[ash-md] Adjusts layout of lists with sticky header rows to match specs

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_popup_ink_drop_style.h"
 #include "ash/common/system/tray/tri_view.h"
@@ skipping 150 matching lines @@
   static std::unique_ptr<views::InkDropMask> CreateInkDropMask(
       TrayPopupInkDropStyle ink_drop_style,
       const views::View* host);
 
   // Creates and returns a horizontal separator line to be drawn between rows
   // in a detailed view. If |left_inset| is true, then the separator is inset on
   // the left by the width normally occupied by an icon. Caller assumes
   // ownership of the returned separator.
   static views::Separator* CreateListItemSeparator(bool left_inset);
 
+  // Creates and returns a horizontal separator line to be drawn between rows
+  // in a detailed view above the header rows. Caller assumes ownership of the

[tdanderson, 2016/11/24 23:37:54]

nit: "above the sub-header rows". I would also prefer the function name to
change to CreateListSubHeaderSeparator(). This makes the naming consistent with
TrayPopupItemStyle::FontStyle::SUB_HEADER that you recently added.

[varkha, 2016/11/28 17:14:39]

Done.

+  // returned separator.
+  static views::Separator* CreateListHeaderSeparator();
+
   // Returns true if it is possible to open WebUI settings in a browser window,
   // i.e., the user is logged in, not on the lock screen, and not in a secondary
   // account flow.
   static bool CanOpenWebUISettings(LoginStatus status);
 
  private:
   // Returns the effective ink drop insets for |host| according to the
   // |ink_drop_style|.
   static gfx::Insets GetInkDropInsets(TrayPopupInkDropStyle ink_drop_style);
 
   // Returns the effective ink drop bounds for |host| according to the
   // |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_