Removes |old| parameter from OnWindowPropertyChanged()

ash/wm/common/always_on_top_controller.h

 // 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.
 
 #ifndef ASH_WM_COMMON_ALWAYS_ON_TOP_CONTROLLER_H_
 #define ASH_WM_COMMON_ALWAYS_ON_TOP_CONTROLLER_H_
 
 #include <memory>
 
 #include "ash/wm/common/ash_wm_common_export.h"
@@ skipping 18 matching lines @@
   WorkspaceLayoutManager* GetLayoutManager() const;
 
   void SetLayoutManagerForTest(
       std::unique_ptr<WorkspaceLayoutManager> layout_manager);
 
  private:
   // Overridden from wm::WmWindowObserver:
   void OnWindowTreeChanged(wm::WmWindow* window,
                            const TreeChangeParams& params) override;
   void OnWindowPropertyChanged(wm::WmWindow* window,
-                               wm::WmWindowProperty property,
-                               intptr_t old) override;
+                               wm::WmWindowProperty property) override;
   void OnWindowDestroying(wm::WmWindow* window) override;
 
   wm::WmWindow* always_on_top_container_;
 
   DISALLOW_COPY_AND_ASSIGN(AlwaysOnTopController);
 };
 
 }  // namepsace ash
 
 #endif  // ASH_WM_COMMON_ALWAYS_ON_TOP_CONTROLLER_H_