UserTypeFactory configurable setMaxAllowed

We provide support in config_user_types.xml to change the max number of
users allowed of a given user type. This could, e.g., allow multiple
Guest users. Note that even though it can be configured, that doesn't
mean it'll work - to have more than one Guest user additional work in
UMS and other places would be required.

Test: atest UserManagerServiceUserTypeTest
Bug: 256690588
Change-Id: I02b212bb9a046bbf5662fea05d833f1717e23327

core/res/res/xml/config_user_types.xml

@@ -83,6 +83,8 @@ Supported optional properties (to be used as shown in the example above) are as
 For profile and full users:
     default-restrictions (with values defined in UserRestrictionUtils.USER_RESTRICTIONS)
     enabled
+    user-properties
+    max-allowed
 For profile users only:
     max-allowed-per-parent
     icon-badge

services/core/java/com/android/server/pm/UserTypeFactory.java

@@ -388,6 +388,7 @@ public final class UserTypeFactory {
                 }
 
                 setIntAttribute(parser, "enabled", builder::setEnabled);
+                setIntAttribute(parser, "max-allowed", builder::setMaxAllowed);
 
                 // Process child elements.
                 final int depth = parser.getDepth();

services/tests/servicestests/res/xml/usertypes_test_full.xml

@@ -16,7 +16,8 @@
 <user-types>
     <full-type
         name='android.test.1'
-        max-allowed-per-parent='12' >
+        max-allowed-per-parent='12'
+        max-allowed='17' >
         <default-restrictions no_remove_user='true' no_bluetooth='true' />
         <badge-colors>
             <item res='@*android:color/profile_badge_1' />

services/tests/servicestests/src/com/android/server/pm/UserManagerServiceUserTypeTest.java

@@ -347,6 +347,7 @@ public class UserManagerServiceUserTypeTest {
         UserTypeDetails details = builders.get(userTypeFull).createUserTypeDetails();
         assertEquals(UNLIMITED_NUMBER_OF_USERS, details.getMaxAllowedPerParent());
         assertFalse(details.isEnabled());
+        assertEquals(17, details.getMaxAllowed());
         assertTrue(UserRestrictionsUtils.areEqual(
                 makeRestrictionsBundle("no_remove_user", "no_bluetooth"),
                 details.getDefaultRestrictions()));