1 files changed, 39 insertions, 0 deletions
diff --git a/testing/web-platform/tests/x-frame-options/support/nested.py b/testing/web-platform/tests/x-frame-options/support/nested.py
new file mode 100644
index 0000000000..78c8c18466
--- /dev/null
+++ b/testing/web-platform/tests/x-frame-options/support/nested.py
@@ -0,0 +1,39 @@
+def main(request, response):
+    origin = request.GET.first(b"origin");
+    value = request.GET.first(b"value");
+    # This is used to solve the race condition we have for postMessages
+    shouldSucceed = request.GET.first(b"loadShouldSucceed", b"false");
+    return ([(b"Content-Type", b"text/html")],
+            b"""<!DOCTYPE html>
+<title>XFO.</title>
+<body>
+<script>
+  var gotMessage = false;
+  window.addEventListener("message", e => {
+    gotMessage = true;
+    window.parent.postMessage(e.data, "*");
+  });
+
+  var i = document.createElement("iframe");
+  i.src = "%s/x-frame-options/support/xfo.py?value=%s";
+  i.onload = _ => {
+    // Why two rAFs? Because that seems to be enough to stop the
+    // load event from racing with the onmessage event.
+    requestAnimationFrame(_ => {
+      requestAnimationFrame(_ => {
+        // The race condition problem we have is it is possible
+        // that the sub iframe is loaded before the postMessage is
+        // dispatched, as a result, the "Failed" message is sent
+        // out. So the way we fixed is we simply let the timeout
+        // to happen if we expect the "Loaded" postMessage to be
+        // sent
+        if (!gotMessage && %s != true) {
+          window.parent.postMessage("Failed", "*");
+        }
+      });
+    });
+  };
+  document.body.appendChild(i);
+</script>
+            """ % (origin, value, shouldSucceed))
+