Return optional for telephone number region name for the unknown case to be localized.

app/src/main/java/org/thoughtcrime/securesms/database/loaders/CountryListLoader.java

@@ -29,7 +29,7 @@ public final class CountryListLoader extends AsyncTaskLoader<ArrayList<Map<Strin
 
     for (String region : regions) {
       Map<String, String> data = new HashMap<>(2);
-      data.put("country_name", PhoneNumberFormatter.getRegionDisplayName(region));
+      data.put("country_name", PhoneNumberFormatter.getRegionDisplayNameLegacy(region));
       data.put("country_code", "+" +PhoneNumberUtil.getInstance().getCountryCodeForRegion(region));
       results.add(data);
     }

app/src/main/java/org/thoughtcrime/securesms/delete/DeleteAccountRepository.java

@@ -29,7 +29,7 @@ class DeleteAccountRepository {
   }
 
   @NonNull String getRegionDisplayName(@NonNull String region) {
-    return PhoneNumberFormatter.getRegionDisplayName(region);
+    return PhoneNumberFormatter.getRegionDisplayName(region).or("");
   }
 
   int getRegionCountryCode(@NonNull String region) {
@@ -73,7 +73,7 @@ class DeleteAccountRepository {
   }
 
   private static @NonNull Country getCountryForRegion(@NonNull String region) {
-    return new Country(PhoneNumberFormatter.getRegionDisplayName(region),
+    return new Country(PhoneNumberFormatter.getRegionDisplayName(region).or(""),
                        PhoneNumberUtil.getInstance().getCountryCodeForRegion(region),
                        region);
   }

app/src/main/java/org/thoughtcrime/securesms/registration/viewmodel/NumberViewState.java

@@ -58,7 +58,7 @@ public final class NumberViewState implements Parcelable {
     }
 
     String regionCode = util.getRegionCodeForCountryCode(countryCode);
-    return PhoneNumberFormatter.getRegionDisplayName(regionCode);
+    return PhoneNumberFormatter.getRegionDisplayNameLegacy(regionCode);
   }
 
   /**
@@ -70,7 +70,7 @@ public final class NumberViewState implements Parcelable {
       String                  regionCode  = util.getRegionCodeForNumber(phoneNumber);
 
       if (regionCode != null) {
-        return PhoneNumberFormatter.getRegionDisplayName(regionCode);
+        return PhoneNumberFormatter.getRegionDisplayNameLegacy(regionCode);
       }
 
     } catch (NumberParseException e) {

libsignal/service/src/main/java/org/whispersystems/signalservice/api/util/PhoneNumberFormatter.java

@@ -12,6 +12,8 @@ import com.google.i18n.phonenumbers.PhoneNumberUtil.PhoneNumberFormat;
 import com.google.i18n.phonenumbers.Phonenumber.PhoneNumber;
 
 import org.whispersystems.libsignal.logging.Log;
+import org.whispersystems.libsignal.util.guava.Optional;
+import org.whispersystems.signalservice.internal.util.Util;
 
 import java.util.Locale;
 import java.util.regex.Pattern;
@@ -113,9 +115,22 @@ public class PhoneNumberFormatter {
     }
   }
 
-  public static String getRegionDisplayName(String regionCode) {
-    return (regionCode == null || regionCode.equals("ZZ") || regionCode.equals(PhoneNumberUtil.REGION_CODE_FOR_NON_GEO_ENTITY))
-        ? "Unknown country" : new Locale("", regionCode).getDisplayCountry(Locale.getDefault());
+  /**
+   * @deprecated Use {@link #getRegionDisplayName} as it can be localized when the region is not found.
+   */
+  @Deprecated
+  public static String getRegionDisplayNameLegacy(String regionCode) {
+    return getRegionDisplayName(regionCode).or("Unknown country");
+  }
+
+  public static Optional<String> getRegionDisplayName(String regionCode) {
+    if (regionCode != null && !regionCode.equals("ZZ") && !regionCode.equals(PhoneNumberUtil.REGION_CODE_FOR_NON_GEO_ENTITY)) {
+      String displayCountry = new Locale("", regionCode).getDisplayCountry(Locale.getDefault());
+      if (!Util.isEmpty(displayCountry)) {
+        return Optional.of(displayCountry);
+      }
+    }
+    return Optional.absent();
   }
 
   public static String formatE164(String countryCode, String number) {