Revert 177182 - ViewTest.ChangeNativeViewHierarchyFindRoots failure

ash/test/test_shell_delegate.cc

Index: ash/test/test_shell_delegate.cc
===================================================================
--- ash/test/test_shell_delegate.cc	(revision 177189)
+++ ash/test/test_shell_delegate.cc	(working copy)
@@ -11,6 +11,7 @@
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/test/test_launcher_delegate.h"
+#include "ash/wm/stacking_controller.h"
 #include "ash/wm/window_util.h"
 #include "content/public/test/test_browser_context.h"
 #include "ui/aura/window.h"
@@ -203,6 +204,10 @@
   return std::numeric_limits<double>::min();
 }
 
+aura::client::StackingClient* TestShellDelegate::CreateStackingClient() {
+  return new StackingController;
+}
+
 RootWindowHostFactory* TestShellDelegate::CreateRootWindowHostFactory() {
   return RootWindowHostFactory::Create();
 }