Adds async interface method to PersistentPrefStore.

chrome/common/json_pref_store.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_COMMON_JSON_PREF_STORE_H_
 #define CHROME_COMMON_JSON_PREF_STORE_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "chrome/common/important_file_writer.h"
 #include "chrome/common/persistent_pref_store.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 class DictionaryValue;
 class FilePath;
 class Value;
 
 // A writable PrefStore implementation that is used for user preferences.
 class JsonPrefStore : public PersistentPrefStore,
                       public ImportantFileWriter::DataSerializer {
  public:
-  class Delegate {
-   public:
-    virtual void OnPrefsRead(PrefReadError error, bool no_dir) = 0;
-  };
-
   // |file_message_loop_proxy| is the MessageLoopProxy for a thread on which
   // file I/O can be done.
   JsonPrefStore(const FilePath& pref_filename,
                 base::MessageLoopProxy* file_message_loop_proxy);
   virtual ~JsonPrefStore();
 
   // PrefStore overrides:
   virtual ReadResult GetValue(const std::string& key,
                               const Value** result) const;
   virtual void AddObserver(PrefStore::Observer* observer);
   virtual void RemoveObserver(PrefStore::Observer* observer);
+  virtual bool IsInitializationComplete() const;
 
   // PersistentPrefStore overrides:
   virtual ReadResult GetMutableValue(const std::string& key, Value** result);
   virtual void SetValue(const std::string& key, Value* value);
   virtual void SetValueSilently(const std::string& key, Value* value);
   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(ReadErrorDelegate* error_delegate);
   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:
   // ImportantFileWriter::DataSerializer overrides:
   virtual bool SerializeData(std::string* output);
 
   FilePath path_;
+  scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy_;
 
   scoped_ptr<DictionaryValue> prefs_;
 
   bool read_only_;
 
   // Helper for safely writing pref data.
   ImportantFileWriter writer_;
 
   ObserverList<PrefStore::Observer, true> observers_;
 
-  Delegate* delegate_;
+  scoped_ptr<ReadErrorDelegate> error_delegate_;
+
+  bool initialized_;
 
   DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
 };
 
 #endif  // CHROME_COMMON_JSON_PREF_STORE_H_