Add check for null manger for a11y recents action

Bug: 31986988

Test: Ran A11y cts
Change-Id: Ia6a1e1b921d8b0008edbcf1f1a8d1d3d0eb969c6
(cherry picked from commit 3cdd6c7654)

core/java/android/accessibilityservice/AccessibilityService.java

@@ -334,7 +334,8 @@ public abstract class AccessibilityService extends Service {
     public static final int GLOBAL_ACTION_HOME = 2;
 
     /**
-     * Action to toggle showing the overview of recent apps
+     * Action to toggle showing the overview of recent apps. Will fail on platforms that don't
+     * show recent apps.
      */
     public static final int GLOBAL_ACTION_RECENTS = 3;
 

services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java

@@ -2891,8 +2891,8 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
                         sendDownAndUpKeyEvents(KeyEvent.KEYCODE_HOME);
                     } return true;
                     case AccessibilityService.GLOBAL_ACTION_RECENTS: {
-                        openRecents();
-                    } return true;
+                        return openRecents();
+                    }
                     case AccessibilityService.GLOBAL_ACTION_NOTIFICATIONS: {
                         expandNotifications();
                     } return true;
@@ -3385,14 +3385,19 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
             Binder.restoreCallingIdentity(token);
         }
 
-        private void openRecents() {
+        private boolean openRecents() {
             final long token = Binder.clearCallingIdentity();
-
-            StatusBarManagerInternal statusBarService = LocalServices.getService(
-                    StatusBarManagerInternal.class);
-            statusBarService.toggleRecentApps();
-
-            Binder.restoreCallingIdentity(token);
+            try {
+                StatusBarManagerInternal statusBarService = LocalServices.getService(
+                        StatusBarManagerInternal.class);
+                if (statusBarService == null) {
+                    return false;
+                }
+                statusBarService.toggleRecentApps();
+            } finally {
+                Binder.restoreCallingIdentity(token);
+            }
+            return true;
         }
 
         private void showGlobalActions() {