Fix visibility of AddUser when toggling multiuser.

- when enabling multi user, also need to update the visibility of the
Add user preference, but need to check the add user capability as well.

Change-Id: Ia243901c7537bdb39ca3a39aed559b003f803e4d
Fixes: 115397726
Test: make RunSettingsRoboTests

src/com/android/settings/users/UserSettings.java

@@ -964,9 +964,10 @@ public class UserSettings extends SettingsPreferenceFragment
                 mAddUserWhenLockedPreferenceController.getPreferenceKey());
         mAddUserWhenLockedPreferenceController.updateState(addUserOnLockScreen);
         mMultiUserFooterPreferenceController.updateState(null /* preference */);
+        mAddUser.setVisible(mUserCaps.mCanAddUser && Utils.isDeviceProvisioned(context)
+                && mUserCaps.mUserSwitcherEnabled);
         mUserListCategory.setVisible(mUserCaps.mUserSwitcherEnabled);
         if (!mUserCaps.mUserSwitcherEnabled) {
-            mAddUser.setVisible(false);
             return;
         }
 

tests/robotests/src/com/android/settings/users/UserSettingsTest.java

@@ -212,4 +212,31 @@ public class UserSettingsTest {
 
     }
 
+    @Test
+    public void updateUserList_canAddUserAndSwitchUser_shouldShowAddUser() {
+        Settings.Global.putInt(mContext.getContentResolver(),
+            Settings.Global.DEVICE_PROVISIONED, 1);
+        final RestrictedPreference addUser = mock(RestrictedPreference.class);
+
+        mUserCapabilities.mCanAddUser = true;
+        mUserCapabilities.mDisallowAddUser = false;
+        mUserCapabilities.mUserSwitcherEnabled = true;
+
+        ReflectionHelpers.setField(mFragment, "mUserManager", mUserManager);
+        ReflectionHelpers.setField(mFragment, "mUserCaps", mUserCapabilities);
+        ReflectionHelpers.setField(mFragment, "mDefaultIconDrawable", mDefaultIconDrawable);
+        ReflectionHelpers.setField(mFragment, "mAddingUser", false);
+        mFragment.mMePreference = mMePreference;
+        mFragment.mUserListCategory = mock(PreferenceCategory.class);
+        mFragment.mAddUser = addUser;
+
+        doReturn(mock(PreferenceScreen.class)).when(mFragment).getPreferenceScreen();
+        doReturn("Test summary").when(mFragment).getString(anyInt(), anyInt());
+
+        mFragment.updateUserList();
+
+        verify(addUser).setVisible(true);
+
+    }
+
 }