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

chrome/browser/content_settings/content_settings_policy_provider.cc

Index: chrome/browser/content_settings/content_settings_policy_provider.cc
diff --git a/chrome/browser/content_settings/content_settings_policy_provider.cc b/chrome/browser/content_settings/content_settings_policy_provider.cc
index a13ca7724a898b9690856df2a28af3a53cf49f33..b81f4cd0e095a6ad1aa77f95ab42632b6097cbb8 100644
--- a/chrome/browser/content_settings/content_settings_policy_provider.cc
+++ b/chrome/browser/content_settings/content_settings_policy_provider.cc
@@ -277,12 +277,12 @@ void PolicyProvider::RegisterUserPrefs(PrefService* prefs) {
                           PrefService::UNSYNCABLE_PREF);
 }
 
-PolicyProvider::PolicyProvider(HostContentSettingsMap* map,
+PolicyProvider::PolicyProvider(Observer* observer,
                                PrefService* prefs,
                                DefaultProviderInterface* default_provider)
-    : host_content_settings_map_(map),
-      prefs_(prefs),
+    : prefs_(prefs),
       default_provider_(default_provider) {
+  AddObserver(observer);
   ReadManagedContentSettings(false);
 
   pref_change_registrar_.Init(prefs_);
@@ -428,22 +428,11 @@ void PolicyProvider::ClearAllContentSettingsRules(
 
 void PolicyProvider::ShutdownOnUIThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  RemoveAllObserver();
   if (!prefs_)
     return;
   pref_change_registrar_.RemoveAll();
   prefs_ = NULL;
-  host_content_settings_map_ = NULL;
-}
-
-void PolicyProvider::NotifyObservers(
-    const ContentSettingsDetails& details) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  if (host_content_settings_map_ == NULL)
-    return;
-  NotificationService::current()->Notify(
-      chrome::NOTIFICATION_CONTENT_SETTINGS_CHANGED,
-      Source<HostContentSettingsMap>(host_content_settings_map_),
-      Details<const ContentSettingsDetails>(&details));
 }
 
 void PolicyProvider::Observe(int type,