MD Settings: add "Use system title bar and borders"

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 3e68105a544fbe582117ef14c96542870d7fc074..ac25fe3307f05839f4d76491aa8a16e726612238 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1040,9 +1040,11 @@ const char kShowUpdatePromotionInfoBar[] =
     "browser.show_update_promotion_info_bar";
 #endif
 
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 // Boolean that is false if we should show window manager decorations.  If
 // true, we draw a custom chrome frame (thicker title bar and blue border).
 const char kUseCustomChromeFrame[] = "browser.custom_chrome_frame";
+#endif
 
 const char kBackShortcutBubbleShownCount[] =
     "browser.back_shortcut_bubble_shown_count";