make StackingClient dispatch to either ash or desktop

ui/aura/client/stacking_client.cc

Index: ui/aura/client/stacking_client.cc
diff --git a/ui/aura/client/stacking_client.cc b/ui/aura/client/stacking_client.cc
index 2bab5210618ec78eaecd32e10e403f940d81e746..9c821a5faa98a15fc3963d2416c816cbd542a16b 100644
--- a/ui/aura/client/stacking_client.cc
+++ b/ui/aura/client/stacking_client.cc
@@ -24,27 +24,5 @@ StackingClient* GetStackingClient() {
   return Env::GetInstance()->stacking_client();
 }
 
-void SetStackingClient(Window* window, StackingClient* stacking_client) {
-  if (window) {
-    RootWindow* root_window = window->GetRootWindow();
-    DCHECK(root_window);
-    root_window->SetProperty(kRootWindowStackingClientKey, stacking_client);
-  } else {
-    SetStackingClient(stacking_client);
-  }
-}
-
-StackingClient* GetStackingClient(Window* window) {
-  if (window) {
-    RootWindow* root_window = window->GetRootWindow();
-    DCHECK(root_window);
-    StackingClient* root_window_stacking_client =
-        root_window->GetProperty(kRootWindowStackingClientKey);
-    if (root_window_stacking_client)
-      return root_window_stacking_client;
-  }
-  return GetStackingClient();
-}
-
 }  // namespace client
 }  // namespace aura