Removes |old| parameter from OnWindowPropertyChanged()

ash/wm/common/workspace/workspace_layout_manager.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_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_H_
 #define ASH_WM_COMMON_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_H_
 
 #include <memory>
 #include <set>
 
@@ skipping 53 matching lines @@
 
   // wm::WmRootWindowControllerObserver overrides:
   void OnWorkAreaChanged() override;
   void OnFullscreenStateChanged(bool is_fullscreen) override;
 
   // Overriden from wm::WmWindowObserver:
   void OnWindowTreeChanged(
       wm::WmWindow* window,
       const wm::WmWindowObserver::TreeChangeParams& params) override;
   void OnWindowPropertyChanged(wm::WmWindow* window,
-                               wm::WmWindowProperty property,
-                               intptr_t old) override;
+                               wm::WmWindowProperty property) override;
   void OnWindowStackingChanged(wm::WmWindow* window) override;
   void OnWindowDestroying(wm::WmWindow* window) override;
   void OnWindowBoundsChanged(wm::WmWindow* window,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds) override;
 
   // wm::WmActivationObserver overrides:
   void OnWindowActivated(wm::WmWindow* gained_active,
                          wm::WmWindow* lost_active) override;
 
@@ skipping 54 matching lines @@
   // A window which covers the full container and which gets inserted behind the
   // topmost visible window.
   std::unique_ptr<WorkspaceLayoutManagerBackdropDelegate> backdrop_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceLayoutManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_COMMON_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_H_