[Core] Add JSDoc for model components

Add JSDoc for components of modelService exposed
by platform/core. Part of ongoing preparation for
review and integration; WTD-573.

platform/core/src/models/PersistedModelProvider.js

@@ -9,8 +9,15 @@ define(
         "use strict";
 
         /**
+         * A model service which reads domain object models from an external
+         * persistence service.
          *
          * @constructor
+         * @param {PersistenceService} persistenceService the service in which
+         *        domain object models are persisted.
+         * @param $q Angular's $q service, for working with promises
+         * @param {string} SPACE the name of the persistence space from which
+         *        models should be retrieved.
          */
         function PersistedModelProvider(persistenceService, $q, SPACE) {
             function promiseModels(ids) {
@@ -26,6 +33,22 @@ define(
             }
 
             return {
+                /**
+                 * Get models with the specified identifiers.
+                 *
+                 * This will invoke the underlying persistence service to
+                 * retrieve object models which match the provided
+                 * identifiers.
+                 *
+                 * Note that the returned object may contain a subset or a
+                 * superset of the models requested.
+                 *
+                 * @param {string[]} ids an array of domain object identifiers
+                 * @returns {Promise.<object>} a promise for  an object
+                 *          containing key-value pairs,
+                 *          where keys are object identifiers and values
+                 *          are object models.
+                 */
                 getModels: promiseModels
             };
         }