Disable switching users until user 0 is unlocked

Switching with user0 locked can be re-enabled by setting
allow_user_switching_when_system_user_locked flag to a non-zero value

Bug: 26933989
Change-Id: I0958058f1cc8a059db9c20930e07183c14c8460a
diff --git a/packages/SystemUI/src/com/android/systemui/qs/tiles/UserDetailView.java b/packages/SystemUI/src/com/android/systemui/qs/tiles/UserDetailView.java
index 2c8a478..da98762 100644
--- a/packages/SystemUI/src/com/android/systemui/qs/tiles/UserDetailView.java
+++ b/packages/SystemUI/src/com/android/systemui/qs/tiles/UserDetailView.java
@@ -82,6 +82,9 @@
             }
             v.setActivated(item.isCurrent);
             v.setDisabledByAdmin(item.isDisabledByAdmin);
+            if (!item.isSwitchToEnabled) {
+                v.setEnabled(false);
+            }
             v.setTag(item);
             return v;
         }
@@ -94,7 +97,7 @@
                 final Intent intent = RestrictedLockUtils.getShowAdminSupportDetailsIntent(
                         mContext, tag.enforcedAdmin);
                 mController.startActivity(intent);
-            } else {
+            } else if (tag.isSwitchToEnabled) {
                 MetricsLogger.action(mContext, MetricsEvent.QS_SWITCH_USER);
                 switchTo(tag);
             }