Make sure WindowObservers are removed from window before destruction

chrome/browser/ui/ash/multi_user/multi_user_window_manager_chromeos.cc

 // Copyright 2013 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 "chrome/browser/ui/ash/multi_user/multi_user_window_manager_chromeos.h"
 
 #include "apps/shell_window.h"
 #include "apps/shell_window_registry.h"
 #include "ash/ash_switches.h"
 #include "ash/multi_profile_uma.h"
@@ skipping 345 matching lines @@
 
 void MultiUserWindowManagerChromeOS::OnWindowDestroyed(aura::Window* window) {
   if (GetWindowOwner(window).empty()) {
     // This must be a window in the transient chain - remove it and its
     // children from the owner.
     RemoveTransientOwnerRecursive(window);
     return;
   }
   // Remove the state and the window observer.
   ash::wm::GetWindowState(window)->RemoveObserver(this);
-  window->RemoveObserver(this);
   // Remove the window from the owners list.
   delete window_to_entry_[window];
   window_to_entry_.erase(window);
 }
 
 void MultiUserWindowManagerChromeOS::OnWindowVisibilityChanging(
     aura::Window* window, bool visible) {
   // This command gets called first and immediately when show or hide gets
   // called. We remember here the desired state for restoration IF we were
   // not ourselves issuing the call.
@@ skipping 208 matching lines @@
     // To prevent these commands from being recorded as any other commands, we
     // are suppressing any window entry changes while this is going on.
     // Instead of calling SetWindowVisible, only show gets called here since all
     // dependents have been shown previously already.
     base::AutoReset<bool> suppressor(&suppress_visibility_changes_, true);
     window->Show();
   }
 }
 
 }  // namespace chrome