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

chrome/browser/ui/views/dropdown_bar_host.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_DROPDOWN_BAR_HOST_H_
 #define CHROME_BROWSER_UI_VIEWS_DROPDOWN_BAR_HOST_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/public/browser/native_web_keyboard_event.h"
@@ skipping 163 matching lines @@
   views::FocusManager* focus_manager_;
 
   // True if the accelerator target for Esc key is registered.
   bool esc_accel_target_registered_;
 
   // Tracks and stores the last focused view which is not the DropdownBarView
   // or any of its children. Used to restore focus once the DropdownBarView is
   // closed.
   scoped_ptr<views::ExternalFocusTracker> focus_tracker_;
 
+#if defined(USE_AURA)
+  // The host view is a view maintained by the drop down bar in |browser_view_|
+  // to denote the z-order of the drop down bar relative to child views of
+  // |browser_view_| which have layers and NativeViews attached to a child
+  // NativeViewHost of |browser_view_|.
+  // TODO: implement a similar mechanism for Windows.
+  scoped_ptr<views::View> host_view_;
+#endif  // USE_AURA
+
   // Host is the Widget implementation that is created and maintained by the
   // dropdown bar. It contains the DropdownBarView.
   scoped_ptr<views::Widget> host_;
 
   // A flag to manually manage visibility. GTK/X11 is asynchronous and
   // the state of the widget can be out of sync.
   bool is_visible_;
 
   DISALLOW_COPY_AND_ASSIGN(DropdownBarHost);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_DROPDOWN_BAR_HOST_H_