Update desktop tree when Aura windows are removed.

ui/views/accessibility/ax_window_obj_wrapper.cc

 // Copyright 2014 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/views/accessibility/ax_window_obj_wrapper.h"
 
 #include <stddef.h>
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_node_data.h"
@@ skipping 43 matching lines @@
                                     base::UTF16ToUTF8(window_->title()));
   out_node_data->state = 0;
   out_node_data->location = gfx::RectF(window_->bounds());
 }
 
 int32_t AXWindowObjWrapper::GetID() {
   return AXAuraObjCache::GetInstance()->GetID(window_);
 }
 
 void AXWindowObjWrapper::OnWindowDestroyed(aura::Window* window) {
-  AXAuraObjCache::GetInstance()->Remove(window);
+  AXAuraObjCache::GetInstance()->Remove(window, nullptr);
+}
+
+void AXWindowObjWrapper::OnWindowDestroying(aura::Window* window) {
+  Widget* widget = Widget::GetWidgetForNativeView(window);
+  if (widget)
+    AXAuraObjCache::GetInstance()->Remove(widget);
+}
+
+void AXWindowObjWrapper::OnWindowHierarchyChanged(
+    const HierarchyChangeParams& params) {
+  if (params.phase == WindowObserver::HierarchyChangeParams::HIERARCHY_CHANGED)
+    AXAuraObjCache::GetInstance()->Remove(params.target, params.old_parent);
 }
 
 }  // namespace views