Clean up pref change notification handling.

chrome/browser/prefs/pref_notifier.h

 // Copyright (c) 2010 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_BROWSER_PREFS_PREF_NOTIFIER_H_
 #define CHROME_BROWSER_PREFS_PREF_NOTIFIER_H_
 #pragma once
 
 #include <string>
-#include <vector>
 
-#include "base/hash_tables.h"
-#include "base/non_thread_safe.h"
-#include "base/observer_list.h"
-#include "chrome/common/notification_observer.h"
-#include "chrome/common/notification_registrar.h"
+// Delegate interface used by PrefValueStore to notify its owner about changes
+// to the preference values.
+// TODO(mnissler, danno): Move this declaration to pref_value_store.h once we've
+// cleaned up all public uses of this interface.
+class PrefNotifier {
+ public:
+  virtual ~PrefNotifier() {}
 
-class NotificationObserver;
-class PrefService;
-class PrefValueStore;
-class Value;
+  // Sends out a change notification for the preference identified by
+  // |pref_name|.
+  virtual void OnPreferenceChanged(const std::string& pref_name) = 0;
 
-// Registers observers for particular preferences and sends notifications when
-// preference values or sources (i.e., which preference layer controls the
-// preference) change.
-class PrefNotifier : public NonThreadSafe,
-                     public NotificationObserver {
- public:
-  // PrefStores must be listed here in order from highest to lowest priority.
-  //   MANAGED_PLATFORM contains all managed preference values that are
-  //       provided by a platform-specific policy mechanism (e.g. Windows
-  //       Group Policy).
-  //   DEVICE_MANAGEMENT contains all managed preference values supplied
-  //       by the device management server (cloud policy).
-  //   EXTENSION contains preference values set by extensions.
-  //   COMMAND_LINE contains preference values set by command-line switches.
-  //   USER contains all user-set preference values.
-  //   RECOMMENDED contains all recommended (policy) preference values.
-  //   DEFAULT contains all application default preference values.
-  // This enum is kept in pref_notifier.h rather than pref_value_store.h in
-  // order to minimize additional headers needed by the *PrefStore files.
-  enum PrefStoreType {
-    // INVALID_STORE is not associated with an actual PrefStore but used as
-    // an invalid marker, e.g. as a return value.
-    INVALID_STORE = -1,
-    MANAGED_PLATFORM_STORE = 0,
-    DEVICE_MANAGEMENT_STORE,
-    EXTENSION_STORE,
-    COMMAND_LINE_STORE,
-    USER_STORE,
-    RECOMMENDED_STORE,
-    DEFAULT_STORE,
-    PREF_STORE_TYPE_MAX = DEFAULT_STORE
-  };
-
-  // The |service| with which this notifier is associated will be sent as the
-  // source of any notifications.
-  PrefNotifier(PrefService* service, PrefValueStore* value_store);
-
-  virtual ~PrefNotifier();
-
-  // For the given pref_name, fire any observer of the pref if the effective
-  // value of the pref or the store controlling its value has changed, been
-  // added, or been removed (but not if it's re-setting the same value it had
-  // already). |new_store| should be the PrefStoreType of the store reporting
-  // the change.
-  void OnPreferenceSet(const char* pref_name,
-                       PrefNotifier::PrefStoreType new_store);
-
-  // Convenience method to be called when a preference is set in the
-  // USER_STORE. See OnPreferenceSet().
-  void OnUserPreferenceSet(const char* pref_name);
-
-  // For the given pref_name, fire any observer of the pref. Virtual so it can
-  // be mocked for unit testing.
-  virtual void FireObservers(const char* path);
-
-  // If the pref at the given path changes, we call the observer's Observe
-  // method with PREF_CHANGED.
-  void AddPrefObserver(const char* path, NotificationObserver* obs);
-  void RemovePrefObserver(const char* path, NotificationObserver* obs);
-
- protected:
-  // A map from pref names to a list of observers.  Observers get fired in the
-  // order they are added. These should only be accessed externally for unit
-  // testing.
-  typedef ObserverList<NotificationObserver> NotificationObserverList;
-  typedef base::hash_map<std::string, NotificationObserverList*>
-      PrefObserverMap;
-  const PrefObserverMap* pref_observers() { return &pref_observers_; }
-
- private:
-  // Weak references.
-  PrefService* pref_service_;
-  PrefValueStore* pref_value_store_;
-
-  NotificationRegistrar registrar_;
-
-  PrefObserverMap pref_observers_;
-
-  // Called after a policy refresh to notify relevant preference observers.
-  // |changed_prefs_paths| is the vector of preference paths changed by the
-  // policy update. It is passed by value and not reference because
-  // this method is called asynchronously as a callback from another thread.
-  // Copying the vector guarantees that the vector's lifecycle spans the
-  // method's invocation.
-  void FireObserversForRefreshedManagedPrefs(
-      std::vector<std::string> changed_prefs_paths);
-
-  // NotificationObserver methods:
-  virtual void Observe(NotificationType type,
-                       const NotificationSource& source,
-                       const NotificationDetails& details);
-
-  DISALLOW_COPY_AND_ASSIGN(PrefNotifier);
+  // Broadcasts the intialization completed notification.
+  virtual void OnInitializationCompleted() = 0;
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_NOTIFIER_H_