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

components/prefs/default_pref_store.h

 // Copyright (c) 2012 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_DEFAULT_PREF_STORE_H_
-#define COMPONENTS_PREFS_DEFAULT_PREF_STORE_H_
+#ifndef BASE_PREFS_DEFAULT_PREF_STORE_H_
+#define BASE_PREFS_DEFAULT_PREF_STORE_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/values.h"
 #include "components/prefs/base_prefs_export.h"
 #include "components/prefs/pref_store.h"
 #include "components/prefs/pref_value_map.h"
 
 // Used within a PrefRegistry to keep track of default preference values.
-class COMPONENTS_PREFS_EXPORT DefaultPrefStore : public PrefStore {
+class BASE_PREFS_EXPORT DefaultPrefStore : public PrefStore {
  public:
   typedef PrefValueMap::const_iterator const_iterator;
 
   DefaultPrefStore();
 
   // PrefStore implementation:
   bool GetValue(const std::string& key,
                 const base::Value** result) const override;
   void AddObserver(PrefStore::Observer* observer) override;
   void RemoveObserver(PrefStore::Observer* observer) override;
@@ skipping 14 matching lines @@
  private:
   ~DefaultPrefStore() override;
 
   PrefValueMap prefs_;
 
   base::ObserverList<PrefStore::Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(DefaultPrefStore);
 };
 
-#endif  // COMPONENTS_PREFS_DEFAULT_PREF_STORE_H_
+#endif  // BASE_PREFS_DEFAULT_PREF_STORE_H_