Closes PiP menu on device lock

Bug: 141322738
Test: Expand PiP then device lock and unlock
Change-Id: I0ffd3265e779946bc4e87dd0558ea139eb680bb3

packages/SystemUI/src/com/android/systemui/pip/phone/PipMenuActivity.java

@@ -247,6 +247,9 @@ public class PipMenuActivity extends Activity {
     protected void onStop() {
         super.onStop();
 
+        // In cases such as device lock, hide and finish it so that it can be recreated on the top
+        // next time it starts, see also {@link #onUserLeaveHint}
+        hideMenu();
         cancelDelayedFinish();
     }