Adds async interface method to PersistentPrefStore.

chrome/common/json_pref_store.h

Index: chrome/common/json_pref_store.h
diff --git a/chrome/common/json_pref_store.h b/chrome/common/json_pref_store.h
index d8da37d08f1c5b34906c1334c7372a6f96a0f6ae..4c2100bca2a8b2c5307e08f278a9ca75949ebf98 100644
--- a/chrome/common/json_pref_store.h
+++ b/chrome/common/json_pref_store.h
@@ -51,15 +51,17 @@ class JsonPrefStore : public PersistentPrefStore,
   virtual void RemoveValue(const std::string& key);
   virtual bool ReadOnly() const;
   virtual PrefReadError ReadPrefs();
-  // todo(altimofeev): move it to the PersistentPrefStore inteface.
-  void ReadPrefs(Delegate* delegate);
+  virtual void ReadPrefsAsync();
+  virtual void GetErrors(PrefReadError* error, bool* is_fatal);
   virtual bool WritePrefs();
   virtual void ScheduleWritePrefs();
   virtual void CommitPendingWrite();
   virtual void ReportValueChanged(const std::string& key);
 
   // This method is called after JSON file has been read. Method takes
-  // ownership of the |value| pointer.
+  // ownership of the |value| pointer. Note, this method is used with
+  // asynchronous file reading, so class exposes it only for the internal needs.
+  // (read: do not call it manually).
   void OnFileRead(Value* value_owned, PrefReadError error, bool no_dir);
 
  private:
@@ -77,7 +79,8 @@ class JsonPrefStore : public PersistentPrefStore,
 
   ObserverList<PrefStore::Observer, true> observers_;
 
-  Delegate* delegate_;
+  PrefReadError error_;
+  bool is_fatal_;
 
   DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
 };