Use PrefChangeRegistrar everywhere

chrome/browser/cocoa/preferences_window_controller.h

Index: chrome/browser/cocoa/preferences_window_controller.h
diff --git a/chrome/browser/cocoa/preferences_window_controller.h b/chrome/browser/cocoa/preferences_window_controller.h
index e7b8383e8b5d2efb70f93dee2c551172d9f025e0..54d4778d58a609ff18480fe03e0223cc42b9d0c8 100644
--- a/chrome/browser/cocoa/preferences_window_controller.h
+++ b/chrome/browser/cocoa/preferences_window_controller.h
@@ -9,6 +9,7 @@
 #include "chrome/browser/options_window.h"
 #include "chrome/browser/prefs/pref_member.h"
 #include "chrome/browser/prefs/pref_set_observer.h"
+#include "chrome/browser/prefs/pref_change_registrar.h"
 
 namespace PreferencesWindowControllerInternal {
 class PrefObserverBridge;
@@ -45,6 +46,7 @@ class ProfileSyncService;
   ProfileSyncService* syncService_;
   scoped_ptr<PreferencesWindowControllerInternal::PrefObserverBridge>
       observer_;  // Watches for pref changes.
+  PrefChangeRegistrar registrar_;  // Manages pref change observer registration.
   scoped_nsobject<WindowSizeAutosaver> sizeSaver_;
   NSView* currentPrefsView_;  // weak ref - current prefs page view.
   scoped_ptr<PreferencesWindowControllerInternal::ManagedPrefsBannerState>