Use PrefChangeRegistrar everywhere

chrome/browser/host_zoom_map.cc

Index: chrome/browser/host_zoom_map.cc
diff --git a/chrome/browser/host_zoom_map.cc b/chrome/browser/host_zoom_map.cc
index 0c1d96a22c998f0f2a22f7a90dd60dc92130e489..cb67a04477ab33e2f39a42d3c6259553aa37bc9e 100644
--- a/chrome/browser/host_zoom_map.cc
+++ b/chrome/browser/host_zoom_map.cc
@@ -27,8 +27,10 @@ HostZoomMap::HostZoomMap(Profile* profile)
   // Don't observe pref changes (e.g. from sync) in Incognito; once we create
   // the incognito window it should have no further connection to the main
   // profile/prefs.
-  if (!profile_->IsOffTheRecord())
-    profile_->GetPrefs()->AddPrefObserver(prefs::kPerHostZoomLevels, this);
+  if (!profile_->IsOffTheRecord()) {
+    pref_change_registrar_.Init(profile_->GetPrefs());
+    pref_change_registrar_.Add(prefs::kPerHostZoomLevels, this);
+  }
 }
 
 void HostZoomMap::Load() {
@@ -128,7 +130,7 @@ void HostZoomMap::Shutdown() {
                     NotificationType::PROFILE_DESTROYED,
                     Source<Profile>(profile_));
   if (!profile_->IsOffTheRecord())
-    profile_->GetPrefs()->RemovePrefObserver(prefs::kPerHostZoomLevels, this);
+    pref_change_registrar_.RemoveAll();
   profile_ = NULL;
 }