The UI language rather than the locale is now used to pick Chrome's language ...

base/i18n/rtl.h

Index: base/i18n/rtl.h
===================================================================
--- base/i18n/rtl.h	(revision 66182)
+++ base/i18n/rtl.h	(working copy)
@@ -6,6 +6,8 @@
 #define BASE_I18N_RTL_H_
 #pragma once
 
+#include <string>
+
 #include "base/compiler_specific.h"
 #include "base/string16.h"
 #include "build/build_config.h"
@@ -29,11 +31,6 @@
   LEFT_TO_RIGHT,
 };
 
-#if defined(OS_WIN)
-// Get language and region from the OS. Used by Chrome Frame.
-void GetLanguageAndRegionFromOS(std::string* lang, std::string* region);
-#endif
-
 // Get the locale that the currently running process has been configured to use.
 // The return value is of the form language[-country] (e.g., en-US) where the
 // language is the 2 or 3 letter code from ISO-639.