Fix issue "open battery settings, switch locale, apps are still in old locale" into pi-dev

Clear uid to package detail cache by checking locale before use.

Fixes: 62422871
Test: RunSettingsRoboTest pass,
manual test
(1) open advance battery settings page,
(2) switch locale,
(3) back to advance battery settings page  => pass
manual test
(1) open advance battery settings page, and then back to settings main page
(2) switch locale,
(3) go to advance battery settings page  => pass

Change-Id: Ifac830706539022cd9bf51d3f33e728aadc163f4

tests/robotests/src/com/android/settings/fuelgauge/BatteryEntryTest.java

@@ -39,6 +39,8 @@ import org.mockito.junit.MockitoJUnit;
 import org.mockito.junit.MockitoRule;
 import org.robolectric.RobolectricTestRunner;
 
+import java.util.Locale;
+
 @RunWith(RobolectricTestRunner.class)
 public class BatteryEntryTest {
 
@@ -148,4 +150,17 @@ public class BatteryEntryTest {
 
         assertThat(entry.extractPackagesFromSipper(entry.sipper)).isEqualTo(entry.sipper.mPackages);
     }
+
+    @Test
+    public void testUidCache_switchLocale_shouldCleanCache() {
+        BatteryEntry.stopRequestQueue();
+
+        Locale.setDefault(new Locale("en_US"));
+        BatteryEntry.sUidCache.put(Integer.toString(APP_UID), null);
+        assertThat(BatteryEntry.sUidCache).isNotEmpty();
+
+        Locale.setDefault(new Locale("zh_TW"));
+        createBatteryEntryForApp();
+        assertThat(BatteryEntry.sUidCache).isEmpty(); // check if cache is clear
+    }
 }