Plumb IterationInfo from telemetry to a diagnostic

tracing/tracing/metrics/metric_map_function.html

Index: tracing/tracing/metrics/metric_map_function.html
diff --git a/tracing/tracing/metrics/metric_map_function.html b/tracing/tracing/metrics/metric_map_function.html
index 644574394867e6a5341385392c9534db8daf2a04..a460c99f6d11fa906feea1941bf62a4dd4f8d50a 100644
--- a/tracing/tracing/metrics/metric_map_function.html
+++ b/tracing/tracing/metrics/metric_map_function.html
@@ -14,18 +14,35 @@ found in the LICENSE file.
 'use strict';
 
 tr.exportTo('tr.metrics', function() {
+  /**
+   * @param {!pi.mre.MreResult} result
+   * @param {!tr.model.Model} model
+   * @param {!Object} options
+   */
   function metricMapFunction(result, model, options) {
     if (options === undefined)
       throw new Error('Expected an options dict.');
+
     var metricName = options.metric;
     if (metricName === undefined)
       throw new Error('A metric name should be specified.');
+
     var values = new tr.v.ValueSet();
+
     var metric = tr.metrics.MetricRegistry.findTypeInfoWithName(metricName);
     if (metric === undefined)
       throw new Error('"' + metricName + '" is not a registered metric.');
     metric.constructor(values, model);
 
+    // Values can be separated from their ValueSet and mixed into ValueSets with
+    // Values from other iterations, so add IterationInfo to each Value.
+    if (options.iterInfo) {
+      var iterInfo = new tr.v.d.IterationInfo(options.iterInfo);
+      values.map(function(value) {
+        value.diagnostics.add('iterInfo', iterInfo);
+      });
+    }
+
     result.addPair('values', values.valueDicts);
   }