Utilizing FirebaseAuth#setLanguageCode to localize verification emails & SMS messages. (#946)

Author: Jacob Stimes

auth/src/main/java/com/firebase/ui/auth/AuthUI.java

@@ -16,6 +16,7 @@
 
 import android.app.Activity;
 import android.content.Intent;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -57,6 +58,7 @@
 import java.util.HashSet;
 import java.util.IdentityHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Set;
 
 /**
@@ -146,6 +148,11 @@ public class AuthUI {
     private AuthUI(FirebaseApp app) {
         mApp = app;
         mAuth = FirebaseAuth.getInstance(mApp);
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            mAuth.setLanguageCode(Locale.getDefault().getLanguage());
+        } else {
+            mAuth.setLanguageCode(Locale.getDefault().toLanguageTag());
+        }
     }
 
     /**