Merge "Add null check to work around async unregistration of receiver" into sc-v2-dev am: f9a8735e5b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15317993

Change-Id: I22471dfbdf57edc583ae56fe7a4f88d9748dc0e3

packages/SystemUI/src/com/android/systemui/navigationbar/NavigationBar.java

@@ -1643,10 +1643,8 @@ public class NavigationBar implements View.OnAttachStateChangeListener,
     private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
-            // This receiver is unregistered when the view is detached, but on devices with multiple
-            // displays, it can sometimes still receive an ACTION_SCREEN_ON/ACTION_SCREEN_OFF on
-            // display switch, after it was detached, so this null check ensures no crash in that
-            // scenario.
+            // TODO(193941146): Currently unregistering a receiver through BroadcastDispatcher is
+            // async, but we've already cleared the fields. Just return early in this case.
             if (mNavigationBarView == null) {
                 return;
             }