Delete base/prefs and update callers to use components.

components/prefs/pref_service_factory.cc

Index: components/prefs/pref_service_factory.cc
diff --git a/components/prefs/pref_service_factory.cc b/components/prefs/pref_service_factory.cc
index e8b9bb448786ee7c456cd454c1dec3966651003c..663695da98895e0b18f7bd4297fc261e71bff5eb 100644
--- a/components/prefs/pref_service_factory.cc
+++ b/components/prefs/pref_service_factory.cc
@@ -13,8 +13,6 @@
 #include "components/prefs/pref_service.h"
 #include "components/prefs/pref_value_store.h"
 
-namespace base {
-
 namespace {
 
 // Do-nothing default implementation.
@@ -61,5 +59,3 @@ scoped_ptr<PrefService> PrefServiceFactory::Create(
                       async_));
   return pref_service;
 }
-
-}  // namespace base