[Persistence] Add capability decorator

Add capability decorator such that persistence queuing functionality
can be added on to the regular persistence capability of a domain
object. WTD-1033.

platform/persistence/overwrite/src/QueuingPersistenceCapabilityDecorator.js

@@ -0,0 +1,75 @@
+/*global define,Promise*/
+
+/**
+ * Module defining CoreCapabilityProvider. Created by vwoeltje on 11/7/14.
+ */
+define(
+    ['./QueuingPersistenceCapability'],
+    function (QueuingPersistenceCapability) {
+        "use strict";
+
+        /**
+         * Capability decorator. Adds queueing support to persistence
+         * capabilities for domain objects, such that persistence attempts
+         * will be handled in batches (allowing failure notification to
+         * also be presented in batches.)
+         *
+         * @constructor
+         */
+        function QueuingPersistenceCapabilityDecorator(
+            persistenceQueue,
+            capabilityService
+        ) {
+
+            function decoratePersistence(capabilities) {
+                var originalPersistence = capabilities.persistence;
+                if (originalPersistence) {
+                    capabilities.persistence = function (domainObject) {
+                        // Get/instantiate the original
+                        var original =
+                            (typeof originalPersistence === 'function') ?
+                                    originalPersistence(domainObject) :
+                                    originalPersistence;
+
+                        // Provide a decorated version
+                        return new QueuingPersistenceCapability(
+                            persistenceQueue,
+                            original,
+                            domainObject
+                        );
+                    };
+                }
+                return capabilities;
+            }
+
+            function getCapabilities(model) {
+                return capabilityService.getCapabilities(model)
+                    .then(decoratePersistence);
+            }
+
+            return {
+                /**
+                 * Get all capabilities associated with a given domain
+                 * object.
+                 *
+                 * This returns a promise for an object containing key-value
+                 * pairs, where keys are capability names and values are
+                 * either:
+                 *
+                 * * Capability instances
+                 * * Capability constructors (which take a domain object
+                 *   as their argument.)
+                 *
+                 *
+                 * @param {*} model the object model
+                 * @returns {Object.<string,function|Capability>} all
+                 *     capabilities known to be valid for this model, as
+                 *     key-value pairs
+                 */
+                getCapabilities: getCapabilities
+            };
+        }
+
+        return QueuingPersistenceCapabilityDecorator;
+    }
+);