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

components/prefs/pref_value_map.h

Index: components/prefs/pref_value_map.h
diff --git a/components/prefs/pref_value_map.h b/components/prefs/pref_value_map.h
index 988a63891976904620d5d1238e361a184e5318a0..56c32b0d9e89bd3e3bbc12ab06618c21fe1730da 100644
--- a/components/prefs/pref_value_map.h
+++ b/components/prefs/pref_value_map.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_PREFS_PREF_VALUE_MAP_H_
-#define COMPONENTS_PREFS_PREF_VALUE_MAP_H_
+#ifndef BASE_PREFS_PREF_VALUE_MAP_H_
+#define BASE_PREFS_PREF_VALUE_MAP_H_
 
 #include <string>
 #include <vector>
@@ -18,7 +18,7 @@
 }
 
 // A generic string to value map used by the PrefStore implementations.
-class COMPONENTS_PREFS_EXPORT PrefValueMap {
+class BASE_PREFS_EXPORT PrefValueMap {
  public:
   using Map = base::ScopedPtrHashMap<std::string, scoped_ptr<base::Value>>;
   using iterator = Map::iterator;
@@ -88,4 +88,4 @@
   DISALLOW_COPY_AND_ASSIGN(PrefValueMap);
 };
 
-#endif  // COMPONENTS_PREFS_PREF_VALUE_MAP_H_
+#endif  // BASE_PREFS_PREF_VALUE_MAP_H_