[Time Conductor] Maintain domain state

Maintain domain state in the time conductor; add a default list of
domains to choose from.

platform/features/conductor/bundle.json

@@ -18,7 +18,17 @@
             {
                 "key": "conductorService",
                 "implementation": "ConductorService.js",
-                "depends": [ "now" ]
+                "depends": [ "now", "TIME_CONDUCTOR_DOMAINS" ]
+            }
+        ],
+        "contants": [
+            {
+                "key": "TIME_CONDUCTOR_DOMAINS",
+                "value": [
+                    { "key": "time", "name": "Time" },
+                    { "key": "yesterday", "name": "Yesterday" }
+                ],
+                "comment": "Placeholder; to be replaced by inspection of available domains."
             }
         ]
     }

platform/features/conductor/src/ConductorService.js

@@ -39,12 +39,15 @@ define(
          * @param {Function} now a function which returns the current time
          *        as a UNIX timestamp, in milliseconds
          */
-        function ConductorService(now) {
+        function ConductorService(now, domains) {
             var initialEnd =
                 Math.ceil(now() /  SIX_HOURS_IN_MS) * SIX_HOURS_IN_MS;
 
-            this.conductor =
+            this.conductor = new TimeConductor(
-                new TimeConductor(initialEnd - ONE_DAY_IN_MS, initialEnd);
+                initialEnd - ONE_DAY_IN_MS,
+                initialEnd,
+                domains
+            );
         }
 
         /**

platform/features/conductor/src/TimeConductor.js

@@ -40,9 +40,11 @@ define(
          * @param {number} start the initial start time
          * @param {number} end the initial end time
          */
-        function TimeConductor(start, end) {
+        function TimeConductor(start, end, domains) {
             this.inner = { start: start, end: end };
             this.outer = { start: start, end: end };
+            this.domains = domains;
+            this.domain = domains[0];
         }
 
         /**
@@ -94,6 +96,32 @@ define(
             return this.inner.end;
         };
 
+        /**
+         * Get available domain options which can be used to bound time
+         * selection.
+         * @returns {TelemetryDomain[]} available domains
+         */
+        TimeConductor.prototype.domainOptions = function () {
+            return this.domains;
+        };
+
+        /**
+         * Get or set (if called with an argument) the active domain.
+         * @param {string} [key] the key identifying the domain choice
+         * @returns {TelemetryDomain} the active telemetry domain
+         */
+        TimeConductor.prototype.activeDomain = function (key) {
+            var i;
+            if (arguments.length > 0) {
+                for (i = 0; i < this.domains.length; i += 1) {
+                    if (this.domains[i].key === key) {
+                        this.domain = this.domains[i];
+                    }
+                }
+            }
+            return this.domain;
+        };
+
         return TimeConductor;
     }
 );