Fixes NPE in TileQueryHelper

Change-Id: I475efd88aeb5a7db45e844131cf302b23d28f1a9
Fixes: 121271663
Test: atest

packages/SystemUI/src/com/android/systemui/qs/customize/TileQueryHelper.java

@@ -87,6 +87,8 @@ public class TileQueryHelper {
         if (current != null) {
             // The setting QS_TILES is not populated immediately upon Factory Reset
             possibleTiles.addAll(Arrays.asList(current.split(",")));
+        } else {
+            current = "";
         }
         String[] stockSplit =  stock.split(",");
         for (String spec : stockSplit) {

packages/SystemUI/tests/src/com/android/systemui/qs/customize/TileQueryHelperTest.java

@@ -218,4 +218,12 @@ public class TileQueryHelperTest extends SysuiTestCase {
         }
         assertFalse(specs.contains("other"));
     }
+
+    @Test
+    public void testQueryTiles_nullSetting() {
+        Settings.Secure.putString(mContext.getContentResolver(), Settings.Secure.QS_TILES, null);
+        mContext.getOrCreateTestableResources().addOverride(R.string.quick_settings_tiles_stock,
+                STOCK_TILES);
+        mTileQueryHelper.queryTiles(mQSTileHost);
+    }
 }