[Chrome OS MD] Draw a 1px separator between 2 tray items

ash/common/system/web_notification/web_notification_tray.cc

 // Copyright (c) 2012 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.
 
 #include "ash/common/system/web_notification/web_notification_tray.h"
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/shelf_constants.h"
@@ skipping 197 matching lines @@
       icon_(new WebNotificationIcon),
       show_message_center_on_unlock_(false),
       should_update_tray_content_(false),
       should_block_shelf_auto_hide_(false) {
   DCHECK(shelf);
   DCHECK(status_area_window_);
   DCHECK(system_tray_);
 
   tray_container()->AddChildView(icon_);
   SetContentsBackground();
-  tray_container()->SetBorder(views::Border::NullBorder());
   message_center_tray_.reset(new message_center::MessageCenterTray(
       this, message_center::MessageCenter::Get()));
   popup_alignment_delegate_.reset(new AshPopupAlignmentDelegate(shelf));
   popup_collection_.reset(new message_center::MessagePopupCollection(
       message_center(), message_center_tray_.get(),
       popup_alignment_delegate_.get()));
   const display::Display& display =
       status_area_window_->GetDisplayNearestWindow();
   popup_alignment_delegate_->StartObserving(display::Screen::GetScreen(),
                                             display);
@@ skipping 106 matching lines @@
 void WebNotificationTray::UpdateAfterLoginStatusChange(
     LoginStatus login_status) {
   message_center()->SetLockedState(login_status == LoginStatus::LOCKED);
   OnMessageCenterTrayChanged();
 }
 
 void WebNotificationTray::SetShelfAlignment(ShelfAlignment alignment) {
   if (alignment == shelf_alignment())
     return;
   TrayBackgroundView::SetShelfAlignment(alignment);
-  // Every time shelf alignment is updated, StatusAreaWidgetDelegate resets the
-  // border to a non-null border. So, we need to remove it.
-  tray_container()->SetBorder(views::Border::NullBorder());
   // Destroy any existing bubble so that it will be rebuilt correctly.
   message_center_tray_->HideMessageCenterBubble();
   message_center_tray_->HidePopupBubble();
 }
 
 void WebNotificationTray::AnchorUpdated() {
   if (message_center_bubble()) {
     message_center_bubble()->bubble_view()->UpdateBubble();
     UpdateBubbleViewArrow(message_center_bubble()->bubble_view());
   }
@@ skipping 150 matching lines @@
 
 message_center::MessageCenterBubble*
 WebNotificationTray::GetMessageCenterBubbleForTest() {
   if (!message_center_bubble())
     return NULL;
   return static_cast<message_center::MessageCenterBubble*>(
       message_center_bubble()->bubble());
 }
 
 }  // namespace ash