aura-mus: Make StackAtTop() proxy to the window manager.

services/ui/ws/test_utils.h

 // Copyright 2016 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.
 
 #ifndef SERVICES_UI_WS_TEST_UTILS_H_
 #define SERVICES_UI_WS_TEST_UTILS_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 340 matching lines @@
       const std::unordered_map<std::string, std::vector<uint8_t>>& properties)
       override;
   void WmClientJankinessChanged(ClientSpecificId client_id,
                                 bool janky) override;
   void WmPerformMoveLoop(uint32_t change_id,
                          uint32_t window_id,
                          mojom::MoveLoopSource source,
                          const gfx::Point& cursor_location) override;
   void WmCancelMoveLoop(uint32_t window_id) override;
   void WmDeactivateWindow(uint32_t window_id) override;
+  void WmStackAtTop(uint32_t change_id, uint32_t window_id) override;
   void OnAccelerator(uint32_t ack_id,
                      uint32_t accelerator_id,
                      std::unique_ptr<ui::Event> event) override;
 
   bool on_perform_move_loop_called_ = false;
 
   bool got_create_top_level_window_;
   uint32_t change_id_;
 
   bool on_accelerator_called_;
@@ skipping 302 matching lines @@
 ServerWindow* NewWindowInTree(WindowTree* tree, ClientWindowId* client_id);
 ServerWindow* NewWindowInTreeWithParent(WindowTree* tree,
                                         ServerWindow* parent,
                                         ClientWindowId* client_id);
 
 }  // namespace test
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_TEST_UTILS_H_