Adds async interface method to PersistentPrefStore.

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 f9d415f3ec3e9567b575c9bdedc0d1d0ce587b5a..8e5405f3e7572becde3ccba26e58bf9a416b03e3 100644
--- a/chrome/browser/prefs/pref_service.h
+++ b/chrome/browser/prefs/pref_service.h
@@ -41,7 +41,7 @@ class PrefServiceDelegate {
 };
 
 class PrefService : public base::NonThreadSafe,
-                    public JsonPrefStore::Delegate {
+                    public PrefStore::Observer {
  public:
   // A helper class to store all the information associated with a preference.
   class Preference {
@@ -120,10 +120,6 @@ class PrefService : public base::NonThreadSafe,
     DISALLOW_COPY_AND_ASSIGN(Preference);
   };
 
-  // JsonPrefStore::Delegate implementaion.
-  virtual void OnPrefsRead(PersistentPrefStore::PrefReadError error,
-                           bool no_dir);
-
   // Factory method that creates a new instance of a PrefService with the
   // applicable PrefStores. The |pref_filename| points to the user preference
   // file. The |profile| is the one to which these preferences apply; it may be
@@ -263,6 +259,10 @@ class PrefService : public base::NonThreadSafe,
               DefaultPrefStore* default_store,
               PrefServiceDelegate* delegate);
 
+  // PrefStore::Observer implementation:
+  virtual void OnPrefValueChanged(const std::string&) {}
+  virtual void OnInitializationCompleted();
+
   // The PrefNotifier handles registering and notifying preference observers.
   // It is created and owned by this PrefService. Subclasses may access it for
   // unit testing.