Remove more dead app list code.

ui/app_list/app_list_folder_item.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 "ui/app_list/app_list_folder_item.h"
 
 #include "base/guid.h"
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_item_list.h"
 #include "ui/gfx/geometry/rect.h"
@@ skipping 42 matching lines @@
 }
 
 AppListItem* AppListFolderItem::FindChildItem(const std::string& id) {
   return item_list_->FindItem(id);
 }
 
 size_t AppListFolderItem::ChildItemCount() const {
   return item_list_->item_count();
 }
 
-void AppListFolderItem::OnExtensionPreferenceChanged() {
-  for (size_t i = 0; i < item_list_->item_count(); ++i)
-    item_list_->item_at(i)->OnExtensionPreferenceChanged();
-}
-
 bool AppListFolderItem::CompareForTest(const AppListItem* other) const {
   if (!AppListItem::CompareForTest(other))
     return false;
   const AppListFolderItem* other_folder =
       static_cast<const AppListFolderItem*>(other);
   if (other_folder->item_list()->item_count() != item_list_->item_count())
     return false;
   for (size_t i = 0; i < item_list_->item_count(); ++i) {
     if (!item_list()->item_at(i)->CompareForTest(
             other_folder->item_list()->item_at(i)))
       return false;
   }
   return true;
 }
 
 std::string AppListFolderItem::GenerateId() {
   return base::GenerateGUID();
 }
 
 void AppListFolderItem::OnFolderImageUpdated() {
   SetIcon(folder_image_.icon());
 }
 
 }  // namespace app_list