QS: Update embedded vol panel when re-attached to window.

We intentionally drop interim updates when the panel is not
visible, but we should catch up when it becomes visible again.

Not a problem for the dialog panel, since it is torn down / recreated
each time.

Bug:15573750
Change-Id: I717b5d459acb25f9610222e9913d7b8eb71cdd00

packages/SystemUI/src/com/android/systemui/qs/tiles/NotificationsTile.java

@@ -69,6 +69,7 @@ public class NotificationsTile extends QSTile<NotificationsTile.NotificationsSta
 
             @Override
             public void onViewAttachedToWindow(View v) {
+                vp.updateStates();
                 volumeComponent.setVolumePanel(vp);
             }
         });