Revert of Move base/prefs to components/prefs

base/prefs/default_pref_store.h

Index: base/prefs/default_pref_store.h
diff --git a/base/prefs/default_pref_store.h b/base/prefs/default_pref_store.h
index e590bf805dda0256836e04ec13eaa7ff160180dc..ac5364d2bb166e407d4b3ca7671b499c79c4f85e 100644
--- a/base/prefs/default_pref_store.h
+++ b/base/prefs/default_pref_store.h
@@ -2,6 +2,52 @@
 // 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/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/prefs/base_prefs_export.h"
+#include "base/prefs/pref_store.h"
+#include "base/prefs/pref_value_map.h"
+#include "base/values.h"
+
+// Used within a PrefRegistry to keep track of default preference values.
+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;
+  bool HasObservers() const override;
+
+  // Sets a |value| for |key|. Should only be called if a value has not been
+  // set yet; otherwise call ReplaceDefaultValue().
+  void SetDefaultValue(const std::string& key, scoped_ptr<base::Value> value);
+
+  // Replaces the the value for |key| with a new value. Should only be called
+  // if a value has alreday been set; otherwise call SetDefaultValue().
+  void ReplaceDefaultValue(const std::string& key,
+                           scoped_ptr<base::Value> value);
+
+  const_iterator begin() const;
+  const_iterator end() const;
+
+ private:
+  ~DefaultPrefStore() override;
+
+  PrefValueMap prefs_;
+
+  base::ObserverList<PrefStore::Observer, true> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultPrefStore);
+};
+
+#endif  // BASE_PREFS_DEFAULT_PREF_STORE_H_