Reorder the NativeViews attached to a view via kViewHostKey according to the position of the view

ui/views/view_constants_aura.h

+// Copyright (c) 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.
+
+#ifndef UI_VIEWS_VIEW_CONSTANTS_AURA_H_
+#define UI_VIEWS_VIEW_CONSTANTS_AURA_H_
+
+#include "ui/aura/window.h"
+#include "ui/views/views_export.h"
+
+namespace views {
+class View;
+
+// A property key to indicate the window's host view. If specified, the host
+// view determines the z-order of the window in its parent widget. The host
+// view must have the same parent widget as the window on which the property
+// is set. The z-order of the window is set to the z-order of the host view in
+// the view tree relative to:
+// - views with layers.
+// - views bound to a window via the kHostViewKey.
+VIEWS_EXPORT extern const aura::WindowProperty<View*>* const kHostViewKey;
+
+}  // namespace views
+
+#endif  // UI_VIEWS_VIEW_CONSTANTS_AURA_H_