Draft change to use base::Closure instead of PrefObserver in PrefChangeRegistrar.

chrome/browser/prefs/pref_service.cc

Index: chrome/browser/prefs/pref_service.cc
diff --git a/chrome/browser/prefs/pref_service.cc b/chrome/browser/prefs/pref_service.cc
index 40ae0d30b0261aae0a69afaa4011fde313392145..3df46209a824893bdbd6764a2415d7f7afcef7b5 100644
--- a/chrome/browser/prefs/pref_service.cc
+++ b/chrome/browser/prefs/pref_service.cc
@@ -769,11 +769,12 @@ const ListValue* PrefService::GetList(const char* path) const {
   return static_cast<const ListValue*>(value);
 }
 
-void PrefService::AddPrefObserver(const char* path, PrefObserver* obs) {
+void PrefService::AddPrefObserver(const char* path, const base::Closure& obs) {
   pref_notifier_->AddPrefObserver(path, obs);
 }
 
-void PrefService::RemovePrefObserver(const char* path, PrefObserver* obs) {
+void PrefService::RemovePrefObserver(const char* path,
+                                     const base::Closure& obs) {
   pref_notifier_->RemovePrefObserver(path, obs);
 }