Move scoped_temp_dir from base to base/files

Also add to base namespace.

BUG=

Review URL: https://codereview.chromium.org/11359217

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168281 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/prefs/pref_service_unittest.cc b/chrome/browser/prefs/pref_service_unittest.cc
index 883f50a..29fa1dd3 100644
--- a/chrome/browser/prefs/pref_service_unittest.cc
+++ b/chrome/browser/prefs/pref_service_unittest.cc
@@ -6,12 +6,12 @@
 
 #include "base/command_line.h"
 #include "base/file_util.h"
+#include "base/files/scoped_temp_dir.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/prefs/json_pref_store.h"
 #include "base/prefs/public/pref_change_registrar.h"
 #include "base/prefs/testing_pref_store.h"
-#include "base/scoped_temp_dir.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/policy/configuration_policy_pref_store.h"
@@ -301,7 +301,7 @@
   }
 
   // The path to temporary directory used to contain the test operations.
-  ScopedTempDir temp_dir_;
+  base::ScopedTempDir temp_dir_;
   // The path to the directory where the test data is stored.
   FilePath data_dir_;
   // A message loop that we can use as the file thread message loop.