Remove non-MD code from TrayBackgroundView

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/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 279 matching lines @@
     : TrayBackgroundView(shelf),
       status_area_window_(status_area_window),
       system_tray_(system_tray),
       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_);
 
+  SetContentsBackground();
   if (MaterialDesignController::IsShelfMaterial()) {
     SetInkDropMode(InkDropMode::ON);
-    SetContentsBackground(false);
     gfx::ImageSkia bell_image =
         CreateVectorIcon(kShelfNotificationsIcon, kShelfIconColor);
     const gfx::Size bell_icon_size = kTrayItemInnerIconSize;
     bell_icon_.reset(new WebNotificationImage(
         bell_image, bell_icon_size, animation_container_.get(), this));
   } else {
-    SetContentsBackground(true);
     gfx::ImageSkia bell_image =
         CreateVectorIcon(gfx::VectorIconId::NOTIFICATIONS, kNoUnreadIconSize,
                          kWebNotificationColorNoUnread);
     const gfx::Size bell_icon_size = kTrayItemInnerBellIconSizeNonMd;
     bell_icon_.reset(new WebNotificationImage(
         bell_image, bell_icon_size, animation_container_.get(), this));
   }
   tray_container()->AddChildView(bell_icon_.get());
 
   counter_.reset(new WebNotificationLabel(animation_container_.get(), this));
@@ skipping 338 matching lines @@
 
 message_center::MessageCenterBubble*
 WebNotificationTray::GetMessageCenterBubbleForTest() {
   if (!message_center_bubble())
     return nullptr;
   return static_cast<message_center::MessageCenterBubble*>(
       message_center_bubble()->bubble());
 }
 
 }  // namespace ash