Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/webui/options/startup_pages_handler.cc

 // Copyright (c) 2012 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/webui/options/startup_pages_handler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/string_number_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
@@ skipping 112 matching lines @@
 }
 
 void StartupPagesHandler::OnItemsAdded(int start, int length) {
   OnModelChanged();
 }
 
 void StartupPagesHandler::OnItemsRemoved(int start, int length) {
   OnModelChanged();
 }
 
-void StartupPagesHandler::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  if (type == chrome::NOTIFICATION_PREF_CHANGED) {
-    std::string* pref = content::Details<std::string>(details).ptr();
-    if (*pref == prefs::kURLsToRestoreOnStartup) {
-      UpdateStartupPages();
-    } else {
-      NOTREACHED();
-    }
+void StartupPagesHandler::OnPreferenceChanged(PrefServiceBase* service,
+                                              const std::string& pref_name) {
+  if (pref_name == prefs::kURLsToRestoreOnStartup) {
+    UpdateStartupPages();
   } else {
     NOTREACHED();
   }
 }
 
 void StartupPagesHandler::SetStartupPagesToCurrentPages(
     const ListValue* args) {
   startup_custom_pages_table_model_->SetToCurrentlyOpenPages();
 }
 
@@ skipping 105 matching lines @@
 
 void StartupPagesHandler::OnResultChanged(bool default_match_changed) {
   const AutocompleteResult& result = autocomplete_controller_->result();
   ListValue suggestions;
   OptionsUI::ProcessAutocompleteSuggestions(result, &suggestions);
   web_ui()->CallJavascriptFunction(
       "StartupOverlay.updateAutocompleteSuggestions", suggestions);
 }
 
 }  // namespace options