CrOS - Fix position of notification bubble for lock screen.

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 361 matching lines @@
     max_height = bounds_in_root.bottom();
   }
   message_center_bubble->SetMaxHeight(
       std::max(0, max_height - GetTrayConstant(TRAY_SPACING)));
   if (show_settings)
     message_center_bubble->SetSettingsVisible();
 
   // For vertical shelf alignments, anchor to the WebNotificationTray, but for
   // horizontal (i.e. bottom) shelves, anchor to the system tray.
   TrayBackgroundView* anchor_tray = this;
-  if (shelf_alignment() == SHELF_ALIGNMENT_BOTTOM) {
+  if (IsHorizontalAlignment(shelf_alignment())) {
     anchor_tray = WmShelf::ForWindow(status_area_window_)
                       ->GetStatusAreaWidget()
                       ->system_tray();
   }
 
   message_center_bubble_.reset(new WebNotificationBubbleWrapper(
       this, anchor_tray, message_center_bubble));
 
   system_tray_->SetHideNotifications(true);
   shelf()->UpdateAutoHideState();
@@ skipping 278 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