Remove dead code related to Notification View Bubble

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 424 matching lines @@
 
 bool WebNotificationTray::ShouldBlockShelfAutoHide() const {
   return should_block_shelf_auto_hide_;
 }
 
 bool WebNotificationTray::IsMessageCenterBubbleVisible() const {
   return (message_center_bubble() &&
           message_center_bubble()->bubble()->IsVisible());
 }
 
-bool WebNotificationTray::IsMouseInNotificationBubble() const {
-  return false;
-}
-
 void WebNotificationTray::ShowMessageCenterBubble() {
   if (!IsMessageCenterBubbleVisible())
     message_center_tray_->ShowMessageCenterBubble();
 }
 
 void WebNotificationTray::UpdateAfterLoginStatusChange(
     LoginStatus login_status) {
   message_center()->SetLockedState(login_status == LoginStatus::LOCKED);
   OnMessageCenterTrayChanged();
 }
@@ skipping 208 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