Revert of Move base/prefs to components/prefs

base/prefs/pref_notifier.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.
 
-// TODO(brettw) remove this forwarding header when prefs is completely moved to
-// components.
-#include "components/prefs/pref_notifier.h"
+#ifndef BASE_PREFS_PREF_NOTIFIER_H_
+#define BASE_PREFS_PREF_NOTIFIER_H_
+
+#include <string>
+
+// 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() {}
+
+  // Sends out a change notification for the preference identified by
+  // |pref_name|.
+  virtual void OnPreferenceChanged(const std::string& pref_name) = 0;
+
+  // Broadcasts the intialization completed notification.
+  virtual void OnInitializationCompleted(bool succeeded) = 0;
+};
+
+#endif  // BASE_PREFS_PREF_NOTIFIER_H_