Make the hcsm and its providers communicate via an observer interface.

chrome/browser/content_settings/content_settings_pref_provider.cc

Index: chrome/browser/content_settings/content_settings_pref_provider.cc
diff --git a/chrome/browser/content_settings/content_settings_pref_provider.cc b/chrome/browser/content_settings/content_settings_pref_provider.cc
index e6c7c90fc9c84d76dba6edd87736e93321e246c6..e2fc530eb9bf8153c4581757614b02c355416b89 100644
--- a/chrome/browser/content_settings/content_settings_pref_provider.cc
+++ b/chrome/browser/content_settings/content_settings_pref_provider.cc
@@ -384,14 +384,14 @@ void PrefProvider::RegisterUserPrefs(PrefService* prefs) {
                                 PrefService::UNSYNCABLE_PREF);
 }
 
-PrefProvider::PrefProvider(HostContentSettingsMap* map,
+PrefProvider::PrefProvider(Observer* observer,
                            PrefService* prefs,
                            bool incognito)
   : prefs_(prefs),
-    host_content_settings_map_(map),
     is_incognito_(incognito),
     updating_preferences_(false) {
   DCHECK(prefs_);
+  AddObserver(observer);
   if (!is_incognito_) {
     // Migrate obsolete preferences.
     MigrateObsoletePerhostPref();
@@ -566,7 +566,7 @@ void PrefProvider::Observe(
     int type,
     const NotificationSource& source,
     const NotificationDetails& details) {
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   if (type == chrome::NOTIFICATION_PREF_CHANGED) {
     DCHECK_EQ(prefs_, Source<PrefService>(source).ptr());
@@ -897,22 +897,12 @@ void PrefProvider::CanonicalizeContentSettingsExceptions(
   }
 }
 
-void PrefProvider::NotifyObservers(
-    const ContentSettingsDetails& details) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK(host_content_settings_map_);
-  NotificationService::current()->Notify(
-      chrome::NOTIFICATION_CONTENT_SETTINGS_CHANGED,
-      Source<HostContentSettingsMap>(host_content_settings_map_),
-      Details<const ContentSettingsDetails>(&details));
-}
-
 void PrefProvider::ShutdownOnUIThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(prefs_);
+  RemoveAllObserver();
   pref_change_registrar_.RemoveAll();
   prefs_ = NULL;
-  host_content_settings_map_ = NULL;
 }
 
 void PrefProvider::MigrateObsoletePerhostPref() {