Fix the content_browsertests everywhere maybe.

ash/shell_delegate.h

Index: ash/shell_delegate.h
diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index 6a9dd08bb1c6551ae5aa1223a6e9bf818a14e627..11482d528c9fa796c3a7574a612c186cc1797e65 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -22,7 +22,6 @@ namespace aura {
 class RootWindow;
 class Window;
 namespace client {
-class StackingClient;
 class UserActionClient;
 }
 }
@@ -219,9 +218,6 @@ class ASH_EXPORT ShellDelegate {
   // 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;