Revert 177182 - ViewTest.ChangeNativeViewHierarchyFindRoots failure

ash/shell.cc

Index: ash/shell.cc
===================================================================
--- ash/shell.cc	(revision 177189)
+++ ash/shell.cc	(working copy)
@@ -56,6 +56,7 @@
 #include "ash/wm/session_state_controller.h"
 #include "ash/wm/session_state_controller_impl.h"
 #include "ash/wm/session_state_controller_impl2.h"
+#include "ash/wm/stacking_controller.h"
 #include "ash/wm/system_gesture_event_filter.h"
 #include "ash/wm/system_modal_container_event_filter.h"
 #include "ash/wm/system_modal_container_layout_manager.h"
@@ -70,6 +71,7 @@
 #include "base/command_line.h"
 #include "base/debug/leak_annotations.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/stacking_client.h"
 #include "ui/aura/client/user_action_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/focus_manager.h"
@@ -500,6 +502,9 @@
   // Create Controllers that may need root window.
   // TODO(oshima): Move as many controllers before creating
   // RootWindowController as possible.
+  stacking_client_.reset(delegate_->CreateStackingClient());
+  if (stacking_client_.get())
+    aura::client::SetStackingClient(stacking_client_.get());
   visibility_controller_.reset(new AshVisibilityController);
   drag_drop_controller_.reset(new internal::DragDropController);
   user_action_client_.reset(delegate_->CreateUserActionClient());
@@ -830,6 +835,10 @@
       DoInitialAnimation();
 }
 
+aura::client::StackingClient* Shell::stacking_client() {
+  return stacking_client_.get();
+}
+
 void Shell::InitRootWindowController(
     internal::RootWindowController* controller) {
   aura::RootWindow* root_window = controller->root_window();