Revert of Refine ash shelf tooltip closing on non-mash ChromeOS.

ash/shelf/shelf_layout_manager.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/shelf/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <string>
@@ skipping 218 matching lines @@
 
 void ShelfLayoutManager::PrepareForShutdown() {
   // Clear all event filters, otherwise sometimes those filters may catch
   // synthesized mouse event and cause crashes during the shutdown.
   set_workspace_controller(NULL);
   auto_hide_event_filter_.reset();
   bezel_event_filter_.reset();
   // Stop observing window change, otherwise we can attempt to update a
   // partially destructed shelf.
   aura::client::GetActivationClient(root_window_)->RemoveObserver(this);
-  FOR_EACH_OBSERVER(ShelfLayoutManagerObserver, observers_, WillDeleteShelf());
 }
 
 bool ShelfLayoutManager::IsVisible() const {
   // status_area_widget() may be NULL during the shutdown.
   return shelf_->status_area_widget() &&
       shelf_->status_area_widget()->IsVisible() &&
       (state_.visibility_state == SHELF_VISIBLE ||
        (state_.visibility_state == SHELF_AUTO_HIDE &&
         state_.auto_hide_state == SHELF_AUTO_HIDE_SHOWN));
 }
@@ skipping 911 matching lines @@
     return false;
   }
   if (session_state_delegate->IsUserSessionBlocked() ||
       state_.is_adding_user_screen) {
     return true;
   }
   return false;
 }
 
 }  // namespace ash