Merge to M58: Support redirect responses for NavigationPreload

third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/navigation-preload/resources/redirect-worker.js

Index: third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/navigation-preload/resources/redirect-worker.js
diff --git a/third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/navigation-preload/resources/redirect-worker.js b/third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/navigation-preload/resources/redirect-worker.js
new file mode 100644
index 0000000000000000000000000000000000000000..f7479edef9290c98c574a2dc72bc37fbd1f9b177
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/navigation-preload/resources/redirect-worker.js
@@ -0,0 +1,32 @@
+self.addEventListener('activate', event => {
+    event.waitUntil(
+        self.registration.navigationPreload.enable());
+  });
+
+function get_response_info(r) {
+  var info = {
+    type: r.type,
+    url: r.url,
+    status: r.status,
+    ok: r.ok,
+    statusText: r.statusText,
+    headers: []
+  };
+  r.headers.forEach((value, name) => { info.headers.push([value, name]); });
+  return info;
+}
+
+function post_to_page(data) {
+  return self.clients.matchAll()
+    .then(clients => clients.forEach(client => client.postMessage(data)));
+}
+
+self.addEventListener('fetch', event => {
+    event.respondWith(
+      event.preloadResponse
+        .then(
+          res => {
+            return post_to_page(get_response_info(res)).then(_ => res);
+          },
+          err => new Response(err.toString())));
+  });