Add initial resource load priority layout tests

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

Bug: 882344
Change-Id: I42e264f9fc1591129091aa9f18b258a4e2313181
Reviewed-on: https://chromium-review.googlesource.com/c/1249400
Commit-Queue: Dominic Farolino <domfarolino@gmail.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604181}

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

+<title>ResourceLoadPriority tests</title>
+
+<script src="resources/common.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+function openWindow(url) {
+  const win = window.open(url, '_blank');
+  add_result_callback(() => win.close());
+  return win;
+}
+
+function resource_load_priority_test(windowURL, expected_priority, description) {
+  promise_test(async () => {
+    openWindow('resources/' + windowURL);
+    const priority_event =
+      await new Promise(resolve => window.onmessage = resolve);
+    assert_not_equals(priority_event.data,
+                      'FAILED',
+                      'The resource failed to load for some reason.');
+
+    assert_equals(priority_event.data, expected_priority);
+  }, description);
+}
+
+resource_load_priority_test(
+  'off-screen-image.html', kLow,
+  'Off-screen images should be loaded with kLow priority');
+
+resource_load_priority_test(
+  'render-blocking-stylesheet.html', kVeryHigh,
+  'Render-blocking style sheets should be loaded with kVeryHigh priority');
+
+resource_load_priority_test(
+  'parser-blocking-script.html', kHigh,
+  'Parser-blocking scripts should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'async-script.html', kHigh,
+  'Async scripts should be loaded with kLow priority');
+
+resource_load_priority_test(
+  'defer-script.html', kHigh,
+  'Deferred scripts should be loaded with kLow priority');
+
+resource_load_priority_test(
+  'module-script.html', kHigh,
+  'Module scripts should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'iframe.html', kVeryHigh, 'Iframes should be loaded with kVeryHigh priority');
+
+resource_load_priority_test(
+  'fetch.html', kHigh,
+  'Requests from the Fetch API should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'xhr.html', kHigh, 'XHRs should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'sync-xhr.html', kVeryHigh,
+  'Synchronous XHRs should be loaded with kVeryHigh priority');
+
+// Preload tests.
+resource_load_priority_test(
+  'preload/as-style.html', kVeryHigh,
+  'Preloaded style sheets should be loaded with kVeryHigh priority');
+
+resource_load_priority_test(
+  'preload/as-script.html', kHigh,
+  'Preloaded scripts should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'preload/as-font.html', kHigh,
+  'Preloaded fonts should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'preload/as-audio.html', kLow,
+  'Preloaded audio files should be loaded with kLow priority');
+
+resource_load_priority_test(
+  'preload/as-video.html', kLow,
+  'Preloaded videos should be loaded with kLow priority');
+
+resource_load_priority_test(
+  'preload/as-fetch.html', kHigh,
+  'Preloaded fetches should be loaded with kHigh priority');
+
+resource_load_priority_test(
+  'preload/as-image.html', kLow,
+  'Preloaded images should be loaded with kLow priority');
+</script>

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

+<script src="common.js"></script>
+<script src="../../resources/dummy.js" async onload="reportPriority(this.src)" onerror="reportFailure()"></script>

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

+/**
+ * These values map to some of the the current
+ * priority enum members in blink::ResourceLoadPriority.
+ * The values are exposed through window.internals
+ * and in these tests, we use the below variables to represent
+ * the exposed values in a readable way.
+ */
+const kLow = 1,
+      kMedium = 2,
+      kHigh = 3,
+      kVeryHigh = 4;
+
+function reportPriority(url, optionalDoc) {
+  const documentToUse = optionalDoc ? optionalDoc : document;
+  const loadPriority = internals.getResourcePriority(url, documentToUse);
+  window.opener.postMessage(loadPriority, '*');
+}
+
+function reportFailure() {
+  window.opener.postMessage('FAILED', '*');
+}

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

+<script src="common.js"></script>
+<script src="../../resources/dummy.js" defer onload="reportPriority(this.src)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/fetch.html

+<script src="common.js"></script>
+<script>
+  fetch('../../resources/dummy.html')
+    .then(response => {
+      reportPriority(response.url);
+    })
+    .catch(() => {
+      reportFailure();
+    });
+</script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/iframe.html

+<script src="common.js"></script>
+<iframe src="../../resources/dummy.html" onload="reportPriority(this.src, this.contentDocument)" onerror="reportFailure()"></iframe>

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

+<script src="common.js"></script>
+<script src="../../resources/dummy.js" type=module onload="reportPriority(this.src)" onerror="reportFailure()"></script>

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

+<script src="common.js"></script>
+<script>
+  const image = new Image();
+  image.src = '../../resources/square.png';
+
+  image.onload = e => {
+    reportPriority(image.src);
+  };
+
+  image.onerror = e => reportFailure;
+</script>

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

+<script src="common.js"></script>
+<script src="../../resources/dummy.js" onload="reportPriority(this.src)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-audio.html

+<script src="../common.js"></script>
+
+<link rel="preload" as="audio" href="../../../resources/test.wav" type="audio/wav" onload="reportPriority(this.href)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-fetch.html

+<script src="../common.js"></script>
+
+<link rel="preload" as="fetch" href=../../../resources/dummy.html onload="reportPriority(this.href)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-font.html

+<script src="../common.js"></script>
+
+<link rel="preload" as="font" href=../../../resources/Ahem.ttf type="font/ttf" onload="reportPriority(this.href)" onerror="reportFailure()">

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-image.html

+<script src="../common.js"></script>
+
+<link rel="preload" as="image" href="../../../resources/square.png" onload="reportPriority(this.href)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-script.html

+<script src="../common.js"></script>
+
+<link rel="preload" as="script" href="../../../resources/dummy.js" onload="reportPriority(this.href)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-style.html

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

third_party/WebKit/LayoutTests/http/tests/priorities/resources/preload/as-video.html

+<script src="../common.js"></script>
+
+<link rel="preload" as="video" href=../../../resources/test.mp4 type="video/mp4" onload="reportPriority(this.href)" onerror="reportFailure()"></script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/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" onload="reportPriority(this.href)" onerror="reportFailure()">

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

+<script src="common.js"></script>
+<script>
+  const xhr = new XMLHttpRequest();
+  xhr.open('GET', '../../resources/dummy.html', false);
+  xhr.send();
+
+  if (xhr.status === 200)
+    reportPriority(xhr.responseURL);
+  else
+    reportFailure();
+</script>

third_party/WebKit/LayoutTests/http/tests/priorities/resources/xhr.html

+<script src="common.js"></script>
+<script>
+  const xhr = new XMLHttpRequest();
+  xhr.open('GET', '../../resources/dummy.html');
+  xhr.send();
+
+  xhr.onload = e => {
+    reportPriority(xhr.responseURL);
+  }
+
+  xhr.onerror = reportFailure;
+</script>