Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/content_settings/content_settings_default_provider.cc

Index: chrome/browser/content_settings/content_settings_default_provider.cc
diff --git a/chrome/browser/content_settings/content_settings_default_provider.cc b/chrome/browser/content_settings/content_settings_default_provider.cc
index 28fd5cd674dd194ade9c0dd0c284349e07a0630f..6a3e97fa252b2cdb65e5cdc343b98e906095970e 100644
--- a/chrome/browser/content_settings/content_settings_default_provider.cc
+++ b/chrome/browser/content_settings/content_settings_default_provider.cc
@@ -276,37 +276,31 @@ void DefaultProvider::ShutdownOnUIThread() {
   prefs_ = NULL;
 }
 
-void DefaultProvider::Observe(int type,
-                              const content::NotificationSource& source,
-                              const content::NotificationDetails& details) {
+void DefaultProvider::OnPreferenceChanged(PrefServiceBase* service,
+                                          const std::string& name) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  if (type == chrome::NOTIFICATION_PREF_CHANGED) {
-    DCHECK_EQ(prefs_, content::Source<PrefService>(source).ptr());
-    if (updating_preferences_)
-      return;
-
-    std::string* name = content::Details<std::string>(details).ptr();
-    if (*name == prefs::kDefaultContentSettings) {
-      ReadDefaultSettings(true);
-    } else if (*name == prefs::kGeolocationDefaultContentSetting) {
-      MigrateObsoleteGeolocationPref();
-      // Return and don't send a notifications. Migrating the obsolete
-      // geolocation pref will change the prefs::kDefaultContentSettings and
-      // cause the notification to be fired.
-      return;
-    } else {
-      NOTREACHED() << "Unexpected preference observed";
-      return;
-    }
-
-    NotifyObservers(ContentSettingsPattern(),
-                    ContentSettingsPattern(),
-                    CONTENT_SETTINGS_TYPE_DEFAULT,
-                    std::string());
+  DCHECK_EQ(prefs_, service);
+  if (updating_preferences_)
+    return;
+
+  if (name == prefs::kDefaultContentSettings) {
+    ReadDefaultSettings(true);
+  } else if (name == prefs::kGeolocationDefaultContentSetting) {
+    MigrateObsoleteGeolocationPref();
+    // Return and don't send a notifications. Migrating the obsolete
+    // geolocation pref will change the prefs::kDefaultContentSettings and
+    // cause the notification to be fired.
+    return;
   } else {
-    NOTREACHED() << "Unexpected notification";
+    NOTREACHED() << "Unexpected preference observed";
+    return;
   }
+
+  NotifyObservers(ContentSettingsPattern(),
+                  ContentSettingsPattern(),
+                  CONTENT_SETTINGS_TYPE_DEFAULT,
+                  std::string());
 }
 
 void DefaultProvider::ReadDefaultSettings(bool overwrite) {