Remove dead code related to Notification View Bubble

ash/common/system/tray/system_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/tray/system_tray.h"
 
 #include <algorithm>
 #include <map>
 #include <vector>
 
@@ skipping 476 matching lines @@
 views::View* SystemTray::GetHelpButtonView() const {
   if (MaterialDesignController::IsSystemTrayMenuMaterial())
     return tray_tiles_->GetHelpButtonView();
   return tray_date_->GetHelpButtonView();
 }
 
 TrayAudio* SystemTray::GetTrayAudio() const {
   return tray_audio_;
 }
 
-bool SystemTray::CloseNotificationBubbleForTest() const {
-  if (!notification_bubble_)
-    return false;
-  notification_bubble_->bubble()->Close();
-  return true;
-}
-
 // Private methods.
 
 bool SystemTray::HasSystemBubbleType(SystemTrayBubble::BubbleType type) {
   DCHECK(type != SystemTrayBubble::BUBBLE_TYPE_NOTIFICATION);
   return system_bubble_.get() && system_bubble_->bubble_type() == type;
 }
 
 void SystemTray::DestroySystemBubble() {
   CloseSystemBubbleAndDeactivateSystemTray();
   detailed_item_ = NULL;
@@ skipping 390 matching lines @@
           .work_area()
           .height();
   if (work_area_height > 0) {
     UMA_HISTOGRAM_CUSTOM_COUNTS(
         "Ash.SystemMenu.PercentageOfWorkAreaHeightCoveredByMenu",
         100 * bubble_view->height() / work_area_height, 1, 300, 100);
   }
 }
 
 }  // namespace ash