[ash-md] Stacks child layers properly for sticky header rows

ash/common/system/tray/tray_popup_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 ASH_COMMON_SYSTEM_TRAY_TRAY_POPUP_UTILS_H_
 #define ASH_COMMON_SYSTEM_TRAY_TRAY_POPUP_UTILS_H_
 
 #include "ash/common/login_status.h"
 #include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/tray_popup_ink_drop_style.h"
@@ skipping 96 matching lines @@
   static views::ToggleButton* CreateToggleButton(
       views::ButtonListener* listener,
       int accessible_name_id);
 
   // Creates a default focus painter used for most things in tray popups.
   static std::unique_ptr<views::Painter> CreateFocusPainter();
 
   // Sets up |view| to be a sticky header in a tray detail scroll view.
   static void ConfigureAsStickyHeader(views::View* view);
 
+  // Configures a |view| to have a visible separator below.
+  static void ShowStickyHeaderSeparator(views::View* view, bool show_separator);
+
   // Configures |container_view| just like CreateDefaultRowView() would
   // configure |container| on its returned TriView. To be used when mutliple
   // targetable areas are required within a single row.
   static void ConfigureContainer(TriView::Container container,
                                  views::View* container_view);
 
   // Creates a button for use in the system menu that only has a visible border
   // when being hovered/clicked. Caller assumes ownership.
   static views::LabelButton* CreateTrayPopupBorderlessButton(
       views::ButtonListener* listener,
@@ skipping 76 matching lines @@
   // |ink_drop_style|.
   static gfx::Rect GetInkDropBounds(TrayPopupInkDropStyle ink_drop_style,
                                     const views::View* host);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(TrayPopupUtils);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_TRAY_POPUP_UTILS_H_