Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/views/location_bar/location_bar_view.cc

Index: chrome/browser/ui/views/location_bar/location_bar_view.cc
diff --git a/chrome/browser/ui/views/location_bar/location_bar_view.cc b/chrome/browser/ui/views/location_bar/location_bar_view.cc
index fc4665c51bd08c30bd124cfb6d9ccf9337962cfd..d8dd138f6ec9e346cdba6fe1e1ad22c0d513cfbc 100644
--- a/chrome/browser/ui/views/location_bar/location_bar_view.cc
+++ b/chrome/browser/ui/views/location_bar/location_bar_view.cc
@@ -1576,13 +1576,6 @@ void LocationBarView::Observe(int type,
                               const content::NotificationSource& source,
                               const content::NotificationDetails& details) {
   switch (type) {
-    case chrome::NOTIFICATION_PREF_CHANGED: {
-      std::string* name = content::Details<std::string>(details).ptr();
-      if (*name == prefs::kEditBookmarksEnabled)
-        Update(NULL);
-      break;
-    }
-
     case chrome::NOTIFICATION_EXTENSION_LOCATION_BAR_UPDATED: {
       // Only update if the updated action box was for the active tab contents.
       WebContents* target_tab = content::Details<WebContents>(details).ptr();
@@ -1596,6 +1589,12 @@ void LocationBarView::Observe(int type,
   }
 }
 
+void LocationBarView::OnPreferenceChanged(PrefServiceBase* service,
+                                          const std::string& pref_name) {
+  if (pref_name == prefs::kEditBookmarksEnabled)
+    Update(NULL);
+}
+
 int LocationBarView::GetInternalHeight(bool use_preferred_size) {
   int total_height =
       use_preferred_size ? GetPreferredSize().height() : height();