[Search] Add digest indicator

Add digest indicator to example/profiling to aid in diagnosing
digest-related performance issues (or ruling out excessive digest
cycles as a cause of performance issues.)

example/profiling/bundle.json

@@ -4,6 +4,10 @@
             {
                 "implementation": "WatchIndicator.js",
                 "depends": ["$interval", "$rootScope"]
+            },
+            {
+                "implementation": "DigestIndicator.js",
+                "depends": ["$interval", "$rootScope"]
             }
         ]
     }

example/profiling/src/DigestIndicator.js

@@ -0,0 +1,77 @@
+/*****************************************************************************
+ * 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 the number of digests that have occurred since the
+         * indicator was first instantiated.
+         * @constructor
+         * @param $interval Angular's $interval
+         * @implements {Indicator}
+         */
+        function DigestIndicator($interval, $rootScope) {
+            var digests = 0,
+                displayed = 0,
+                start = Date.now();
+
+            function update() {
+                var secs = (Date.now() - start) / 1000;
+                displayed = Math.round(digests / secs);
+            }
+
+            function increment() {
+                digests += 1;
+            }
+
+            $rootScope.$watch(increment);
+
+            // Update state every second
+            $interval(update, 1000);
+
+            // Provide initial state, too
+            update();
+
+            return {
+                getGlyph: function () {
+                    return ".";
+                },
+                getGlyphClass: function () {
+                    return undefined;
+                },
+                getText: function () {
+                    return displayed + " digests/sec";
+                },
+                getDescription: function () {
+                    return "";
+                }
+            };
+        }
+
+        return DigestIndicator;
+
+    }
+);