Protect AppListItemList Add/Remove and fix sync bugs

chrome/browser/ui/app_list/fast_show_pickler.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/fast_show_pickler.h"
 
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/app_list/app_list_item.h"
 #include "ui/gfx/image/image_skia_rep.h"
 
@@ skipping 190 matching lines @@
   if (!result->WriteInt((int) model->item_list()->item_count()))
     return scoped_ptr<Pickle>();
   for (size_t i = 0; i < model->item_list()->item_count(); ++i) {
     if (!PickleAppListItem(result.get(), model->item_list()->item_at(i)))
       return scoped_ptr<Pickle>();
   }
   return result.Pass();
 }
 
 void FastShowPickler::CopyOver(AppListModel* src, AppListModel* dest) {
-  dest->item_list()->DeleteItemsByType(NULL /* all items */);
+  DCHECK_EQ(0u, dest->item_list()->item_count());
   for (size_t i = 0; i < src->item_list()->item_count(); i++) {
     AppListItem* src_item = src->item_list()->item_at(i);
     AppListItem* dest_item = new AppListItem(src_item->id());
     CopyOverItem(src_item, dest_item);
-    dest->item_list()->AddItem(dest_item);
+    dest->AddItem(dest_item);
   }
 }
 
 scoped_ptr<AppListModel>
 FastShowPickler::UnpickleAppListModelForFastShow(Pickle* pickle) {
   PickleIterator it(*pickle);
   int read_version = 0;
   if (!it.ReadInt(&read_version))
     return scoped_ptr<AppListModel>();
   if (read_version != kVersion)
     return scoped_ptr<AppListModel>();
   int app_count = 0;
   if (!it.ReadInt(&app_count))
     return scoped_ptr<AppListModel>();
 
   scoped_ptr<AppListModel> model(new AppListModel);
   for (int i = 0; i < app_count; ++i) {
     scoped_ptr<AppListItem> item(UnpickleAppListItem(&it).Pass());
     if (!item)
       return scoped_ptr<AppListModel>();
-    model->item_list()->AddItem(item.release());
+    model->AddItem(item.release());
   }
 
   return model.Pass();
 }