Fix sort order of unlaunched apps on app list start page.

chrome/browser/ui/app_list/search/app_search_provider.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/search/app_search_provider.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 94 matching lines @@
       id_to_app_list_index[top_level_item_list_->item_at(i)->id()] = i;
     }
 
     for (const App* app : apps_) {
       scoped_ptr<AppResult> result(
           new AppResult(profile_, app->app_id(), list_controller_, true));
       result->set_title(app->indexed_name().text());
 
       // Use the app list order to tiebreak apps that have never been launched.
       if (app->last_launch_time().is_null()) {
-        result->set_relevance(
-            kUnlaunchedAppRelevanceStepSize *
-            (apps_.size() - id_to_app_list_index[app->app_id()]));
+        auto it = id_to_app_list_index.find(app->app_id());
+        // If it's in a folder, it won't be in |id_to_app_list_index|. Rank
+        // those as if they are at the end of the list.
+        size_t app_list_index =
+            it == id_to_app_list_index.end() ? apps_.size() : (*it).second;
+        if (app_list_index > apps_.size())
+          app_list_index = apps_.size();
+
+        result->set_relevance(kUnlaunchedAppRelevanceStepSize *
+                              (apps_.size() - app_list_index));
       } else {
         result->UpdateFromLastLaunched(clock_->Now(), app->last_launch_time());
       }
       Add(result.Pass());
     }
   } else {
     for (const App* app : apps_) {
       scoped_ptr<AppResult> result(
           new AppResult(profile_, app->app_id(), list_controller_, false));
       TokenizedStringMatch match;
@@ skipping 52 matching lines @@
   RefreshApps();
   if (!update_results_factory_.HasWeakPtrs()) {
     base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&AppSearchProvider::UpdateResults,
                    update_results_factory_.GetWeakPtr()));
   }
 }
 
 }  // namespace app_list