Add resource load priority Service Worker tests

This CL adds resource load priority tests ensuring that the priority of
requests that pass through a Service Worker is preserved.

R=kinuko@chromium.org, kouhei@chromium.org, yhirano@chromium.org

Bug: 872776
Change-Id: I74f334359b3255fcac5c13fbdb9f1e601af0f8f0
Reviewed-on: https://chromium-review.googlesource.com/c/1316104
Commit-Queue: Dominic Farolino <domfarolino@gmail.com>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606689}

third_party/WebKit/LayoutTests/http/tests/priorities/resource-load-priorities-service-worker.https-expected.txt

+This is a testharness.js-based test.
+PASS registering service worker
+PASS Requests from the Fetch API passing through a Service Worker should be loaded with kHigh priority
+PASS Render-blocking style sheets requests passing through a Service Worker should be loaded with kVeryHigh priority
+FAIL Async scripts passing through a Service Worker should be loaded with kLow priority assert_equals: expected 1 but got 3
+FAIL Deferred scripts passing through a Service Worker should be loaded with kLow priority assert_equals: expected 1 but got 3
+PASS Module scripts passing through a Service Worker should be loaded with kHigh priority
+PASS XHRs passing through a Service Worker should be loaded with kHigh priority
+PASS Parser-blocking scripts passing through a Service Worker should be loaded with kHigh priority
+FAIL Off-screen images passing through a Service Worker should be loaded with kLow priority assert_equals: expected 1 but got 3
+FAIL Prefetches passing through a Service Worker should be loaded with kLowest priority assert_equals: expected 0 but got 3
+PASS unregistering service worker
+Harness: the test ran to completion.
+

third_party/WebKit/LayoutTests/http/tests/priorities/resource-load-priorities-service-worker.https.html

+<title>ResourceLoadPriority tests through Service Worker</title>
+
+<script src="resources/common.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/serviceworker/resources/test-helpers.js"></script>
+
+<script>
+function openWindow(url, t) {
+  const win = window.open(url, '_blank');
+  t.add_cleanup(() => win.close());
+}
+
+function resource_load_priority_service_worker_test(url, expected_priority,
+                                                    description) {
+  promise_test(t => {
+    const serviceWorkerPriority = new Promise(resolve => {
+      navigator.serviceWorker.onmessage = resolve;
+    });
+
+    const subresourceFinishedLoading = new Promise(resolve => {
+      window.onmessage = e => {
+        assert_not_equals(e.data, 'FAILED',
+        `Resources requested in the test window ${url} should have loaded`);
+        resolve();
+      }
+    });
+
+    openWindow(url, t);
+
+    return Promise.all([serviceWorkerPriority, subresourceFinishedLoading])
+      .then(promiseValues => {
+        // Return the promise value associated with the service worker priority event.
+        return promiseValues[0];
+      })
+      .then(priority_event => {
+        assert_not_equals(priority_event.data, 'FAILED',
+          'The resource failed to load for some reason.');
+        assert_equals(priority_event.data, expected_priority);
+      });
+  }, description);
+}
+
+promise_test(t => {
+  return service_worker_unregister_and_register(t,
+    'service-worker-get-priority.js', '/priorities/')
+    .then(r => {
+      return wait_for_state(t, r.installing, 'activated');
+    });
+}, 'registering service worker');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/fetch.html', kHigh,
+  'Requests from the Fetch API passing through a Service Worker should be ' +
+  'loaded with kHigh priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/render-blocking-stylesheet.html', kVeryHigh,
+  'Render-blocking style sheets requests passing through a Service Worker ' +
+  'should be loaded with kVeryHigh priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/async-script.html', kLow,
+  'Async scripts passing through a Service Worker should be loaded with kLow ' +
+  'priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/defer-script.html', kLow,
+  'Deferred scripts passing through a Service Worker should be loaded with ' +
+  'kLow priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/module-script.html', kHigh,
+  'Module scripts passing through a Service Worker should be loaded with ' +
+  'kHigh priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/xhr.html', kHigh,
+  'XHRs passing through a Service Worker should be loaded with kHigh priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/parser-blocking-script.html', kHigh,
+  'Parser-blocking scripts passing through a Service Worker should be loaded ' +
+  'with kHigh priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/off-screen-image.html', kLow,
+  'Off-screen images passing through a Service Worker should be loaded with ' +
+  'kLow priority');
+
+resource_load_priority_service_worker_test(
+  'resources/service-worker/prefetch.html', kVeryLow,
+  'Prefetches passing through a Service Worker should be loaded with kLowest ' +
+  'priority');
+
+// TODO(domfarolino): Add a synchronous XHR test when https://crbug.com/602051
+// is resolved.
+
+promise_test(t => {
+  return service_worker_unregister(t, '/priorities/');
+}, 'unregistering service worker');
+</script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/common.js

@@ -5,7 +5,8 @@
  * and in these tests, we use the below variables to represent
  * the exposed values in a readable way.
  */
-const kLow = 1,
+const kVeryLow = 0,
+      kLow = 1,
       kMedium = 2,
       kHigh = 3,
       kVeryHigh = 4;
@@ -16,6 +17,10 @@ function reportPriority(url, optionalDoc) {
   window.opener.postMessage(loadPriority, '*');
 }
 
+function reportLoaded() {
+  window.opener.postMessage('LOADED', '*');
+}
+
 function reportFailure() {
   window.opener.postMessage('FAILED', '*');
 }

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/async-script.html

+<script src="../common.js"></script>
+<script src="../../../resources/dummy.js?async&getPriority" async onload="reportLoaded()" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/defer-script.html

+<script src="../common.js"></script>
+<script src="../../../resources/dummy.js?defer&getPriority" defer onload="reportLoaded()" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/fetch.html

+<script src="../common.js"></script>
+<script>
+  fetch('../../../resources/dummy.html?getPriority')
+    .then(reportLoaded, reportFailure);
+</script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/module-script.html

+<script src="../common.js"></script>
+<script src="../../../resources/dummy.js?module&getPriority" type=module onload="reportLoaded()" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/off-screen-image.html

+<script src="../common.js"></script>
+<script>
+  const image = new Image();
+  image.src = '../../../resources/square.png?getPriority';
+
+  image.onload = reportLoaded;
+  image.onerror = reportFailure;
+</script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/parser-blocking-script.html

+<script src="../common.js"></script>
+<script src="../../../resources/dummy.js?normal&getPriority" onload="reportLoaded()" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/prefetch.html

+<script src="../common.js"></script>
+<link rel=prefetch href="../../../resources/dummy.html?getPriority" onload="reportLoaded()" onerror="reportFailure()">

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/render-blocking-stylesheet.html

+<script src="../common.js"></script>
+
+<!-- Media-matching style sheets block rendering, and are critical -->
+<link rel="stylesheet" href="../../../resources/dummy.css?getPriority" onload="reportLoaded()" onerror="reportFailure()">

third_party/WebKit/LayoutTests/http/tests/priorities/resources/service-worker/xhr.html

+<script src="../common.js"></script>
+<script>
+  const xhr = new XMLHttpRequest();
+  xhr.open('GET', '../../../resources/dummy.html?getPriority');
+  xhr.send();
+
+  xhr.onload = reportLoaded;
+  xhr.onerror = reportFailure;
+</script>

third_party/WebKit/LayoutTests/http/tests/priorities/service-worker-get-priority.js

+addEventListener('fetch', e => {
+  if (e.request.url.endsWith('getPriority'))
+    e.respondWith(fetchAndMessagePriority(e.request));
+});
+
+async function fetchAndMessagePriority(request) {
+  const response = await fetch(request);
+  const priority = internals.getResourcePriority(request.url, this);
+  const clientArray = await clients.matchAll({includeUncontrolled: true});
+  clientArray.forEach(client => {
+    client.postMessage(priority);
+  });
+
+  return response;
+}