Fixing a couple nav bar crashes am: a7c9bec46c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15744882

Change-Id: I65dd5d2bb51a68277b10e643bbb62270e82ab0e7

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

@@ -422,6 +422,12 @@ public class NavigationBar implements View.OnAttachStateChangeListener,
             new Handler(Looper.getMainLooper())) {
         @Override
         public void onChange(boolean selfChange, Uri uri) {
+            // TODO(b/198002034): Content observers currently can still be called back after being
+            // unregistered, and in this case we can ignore the change if the nav bar has been
+            // destroyed already
+            if (mNavigationBarView == null) {
+                return;
+            }
             updateAssistantEntrypoints();
         }
     };
@@ -648,7 +654,7 @@ public class NavigationBar implements View.OnAttachStateChangeListener,
         if (mIsOnDefaultDisplay) {
             final RotationButtonController rotationButtonController =
                     mNavigationBarView.getRotationButtonController();
-            rotationButtonController.addRotationCallback(mRotationWatcher);
+            rotationButtonController.setRotationCallback(mRotationWatcher);
 
             // Reset user rotation pref to match that of the WindowManager if starting in locked
             // mode. This will automatically happen when switching from auto-rotate to locked mode.
@@ -687,6 +693,9 @@ public class NavigationBar implements View.OnAttachStateChangeListener,
 
     @Override
     public void onViewDetachedFromWindow(View v) {
+        final RotationButtonController rotationButtonController =
+                mNavigationBarView.getRotationButtonController();
+        rotationButtonController.setRotationCallback(null);
         mNavigationBarView.getBarTransitions().destroy();
         mNavigationBarView.getLightTransitionsController().destroy(mContext);
         mOverviewProxyService.removeCallback(mOverviewProxyListener);

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

@@ -279,7 +279,7 @@ public class NavigationBarView extends FrameLayout implements
             new RotationButtonUpdatesCallback() {
                 @Override
                 public void onVisibilityChanged(boolean visible) {
-                    if (visible) {
+                    if (visible && mAutoHideController != null) {
                         // If the button will actually become visible and the navbar is about
                         // to hide, tell the statusbar to keep it around for longer
                         mAutoHideController.touchAutoHide();

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

@@ -183,7 +183,7 @@ public class RotationButtonController {
         TaskStackChangeListeners.getInstance().unregisterTaskStackListener(mTaskStackListener);
     }
 
-    void addRotationCallback(Consumer<Integer> watcher) {
+    void setRotationCallback(Consumer<Integer> watcher) {
         mRotWatcherListener = watcher;
     }