Add additional CHECKs to AppListModel.

ui/app_list/app_list_item_list_unittest.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_item_list.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/stringprintf.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/app_list/app_list_folder_item.h"
@@ skipping 195 matching lines @@
   size_t index;
   EXPECT_TRUE(FindItemIndex(item_1->id(), &index));
   EXPECT_EQ(index, 1u);
 
   scoped_ptr<AppListItem> item_removed = RemoveItem(item_1->id());
   EXPECT_EQ(item_removed, item_1);
   EXPECT_FALSE(FindItem(item_1->id()));
   EXPECT_EQ(item_list_.item_count(), 2u);
   EXPECT_EQ(observer_.items_removed(), 1u);
   EXPECT_TRUE(VerifyItemListOrdinals());
-
-  scoped_ptr<AppListItem> not_found_item = RemoveItem("Bogus");
-  EXPECT_FALSE(not_found_item.get());
 }
 
 TEST_F(AppListItemListTest, MoveItem) {
   CreateAndAddItem(GetItemId(0));
   CreateAndAddItem(GetItemId(1));
   CreateAndAddItem(GetItemId(2));
   CreateAndAddItem(GetItemId(3));
 
   EXPECT_TRUE(VerifyItemOrder4(0, 1, 2, 3));
 
@@ skipping 134 matching lines @@
   EXPECT_TRUE(VerifyItemListOrdinals());
   EXPECT_TRUE(VerifyItemOrder4(2, 0, 3, 1));
   // last -> last
   item_list_.SetItemPosition(item_list_.item_at(3),
                              item_list_.item_at(3)->position().CreateAfter());
   EXPECT_TRUE(VerifyItemListOrdinals());
   EXPECT_TRUE(VerifyItemOrder4(2, 0, 3, 1));
 }
 
 }  // namespace app_list