[Settings] Add a verification flow for exiting repair mode

Handles the ACTION_CONFIRM_REPAIR_MODE_DEVICE_CREDENTIAL
intent to launch the confirm device credential activity for
users to exiting repair mode. The activity passes a special
user id USER_REPAIR_MODE to the framework and verify credentials
that the user enrolled in normal mode.

Bug: 277561275
Test: am start -a android.app.action.PREPARE_REPAIR_MODE_DEVICE_CREDENTIAL
      settings put global repair_mode_active 1
      am start -a android.app.action.CONFIRM_REPAIR_MODE_DEVICE_CREDENTIAL
      The credential is verified successfully.
Change-Id: I9ffe32f9925ee2b990c49d5674d27196a4c9edf7

src/com/android/settings/Utils.java

@@ -708,9 +708,13 @@ public final class Utils extends com.android.settingslib.Utils {
         final int userId = bundle.getInt(Intent.EXTRA_USER_ID, UserHandle.myUserId());
         if (userId == LockPatternUtils.USER_FRP) {
             return allowAnyUser ? userId : checkUserOwnsFrpCredential(context, userId);
-        } else {
-            return allowAnyUser ? userId : enforceSameOwner(context, userId);
         }
+        if (userId == LockPatternUtils.USER_REPAIR_MODE) {
+            enforceRepairModeActive(context);
+            // any users can exit repair mode
+            return userId;
+        }
+        return allowAnyUser ? userId : enforceSameOwner(context, userId);
     }
 
     /**
@@ -729,6 +733,16 @@ public final class Utils extends com.android.settingslib.Utils {
                 + " does not own frp credential.");
     }
 
+    /**
+     * Throws {@link SecurityException} if repair mode is not active on the device.
+     */
+    private static void enforceRepairModeActive(Context context) {
+        if (LockPatternUtils.isRepairModeActive(context)) {
+            return;
+        }
+        throw new SecurityException("Repair mode is not active on the device.");
+    }
+
     /**
      * Returns the given user id if it belongs to the current user.
      *