Revert of Delete base/prefs and update callers to use components.

components/prefs/pref_change_registrar.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 COMPONENTS_PREFS_PREF_CHANGE_REGISTRAR_H_
-#define COMPONENTS_PREFS_PREF_CHANGE_REGISTRAR_H_
+#ifndef BASE_PREFS_PREF_CHANGE_REGISTRAR_H_
+#define BASE_PREFS_PREF_CHANGE_REGISTRAR_H_
 
 #include <map>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "components/prefs/base_prefs_export.h"
 #include "components/prefs/pref_observer.h"
 
 class PrefService;
 
 // Automatically manages the registration of one or more pref change observers
 // with a PrefStore. Functions much like NotificationRegistrar, but specifically
 // manages observers of preference changes. When the Registrar is destroyed,
 // all registered observers are automatically unregistered with the PrefStore.
-class COMPONENTS_PREFS_EXPORT PrefChangeRegistrar : public PrefObserver {
+class BASE_PREFS_EXPORT PrefChangeRegistrar : public PrefObserver {
  public:
   // You can register this type of callback if you need to know the
   // path of the preference that is changing.
   typedef base::Callback<void(const std::string&)> NamedChangeCallback;
 
   PrefChangeRegistrar();
   virtual ~PrefChangeRegistrar();
 
   // Must be called before adding or removing observers. Can be called more
   // than once as long as the value of |service| doesn't change.
@@ skipping 38 matching lines @@
                                     const std::string& pref_name);
 
   typedef std::map<std::string, NamedChangeCallback> ObserverMap;
 
   ObserverMap observers_;
   PrefService* service_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefChangeRegistrar);
 };
 
-#endif  // COMPONENTS_PREFS_PREF_CHANGE_REGISTRAR_H_
+#endif  // BASE_PREFS_PREF_CHANGE_REGISTRAR_H_