Allow alternative time zone ID to be set device's zone.

If America/Godthab is set as device time zone, display it as if
America/Nuuk is chosen.
If time zone is known, but is not an alternative and not shown
in time zone picker, region will de derived from user's locale.

Bug: 155738410
Test: atest com.android.settings.datetime.timezone.model
Test: set persist.sys.timezone via adb and checked
Date & Time screen

Change-Id: I168fb4319e144dbe9e2496d06a681d4c09b411c0

tests/robotests/src/com/android/settings/datetime/timezone/model/TimeZoneDataTest.java

@@ -92,4 +92,23 @@ public class TimeZoneDataTest {
                 .containsExactly("US", "GB");
         assertThat(timeZoneData.lookupCountryCodesForZoneId("Unknown/Secret_City2")).isEmpty();
     }
+
+    @Test
+    public void lookupCountryCodesForNonCanonicalZoneId_returnsCurrentZone() {
+        TimeZoneData timeZoneData = new TimeZoneData(mCountryZonesFinder);
+
+        CountryTimeZones greenland = mock(CountryTimeZones.class);
+        when(greenland.getCountryIso()).thenReturn("gl");
+        when(greenland.getTimeZoneMappings()).thenReturn(Arrays.asList(
+                TimeZoneMapping.createForTests(
+                        "America/Nuuk",
+                        true /* showInPicker */,
+                        null /* notUsedAfter */,
+                        Arrays.asList("America/Godthab"))));
+        when(mCountryZonesFinder.lookupCountryTimeZonesForZoneId("America/Godthab"))
+                .thenReturn(Arrays.asList(greenland));
+
+        assertThat(timeZoneData.lookupCountryCodesForZoneId("America/Godthab"))
+                .containsExactly("GL");
+    }
 }