Revert 177182 - ViewTest.ChangeNativeViewHierarchyFindRoots failure

chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc

Index: chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
===================================================================
--- chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc	(revision 177189)
+++ chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc	(working copy)
@@ -7,9 +7,11 @@
 #include "chrome/browser/chrome_browser_main.h"
 #include "chrome/browser/toolkit_extra_parts.h"
 #include "chrome/browser/ui/aura/active_desktop_monitor.h"
+#include "chrome/browser/ui/aura/stacking_client_aura.h"
 #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"
 
 #if defined(OS_LINUX)
@@ -37,6 +39,8 @@
   {
     gfx::Screen::SetScreenInstance(gfx::SCREEN_TYPE_NATIVE,
                                    views::CreateDesktopScreen());
+    stacking_client_.reset(new views::DesktopStackingClient);
+    aura::client::SetStackingClient(stacking_client_.get());
   }
 #endif
 
@@ -47,6 +51,7 @@
 }
 
 void ChromeBrowserMainExtraPartsAura::PostMainMessageLoopRun() {
+  stacking_client_.reset();
   active_desktop_monitor_.reset();
 
   // aura::Env instance is deleted in BrowserProcessImpl::StartTearDown