Removes |old| parameter from OnWindowPropertyChanged()

ash/wm/common/panels/panel_layout_manager.cc

Index: ash/wm/common/panels/panel_layout_manager.cc
diff --git a/ash/wm/common/panels/panel_layout_manager.cc b/ash/wm/common/panels/panel_layout_manager.cc
index 205242eb964706fa1d84faab06126936467f87f6..8f02d58af218cfc225252f31f3ece216bc9c5d2b 100644
--- a/ash/wm/common/panels/panel_layout_manager.cc
+++ b/ash/wm/common/panels/panel_layout_manager.cc
@@ -447,9 +447,9 @@ void PanelLayoutManager::OnShelfAlignmentChanged() {
 /////////////////////////////////////////////////////////////////////////////
 // PanelLayoutManager, WindowObserver implementation:
 
-void PanelLayoutManager::OnWindowPropertyChanged(wm::WmWindow* window,
-                                                 wm::WmWindowProperty property,
-                                                 intptr_t old) {
+void PanelLayoutManager::OnWindowPropertyChanged(
+    wm::WmWindow* window,
+    wm::WmWindowProperty property) {
   // Trigger a relayout to position the panels whenever the panel icon is set
   // or changes.
   if (property == wm::WmWindowProperty::SHELF_ID)