From 2f3f5cb555144ab1f400c4f51d6b3c8900880eb5 Mon Sep 17 00:00:00 2001
From: Hiroki Nakagawa <nhiroki@chromium.org>
Date: Mon, 25 Apr 2022 21:57:49 -0700
Subject: [PATCH] Prerender: Defer ServiceWorkerRegistration#unregister from
 prerendered pages

The spec requires ServiceWorkerRegistration#unregister to be deferred
until page activation. This CL implements the behavior.
https://wicg.github.io/nav-speculation/prerendering.html#patch-service-workers

Bug: 1305120
Change-Id: Ibf5d888f0636d2ad11c08f16b9b9739824536cb0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3606768
Reviewed-by: Lingqi Chi <lingqi@chromium.org>
Reviewed-by: Asami Doi <asamidoi@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/main@{#995987}
---
 .../prerender/resources/do-nothing-worker.js  |  1 +
 .../resources/service-worker-unregister.html  | 34 +++++++++++
 ...ction-service-worker-unregister.https.html | 56 +++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 speculation-rules/prerender/resources/do-nothing-worker.js
 create mode 100644 speculation-rules/prerender/resources/service-worker-unregister.html
 create mode 100644 speculation-rules/prerender/restriction-service-worker-unregister.https.html
diff --git a/speculation-rules/prerender/resources/do-nothing-worker.js b/speculation-rules/prerender/resources/do-nothing-worker.js
new file mode 100644
index 00000000000000..49ceb2648a9341
--- /dev/null
+++ b/speculation-rules/prerender/resources/do-nothing-worker.js
@@ -0,0 +1 @@
+// Do nothing.
diff --git a/speculation-rules/prerender/resources/service-worker-unregister.html b/speculation-rules/prerender/resources/service-worker-unregister.html
new file mode 100644
index 00000000000000..a78775a5a2c7a5
--- /dev/null
+++ b/speculation-rules/prerender/resources/service-worker-unregister.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
+<script src="/speculation-rules/prerender/resources/utils.js"></script>
+<script src="/speculation-rules/prerender/resources/deferred-promise-utils.js"></script>
+<body>
+<script type="module">
+
+const params = new URLSearchParams(location.search);
+const uid = params.get('uid');
+
+// The main test page (restriction-service-worker-unregister.https.html) loads
+// the initiator page, then the initiator page will prerender itself with the
+// `prerendering` parameter.
+const isPrerendering = params.has('prerendering');
+
+if (!isPrerendering) {
+  loadInitiatorPage();
+} else {
+  const registration =
+      await navigator.serviceWorker.getRegistration(location.href);
+
+  const prerenderEventCollector = new PrerenderEventCollector();
+  const promise = registration.unregister()
+      .then(registration => {
+        prerenderEventCollector.addEvent('service worker unregistered');
+      });
+  prerenderEventCollector.start(
+      promise, 'ServiceWorkerRegistration.unregister');
+}
+
+</script>
+</body>
diff --git a/speculation-rules/prerender/restriction-service-worker-unregister.https.html b/speculation-rules/prerender/restriction-service-worker-unregister.https.html
new file mode 100644
index 00000000000000..669e7ee0a27555
--- /dev/null
+++ b/speculation-rules/prerender/restriction-service-worker-unregister.https.html
@@ -0,0 +1,56 @@
+<!DOCTYPE html>
+<title>ServiceWorkerRegistration.unregister in a prerendered page</title>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
+<script src="/speculation-rules/prerender/resources/utils.js"></script>
+<body>
+<script>
+
+setup(() => assertSpeculationRulesIsSupported());
+
+const uid = token();
+
+const PAGE_URL = `resources/service-worker-unregister.html?uid=${uid}`;
+const WORKER_URL = 'resources/do-nothing-worker.js';
+
+promise_test(async t => {
+  const registration =
+      await navigator.serviceWorker.register(WORKER_URL, {scope: PAGE_URL});
+  t.add_cleanup(_ => registration.unregister());
+
+  const bc = new PrerenderChannel('test-channel', uid);
+  t.add_cleanup(_ => bc.close());
+
+  const gotMessage = new Promise(resolve => {
+    bc.addEventListener('message', e => {
+      resolve(e.data);
+    }, {
+      once: true
+    });
+  });
+  window.open(PAGE_URL, '_blank', 'noopener');
+
+  const result = await gotMessage;
+  const expected = [
+    {event: 'started waiting ServiceWorkerRegistration.unregister',  prerendering: true},
+    {event: 'prerendering change',                                   prerendering: false},
+    {event: 'service worker unregistered',                           prerendering: false},
+    {event: 'finished waiting ServiceWorkerRegistration.unregister', prerendering: false},
+  ];
+  assert_equals(result.length, expected.length);
+  for (let i = 0; i < result.length; i++) {
+    assert_equals(result[i].event, expected[i].event, `event[${i}]`);
+    assert_equals(result[i].prerendering, expected[i].prerendering,
+      `prerendering[${i}]`);
+  }
+
+  // Send a close signal to PrerenderEventCollector on the prerendered page.
+  new PrerenderChannel('close', uid).postMessage('');
+}, 'ServiceWorkerRegistration.unregister() should be deferred in a ' +
+   'prerendered page');
+
+</script>
+</body>
