Fix "Play media to" popup close issue when screen rotate

- Avoid calling getListPreference() in onDialogClose() everytime.
  Due to exception in onDialogClose(). Move preference declaration into if condition.
- Add test case for crash case.

Bug: 119744621
Test: make -j50 RunSettingsRoboTests ROBOTEST_FILTER=UpdatableListPreferenceDialogFragmentTest
Change-Id: Ia20b8289a5863136ea74e02e32b537f6967474e8

src/com/android/settings/widget/UpdatableListPreferenceDialogFragment.java

@@ -84,8 +84,8 @@ public class UpdatableListPreferenceDialogFragment extends PreferenceDialogFragm
 
     @Override
     public void onDialogClosed(boolean positiveResult) {
-        final ListPreference preference = getListPreference();
         if (positiveResult && mClickedDialogEntryIndex >= 0) {
+            final ListPreference preference = getListPreference();
             final String value = mEntryValues[mClickedDialogEntryIndex].toString();
             if (preference.callChangeListener(value)) {
                 preference.setValue(value);
@@ -144,7 +144,8 @@ public class UpdatableListPreferenceDialogFragment extends PreferenceDialogFragm
         return mMetricsCategory;
     }
 
-    private ListPreference getListPreference() {
+    @VisibleForTesting
+    ListPreference getListPreference() {
         return (ListPreference) getPreference();
     }