Allow offset for secondary display position in chrome://settings/display.

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 127 matching lines @@
       language_prefs::kNumMozcMultipleChoicePrefs];
   IntegerPrefMember mozc_integer_prefs_[
       language_prefs::kNumMozcIntegerPrefs];
   BooleanPrefMember xkb_auto_repeat_enabled_;
   IntegerPrefMember xkb_auto_repeat_delay_pref_;
   IntegerPrefMember xkb_auto_repeat_interval_pref_;
 
   BooleanPrefMember enable_screen_lock_;
 
   IntegerPrefMember secondary_display_layout_;
+  IntegerPrefMember secondary_display_offset_;
 
   BooleanPrefMember enable_drm_;
 
   DISALLOW_COPY_AND_ASSIGN(Preferences);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_PREFERENCES_H_