Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/prefs/pref_service.h

Index: chrome/browser/prefs/pref_service.h
diff --git a/chrome/browser/prefs/pref_service.h b/chrome/browser/prefs/pref_service.h
index 82b91676bc53aee3d8127dca81f5b762a89bb77f..7de87d2eadd07f19dc7d14ff3110404385ae27bc 100644
--- a/chrome/browser/prefs/pref_service.h
+++ b/chrome/browser/prefs/pref_service.h
@@ -27,6 +27,8 @@ class PersistentPrefStore;
 class PrefModelAssociator;
 class PrefNotifier;
 class PrefNotifierImpl;
+class PrefObserver;
+class PrefInitObserver;
 class PrefServiceObserver;
 class PrefStore;
 class PrefValueStore;
@@ -271,6 +273,9 @@ class PrefService : public PrefServiceBase, public base::NonThreadSafe {
   // Do not call this after having derived an incognito or per tab pref service.
   void UpdateCommandLinePrefStore(CommandLine* command_line);
 
+  void AddPrefInitObserver(PrefInitObserver* obs);

[Mattias Nissler (ping if slow), 2012/10/30 13:37:07]

needs documentation

+  void RemovePrefInitObserver(PrefInitObserver* obs);
+
  protected:
   // Construct a new pref service. This constructor is what
   // factory methods end up calling and what is used for unit tests.
@@ -300,9 +305,9 @@ class PrefService : public PrefServiceBase, public base::NonThreadSafe {
 
   // PrefServiceBase implementation (protected in base, private here).
   virtual void AddPrefObserver(const char* path,
-                               content::NotificationObserver* obs) OVERRIDE;
+                               PrefObserver* obs) OVERRIDE;
   virtual void RemovePrefObserver(const char* path,
-                                  content::NotificationObserver* obs) OVERRIDE;
+                                  PrefObserver* obs) OVERRIDE;
 
   // Sends notification of a changed preference. This needs to be called by
   // a ScopedUserPrefUpdate if a DictionaryValue or ListValue is changed.