[mac] Send the system spellchecker language to the renderer.

chrome/browser/spellchecker/spellcheck_platform_mac.mm

Index: chrome/browser/spellchecker/spellcheck_platform_mac.mm
diff --git a/chrome/browser/spellchecker/spellcheck_platform_mac.mm b/chrome/browser/spellchecker/spellcheck_platform_mac.mm
index 094b638d1ddf32aa13f4fd5d2667267dd3851ef8..a6d5c9f074e7f35ece8380a0895eff91706c3507 100644
--- a/chrome/browser/spellchecker/spellcheck_platform_mac.mm
+++ b/chrome/browser/spellchecker/spellcheck_platform_mac.mm
@@ -109,6 +109,10 @@ void GetAvailableLanguages(std::vector<std::string>* spellcheck_languages) {
   }
 }
 
+std::string GetSpellCheckerLanguage() {
+  return ConvertLanguageCodeFromMac([SharedSpellChecker() language]);
+}
+
 bool SpellCheckerAvailable() {
   // If this file was compiled, then we know that we are on OS X 10.5 at least
   // and can safely return true here.