Remove dead code related to Notification View Bubble

ash/common/system/web_notification/web_notification_tray.h

 // 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.
 
 #ifndef ASH_COMMON_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_
 #define ASH_COMMON_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 51 matching lines @@
 
   // Returns the current tray bubble height or 0 if there is no bubble.
   int tray_bubble_height_for_test() const;
 
   // Returns true if it should block the auto hide behavior of the shelf.
   bool ShouldBlockShelfAutoHide() const;
 
   // Returns true if the message center bubble is visible.
   bool IsMessageCenterBubbleVisible() const;
 
-  // Returns true if the mouse is inside the notification bubble.
-  bool IsMouseInNotificationBubble() const;
-
   // Shows the message center bubble.
   void ShowMessageCenterBubble();
 
   // Called when the login status is changed.
   void UpdateAfterLoginStatusChange(LoginStatus login_status);
 
   // Overridden from TrayBackgroundView.
   void SetShelfAlignment(ShelfAlignment alignment) override;
   void AnchorUpdated() override;
   base::string16 GetAccessibleNameForTray() override;
@@ skipping 99 matching lines @@
   bool should_block_shelf_auto_hide_;
 
   std::unique_ptr<AshPopupAlignmentDelegate> popup_alignment_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(WebNotificationTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_