Fix ModelPrefUpdater destruction order.

chrome/browser/ui/app_list/app_list_syncable_service.cc

 // Copyright 2013 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/ui/app_list/app_list_syncable_service.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/apps/drive/drive_app_provider.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ skipping 228 matching lines @@
 
   // The extensions for this profile have not yet all been loaded.
   registrar_.Add(this,
                  extensions::NOTIFICATION_EXTENSIONS_READY_DEPRECATED,
                  content::Source<Profile>(profile));
 }
 
 AppListSyncableService::~AppListSyncableService() {
   // Remove observers.
   model_observer_.reset();
+  model_pref_updater_.reset();
 
   STLDeleteContainerPairSecondPointers(sync_items_.begin(), sync_items_.end());
 }
 
 void AppListSyncableService::BuildModel() {
   // For now, use the AppListControllerDelegate associated with the native
   // desktop. TODO(stevenjb): Remove ExtensionAppModelBuilder controller
   // dependency and move the dependent methods from AppListControllerDelegate
   // to an extension service delegate associated with this class.
   AppListControllerDelegate* controller = NULL;
@@ skipping 676 matching lines @@
   } else {
     res += " { " + item_name + " }";
     res += " [" + item_ordinal.ToDebugString() + "]";
     if (!parent_id.empty())
       res += " <" + parent_id.substr(0, 8) + ">";
   }
   return res;
 }
 
 }  // namespace app_list