Ensure we don't set visibility after action is destroyed.

- The activity call to setVisible() does not check before using the
  decor view (which is reset once the activity is destroyed).

Bug: 36469656
Test: Test PIP app which finishes in response to action handling
Change-Id: I50e49bd6e9759c11edd71c0c5cac61939e3bf276

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

@@ -295,7 +295,9 @@ public class PipMenuActivity extends Activity {
                     if (animationFinishedRunnable != null) {
                         animationFinishedRunnable.run();
                     }
-                    setVisible(false);
+                    if (!isDestroyed()) {
+                        setVisible(false);
+                    }
                 }
             });
             mMenuContainerAnimator.addUpdateListener(mMenuBgUpdateListener);