Adding gantt chart to Build Status page on Buildbot Masters

masters/master.chromium/public_html/gantt_chart.js

Index: masters/master.chromium/public_html/gantt_chart.js
diff --git a/masters/master.chromium/public_html/gantt_chart.js b/masters/master.chromium/public_html/gantt_chart.js
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+// 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.
+google.charts.load('current', {'packages':['gantt']});
+
+/**
+ * reconcileSwarmingSteps reconciles a Swarming step's "trigger" step with
+ * it's subsequent "collect results" step.
+ *
+ * Swarming steps in BuildBot create two steps - one to trigger the work
+ * on swarming, and a later step to collect the results.
+ *
+ * The two steps have the same name, except the trigger step has "[trigger] "
+ * prepended to the name.
+ *
+ * This function consolidates the two steps into one by using the start
+ * time from the trigger step and the end time from the "collect results"
+ * step.
+ *
+ * This function assumes that a trigger step will be found before the
+ * corresponding "collect results" step in the list of steps.
+ * @param {Array<Object>} steps List of step objects. Each step object
+ *     has the following properties: name {string}, start {Date}, end {Date}
+ */
+function reconcileSwarmingSteps(steps) {
+  let reconciledSteps = [];
+  let triggerSteps = {};
+
+  for (let s of steps) {
+    // trigger steps have names like "[trigger] TheRestOfTheNameGoesHere..."
+    let isTriggerStep = /\[trigger\] (.*)/.exec(s.name);
+    if (isTriggerStep) {
+      triggerSteps[isTriggerStep[1]] = s;
+    } else {
+      if (triggerSteps[s.name]) {
+        s.start = triggerSteps[s.name].start;
+      }
+      reconciledSteps.push(s);
+    }
+  }
+
+  return reconciledSteps;
+};
+
+function drawChart(steps) {
+  let data = new google.visualization.DataTable();
+  data.addColumn('string', 'Task ID');
+  data.addColumn('string', 'Task Name');
+  data.addColumn('string', 'Resource');
+  data.addColumn('date', 'Start Date');
+  data.addColumn('date', 'End Date');
+  data.addColumn('number', 'Duration');
+  data.addColumn('number', 'Percent Complete');
+  data.addColumn('string', 'Dependencies');
+
+  for (s of steps) {
+    data.addRow([s.name, s.name, null, s.start, s.end, null, 100, null]);
+  }
+
+  let trackHeight = 25;
+  let options = {
+    height: data.getNumberOfRows() * trackHeight,
+    gantt: {
+      trackHeight: trackHeight,
+      barHeight: trackHeight * 0.8,
+      labelMaxWidth: 500,
+    }
+  };
+
+  let chart = new google.visualization.Gantt(
+      document.getElementById('chart_div'));
+  chart.draw(data, options);
+}
+
+let chartVisible = false;
+function toggleChart(rawSteps) {
+  if (chartVisible) {
+    document.getElementById('chart_div').style.display = 'none';
+    chartVisible = false;
+  } else {
+    document.getElementById('chart_div').style.display = 'block';
+    let steps = reconcileSwarmingSteps(rawSteps);
+    drawChart(steps);
+    chartVisible = true;
+  }
+}