MacViews: Be robust against Views manipulating Layers during Widget::Close().

ui/views/widget/native_widget_mac.mm

 // 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/widget/native_widget_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include <utility>
 
@@ skipping 179 matching lines @@
 const ui::Compositor* NativeWidgetMac::GetCompositor() const {
   return bridge_ && bridge_->layer() ? bridge_->layer()->GetCompositor()
                                      : nullptr;
 }
 
 const ui::Layer* NativeWidgetMac::GetLayer() const {
   return bridge_ ? bridge_->layer() : nullptr;
 }
 
 void NativeWidgetMac::ReorderNativeViews() {
-  if (bridge_) {
-    bridge_->SetRootView(GetWidget()->GetRootView());
+  if (bridge_)
     bridge_->ReorderChildViews();
-  }
 }
 
 void NativeWidgetMac::ViewRemoved(View* view) {
   DragDropClientMac* client = bridge_ ? bridge_->drag_drop_client() : nullptr;
   if (client)
     client->drop_helper()->ResetTargetViewIfEquals(view);
 }
 
 void NativeWidgetMac::SetNativeWindowProperty(const char* name, void* value) {
   if (bridge_)
@@ skipping 566 matching lines @@
   [[ViewsNSWindowCloseAnimator alloc] initWithWindow:window];
 }
 
 - (void)animationDidEnd:(NSAnimation*)animation {
   [window_ close];
   [animation_ setDelegate:nil];
   [self release];
 }
 
 @end