Use PrefChangeRegistrar everywhere

chrome/browser/gtk/options/general_page_gtk.cc

Index: chrome/browser/gtk/options/general_page_gtk.cc
diff --git a/chrome/browser/gtk/options/general_page_gtk.cc b/chrome/browser/gtk/options/general_page_gtk.cc
index fb4db2b4beb8f43fea6da303a1552fb66e76c16e..734ee8c753b6d47b83120e29baa360e28e0b609d 100644
--- a/chrome/browser/gtk/options/general_page_gtk.cc
+++ b/chrome/browser/gtk/options/general_page_gtk.cc
@@ -95,8 +95,9 @@ GeneralPageGtk::GeneralPageGtk(Profile* profile)
       InitDefaultBrowserGroup(), false);
 #endif
 
-  profile->GetPrefs()->AddPrefObserver(prefs::kRestoreOnStartup, this);
-  profile->GetPrefs()->AddPrefObserver(prefs::kURLsToRestoreOnStartup, this);
+  registrar_.Init(profile->GetPrefs());
+  registrar_.Add(prefs::kRestoreOnStartup, this);
+  registrar_.Add(prefs::kURLsToRestoreOnStartup, this);
 
   new_tab_page_is_home_page_.Init(prefs::kHomePageIsNewTabPage,
       profile->GetPrefs(), this);
@@ -108,10 +109,6 @@ GeneralPageGtk::GeneralPageGtk(Profile* profile)
 }
 
 GeneralPageGtk::~GeneralPageGtk() {
-  profile()->GetPrefs()->RemovePrefObserver(prefs::kRestoreOnStartup, this);
-  profile()->GetPrefs()->RemovePrefObserver(
-      prefs::kURLsToRestoreOnStartup, this);
-
   if (template_url_model_)
     template_url_model_->RemoveObserver(this);