Fix app list item indexing bug.

ui/app_list/views/search_result_answer_card_view_unittest.cc

 // Copyright 2017 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/views/search_result_answer_card_view.h"
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_node_data.h"
@@ skipping 43 matching lines @@
     result->set_view(result_view_.get());
     result->set_relevance(kRelevance);
     results->Add(std::move(result));
 
     // Adding results will schedule Update().
     RunPendingMessages();
     result_container_view_->OnContainerSelected(false, false);
   }
 
   int GetOpenResultCountAndReset(int ranking) {
+    EXPECT_GT(view_delegate_.open_search_result_counts().count(ranking), 0u);
     int result = view_delegate_.open_search_result_counts()[ranking];
     view_delegate_.open_search_result_counts().clear();
     return result;
   }
 
   void ClearSelectedIndex() { result_container_view_->ClearSelectedIndex(); }
 
   void DeleteResult() {
     GetResults()->DeleteAt(0);
     RunPendingMessages();
@@ skipping 96 matching lines @@
   DeleteResult();
   EXPECT_EQ(0UL, GetResults()->item_count());
   EXPECT_EQ(nullptr, result_view()->parent());
   EXPECT_EQ(0, GetYSize());
   ASSERT_FALSE(search_card_view()->visible());
   EXPECT_EQ(0, GetContainerScore());
 }
 
 }  // namespace test
 }  // namespace app_list