Revert of Revert "Typecheck JS files for chrome://extensions"

ui/webui/resources/js/cr/ui/list_item.js

Index: ui/webui/resources/js/cr/ui/list_item.js
diff --git a/ui/webui/resources/js/cr/ui/list_item.js b/ui/webui/resources/js/cr/ui/list_item.js
index a670a1f27f424f5fffc8623a2abbcedb3c5c5445..e548a8080186febe25af62b5dc25a7e0313748e7 100644
--- a/ui/webui/resources/js/cr/ui/list_item.js
+++ b/ui/webui/resources/js/cr/ui/list_item.js
@@ -6,7 +6,6 @@
 
   /**
    * Creates a new list item element.
-   * @param {string} opt_label The text label for the item.
    * @constructor
    * @extends {HTMLLIElement}
    */
@@ -49,7 +48,6 @@
   /**
    * Whether the item is selected. Setting this does not update the underlying
    * selection model. This is only used for display purpose.
-   * @type {boolean}
    */
   cr.defineProperty(ListItem, 'selected', cr.PropertyKind.BOOL_ATTR,
                     function() {
@@ -59,13 +57,12 @@
   /**
    * Whether the item is the lead in a selection. Setting this does not update
    * the underlying selection model. This is only used for display purpose.
-   * @type {boolean}
    */
   cr.defineProperty(ListItem, 'lead', cr.PropertyKind.BOOL_ATTR);
 
   /**
    * This item's index in the containing list.
-   * @type {number}
+   * type {number}
    */
   cr.defineProperty(ListItem, 'listIndex');