[Workers] Add example worker

Add an example worker which inefficiently calculates
fibonacci numbers outside of the UI thread, for #12.

example/worker/README.md

@@ -0,0 +1 @@
+Example of running a Web Worker using the `workerService`.

example/worker/bundle.json

@@ -0,0 +1,16 @@
+{
+    "extensions": {
+        "indicators": [
+            {
+                "implementation": "FibonacciIndicator.js",
+                "depends": [ "workerService", "$rootScope" ]
+            }
+        ],
+        "workers": [
+            {
+                "key": "example.fibonacci",
+                "scriptUrl": "FibonacciWorker.js"
+            }
+        ]
+    }
+}

example/worker/src/FibonacciIndicator.js

@@ -0,0 +1,70 @@
+/*****************************************************************************
+ * Open MCT Web, Copyright (c) 2014-2015, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT Web is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT Web includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        /**
+         * Displays Fibonacci numbers in the status area.
+         * @constructor
+         */
+        function FibonacciIndicator(workerService, $rootScope) {
+            var latest,
+                counter = 0,
+                worker = workerService.run('example.fibonacci');
+
+            function requestNext() {
+                worker.postMessage([counter]);
+                counter += 1;
+            }
+
+            function handleResponse(event) {
+                latest = event.data;
+                $rootScope.$apply();
+                requestNext();
+            }
+
+            worker.onmessage = handleResponse;
+            requestNext();
+
+            return {
+                getGlyph: function () {
+                    return "?";
+                },
+                getText: function () {
+                    return latest;
+                },
+                getGlyphClass: function () {
+                    return "";
+                },
+                getDescription: function () {
+                    return "";
+                }
+            };
+        }
+
+        return FibonacciIndicator;
+    }
+);

example/worker/src/FibonacciWorker.js

@@ -0,0 +1,15 @@
+/*global onmessage,postMessage*/
+(function () {
+    "use strict";
+
+    // Calculate fibonacci numbers inefficiently.
+    // We can do this because we're on a background thread, and
+    // won't halt the UI.
+    function fib(n) {
+        return n < 2 ? n : (fib(n - 1) + fib(n - 2));
+    }
+
+    onmessage = function (event) {
+        postMessage(fib(event.data));
+    };
+}());

platform/execution/bundle.json

@@ -3,6 +3,7 @@
         "services": [
             {
                 "key": "workerService",
+                "implementation": "WorkerService.js",
                 "depends": [ "$window", "workers[]" ]
             }
         ]