Apply the namespace migration for "selectfile.last_directory" user-pref as well.

chrome/browser/chromeos/preferences.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_PREFERENCES_H_
 #define CHROME_BROWSER_CHROMEOS_PREFERENCES_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 106 matching lines @@
   DoublePrefMember screen_magnifier_scale_;
   IntegerPrefMember speed_factor_;
   IntegerPrefMember mouse_sensitivity_;
   IntegerPrefMember touchpad_sensitivity_;
   BooleanPrefMember primary_mouse_button_right_;
   BooleanPrefMember use_24hour_clock_;
   BooleanPrefMember disable_drive_;
   BooleanPrefMember disable_drive_over_cellular_;
   BooleanPrefMember disable_drive_hosted_files_;
   FilePathPrefMember download_default_directory_;
+  FilePathPrefMember select_file_last_directory_;
 
   // Input method preferences.
   StringPrefMember preferred_languages_;
   StringPrefMember preload_engines_;
   StringPrefMember current_input_method_;
   StringPrefMember previous_input_method_;
   StringPrefMember filtered_extension_imes_;
 
   BooleanPrefMember chewing_boolean_prefs_[
       language_prefs::kNumChewingBooleanPrefs];
@@ skipping 40 matching lines @@
   BooleanPrefMember power_use_audio_activity_;
   BooleanPrefMember power_use_video_activity_;
   DoublePrefMember power_presentation_idle_delay_factor_;
 
   DISALLOW_COPY_AND_ASSIGN(Preferences);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_PREFERENCES_H_