DOMUI prefs: Fix a race condition in pushing search engine information to DOMUI

chrome/browser/dom_ui/search_engine_manager_handler.cc

 // Copyright (c) 2010 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/dom_ui/search_engine_manager_handler.h"
 
 #include "app/l10n_util.h"
 #include "base/callback.h"
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/search_engines/keyword_editor_controller.h"
 #include "chrome/browser/search_engines/template_url_table_model.h"
 #include "chrome/common/url_constants.h"
 #include "grit/generated_resources.h"
 #include "grit/locale_settings.h"
 
 SearchEngineManagerHandler::SearchEngineManagerHandler() {
 }
 
 SearchEngineManagerHandler::~SearchEngineManagerHandler() {
   if (controller_.get() && controller_->table_model())
     controller_->table_model()->SetObserver(NULL);
 }
 
 void SearchEngineManagerHandler::Initialize() {
   controller_.reset(new KeywordEditorController(dom_ui_->GetProfile()));
-  controller_->table_model()->SetObserver(this);
+  if (controller_.get()) {
+    controller_->table_model()->SetObserver(this);
+    OnModelChanged();
+  }
 }
 
 void SearchEngineManagerHandler::GetLocalizedValues(
     DictionaryValue* localized_strings) {
   DCHECK(localized_strings);
 
   localized_strings->SetString("searchEngineManagerPage",
       l10n_util::GetStringUTF16(IDS_SEARCH_ENGINES_EDITOR_WINDOW_TITLE));
   localized_strings->SetString("searchEngineTableNameHeader",
       l10n_util::GetStringUTF16(IDS_SEARCH_ENGINES_EDITOR_DESCRIPTION_COLUMN));
@@ skipping 12 matching lines @@
 void SearchEngineManagerHandler::RegisterMessages() {
   dom_ui_->RegisterMessageCallback(
       "managerSetDefaultSearchEngine",
       NewCallback(this, &SearchEngineManagerHandler::SetDefaultSearchEngine));
   dom_ui_->RegisterMessageCallback(
       "removeSearchEngine",
       NewCallback(this, &SearchEngineManagerHandler::RemoveSearchEngine));
 }
 
 void SearchEngineManagerHandler::OnModelChanged() {
+  if (!controller_->loaded())
+    return;
+
   ListValue engine_list;
 
   // Find the default engine.
   const TemplateURL* default_engine =
       controller_->url_model()->GetDefaultSearchProvider();
   int default_index = controller_->table_model()->IndexOfTemplateURL(
       default_engine);
 
   // Add the first group (default search engine options).
   engine_list.Append(CreateDictionaryForHeading(0));
@@ skipping 79 matching lines @@
   if (!ExtractIntegerValue(value, &index)) {
     NOTREACHED();
     return;
   }
   if (index < 0 || index >= controller_->table_model()->RowCount())
     return;
 
   if (controller_->CanRemove(controller_->GetTemplateURL(index)))
     controller_->RemoveTemplateURL(index);
 }