COOP: use BroadcastChannel as opener isn't always there

html/cross-origin-embedder-policy/resources/script-factory.js

@@ -1,8 +1,9 @@
 // This creates a serialized <script> element that is useful for blob/data/srcdoc-style tests.
 
-function createScript(sameOrigin, crossOrigin, parent="parent", id="") {
+function createScript(sameOrigin, crossOrigin, type="parent", id="") {
   return `<script>
 const data = { id: "${id}",
+               opener: !!window.opener,
                origin: window.origin,
                sameOriginNoCORPSuccess: false,
                crossOriginNoCORPFailure: false };
@@ -18,6 +19,14 @@ if ("${sameOrigin}" !== "null") {
   records.push(record(fetch("${sameOrigin}/common/blank.html", { mode: "no-cors" }), "sameOriginNoCORPSuccess", true));
 }
 
-Promise.all(records).then(() => window.${parent}.postMessage(data, "*"));
+Promise.all(records).then(() => {
+  // Using BroadcastChannel is useful for blob: URLs, which are always same-origin
+  if ("${type}" === "channel") {
+    const bc = new BroadcastChannel("${id}");
+    bc.postMessage(data);
+  } else {
+    window.${type}.postMessage(data, "*");
+  }
+});
 <\/script>`;
 }

html/cross-origin-opener-policy/coep-blob-popup.https.html

@@ -9,8 +9,9 @@
   promise_test(t => {
     const origins = get_host_info();
     const id = `tut mir leid ${type}`;
-    const blob = new Blob([createScript(origins.ORIGIN, origins.HTTPS_REMOTE_ORIGIN, "opener", id)], {type: "text/html"});
+    const blob = new Blob([createScript(origins.ORIGIN, origins.HTTPS_REMOTE_ORIGIN, "channel", id)], {type: "text/html"});
     const blobURL = URL.createObjectURL(blob);
+    const bc = new BroadcastChannel(id);
 
     if (type === "window.open()") {
       const popup = window.open(blobURL);
@@ -32,13 +33,18 @@
     }
 
     return new Promise(resolve => {
-      window.addEventListener("message", t.step_func(({ data }) => {
+      bc.onmessage = t.step_func(({ data }) => {
         assert_equals(data.id, id);
         assert_equals(data.origin, window.origin);
         assert_true(data.sameOriginNoCORPSuccess, "Same-origin without CORP did not succeed");
         assert_true(data.crossOriginNoCORPFailure, "Cross-origin without CORP did not fail");
+        if (type === "<a rel=noopener>") {
+          assert_false(data.opener);
+        } else {
+          assert_true(data.opener);
+        }
         resolve();
-      }));
+      });
     });
   }, `COOP+COEP blob URL popup: ${type}`);
 });