Hide 'Add Users' Button for supervised users.

When the owner of the device is a supervised user, then remove
the 'Add Users' button in users_page.

Bug: 945082
Change-Id: Ib3acc6aaa955165471ca1faa36186bf3efe1dd49
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1722986Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Commit-Queue: Yilkal Abe <yilkal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682063}

chrome/browser/resources/settings/people_page/users_page.html

@@ -58,11 +58,11 @@
     <div class="list-frame">
       <settings-user-list prefs="[[prefs]]"
           disabled="[[isEditingUsersDisabled_(isOwner_, isWhitelistManaged_,
-              prefs.cros.accounts.allowGuest.value)]]">
+              prefs.cros.accounts.allowGuest.value, isChild_)]]">
       </settings-user-list>
       <div id="add-user-button" class="list-item"
           hidden="[[isEditingUsersDisabled_(isOwner_, isWhitelistManaged_,
-              prefs.cros.accounts.allowGuest.value)]]">
+              prefs.cros.accounts.allowGuest.value, isChild_)]]">
         <a is="action-link" class="list-button" on-click="openAddUserDialog_">
           $i18n{addUsers}
         </a>

chrome/browser/resources/settings/people_page/users_page.js

@@ -30,6 +30,14 @@ Polymer({
       type: Boolean,
       value: false,
     },
+
+    /** @private */
+    isChild_: {
+      type: Boolean,
+      value: function() {
+        return loadTimeData.getBoolean('isSupervised');
+      },
+    },
   },
 
   /** @override */
@@ -71,11 +79,13 @@ Polymer({
    * @param {boolean} isOwner
    * @param {boolean} isWhitelistManaged
    * @param {boolean} allowGuest
+   * @param {boolean} isChild
    * @private
    * @return {boolean}
    */
-  isEditingUsersDisabled_: function(isOwner, isWhitelistManaged, allowGuest) {
-    return !isOwner || isWhitelistManaged || allowGuest;
+  isEditingUsersDisabled_: function(
+      isOwner, isWhitelistManaged, allowGuest, isChild) {
+    return !isOwner || isWhitelistManaged || allowGuest || isChild;
   },
 
   /** @return {boolean} */