Nukes aura::WindowDestructionObserver. It's effectively the same as

ui/aura/window.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/window.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/event_client.h"
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/client/stacking_client.h"
 #include "ui/aura/client/visibility_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/layout_manager.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window_delegate.h"
-#include "ui/aura/window_destruction_observer.h"
 #include "ui/aura/window_observer.h"
+#include "ui/aura/window_tracker.h"
 #include "ui/base/animation/multi_animation.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/path.h"
 #include "ui/gfx/screen.h"
 
 namespace aura {
 
 namespace {
@@ skipping 982 matching lines @@
 void Window::NotifyWindowVisibilityChanged(aura::Window* target,
                                            bool visible) {
   if (!NotifyWindowVisibilityChangedDown(target, visible)) {
     return; // |this| has been deleted.
   }
   NotifyWindowVisibilityChangedUp(target, visible);
 }
 
 bool Window::NotifyWindowVisibilityChangedAtReceiver(aura::Window* target,
                                                      bool visible) {
-  // |this| may be deleted during a call to OnWindowVisibilityChanged
-  // on one of the observers. We create an local observer for that. In
-  // that case we exit without further access to any members.
-  WindowDestructionObserver destruction_observer(this);
+  // |this| may be deleted during a call to OnWindowVisibilityChanged() on one
+  // of the observers. We create an local observer for that. In that case we
+  // exit without further access to any members.
+  WindowTracker tracker;
+  tracker.Add(this);
   FOR_EACH_OBSERVER(WindowObserver, observers_,
                     OnWindowVisibilityChanged(target, visible));
-  return !destruction_observer.destroyed();
+  return tracker.Contains(this);
 }
 
 bool Window::NotifyWindowVisibilityChangedDown(aura::Window* target,
                                                bool visible) {
   if (!NotifyWindowVisibilityChangedAtReceiver(target, visible))
     return false; // |this| was deleted.
   std::set<const Window*> child_already_processed;
   bool child_destroyed = false;
   do {
     child_destroyed = false;
@@ skipping 80 matching lines @@
   bool contains_mouse = false;
   if (IsVisible()) {
     RootWindow* root_window = GetRootWindow();
     contains_mouse = root_window &&
         ContainsPointInRoot(root_window->GetLastMouseLocationInRoot());
   }
   return contains_mouse;
 }
 
 }  // namespace aura