1 files changed, 28 insertions, 0 deletions
diff --git a/browser/components/resistfingerprinting/test/browser/file_hwconcurrency_aboutblank_iframee.html b/browser/components/resistfingerprinting/test/browser/file_hwconcurrency_aboutblank_iframee.html
new file mode 100644
index 0000000000..79edbefe24
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/browser/file_hwconcurrency_aboutblank_iframee.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<meta charset="utf8">
+<script>
+window.onload = async () => {
+  parent.postMessage("ready", "*");
+}
+
+window.addEventListener("message", async function listener(event) {
+  if (event.data[0] == "gimme") {
+  	var iframe = document.createElement("iframe");
+    iframe.src = "about:blank?foo";
+    document.body.append(iframe);
+
+    function test() {
+      let result = {
+        hardwareConcurrency : navigator.hardwareConcurrency
+      };
+
+      window.parent.document.querySelector("#result").textContent = JSON.stringify(result);
+    }
+
+    iframe.contentWindow.eval(`(${test})()`);
+
+    parent.postMessage(JSON.parse(document.querySelector("#result").textContent), "*")
+  }
+});
+</script>
+<output id="result"></output>