[Pages] Add comments

Add comments to controller for Page objects in preparation
for integration, WTD-1158.

platform/features/pages/src/EmbeddedPageController.js

@@ -5,8 +5,15 @@ define(
     function () {
         "use strict";
 
+        /**
+         * Controller for embedded web pages; serves simply as a
+         * wrapper for `$sce` to mark pages as trusted.
+         */
         function EmbeddedPageController($sce) {
             return {
+                /**
+                 * Alias of `$sce.trustAsResourceUrl`.
+                 */
                 trust: function (url) {
                     return $sce.trustAsResourceUrl(url);
                 }