Fix Robolectric broken on SplitController

Fixes: 198563284
Test: robotest
Change-Id: I1f4cd3c972fed4da171feadb8c31b858c85c6757
diff --git a/tests/robotests/Android.bp b/tests/robotests/Android.bp
index 9b2e97f..43bcec7 100644
--- a/tests/robotests/Android.bp
+++ b/tests/robotests/Android.bp
@@ -50,6 +50,7 @@
         "contextualcards",
         "settings-logtags",
         "zxing-core-1.7",
+        "windowExtLib",
     ],
 
     aaptflags: ["--extra-packages com.android.settings"],