Apply Delayed Code Review Comments to Task Scheduler Internals

chrome/browser/resources/task_scheduler_internals/index.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-var TaskSchedulerInternals = {};
+/** @typedef {{min: number, max: number, count: number}} */
+var Bucket;
 
-/**
- * Updates the histograms on the page.
- * @param {Array<Object>} histograms Array of histogram objects.
- */
-TaskSchedulerInternals.updateHistograms = function(histograms) {
-  var histogramContainer = $('histogram-container');
-  for (var i in histograms) {
-    var histogram = histograms[i];
-    var title = document.createElement('div');
-    title.textContent = histogram.name;
-    histogramContainer.appendChild(title);
-    if (histogram.buckets.length > 0) {
-      histogramContainer.appendChild(
-          TaskSchedulerInternals.createHistogramTable(histogram.buckets));
-    } else {
-      var unavailable = document.createElement('div');
-      unavailable.textContent = 'No Data Recorded';
-      histogramContainer.appendChild(unavailable);
+/** @typedef {{name: string, buckets: !Array<Bucket>}} */
+var Histogram;
+
+var TaskSchedulerInternals = {
+  /**
+   * Updates the histograms on the page.
+   * @param {!Array<!Histogram>} histograms Array of histogram objects.
+   */
+  updateHistograms: function(histograms) {
+    var histogramContainer = $('histogram-container');
+    for (var i in histograms) {
+      var histogram = histograms[i];
+      var title = document.createElement('div');
+      title.textContent = histogram.name;
+      histogramContainer.appendChild(title);
+      if (histogram.buckets.length > 0) {
+        histogramContainer.appendChild(
+            TaskSchedulerInternals.createHistogramTable(histogram.buckets));
+      } else {
+        var unavailable = document.createElement('div');
+        unavailable.textContent = 'No Data Recorded';
+        histogramContainer.appendChild(unavailable);
+      }
     }
+  },
+
+  /**
+   * Returns a table representation of the histogram buckets.
+   * @param {Object} buckets The histogram buckets.
+   * @return {Object} A table element representation of the histogram buckets.
+   */
+  createHistogramTable: function(buckets) {
+    var table = document.createElement('table');
+    var headerRow = document.createElement('tr');
+    var dataRow = document.createElement('tr');
+    for (var i in buckets) {
+      var bucket = buckets[i];
+      var header = document.createElement('th');
+      header.textContent = `${bucket.min}-${bucket.max}`;
+      headerRow.appendChild(header);
+      var data = document.createElement('td');
+      data.textContent = bucket.count;
+      dataRow.appendChild(data);
+    }
+    table.appendChild(headerRow);
+    table.appendChild(dataRow);
+    return table;
+  },
+
+  /**
+   * Handles callback from onGetTaskSchedulerData.
+   * @param {Object} data Dictionary containing all task scheduler metrics.
+   */
+  onGetTaskSchedulerData: function(data) {
+    $('status').textContent =
+        data.instantiated ? 'Instantiated' : 'Not Instantiated';
+    $('details').hidden = !data.instantiated;
+    if (!data.instantiated)
+      return;
+
+    TaskSchedulerInternals.updateHistograms(data.histograms);
   }
 };
 
-/**
- * Returns a table representation of the histogram buckets.
- * @param {Object} buckets The histogram buckets.
- * @return {Object} A table element representation of the histogram buckets.
- */
-TaskSchedulerInternals.createHistogramTable = function(buckets) {
-  var table = document.createElement('table');
-  var headerRow = document.createElement('tr');
-  var dataRow = document.createElement('tr');
-  for (var i in buckets) {
-    var bucket = buckets[i];
-    var header = document.createElement('th');
-    header.textContent = bucket.min + '-' + bucket.max;
-    headerRow.appendChild(header);
-    var data = document.createElement('td');
-    data.textContent = bucket.count;
-    dataRow.appendChild(data);
-  }
-  table.appendChild(headerRow);
-  table.appendChild(dataRow);
-  return table;
-};
-
-/**
- * Handles callback from onGetTaskSchedulerData.
- * @param {Object} data Dictionary containing all task scheduler metrics.
- */
-TaskSchedulerInternals.onGetTaskSchedulerData = function(data) {
-  $('status').textContent =
-      data.instantiated ? 'Instantiated' : 'Not Instantiated';
-  $('details').hidden = !data.instantiated;
-  if (!data.instantiated)
-    return;
-
-  TaskSchedulerInternals.updateHistograms(data.histograms);
-};
-
 document.addEventListener('DOMContentLoaded', function() {
   chrome.send('getTaskSchedulerData');
 });