Refactor Histogram relationship diagnostics.

tracing/tracing/metrics/system_health/expected_queueing_time_metric.html

Index: tracing/tracing/metrics/system_health/expected_queueing_time_metric.html
diff --git a/tracing/tracing/metrics/system_health/expected_queueing_time_metric.html b/tracing/tracing/metrics/system_health/expected_queueing_time_metric.html
index 9b868401c1da6f3b9edaf290de07b00c0ec0926a..7e35798c8711cc8f23fb6fd11ea4a3e29f628925 100644
--- a/tracing/tracing/metrics/system_health/expected_queueing_time_metric.html
+++ b/tracing/tracing/metrics/system_health/expected_queueing_time_metric.html
@@ -136,7 +136,9 @@ tr.exportTo('tr.metrics.sh', function() {
           tr.e.chrome.maxExpectedQueueingTimeInSlidingWindow(
               rendererHelper.mainThread.bounds.min,
               rendererHelper.mainThread.bounds.max,
-              WINDOW_SIZE_MS, tasks));
+              WINDOW_SIZE_MS, tasks), {
+                v8: tr.v.d.Breakdown.fromEntries(/*TODO*/),
+              });
       const interactiveTimestamps =
         rendererToInteractiveTimestamps.get(rendererHelper.pid);
       if (interactiveTimestamps.length === 0) continue;
@@ -151,7 +153,9 @@ tr.exportTo('tr.metrics.sh', function() {
       interactiveHistogram.addSample(
           tr.e.chrome.maxExpectedQueueingTimeInSlidingWindow(
               interactiveWindow.min, interactiveWindow.max,
-              WINDOW_SIZE_MS, tasks));
+              WINDOW_SIZE_MS, tasks), {
+                v8: tr.v.d.Breakdown.fromEntries(/*TODO*/),
+              });
     }
     addV8ContributionToExpectedQueueingTime_(
         eqtName, getEventTimes, totalHistogram, interactiveHistogram,
@@ -179,19 +183,19 @@ tr.exportTo('tr.metrics.sh', function() {
       eqtName, getEventTimes, totalEqtHistogram, interactiveEqtHistogram,
       rendererToInteractiveTimestamps, histograms, model) {
     if (!model.categories.includes('v8')) return;
-    const breakdownForTotal = new tr.v.d.RelatedHistogramMap();
-    const breakdownForInteractive = new tr.v.d.RelatedHistogramMap();
+    const totalRelatedNames = new tr.v.d.RelatedNameMap();
+    const interactiveRelatedNames = new tr.v.d.RelatedNameMap();
     const eventNamesWithTaskExtractors =
         getV8EventNamesWithTaskExtractors_(getEventTimes);
     for (const [eventName, getTasks] of eventNamesWithTaskExtractors) {
       const contribution = contributionToExpectedQueueingTime_(
           eqtName, eventName, getTasks, rendererToInteractiveTimestamps,
           histograms, model);
-      breakdownForTotal.set(eventName, contribution.total);
-      breakdownForInteractive.set(eventName, contribution.interactive);
+      totalRelatedNames.set(eventName, contribution.total.name);
+      interactiveRelatedNames.set(eventName, contribution.interactive.name);
     }
-    totalEqtHistogram.diagnostics.set('v8', breakdownForTotal);
-    interactiveEqtHistogram.diagnostics.set('v8', breakdownForInteractive);
+    totalEqtHistogram.diagnostics.set('v8', totalRelatedNames);
+    interactiveEqtHistogram.diagnostics.set('v8', interactiveRelatedNames);
   }
 
   /**