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

components/prefs/scoped_user_pref_update.h

Index: components/prefs/scoped_user_pref_update.h
diff --git a/components/prefs/scoped_user_pref_update.h b/components/prefs/scoped_user_pref_update.h
index bfcdb3f55744b669236a0159350b4d64ea5038f6..5a2c3aec9649e0203593e0b587efad90f53b3d02 100644
--- a/components/prefs/scoped_user_pref_update.h
+++ b/components/prefs/scoped_user_pref_update.h
@@ -5,8 +5,8 @@
 // A helper class that assists preferences in firing notifications when lists
 // or dictionaries are changed.
 
-#ifndef COMPONENTS_PREFS_SCOPED_USER_PREF_UPDATE_H_
-#define COMPONENTS_PREFS_SCOPED_USER_PREF_UPDATE_H_
+#ifndef BASE_PREFS_SCOPED_USER_PREF_UPDATE_H_
+#define BASE_PREFS_SCOPED_USER_PREF_UPDATE_H_
 
 #include <string>
 
@@ -31,8 +31,7 @@
 // We need this base class mostly for making it a friend of PrefService
 // and getting access to PrefService::GetMutableUserPref and
 // PrefService::ReportUserPrefChanged.
-class COMPONENTS_PREFS_EXPORT ScopedUserPrefUpdateBase
-    : public base::NonThreadSafe {
+class BASE_PREFS_EXPORT ScopedUserPrefUpdateBase : public base::NonThreadSafe {
  protected:
   ScopedUserPrefUpdateBase(PrefService* service, const std::string& path);
 
@@ -106,4 +105,4 @@
 typedef ScopedUserPrefUpdate<base::ListValue, base::Value::TYPE_LIST>
     ListPrefUpdate;
 
-#endif  // COMPONENTS_PREFS_SCOPED_USER_PREF_UPDATE_H_
+#endif  // BASE_PREFS_SCOPED_USER_PREF_UPDATE_H_