scripts/buildperf: Add chart tabs for commit count/time

We triggered a test of an older revision to narrow down when performance
changed. The issue is that git's timestamps are granular to 1s. We'll
usually merge a set of commits at the same time so they will all have
the same timestamp for a block of them. This means that even if we use
the commit date, all the points can't be distinguished on the graph.
The author date doesn't work either as the commits are not merged in
author date order.

To solve this this patch adds the commit_count chart as a separate tab
next to the start_time chart

(From OE-Core rev: b263edd33f6c895238d81ef148c0445fcd0aa268)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/build_perf/html/report.html

@@ -9,7 +9,8 @@
 {% for test in test_data %}
   {% if test.status == 'SUCCESS' %}
     {% for measurement in test.measurements %}
-      {% set chart_elem_id = test.name + '_' + measurement.name + '_chart' %}
+      {% set chart_elem_start_time_id = test.name + '_' + measurement.name + '_chart_start_time' %}
+      {% set chart_elem_commit_count_id = test.name + '_' + measurement.name + '_chart_commit_count' %}
       {% include 'measurement_chart.html' %}
     {% endfor %}
   {% endif %}
@@ -116,6 +117,22 @@ a {
 a:hover {
   color: #8080ff;
 }
+button {
+  background-color: #F3F4F6;
+  border: none;
+  outline: none;
+  cursor: pointer;
+  padding: 10px 12px;
+  transition: 0.3s;
+  border-radius: 8px;
+  color: #3A4353;
+}
+button:hover {
+  background-color: #d6d9e0;
+}
+.tab button.active {
+  background-color: #d6d9e0;
+}
 @media (prefers-color-scheme: dark) {
   :root {
     --text: #e9e8fa;
@@ -126,6 +143,16 @@ a:hover {
     --trborder: #212936;
     --chartborder: #b1b0bf;
   }
+  button {
+    background-color: #28303E;
+    color: #fff;
+  }
+  button:hover {
+    background-color: #545a69;
+  }
+  .tab button.active {
+    background-color: #545a69;
+  }
 }
 </style>
 
@@ -233,7 +260,18 @@ a:hover {
             <tr>
               <td style="width: 75%">
                 {# Linechart #}
-                <div id="{{ test.name }}_{{ measurement.name }}_chart"></div>
+                <div class="tab {{ test.name }}_{{ measurement.name }}_tablinks">
+                  <button class="tablinks active" onclick="openChart(event, '{{ test.name }}_{{ measurement.name }}_start_time', '{{ test.name }}_{{ measurement.name }}')">Chart with start time</button>
+                  <button class="tablinks" onclick="openChart(event, '{{ test.name }}_{{ measurement.name }}_commit_count', '{{ test.name }}_{{ measurement.name }}')">Chart with commit count</button>
+                </div>
+                <div class="{{ test.name }}_{{ measurement.name }}_tabcontent">
+                  <div id="{{ test.name }}_{{ measurement.name }}_start_time" class="tabcontent" style="display: block;">
+                    <div id="{{ test.name }}_{{ measurement.name }}_chart_start_time"></div>
+                  </div>
+                  <div id="{{ test.name }}_{{ measurement.name }}_commit_count" class="tabcontent" style="display: none;">
+                    <div id="{{ test.name }}_{{ measurement.name }}_chart_commit_count"></div>
+                  </div>
+                </div>
               </td>
               <td>
                 {# Measurement statistics #}
@@ -340,6 +378,31 @@ a:hover {
       <div class="preformatted">{{ test.message }}</div>
     {% endif %}
   {% endfor %}
-</div></body>
-</html>
+</div>
 
+<script>
+function openChart(event, chartType, chartName) {
+  let i, tabcontents, tablinks
+  tabcontents = document.querySelectorAll(`.${chartName}_tabcontent > .tabcontent`);
+  tabcontents.forEach((tabcontent) => {
+    tabcontent.style.display = "none";
+  });
+
+  tablinks = document.querySelectorAll(`.${chartName}_tablinks > .tablinks`);
+  tablinks.forEach((tabLink) => {
+    tabLink.classList.remove('active');
+  });
+
+  const targetTab = document.getElementById(chartType)
+  targetTab.style.display = "block";
+
+  // Call resize on the ECharts instance to redraw the chart
+  const chartContainer = targetTab.querySelector('div')
+  echarts.init(chartContainer).resize();
+
+  event.currentTarget.classList.add('active');
+}
+</script>
+
+</body>
+</html>