Implement NativeWidgetMac::ReorderNativeViews

ui/views/widget/widget_mac_utils.h

+// Copyright 2016 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.
+
+#ifndef UI_VIEWS_WIDGET_WIDGET_MAC_UTILS_H_
+#define UI_VIEWS_WIDGET_WIDGET_MAC_UTILS_H_
+
+#import <Cocoa/Cocoa.h>
+
+#include <map>
+
+namespace views {
+
+class Widget;
+class View;
+
+using AssociatedViews = std::map<const views::View*, NSView*>;
+
+void ReorderChildNSViews(Widget* widget,
+                         const AssociatedViews& associated_views);
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WIDGET_WIDGET_MAC_UTILS_H_