aura: Do not attempt to remove the window multiple times on detach.

views/controls/native/native_view_host_aura.cc

 // Copyright (c) 2011 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 "views/controls/native/native_view_host_aura.h"
 
 #include "base/logging.h"
 #include "ui/aura/focus_manager.h"
 #include "ui/aura/window.h"
 #include "views/controls/native/native_view_host.h"
@@ skipping 17 matching lines @@
   host_->GetWidget()->GetNativeView()->AddChild(host_->native_view());
   host_->Layout();
 
   host_->native_view()->AddObserver(this);
 }
 
 void NativeViewHostAura::NativeViewDetaching(bool destroyed) {
   if (!destroyed) {
     host_->native_view()->RemoveObserver(this);
     host_->native_view()->Hide();
-    host_->GetWidget()->GetNativeView()->RemoveChild(host_->native_view());
   }
 }
 
 void NativeViewHostAura::AddedToWidget() {
   if (!host_->native_view())
     return;
 
   aura::Window* widget_window = host_->GetWidget()->GetNativeView();
   if (host_->native_view()->parent() != widget_window)
     widget_window->AddChild(host_->native_view());
@@ skipping 46 matching lines @@
   host_->NativeViewDestroyed();
 }
 
 // static
 NativeViewHostWrapper* NativeViewHostWrapper::CreateWrapper(
     NativeViewHost* host) {
   return new NativeViewHostAura(host);
 }
 
 }  // namespace views