Revert 177182 - ViewTest.ChangeNativeViewHierarchyFindRoots failure

ash/shell_delegate.h

Index: ash/shell_delegate.h
===================================================================
--- ash/shell_delegate.h	(revision 177189)
+++ ash/shell_delegate.h	(working copy)
@@ -22,6 +22,7 @@
 class RootWindow;
 class Window;
 namespace client {
+class StackingClient;
 class UserActionClient;
 }
 }
@@ -218,6 +219,9 @@
   // Creates a menu model of the context for the |root_window|.
   virtual ui::MenuModel* CreateContextMenu(aura::RootWindow* root_window) = 0;
 
+  // Creates the stacking client. Shell takes ownership of the object.
+  virtual aura::client::StackingClient* CreateStackingClient() = 0;
+
   // Creates a root window host factory. Shell takes ownership of the returned
   // value.
   virtual RootWindowHostFactory* CreateRootWindowHostFactory() = 0;