessImpl::StartTearDown
   // after the metrics service is deleted.
 }
 
 namespace chrome {
 
 void AddAuraToolkitExtraParts(ChromeBrowserMainParts* main_parts) {
   main_parts->AddParts(new ChromeBrowserMainExtraPartsAura());
 }
 
 }  // namespace chrome