[Telemetry] Separate out delegator

Separate out handling of delegation related to telemetry,
WTD-806.

platform/telemetry/src/TelemetryDelegator.js

@@ -0,0 +1,45 @@
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        /**
+         * Used to handle telemetry delegation associated with a
+         * given domain object.
+         */
+        function TelemetryDelegator($q) {
+            return {
+                /**
+                 * Promise telemetry-providing objects associated with
+                 * this domain object (either the domain object itself,
+                 * or the objects it delegates)
+                 * @returns {Promise.<DomainObject[]>} domain objects with
+                 *          a telemetry capability
+                 */
+                promiseTelemetryObjects: function (domainObject) {
+                    // If object has been cleared, there are no relevant
+                    // telemetry-providing domain objects.
+                    if (!domainObject) {
+                        return $q.when([]);
+                    }
+
+                    // Otherwise, try delegation first, and attach the
+                    // object itself if it has a telemetry capability.
+                    return $q.when(domainObject.useCapability(
+                        "delegation",
+                        "telemetry"
+                    )).then(function (result) {
+                        var head = domainObject.hasCapability("telemetry") ?
+                                [ domainObject ] : [],
+                            tail = result || [];
+                        return head.concat(tail);
+                    });
+                }
+            };
+        }
+
+        return TelemetryDelegator;
+    }
+);

platform/telemetry/src/TelemetryRequester.js

@@ -0,0 +1,34 @@
+/*global define*/
+
+define(
+    ['./TelemetryDelegator'],
+    function (TelemetryDelegator) {
+        "use strict";
+
+
+        /**
+         * A TelemetryRequester provides an easy interface to request
+         * telemetry associated with a set of domain objects.
+         *
+         * @constructor
+         * @param $q Angular's $q
+         */
+        function TelemetryRequester($q) {
+            var delegator = new TelemetryDelegator($q);
+
+            // Look up domain objects which have telemetry capabilities.
+            // This will either be the object in view, or object that
+            // this object delegates its telemetry capability to.
+            function promiseRelevantObjects(domainObject) {
+                return delegator.promiseTelemetryObjects(domainObject);
+            }
+
+            return {
+
+            };
+        }
+
+        return TelemetryRequester;
+
+    }
+);

platform/telemetry/src/TelemetrySubscription.js

@@ -1,8 +1,8 @@
 /*global define*/
 
 define(
-    ['./TelemetryQueue', './TelemetryTable'],
+    ['./TelemetryQueue', './TelemetryTable', './TelemetryDelegator'],
-    function (TelemetryQueue, TelemetryTable) {
+    function (TelemetryQueue, TelemetryTable, TelemetryDelegator) {
         "use strict";
 
 
@@ -31,7 +31,8 @@ define(
          *        the callback once, with access to the latest data
          */
         function TelemetrySubscription($q, $timeout, domainObject, callback, lossless) {
-            var unsubscribePromise,
+            var delegator = new TelemetryDelegator($q),
+                unsubscribePromise,
                 latestValues = {},
                 telemetryObjects = [],
                 pool = lossless ? new TelemetryQueue() : new TelemetryTable(),
@@ -42,23 +43,7 @@ define(
             // This will either be the object in view, or object that
             // this object delegates its telemetry capability to.
             function promiseRelevantObjects(domainObject) {
-                // If object has been cleared, there are no relevant
+                return delegator.promiseTelemetryObjects(domainObject);
-                // telemetry-providing domain objects.
-                if (!domainObject) {
-                    return $q.when([]);
-                }
-
-                // Otherwise, try delegation first, and attach the
-                // object itself if it has a telemetry capability.
-                return $q.when(domainObject.useCapability(
-                    "delegation",
-                    "telemetry"
-                )).then(function (result) {
-                    var head = domainObject.hasCapability("telemetry") ?
-                            [ domainObject ] : [],
-                        tail = result || [];
-                    return head.concat(tail);
-                });
             }
 
             function updateValuesFromPool() {