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

ash/common/system/chromeos/palette/palette_tray.cc

 // 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.
 
 #include "ash/common/system/chromeos/palette/palette_tray.h"
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
+#include "ash/common/shelf/wm_shelf_observer.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/chromeos/palette/palette_tool.h"
 #include "ash/common/system/chromeos/palette/palette_tool_manager.h"
 #include "ash/common/system/chromeos/palette/palette_utils.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/system/tray/tray_bubble_wrapper.h"
 #include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/tray_popup_header_button.h"
 #include "ash/common/wm_lookup.h"
@@ skipping 75 matching lines @@
       IDS_ASH_STATUS_TRAY_SHUTDOWN);
   settings_button->SetTooltipText(
       l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_SHUTDOWN));
   root->AddChildView(settings_button);
 
   return root;
 }
 
 }  // namespace
 
-PaletteTray::PaletteTray(WmShelf* wm_shelf)
-    : TrayBackgroundView(wm_shelf),
+PaletteTray::PaletteTray(WmShelf* wm_shelf, WmShelfObserver* wm_shelf_observer)
+    : TrayBackgroundView(wm_shelf, wm_shelf_observer),
       palette_tool_manager_(new PaletteToolManager(this)) {
   PaletteTool::RegisterToolInstances(palette_tool_manager_.get());
 
   SetContentsBackground();
 
   SetLayoutManager(new views::FillLayout());
   icon_ = new views::ImageView();
   UpdateTrayIcon();
 
   SetIconBorderForShelfAlignment();
@@ skipping 186 matching lines @@
       WmShell::Get()->GetSessionStateDelegate();
 
   SetVisible(!session_state_delegate->IsScreenLocked() &&
              session_state_delegate->GetSessionState() ==
                  SessionStateDelegate::SESSION_STATE_ACTIVE &&
              WmShell::Get()->system_tray_delegate()->GetUserLoginStatus() !=
                  LoginStatus::KIOSK_APP);
 }
 
 }  // namespace ash