Disallow autofill session for visible background users

Currently, autofill service does not fully support visible background users.
Prevent starting autofill sessions for visible background users to avoid issues with their autofill behavior.

Bug: 375500806
Test: manual - check that autofill is not working for a visible background user.
Flag: EXEMPT bugfix
(cherry picked from https://partner-android-review.googlesource.com/q/commit:9489b856d41b15df98a09e2c5e384e041892ade5)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:bc78ceb189e7ec9ce765d83e3dd7f311ccb6de94)
Merged-In: Ibe368d7dd01d62ad5ca3e36ea3dd93e02077d7ad
Change-Id: Ibe368d7dd01d62ad5ca3e36ea3dd93e02077d7ad

Author: SeokgyunHong

services/autofill/java/com/android/server/autofill/AutofillManagerServiceImpl.java

@@ -92,6 +92,7 @@
 import com.android.server.contentcapture.ContentCaptureManagerInternal;
 import com.android.server.infra.AbstractPerUserSystemService;
 import com.android.server.inputmethod.InputMethodManagerInternal;
+import com.android.server.pm.UserManagerInternal;
 import com.android.server.wm.ActivityTaskManagerInternal;
 
 import java.io.PrintWriter;
@@ -192,6 +193,8 @@ final class AutofillManagerServiceImpl
 
     private final ContentCaptureManagerInternal mContentCaptureManagerInternal;
 
+    private final UserManagerInternal mUserManagerInternal;
+
     private final DisabledInfoCache mDisabledInfoCache;
 
     AutofillManagerServiceImpl(AutofillManagerService master, Object lock,
@@ -208,6 +211,7 @@ final class AutofillManagerServiceImpl
         mInputMethodManagerInternal = LocalServices.getService(InputMethodManagerInternal.class);
         mContentCaptureManagerInternal = LocalServices.getService(
                 ContentCaptureManagerInternal.class);
+        mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);
         mDisabledInfoCache = disableCache;
         updateLocked(disabled);
     }
@@ -379,6 +383,13 @@ long startSessionLocked(@NonNull IBinder activityToken, int taskId, int clientUi
             return 0;
         }
 
+        // TODO(b/376482880): remove this check once autofill service supports visible
+        // background users.
+        if (mUserManagerInternal.isVisibleBackgroundFullUser(mUserId)) {
+            Slog.d(TAG, "Currently, autofill service does not support visible background users.");
+            return 0;
+        }
+
         if (!forAugmentedAutofillOnly && isAutofillDisabledLocked(clientActivity)) {
             // Standard autofill is enabled, but service disabled autofill for this activity; that
             // means no session, unless the activity is allowlisted for augmented autofill