make StackingClient dispatch to either ash or desktop

ui/aura/client/stacking_client.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/aura/client/stacking_client.h"
 
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window_property.h"
 
 DECLARE_WINDOW_PROPERTY_TYPE(aura::client::StackingClient*)
 
 namespace aura {
 namespace client {
 
 DEFINE_WINDOW_PROPERTY_KEY(
     StackingClient*, kRootWindowStackingClientKey, NULL);
 
 void SetStackingClient(StackingClient* stacking_client) {
   Env::GetInstance()->set_stacking_client(stacking_client);
 }
 
 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