Rename ValueSet* to HistogramSet*.

tracing/tracing/metrics/system_health/long_tasks_metric_test.html

Index: tracing/tracing/metrics/system_health/long_tasks_metric_test.html
diff --git a/tracing/tracing/metrics/system_health/long_tasks_metric_test.html b/tracing/tracing/metrics/system_health/long_tasks_metric_test.html
index 60872ad5c6f29bb299b9694f65bd93fb8da7cc49..ba0b1d16f5ad7a81a954b4e139f81c903f18dc26 100644
--- a/tracing/tracing/metrics/system_health/long_tasks_metric_test.html
+++ b/tracing/tracing/metrics/system_health/long_tasks_metric_test.html
@@ -8,7 +8,7 @@ found in the LICENSE file.
 <link rel="import" href="/tracing/core/test_utils.html">
 <link rel="import" href="/tracing/extras/chrome/chrome_user_friendly_category_driver.html">
 <link rel="import" href="/tracing/metrics/system_health/long_tasks_metric.html">
-<link rel="import" href="/tracing/value/value_set.html">
+<link rel="import" href="/tracing/value/histogram_set.html">
 
 <script>
 'use strict';
@@ -61,7 +61,7 @@ tr.b.unittest.testSuite(function() {
       model.addUserFriendlyCategoryDriver(
           tr.e.chrome.ChromeUserFriendlyCategoryDriver);
     });
-    var valueSet = new tr.v.ValueSet();
+    var valueSet = new tr.v.HistogramSet();
     tr.metrics.sh.longTasksMetric(valueSet, model);
     var longTaskHist = tr.b.getOnlyElement(
         valueSet.getValuesNamed('long tasks'));