1 files changed, 85 insertions, 0 deletions
diff --git a/browser/base/content/test/perftest_browser_xhtml_dom.js b/browser/base/content/test/perftest_browser_xhtml_dom.js
new file mode 100644
index 0000000000..f3cc00ec49
--- /dev/null
+++ b/browser/base/content/test/perftest_browser_xhtml_dom.js
@@ -0,0 +1,85 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+/* eslint-env node */
+"use strict";
+
+/* global module */
+async function test(context, commands) {
+  await context.selenium.driver.setContext("chrome");
+  let elementData = await context.selenium.driver.executeAsyncScript(
+    function () {
+      let callback = arguments[arguments.length - 1];
+      (async function () {
+        let lightDOM = document.querySelectorAll("*");
+        let elementsWithoutIDs = {};
+        let idElements = [];
+        let lightDOMDetails = { idElements, elementsWithoutIDs };
+        lightDOM.forEach(n => {
+          if (n.id) {
+            idElements.push(n.id);
+          } else {
+            if (!elementsWithoutIDs.hasOwnProperty(n.localName)) {
+              elementsWithoutIDs[n.localName] = 0;
+            }
+            elementsWithoutIDs[n.localName]++;
+          }
+        });
+        let lightDOMCount = lightDOM.length;
+
+        // Recursively explore shadow DOM:
+        function getShadowElements(root) {
+          let allElems = Array.from(root.querySelectorAll("*"));
+          let shadowRoots = allElems.map(n => n.openOrClosedShadowRoot);
+          for (let innerRoot of shadowRoots) {
+            if (innerRoot) {
+              allElems.push(getShadowElements(innerRoot));
+            }
+          }
+          return allElems;
+        }
+        let totalDOMCount = Array.from(lightDOM, node => {
+          if (node.openOrClosedShadowRoot) {
+            return [node].concat(
+              getShadowElements(node.openOrClosedShadowRoot)
+            );
+          }
+          return node;
+        }).flat().length;
+        let panelMenuCount = document.querySelectorAll(
+          "panel,menupopup,popup,popupnotification"
+        ).length;
+        return {
+          panelMenuCount,
+          lightDOMCount,
+          totalDOMCount,
+          lightDOMDetails,
+        };
+      })().then(callback);
+    }
+  );
+  let { lightDOMDetails } = elementData;
+  delete elementData.lightDOMDetails;
+  lightDOMDetails.idElements.sort();
+  for (let id of lightDOMDetails.idElements) {
+    console.log(id);
+  }
+  console.log("Elements without ids:");
+  for (let [localName, count] of Object.entries(
+    lightDOMDetails.elementsWithoutIDs
+  )) {
+    console.log(count.toString().padStart(4) + " " + localName);
+  }
+  console.log(elementData);
+  await context.selenium.driver.setContext("content");
+  await commands.measure.start("data:text/html,BrowserDOM");
+  commands.measure.addObject(elementData);
+}
+
+module.exports = {
+  test,
+  owner: "Browser Front-end team",
+  name: "Dom-size",
+  description: "Measures the size of the DOM",
+  supportedBrowsers: ["Desktop"],
+  supportedPlatforms: ["Windows", "Linux", "macOS"],
+};