Set NULL if before releasing IBusUiController instance.

chrome/browser/chromeos/input_method/candidate_window_controller_impl.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 "chrome/browser/chromeos/input_method/candidate_window_controller_impl.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 84 matching lines @@
 }
 
 CandidateWindowControllerImpl::CandidateWindowControllerImpl()
     : ibus_ui_controller_(new IBusUiController),
       candidate_window_(NULL),
       infolist_window_(NULL),
       latest_infolist_focused_index_(InfolistWindowView::InvalidFocusIndex()) {
 }
 
 CandidateWindowControllerImpl::~CandidateWindowControllerImpl() {
+  if (DBusThreadManager::Get()->GetIBusPanelService())
+    DBusThreadManager::Get()->GetIBusPanelService()->
+        SetUpCandidateWindowHandler(NULL);
   ibus_ui_controller_->RemoveObserver(this);
   candidate_window_->RemoveObserver(this);
   // ibus_ui_controller_'s destructor will close the connection.
 }
 
 void CandidateWindowControllerImpl::OnHideAuxiliaryText() {
   candidate_window_->HideAuxiliaryText();
 }
 
 void CandidateWindowControllerImpl::OnHideLookupTable() {
@@ skipping 223 matching lines @@
 
   if (candidate_window_rect.y() + infolist_window_size.height() >
       screen_rect.bottom())
     result.set_y(screen_rect.bottom() - infolist_window_size.height());
 
   return result;
 }
 
 }  // namespace input_method
 }  // namespace chromeos