Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-07 19:33:14 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-07 19:33:14 +0000
commit: 36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree: 105e8c98ddea1c1e4784a60a5a6410fa416be2de /testing/web-platform/tests/resource-timing
parent: Initial commit. (diff)
download: firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
214 files changed, 8193 insertions, 0 deletions
diff --git a/testing/web-platform/tests/resource-timing/304-response-recorded.html b/testing/web-platform/tests/resource-timing/304-response-recorded.html
new file mode 100644
index 0000000000..9e1bb3045c
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/304-response-recorded.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing - cached resources generate performance entries</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help"
+  href="https://www.w3.org/TR/resource-timing-2/#resources-included-in-the-performanceresourcetiming-interface"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that a 304 Not Modified resource appears in the
+Performance Timeline.</p>
+<script>
+// Need to fetch the same resource twice; the first will get a 200 response but
+// the second request should be cached and get a 304.
+promise_test(async () => {
+  performance.clearResourceTimings();
+
+  const unique = Math.random();
+  const path = `resources/fake_responses.py?tag=${unique}`;
+
+  await load.xhr_sync(path);
+  await load.xhr_sync(path, {"If-None-Match": `${unique}`});
+  const entries = await new Promise(resolve => {
+    const accumulator = [];
+    new PerformanceObserver(entry_list => {
+      entry_list.getEntries().forEach(entry => {
+        accumulator.push(entry);
+      });
+      if (accumulator.length >= 2) {
+        resolve(accumulator);
+      }
+    }).observe({'type': 'resource', 'buffered': true});
+  });
+
+
+  if (entries.length != 2) {
+    throw new Error(`Expecting 2 but got ${entries.length} entries`);
+  }
+
+  assert_equals(entries[0].name, entries[1].name,
+    "Both entries should have the same name");
+  invariants.assert_tao_pass_no_redirect_http(entries[0]);
+  invariants.assert_tao_pass_304_not_modified_http(entries[1]);
+}, "304 responses should still show up in the PerformanceTimeline");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/CodingConventions.md b/testing/web-platform/tests/resource-timing/CodingConventions.md
new file mode 100644
index 0000000000..39b8d13435
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/CodingConventions.md
@@ -0,0 +1,77 @@
+For [Resource Timing][1] tests, we want to have a consistent and clear coding
+style. The goals of this style are to:
+*   Make it easier for new contributors to find their way around
+*   Help improve readability and maintainability
+*   Help us understand which parts of the spec are tested or not
+Lots of the following rules are arbitrary but the value is realized in
+consistency instead of adhering to the 'perfect' style.
+
+We want the test suite to be navigable. Developers should be able to easily
+find the file or test that is relevant to their work.
+*   Tests should be arranged in files according to which piece of the spec they
+    test
+*   Files should be named using a consistent pattern
+*   HTML files should include useful meta tags
+    *   `<title>` for controlling labels in results pages
+    *   `<link rel="help">` to point at the relevant piece of the spec
+
+We want the test suite to run consistently. Flaky tests are counterproductive.
+*   Prefer `promise_test` to `async_test`
+    *   Note that there’s [still potential for some concurrency][2]; use
+        `add_cleanup()` if needed
+
+We want the tests to be readable. Tests should be written in a modern style
+with recurring patterns.
+*   80 character line limits where we can
+*   Consistent use of anonymous functions
+    *   prefer
+        ```
+        const func1 = param1 => {
+          body();
+        }
+        const func2 = (param1, param2) => {
+          body();
+        }
+        fn(param => {
+            body();
+        });
+        ```
+
+        over
+
+        ```
+        function func1(param1) {
+          body();
+        }
+        function func2(param1, param2) {
+          body();
+        }
+        fn(function(param) {
+            body();
+        });
+        ```
+
+*   Prefer `const` (or, if needed, `let`) to `var`
+*   Contain use of ‘.sub’ in filenames to known helper utilities where possible
+    *   E.g. prefer use of get-host-info.sub.js to `{{host}}` or `{{ports[0]}}`
+        expressions
+*   Avoid use of webperftestharness[extension].js as it’s a layer of cognitive
+    overhead between test content and test intent
+    *   Helper .js files are still encouraged where it makes sense but we want
+        to avoid a testing framework that is specific to Resource Timing (or
+        web performance APIs, in general).
+*   Prefer [`fetch_tests_from_window`][3] to collect test results from embedded
+    iframes instead of hand-rolled `postMessage` approaches
+*   Use the [`assert_*`][4] family of functions to check conformance to the spec
+    but throw exceptions explicitly when the test itself is broken.
+    *    A failed assert indicates "the implementation doesn't conform to the
+         spec"
+    *    Other uncaught exceptions indicate "the test case itself has a bug"
+*   Where possible, we want tests to be scalable - adding another test case
+    should be as simple as calling the tests with new parameters, rather than
+    copying an existing test and modifying it.
+
+[1]: https://www.w3.org/TR/resource-timing-2/
+[2]: https://web-platform-tests.org/writing-tests/testharness-api.html#promise-tests
+[3]: https://web-platform-tests.org/writing-tests/testharness-api.html#consolidating-tests-from-other-documents
+[4]: https://web-platform-tests.org/writing-tests/testharness-api.html#list-of-assertions
diff --git a/testing/web-platform/tests/resource-timing/META.yml b/testing/web-platform/tests/resource-timing/META.yml
new file mode 100644
index 0000000000..662c42cb66
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/META.yml
@@ -0,0 +1,6 @@
+spec: https://w3c.github.io/resource-timing/
+suggested_reviewers:
+  - plehegar
+  - zqzhang
+  - igrigorik
+  - yoavweiss
diff --git a/testing/web-platform/tests/resource-timing/SO-XO-SO-redirect-chain-tao.https.html b/testing/web-platform/tests/resource-timing/SO-XO-SO-redirect-chain-tao.https.html
new file mode 100644
index 0000000000..e6568910e4
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/SO-XO-SO-redirect-chain-tao.https.html
@@ -0,0 +1,64 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates resource timing information for a same-origin=>cross-origin=>same-origin redirect chain without Timing-Allow-Origin.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-cross-origin-resources"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+</head>
+<body>
+<script>
+const {HTTPS_REMOTE_ORIGIN} = get_host_info();
+const SAME_ORIGIN = location.origin;
+// Same-Origin => Cross-Origin => Same-Origin => Same-Origin redirect chain
+let destUrl = `${SAME_ORIGIN}/resource-timing/resources/multi_redirect.py?`;
+destUrl += `page_origin=${SAME_ORIGIN}`;
+destUrl += `&cross_origin=${HTTPS_REMOTE_ORIGIN}`;
+destUrl += `&final_resource=/resource-timing/resources/blank_page_green.htm`;
+
+// No TAO in the redirect chain
+attribute_test(
+  load.iframe, destUrl,
+  invariants.assert_cross_origin_redirected_resource,
+  "Verify that cross origin resources' timings are not exposed when " +
+  "same-origin=>cross-origin=>same-origin redirects have no " +
+  "`Timing-Allow-Origin:` headers.");
+
+// Partial TAO in the redirect chain
+destUrl += '&tao_steps=2';
+attribute_test(
+  load.iframe, destUrl,
+  invariants.assert_cross_origin_redirected_resource,
+  "Verify that cross origin resources' timings are not exposed when " +
+  "same-origin=>cross-origin=>same-origin redirects have " +
+  "`Timing-Allow-Origin:` headers only on some of the responses.");
+
+// Cross-origin => Cross-Origin => Same-Origin => Same-Origin redirect chain.
+destUrl = `${HTTPS_REMOTE_ORIGIN}/resource-timing/resources/multi_redirect.py?`;
+destUrl += `page_origin=${SAME_ORIGIN}`;
+destUrl += `&cross_origin=${HTTPS_REMOTE_ORIGIN}`;
+destUrl += `&final_resource=/resource-timing/resources/blue-with-tao.png`;
+destUrl += `&tao_steps=3`;
+
+// Full redirect chain with `TAO: *`.
+attribute_test(
+  load.image, destUrl,
+  invariants.assert_tao_enabled_cross_origin_redirected_resource,
+  "Verify that cross origin resources' timings are exposed when cross-origin " +
+  "redirects have `Timing-Allow-Origin: *` headers");
+
+// TAO with a specific origin
+destUrl += `&tao_value=${SAME_ORIGIN}`;
+attribute_test(
+  load.image, destUrl,
+  invariants.assert_cross_origin_redirected_resource,
+  "Verify that cross origin resources' timings are not exposed when " +
+  "same-origin=>cross-origin=>same-origin redirects have " +
+  "`Timing-Allow-Origin:` headers with a specific origin.");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/SyntheticResponse.py b/testing/web-platform/tests/resource-timing/SyntheticResponse.py
new file mode 100644
index 0000000000..6f888f3789
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/SyntheticResponse.py
@@ -0,0 +1,50 @@
+from urllib.parse import unquote
+
+from wptserve.utils import isomorphic_decode, isomorphic_encode
+
+import importlib
+sleep = importlib.import_module("resource-timing.sleep")
+
+def main(request, response):
+    index = isomorphic_encode(request.request_path).index(b"?")
+    args = isomorphic_encode(request.request_path[index+1:]).split(b"&")
+    headers = []
+    statusSent = False
+    headersSent = False
+    for arg in args:
+        if arg.startswith(b"ignored"):
+            continue
+        elif arg.endswith(b"ms"):
+            sleep.sleep_at_least(float(arg[0:-2]))
+        elif arg.startswith(b"redirect:"):
+            return (302, u"WEBPERF MARKETING"), [(b"Location", unquote(isomorphic_decode(arg[9:])))], u"TEST"
+
+        elif arg.startswith(b"mime:"):
+            headers.append((b"Content-Type", unquote(isomorphic_decode(arg[5:]))))
+
+        elif arg.startswith(b"send:"):
+            text = unquote(isomorphic_decode(arg[5:]))
+
+            if not statusSent:
+                # Default to a 200 status code.
+                response.writer.write_status(200)
+                statusSent = True
+            if not headersSent:
+                for key, value in headers:
+                    response.writer.write_header(key, value)
+                response.writer.end_headers()
+                headersSent = True
+
+            response.writer.write_content(text)
+        elif arg.startswith(b"status:"):
+            code = int(unquote(isomorphic_decode(arg[7:])))
+            response.writer.write_status(code)
+            if code // 100 == 1:
+                # Terminate informational 1XX responses with an empty line.
+                response.writer.end_headers()
+            else:
+                statusSent = True
+
+#        else:
+#            error "  INVALID ARGUMENT %s" % arg
+
diff --git a/testing/web-platform/tests/resource-timing/TAO-match.html b/testing/web-platform/tests/resource-timing/TAO-match.html
new file mode 100644
index 0000000000..dc0e2f7443
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/TAO-match.html
@@ -0,0 +1,82 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing TAO tests</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help"
+      href="https://www.w3.org/TR/resource-timing-2/#timing-allow-origin"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/common/custom-cors-response.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/tao-response.js"></script>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+
+const run_test = (loader, resource_type) => {
+  attribute_test(loader, remote_tao_response(ORIGIN),
+    invariants.assert_tao_pass_no_redirect_http,
+    `The timing allow check algorithm will pass when the Timing-Allow-Origin ` +
+    `header value contains only the origin. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response('*'),
+    invariants.assert_tao_pass_no_redirect_http,
+    `The timing allow check algorithm will pass when the Timing-Allow-Origin ` +
+    `header value contains only a wildcard. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response(`${ORIGIN},fake`),
+    invariants.assert_tao_pass_no_redirect_http,
+    `The timing allow check algorithm will pass when the Timing-Allow-Origin ` +
+    `header value list contains a case-sensitive match. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response(`${ORIGIN},*`),
+    invariants.assert_tao_pass_no_redirect_http,
+    `The timing allow check algorithm will pass when the Timing-Allow-Origin ` +
+    `header value list contains the origin and a wildcard. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response('fake,*'),
+    invariants.assert_tao_pass_no_redirect_http,
+    `The timing allow check algorithm will pass when the Timing-Allow-Origin ` +
+    `header value list contains a wildcard. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response('null'),
+    invariants.assert_tao_failure_resource,
+    `The timing allow check algorithm will fail when the Timing-Allow-Origin ` +
+    `header value list contains a null origin. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response('*,*'),
+    invariants.assert_tao_pass_no_redirect_http,
+    `The timing allow check algorithm will pass when the Timing-Allow-Origin ` +
+    `header value list contains multiple wildcards. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response(ORIGIN.toUpperCase()),
+    invariants.assert_tao_failure_resource,
+    `The timing allow check algorithm will fail when the Timing-Allow-Origin ` +
+    `header value contains only the uppercased origin. (${resource_type})`);
+
+  attribute_test(loader, remote_tao_response(`${ORIGIN} *`),
+    invariants.assert_tao_failure_resource,
+    `The timing allow check algorithm will fail when the Timing-Allow-Origin ` +
+    `header value contains the origin, a space, then a wildcard. ` +
+    `(${resource_type})`);
+
+  attribute_test(loader, custom_cors_response({}, REMOTE_ORIGIN),
+    invariants.assert_tao_failure_resource,
+    `The timing allow check algorithm will fail when the Timing-Allow-Origin ` +
+    `header is not present. (${resource_type})`);
+};
+
+run_test(load.font, "font");
+run_test(load.iframe, "iframe");
+run_test(load.image, "image");
+run_test(load.script, "script");
+run_test(load.stylesheet, "stylesheet");
+run_test(load.xhr_sync, "XMLHttpRequest");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/TAO-port-mismatch-means-crossorigin.html b/testing/web-platform/tests/resource-timing/TAO-port-mismatch-means-crossorigin.html
new file mode 100644
index 0000000000..f1218d17a0
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/TAO-port-mismatch-means-crossorigin.html
@@ -0,0 +1,46 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>TAO - port mismatch must fail the check</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-timing-allow-origin"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script>
+
+const {ORIGINAL_HOST, PORT, PORT2} = get_host_info();
+
+// The main page is being requested on the default port (PORT), while the
+// subresource will be requested on a separate port (PORT2). The response will
+// have a Timing-Allow-Origin header value with the second port so this page's
+// origin should not be a match.
+const port_mismatch_url = `${location.protocol}//${ORIGINAL_HOST}:${PORT2}` +
+                          `/resource-timing/resources/TAOResponse.py?` +
+                          `tao=origin_port_${PORT2}`;
+attribute_test(
+  fetch, port_mismatch_url, invariants.assert_tao_failure_resource,
+  "A port mismatch must fail the TAO check");
+
+// The same URL as above except the Timing-Allow-Origin header will have the
+// same port as this page's origin. Therefore, this page's origin will match
+// the Timing-Allow-Origin header's value. Therefore, the subresource's timings
+// must be exposed.
+const port_match_url = `${location.protocol}//${ORIGINAL_HOST}:${PORT2}` +
+                       `/resource-timing/resources/TAOResponse.py?` +
+                       `tao=origin_port_${PORT}`;
+attribute_test(
+  fetch, port_match_url, invariants.assert_tao_pass_no_redirect_http,
+  "An identical port must pass the TAO check");
+
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that for a cross origin resource with different ports,
+the timing allow check algorithm will fail when the value of
+Timing-Allow-Origin value has the right host but the wrong port in it.</p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/__init__.py b/testing/web-platform/tests/resource-timing/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/__init__.py
diff --git a/testing/web-platform/tests/resource-timing/body-size-cross-origin.https.html b/testing/web-platform/tests/resource-timing/body-size-cross-origin.https.html
new file mode 100644
index 0000000000..b0340139bf
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/body-size-cross-origin.https.html
@@ -0,0 +1,63 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Verify that encodedBodySize/decodedBodySize are CORS-protected rather than TAO-protected</title>
+<link rel="author" title="Noam Rosenthal" href="nrosenthal@chromium.org">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/common/utils.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+
+async function test_body_size({mode, tao, expected_body_sizes}) {
+    promise_test(async t => {
+        const origin = mode === "same-origin" ? ORIGIN : REMOTE_ORIGIN;
+        const url = new URL(`${origin}/images/red.png?uid=${token()}`,
+                            location.href);
+        const pipes = [];
+        if (mode === "cors")
+            pipes.push("header(Access-Control-Allow-Origin,*)");
+        if (tao)
+            pipes.push("header(Timing-Allow-Origin,*)");
+        const img = document.createElement("img");
+        if (mode === "cors")
+            img.crossOrigin = "anonymous";
+
+        if (pipes.length)
+            url.searchParams.set("pipe", pipes.join("|"));
+        img.src = url.toString();
+        await img.decode();
+        const [entry] = performance.getEntriesByName(url.toString());
+        if (expected_body_sizes) {
+            assert_greater_than(entry.encodedBodySize, 0);
+            assert_greater_than(entry.decodedBodySize, 0);
+        } else {
+            assert_equals(entry.encodedBodySize, 0);
+            assert_equals(entry.decodedBodySize, 0);
+        }
+
+        if (tao || mode === "same-origin")
+          assert_equals(entry.transferSize, entry.encodedBodySize + 300);
+        else
+          assert_equals(entry.transferSize, 0);
+
+    }, `Retrieving a ${mode} resource ${
+        tao ? "with" : "without"} Timing-Allow-Origin should ${
+        expected_body_sizes ? "expose" : "not expose"
+        } body size`);
+}
+
+test_body_size({mode: "same-origin", tao: false, expected_body_sizes: true});
+test_body_size({mode: "same-origin", tao: true, expected_body_sizes: true});
+test_body_size({mode: "no-cors", tao: false, expected_body_sizes: false});
+test_body_size({mode: "no-cors", tao: true, expected_body_sizes: false});
+test_body_size({mode: "cors", tao: false, expected_body_sizes: true});
+test_body_size({mode: "cors", tao: true, expected_body_sizes: true});
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-add-after-full-event.html b/testing/web-platform/tests/resource-timing/buffer-full-add-after-full-event.html
new file mode 100644
index 0000000000..43dc3d84fd
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-add-after-full-event.html
@@ -0,0 +1,27 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-setresourcetimingbuffersize">
+<title>This test validates that setResourceTimingBufferFull behaves appropriately when set to the current buffer level.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    await forceBufferFullEvent();
+    performance.clearResourceTimings();
+    return new Promise(resolve => {
+      new PerformanceObserver(t.step_func(() => {
+        assert_equals(performance.getEntriesByType('resource').length, 1,
+            'The entry should be available in the performance timeline!');
+        resolve();
+      })).observe({type: 'resource'});
+      load.script(scriptResources[2]);
+    });
+}, "Test that entry was added to the buffer after a buffer full event");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-add-entries-during-callback-that-drop.html b/testing/web-platform/tests/resource-timing/buffer-full-add-entries-during-callback-that-drop.html
new file mode 100644
index 0000000000..b00185c5b6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-add-entries-during-callback-that-drop.html
@@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates that synchronously adding entries in onresourcetimingbufferfull callback results in these entries being properly handled.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    await fillUpTheBufferWithSingleResource();
+    performance.addEventListener('resourcetimingbufferfull', () => {
+        performance.setResourceTimingBufferSize(2);
+        // The sync entry is added to the secondary buffer, so will be the last one there and eventually dropped.
+        load.xhr_sync(scriptResources[2]);
+    });
+    // This resource overflows the entry buffer, and goes into the secondary buffer.
+    load.script(scriptResources[1]);
+    await bufferFullFirePromise;
+    checkEntries(2);
+}, "Test that entries synchronously added to the buffer during the callback are dropped");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-add-entries-during-callback.html b/testing/web-platform/tests/resource-timing/buffer-full-add-entries-during-callback.html
new file mode 100644
index 0000000000..d5883d33d5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-add-entries-during-callback.html
@@ -0,0 +1,28 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates that synchronously adding entries in onresourcetimingbufferfull callback results in these entries being properly handled.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    await fillUpTheBufferWithSingleResource();
+    performance.addEventListener('resourcetimingbufferfull', () => {
+        performance.setResourceTimingBufferSize(3);
+        load.xhr_sync(scriptResources[2]);
+    });
+    // This resource overflows the entry buffer, and goes into the secondary buffer.
+    load.script(scriptResources[1]);
+    await bufferFullFirePromise;
+    checkEntries(3);
+}, "Test that entries synchronously added to the buffer during the callback don't get dropped if the buffer is increased");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-add-then-clear.html b/testing/web-platform/tests/resource-timing/buffer-full-add-then-clear.html
new file mode 100644
index 0000000000..5617c30b88
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-add-then-clear.html
@@ -0,0 +1,31 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates that synchronously adding entries in onresourcetimingbufferfull callback results in these entries being properly handled.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    addAssertUnreachedBufferFull(t);
+    await fillUpTheBufferWithSingleResource('resources/empty.js?willbelost');
+    // These resources overflow the entry buffer, and go into the secondary buffer.
+    load.xhr_sync(scriptResources[0]);
+    load.xhr_sync(scriptResources[1]);
+    performance.clearResourceTimings();
+    performance.setResourceTimingBufferSize(3);
+    load.xhr_sync(scriptResources[2]);
+    const entriesAfterAddition = performance.getEntriesByType('resource');
+    await waitForNextTask();
+    checkEntries(3);
+    assert_equals(entriesAfterAddition.length, 0, "No entries should have been added to the primary buffer before the task to 'fire a buffer full event'.");
+}, "Test that if the buffer is cleared after entries were added to the secondary buffer, those entries make it into the primary one");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-decrease-buffer-during-callback.html b/testing/web-platform/tests/resource-timing/buffer-full-decrease-buffer-during-callback.html
new file mode 100644
index 0000000000..3091fcf426
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-decrease-buffer-during-callback.html
@@ -0,0 +1,26 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates that decreasing the buffer size in onresourcetimingbufferfull callback does not result in extra entries being dropped.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    performance.addEventListener('resourcetimingbufferfull', () => {
+        performance.setResourceTimingBufferSize(1);
+    });
+    await fillUpTheBufferWithTwoResources();
+    load.script(scriptResources[2]);
+    await bufferFullFirePromise;
+    checkEntries(2);
+}, "Test that decreasing the buffer limit during the callback does not drop entries");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-eventually.html b/testing/web-platform/tests/resource-timing/buffer-full-eventually.html
new file mode 100644
index 0000000000..6e9d5db483
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-eventually.html
@@ -0,0 +1,31 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<link rel="help"
+      href="http://www.w3.org/TR/resource-timing/#performanceresourcetiming"/>
+<title>This test validates that resource timing implementations have a finite
+       number of entries in their buffer.</title>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+promise_test(t => {
+  return new Promise(resolve => {
+    let counter = 0;
+    performance.onresourcetimingbufferfull = resolve;
+    const loadImagesRecursively = () => {
+      // Load an image.
+      (new Image()).src = "resources/blue.png?" + counter;
+      ++counter;
+      // Yield to enable queueing an entry, then recursively load another image.
+      t.step_timeout(loadImagesRecursively, 0);
+    };
+    loadImagesRecursively();
+  });
+}, "Finite resource timing entries buffer size");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-increase-buffer-during-callback.html b/testing/web-platform/tests/resource-timing/buffer-full-increase-buffer-during-callback.html
new file mode 100644
index 0000000000..dd12dd7afa
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-increase-buffer-during-callback.html
@@ -0,0 +1,26 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates increasing the buffer size in onresourcetimingbufferfull callback of resource timing.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    await fillUpTheBufferWithSingleResource();
+    performance.addEventListener('resourcetimingbufferfull', () => {
+        performance.setResourceTimingBufferSize(2);
+    });
+    await load.script(scriptResources[1]);
+    await bufferFullFirePromise;
+    checkEntries(2);
+}, "Test that increasing the buffer during the callback is enough for entries not to be dropped");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-inspect-buffer-during-callback.html b/testing/web-platform/tests/resource-timing/buffer-full-inspect-buffer-during-callback.html
new file mode 100644
index 0000000000..d5cc8e6ecd
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-inspect-buffer-during-callback.html
@@ -0,0 +1,30 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates the buffer doesn't contain more entries than it should inside onresourcetimingbufferfull callback.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-setresourcetimingbuffersize"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    performance.addEventListener('resourcetimingbufferfull', t.step_func(() => {
+        assert_equals(performance.getEntriesByType("resource").length, 1,
+            "resource timing buffer in resourcetimingbufferfull is the size of the limit");
+        load.xhr_sync(scriptResources[2]);
+        performance.setResourceTimingBufferSize(3);
+        assert_equals(performance.getEntriesByType("resource").length, 1,
+            "A sync request must not be added to the primary buffer just yet, because it is full");
+    }));
+    await forceBufferFullEvent();
+    await waitForNextTask();
+    checkEntries(3);
+}, "Test that entries in the secondary buffer are not exposed during the callback and before they are copied to the primary buffer");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-set-to-current-buffer.html b/testing/web-platform/tests/resource-timing/buffer-full-set-to-current-buffer.html
new file mode 100644
index 0000000000..dc527b9a32
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-set-to-current-buffer.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<title>This test validates that setResourceTimingBufferFull behaves appropriately when set to the current buffer level.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    let result = '';
+    performance.addEventListener('resourcetimingbufferfull', () => {
+        result += 'Event Fired with '  +
+            performance.getEntriesByType('resource').length + ' entries.';
+        performance.clearResourceTimings();
+    });
+    result += 'Before adding entries. ';
+    await fillUpTheBufferWithTwoResources();
+    result += 'After adding entries. ';
+    load.script(scriptResources[2]);
+    await bufferFullFirePromise;
+    assert_equals(result, 'Before adding entries. After adding entries. Event Fired with 2 entries.');
+    const entries = performance.getEntriesByType('resource');
+    assert_equals(entries.length, 1,
+        'Number of entries in resource timing buffer is unexpected');
+    assert_true(entries[0].name.includes(scriptResources[2]),
+        'The entry must correspond to the last resource loaded.')
+}, "Test that adding entries and firing the buffer full event happen in the right order.");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-store-and-clear-during-callback.html b/testing/web-platform/tests/resource-timing/buffer-full-store-and-clear-during-callback.html
new file mode 100644
index 0000000000..3ea0577256
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-store-and-clear-during-callback.html
@@ -0,0 +1,36 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates the behavior of read and clear operation in onresourcetimingbufferfull callback of resource timing.</title>
+<link rel="author" title="Intel" href="http://www.intel.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    await fillUpTheBufferWithSingleResource();
+    const entryBuffer = [];
+    performance.addEventListener('resourcetimingbufferfull', () => {
+      entryBuffer.push(...performance.getEntriesByType('resource'));
+      performance.clearResourceTimings();
+    });
+    load.script(scriptResources[1]);
+    await bufferFullFirePromise;
+    const entries = performance.getEntriesByType('resource');
+    assert_equals(entries.length, 1,
+        "Only the last entry should be stored in resource timing buffer since it's cleared once it overflows.");
+    assert_true(entries[0].name.includes(scriptResources[1]),
+        scriptResources[1]  + " is in the entries buffer");
+    assert_equals(entryBuffer.length, 1,
+        '1 resource timing entry should be moved to entryBuffer.');
+    assert_true(entryBuffer[0].name.includes(scriptResources[0]),
+        scriptResources[0] + ' is in the entryBuffer');
+}, "Test that entries overflowing the buffer trigger the buffer full event, can be stored, and make their way to the primary buffer after it's cleared in the buffer full event.");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-then-decreased.html b/testing/web-platform/tests/resource-timing/buffer-full-then-decreased.html
new file mode 100644
index 0000000000..21912d978b
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-then-decreased.html
@@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates that reducing the buffer size after entries were
+  queued does not drop those entries, nor does it call the
+  resourcetimingbufferfull event callback.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help"
+ href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    addAssertUnreachedBufferFull(t);
+    await fillUpTheBufferWithTwoResources();
+    performance.setResourceTimingBufferSize(1);
+    await waitForNextTask();
+    checkEntries(2);
+}, "Test that if the buffer is reduced after entries were added to it, those" +
+   " entries don't get cleared, nor is the resourcetimingbufferfull event" +
+   " being called.");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-then-increased.html b/testing/web-platform/tests/resource-timing/buffer-full-then-increased.html
new file mode 100644
index 0000000000..de517bf405
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-then-increased.html
@@ -0,0 +1,28 @@
+<!DOCTYPE HTML>
+<html>
+<head onload>
+<meta charset="utf-8" />
+<title>This test validates that synchronously adding entries in onresourcetimingbufferfull callback results in these entries being properly handled.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    addAssertUnreachedBufferFull(t);
+    await fillUpTheBufferWithSingleResource();
+    // These resources overflow the entry buffer, and go into the secondary buffer.
+    load.xhr_sync(scriptResources[1]);
+    load.xhr_sync(scriptResources[2]);
+    // Immediately increase the size: the bufferfull event should not be fired.
+    performance.setResourceTimingBufferSize(3);
+    await waitForNextTask();
+    checkEntries(3);
+}, "Test that overflowing the buffer and immediately increasing its limit does not trigger the resourcetimingbufferfull event");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffer-full-when-populate-entries.html b/testing/web-platform/tests/resource-timing/buffer-full-when-populate-entries.html
new file mode 100644
index 0000000000..f4b1a2e7e7
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffer-full-when-populate-entries.html
@@ -0,0 +1,30 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the functionality of onresourcetimingbufferfull in resource timing.</title>
+<link rel="author" title="Intel" href="http://www.intel.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performance-onresourcetimingbufferfull"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async () => {
+    let bufferFullCount = 0;
+    performance.addEventListener('resourcetimingbufferfull', e => {
+        assert_equals(e.bubbles, false, "Event bubbles attribute is false");
+        bufferFullCount++;
+    });
+    await fillUpTheBufferWithTwoResources();
+    // Overflow the buffer
+    await load.script(scriptResources[2]);
+    await waitForNextTask();
+    checkEntries(2);
+    assert_equals(bufferFullCount, 1, 'onresourcetimingbufferfull should have been invoked once.');
+}, "Test that a buffer full event does not bubble and that resourcetimingbufferfull is called only once per overflow");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/buffered-flag.any.js b/testing/web-platform/tests/resource-timing/buffered-flag.any.js
new file mode 100644
index 0000000000..b46fd00e69
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/buffered-flag.any.js
@@ -0,0 +1,18 @@
+async_test(t => {
+  performance.clearResourceTimings();
+  // First observer creates second in callback to ensure the entry has been dispatched by the time
+  // the second observer begins observing.
+  new PerformanceObserver(() => {
+    // Second observer requires 'buffered: true' to see an entry.
+    new PerformanceObserver(t.step_func_done(list => {
+      const entries = list.getEntries();
+      assert_equals(entries.length, 1, 'There should be 1 resource entry.');
+      assert_equals(entries[0].entryType, 'resource');
+      assert_greater_than(entries[0].startTime, 0);
+      assert_greater_than(entries[0].responseEnd, entries[0].startTime);
+      assert_greater_than(entries[0].duration, 0);
+      assert_true(entries[0].name.endsWith('resources/empty.js'));
+    })).observe({'type': 'resource', buffered: true});
+  }).observe({'entryTypes': ['resource']});
+  fetch('resources/empty.js');
+}, 'PerformanceObserver with buffered flag sees previous resource entries.');
diff --git a/testing/web-platform/tests/resource-timing/cached-image-gets-single-entry.html b/testing/web-platform/tests/resource-timing/cached-image-gets-single-entry.html
new file mode 100644
index 0000000000..2d8c4e2e83
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/cached-image-gets-single-entry.html
@@ -0,0 +1,67 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing: test behavior for cached resources</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/observe-entry.js"></script>
+</head>
+<body>
+<h1>Description</h1>
+<p>Test that a reused resource only appears in the buffer once.</p>
+<script>
+// Need our own image loading helper because the one in resource-loaders.js
+// is desgined to always side-step the HTTP cache but this test relies on the
+// second request being resolved from the cache.
+const load_image = path => new Promise(resolve => {
+  const img = document.createElement('img');
+  img.onload = img.onerror = () => resolve();
+  img.src = path;
+  document.body.append(img);
+});
+
+promise_test(async () => {
+  const blue = "resources/blue.png";
+
+  // First request. Should appear in the timeline.
+  await load_image(blue + "?cacheable");
+
+  // Second request. Should not appear in the timeline.
+  await load_image(blue + "?cacheable");
+
+  // Third request. When this request shows up in the timeline, we know that, if
+  // the second request would generate an entry, that entry would have already
+  // shown up in the timeline. Without this, we'd need to guess at how long to
+  // wait which tends to be flaky.
+  await load_image(blue + "?avoid-cache");
+
+  const entries = await new Promise(resolve => {
+    const accumulator = [];
+    new PerformanceObserver(entry_list => {
+      entry_list.getEntries().forEach(entry => {
+        if (!entry.name.includes("blue.png")) {
+          // Ignore resources other than blue images.
+          return;
+        }
+        accumulator.push(entry);
+
+        // Once we see the 'canary' resource, we don't need to wait anymore.
+        if (entry.name.endsWith('avoid-cache')) {
+          resolve(accumulator);
+        }
+      });
+    }).observe({'type': 'resource', 'buffered': true});
+  });
+
+  assert_equals(entries.length, 2, "There must be exactly 2 entries in the " +
+    "Performance Timeline");
+  assert_true(entries[0].name.endsWith("blue.png?cacheable"));
+  assert_true(entries[1].name.endsWith("blue.png?avoid-cache"));
+}, "When a resource is resolved from cache, there must not be a " +
+  "corresponding entry in the Performance Timeline");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/clear-resource-timings.html b/testing/web-platform/tests/resource-timing/clear-resource-timings.html
new file mode 100644
index 0000000000..7508f8432e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/clear-resource-timings.html
@@ -0,0 +1,22 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the functionality of clearResourceTimings method
+in resource timing.</title>
+<link rel="author" title="Intel" href="http://www.intel.com/" />
+<link rel="help"
+ href="https://www.w3.org/TR/resource-timing-2/#dom-performance-clearresourcetimings">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+test(() => {
+  assert_equals(performance.getEntriesByType("resource").length, 2,
+                "Resource timing entries exist");
+  performance.clearResourceTimings();
+  assert_equals(performance.getEntriesByType("resource").length, 0,
+                "Resource timing entries are cleared");
+}, "Test that clearResourceTimings() clears the performance timeline buffer");
+</script>
+</head>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/connection-reuse.html b/testing/web-platform/tests/resource-timing/connection-reuse.html
new file mode 100644
index 0000000000..a1bc927cfd
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/connection-reuse.html
@@ -0,0 +1,56 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing connection reuse</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/connection-reuse-test.js"></script>
+<script>
+  const {HTTPS_ORIGIN} = get_host_info();
+
+  // Fetches the given subresource a couple times with the same connection.
+  const http_path = "resources/fake_responses.py";
+  connection_reuse_test(http_path,
+    {
+      'on_200': invariants.assert_tao_pass_no_redirect_http,
+      'on_304': invariants.assert_tao_pass_304_not_modified_http,
+    }, "Reuse HTTP connection");
+
+  // Like above, but the subresource is fetched over HTTPS while this page is
+  // fetched over HTTP.
+  const https_url = `${HTTPS_ORIGIN}/resource-timing/${http_path}`;
+  connection_reuse_test(https_url,
+    {
+      'on_200': invariants.assert_tao_pass_no_redirect_https,
+      'on_304': invariants.assert_tao_pass_304_not_modified_https,
+    }, "Reuse HTTPS connection from HTTP page");
+
+  // Like the above mixed-content test but the final resource is behind an HTTP
+  // redirect response.
+  const redirect_path = (() => {
+    // The resource behind the redirect is the same fake_responses.py handler
+    // on the HTTPS origin. Pass it through encodeURIComponent so that it can
+    // be passed through a query-parameter.
+    const redirect_url = encodeURIComponent(https_url)
+    // The request is made to the HTTPS origin with a query parameter that will
+    // cause a 302 response.
+    return `${https_url}?redirect=${redirect_url}`;
+  })();
+  connection_reuse_test(redirect_path,
+    {
+      'on_200': invariants.assert_tao_enabled_cross_origin_redirected_resource,
+      'on_304': invariants.assert_tao_enabled_cross_origin_redirected_resource,
+    }, "Reuse HTTPS connection with redirects from an HTTP page");
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>See <a href="resources/connection-reuse-test.js">the included test
+  script</a></p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/connection-reuse.https.html b/testing/web-platform/tests/resource-timing/connection-reuse.https.html
new file mode 100644
index 0000000000..3461eed472
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/connection-reuse.https.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing connection reuse</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/connection-reuse-test.js"></script>
+<script>
+  connection_reuse_test("resources/fake_responses.py",
+    {
+      'on_200': invariants.assert_tao_pass_no_redirect_https,
+      'on_304': invariants.assert_tao_pass_304_not_modified_https,
+    }, "Reuse an HTTPS connection");
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>See <a href="resources/connection-reuse-test.js">the included test
+  script</a></p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/content-type-parsing.html b/testing/web-platform/tests/resource-timing/content-type-parsing.html
new file mode 100644
index 0000000000..c0081eb413
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/content-type-parsing.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the parsing of content-type of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+
+// Utility function picked from https://github.com/web-platform-tests/wpt/blob/master/mimesniff/mime-types/charset-parameter.window.js
+function isByteCompatible(str) {
+  // see https://fetch.spec.whatwg.org/#concept-header-value-normalize
+  if(/^[\u0009\u0020\u000A\u000D]+|[\u0009\u0020\u000A\u000D]+$/.test(str)) {
+    return "header-value-incompatible";
+  }
+
+  for(let i = 0; i < str.length; i++) {
+    const charCode = str.charCodeAt(i);
+    // See https://fetch.spec.whatwg.org/#concept-header-value
+    if(charCode > 0xFF) {
+      return "incompatible";
+    } else if(charCode === 0x00 || charCode === 0x0A || charCode === 0x0D) {
+      return "header-value-incompatible";
+    }
+  }
+  return "compatible";
+}
+
+// Test for content-type parsing.
+const run_content_type_parsing_tests = (json_entries) => {
+  json_entries.forEach( (json_entry, i) => {
+    promise_test(async t => {
+        let url = "/fetch/content-type/resources/content-type.py?single_header&";
+        json_entry.contentType.forEach(val => {
+          url += "value=" + encodeURIComponent(val) + "&";
+        });
+        fetch(url);
+        const entry = await new Promise(resolve => new PerformanceObserver((entryList, observer) => {
+            observer.disconnect();
+            resolve(entryList.getEntries()[0]);
+        }).observe({entryTypes: ['resource']}));
+        assert_equals(entry.contentType, json_entry["mimeType"]);
+    }, "content-type " + i + " : " + json_entry.contentType);
+  });
+}
+
+// Test for mime-type parsing.
+const run_mime_type_parsing_tests = (json_entries) => {
+  json_entries.forEach( (val, i) => {
+    if(typeof val === "string" || val.navigable === undefined || isByteCompatible(val.input) !== "compatible") {
+      return;
+    }
+    const output = val.output === null ? "" : val.output
+    promise_test(async t => {
+        let url = `/fetch/content-type/resources/content-type.py?single_header&value=${val.input}`;
+        fetch(url);
+        const entry = await new Promise(resolve => new PerformanceObserver((entryList, observer) => {
+            observer.disconnect();
+            resolve(entryList.getEntries()[0]);
+        }).observe({entryTypes: ['resource']}));
+        assert_equals(entry.contentType, output);
+    }, "mime-type " + i + " : " + val.input);
+  });
+}
+
+Promise.all([
+    fetch("/fetch/content-type/resources/content-types.json"),
+    fetch("/mimesniff/mime-types/resources/mime-types.json")
+  ]).then(([res, res2]) => res.json().then(run_content_type_parsing_tests)
+    .then(() => res2.json().then(run_mime_type_parsing_tests)));
+
+</script>
+</body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/content-type.html b/testing/web-platform/tests/resource-timing/content-type.html
new file mode 100644
index 0000000000..f6b1db7d9f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/content-type.html
@@ -0,0 +1,117 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the content-type of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+const SAME_ORIGIN = location.origin;
+
+
+// Content-type for same origin resources is exposed.
+const run_test = (loader, contentType) => {
+  let path = `/resource-timing/resources/content-type.py?content_type=${contentType}`;
+  const url = new URL(path, ORIGIN);
+  attribute_test(
+    loader, url,
+    entry => {
+        assert_equals(entry.contentType, contentType,
+            `content-type for ${entry.name} should be ${contentType}`);
+    });
+}
+
+// Content-type is empty string when a no-cors request is made for cross
+// origin resource.
+// Content-type is empty for cross origin iframes.
+const run_test_cross_origin = (loader, contentType) => {
+  let path = `/resource-timing/resources/content-type.py?content_type=${contentType}`;
+  const url = new URL(path, REMOTE_ORIGIN);
+  attribute_test(
+    loader, url,
+    entry => {
+        assert_equals(entry.contentType, "",
+            `content-type for ${entry.name} should be ""`);
+    });
+}
+
+const resource_loaders_and_types = [
+  [load.font, ["font/woff", "font/otf"]],
+  [load.image, ["image/png", "image/jpg"]],
+  [load.script, ["application/javascript", "text/javascript"]],
+  [load.stylesheet, ["text/css"]],
+  [load.xhr_async, ["application/x-gzip", "application/pdf"]],
+  [load.iframe, ["text/html"]]
+];
+
+resource_loaders_and_types.forEach(resource => {
+  let loader = resource[0];
+  let content_types = resource[1];
+  content_types.forEach(type => {
+    run_test(loader, type);
+    run_test_cross_origin(loader, type);
+  })
+});
+
+
+// Content-type is exposed for cors request for cross-origin resources.
+const run_test_cross_origin_allow_origin = (loader_with_attr,contentType) => {
+  let path = `/resource-timing/resources/content-type.py?content_type=${contentType}&allow_origin=${ORIGIN}`;
+  const url = new URL(path, REMOTE_ORIGIN);
+  loader_with_crossOrigin_attr = async url => {
+    return loader_with_attr(url, {"crossOrigin": "anonymous"});
+  }
+  attribute_test(
+    loader_with_crossOrigin_attr, url,
+    entry => {
+        assert_equals(entry.contentType, contentType,
+            `content-type for ${entry.name} should be ${contentType}`);
+    });
+}
+
+const resource_loaders_with_attrs_and_types = [
+  [load.image_with_attrs, ["image/gif", "image/jpeg"]],
+  [load.script_with_attrs, ["application/javascript", "text/javascript"]],
+  [load.stylesheet_with_attrs, ["text/css"]],
+]
+
+resource_loaders_with_attrs_and_types.forEach(resource => {
+  let loader = resource[0];
+  let content_types = resource[1];
+  content_types.forEach(type => {
+    run_test_cross_origin_allow_origin(loader, type);
+  })
+});
+
+// Content-type for iframes is empty when cross origin redirects are present.
+var destUrl = `${SAME_ORIGIN}/resource-timing/resources/multi_redirect.py?`;
+destUrl += `page_origin=${SAME_ORIGIN}`;
+destUrl += `&cross_origin=${REMOTE_ORIGIN}`;
+destUrl += `&final_resource=/resource-timing/resources/content-type.py?content_type=text/html`;
+attribute_test(
+    load.iframe, new URL(destUrl),
+    entry => {
+        assert_equals(entry.contentType, "",
+            `content-type should be empty for iframes having cross origin redirects`);
+});
+
+
+// Content-type for iframes is exposed for same origin redirects.
+var destUrl = `${SAME_ORIGIN}/resource-timing/resources/redirect-cors.py`;
+destUrl += `?location=${SAME_ORIGIN}/resource-timing/resources/content-type.py?content_type=text/html`;
+attribute_test(
+    load.iframe, new URL(destUrl),
+    entry => {
+        assert_equals(entry.contentType, "text/html",
+            `content-type should be exposed for iframes having only same origin redirects`);
+});
+
+</script>
+</body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/cors-preflight.any.js b/testing/web-platform/tests/resource-timing/cors-preflight.any.js
new file mode 100644
index 0000000000..4b980e7d0a
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/cors-preflight.any.js
@@ -0,0 +1,49 @@
+// META: script=/common/utils.js
+// META: script=/common/get-host-info.sub.js
+
+// Because apache decrements the Keep-Alive max value on each request, the
+// transferSize will vary slightly between requests for the same resource.
+const fuzzFactor = 3;  // bytes
+
+const {HTTP_REMOTE_ORIGIN} = get_host_info();
+const url = new URL('/resource-timing/resources/preflight.py',
+    HTTP_REMOTE_ORIGIN).href;
+
+// The header bytes are expected to be > |minHeaderSize| and
+// < |maxHeaderSize|. If they are outside this range the test will fail.
+const minHeaderSize = 100;
+const maxHeaderSize = 1024;
+
+promise_test(async () => {
+  const checkCorsAllowed = response => response.arrayBuffer();
+  const requirePreflight = {headers: {'X-Require-Preflight' : '1'}};
+  const collectEntries = new Promise(resolve => {
+    let entriesSeen = [];
+    new PerformanceObserver(entryList => {
+      entriesSeen = entriesSeen.concat(entryList.getEntries());
+      if (entriesSeen.length > 2) {
+        throw new Error(`Saw too many PerformanceResourceTiming entries ` +
+            `(${entriesSeen.length})`);
+      }
+      if (entriesSeen.length == 2) {
+        resolve(entriesSeen);
+      }
+    }).observe({"type": "resource"});
+  });
+
+  // Although this fetch doesn't send a pre-flight request, the server response
+  // will allow cross-origin requests explicitly with the
+  // Access-Control-Allow-Origin header.
+  await fetch(url).then(checkCorsAllowed);
+
+  // This fetch will send a pre-flight request to do the CORS handshake
+  // explicitly.
+  await fetch(url, requirePreflight).then(checkCorsAllowed);
+
+  const entries = await collectEntries;
+  assert_greater_than(entries[0].transferSize, 0, 'No-preflight transferSize');
+  const lowerBound = entries[0].transferSize - fuzzFactor;
+  const upperBound = entries[0].transferSize + fuzzFactor;
+  assert_between_exclusive(entries[1].transferSize, lowerBound, upperBound,
+      'Preflighted transferSize');
+}, 'PerformanceResourceTiming sizes fetch with preflight test');
diff --git a/testing/web-platform/tests/resource-timing/cross-origin-iframe.html b/testing/web-platform/tests/resource-timing/cross-origin-iframe.html
new file mode 100644
index 0000000000..69daebffaf
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/cross-origin-iframe.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test ResourceTiming reporting for cross-origin iframe.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/observe-entry.js"></script>
+</head>
+<body>
+<body>
+<script>
+  const {REMOTE_ORIGIN} = get_host_info();
+
+  promise_test(async t => {
+    const iframe = document.createElement('iframe');
+    t.add_cleanup(() => iframe.remove());
+    iframe.src = `${REMOTE_ORIGIN}/resource-timing/resources/green.html`;
+    document.body.appendChild(iframe);
+    const entry = await observe_entry(iframe.src);
+    invariants.assert_tao_failure_resource(entry);
+  }, "A cross-origin iframe should report an opaque RT entry");
+
+  promise_test(async t => {
+    const iframe = document.createElement('iframe');
+    t.add_cleanup(() => iframe.remove());
+    iframe.src = `${REMOTE_ORIGIN}/resource-timing/resources/TAOResponse.py?tao=wildcard`;
+    document.body.appendChild(iframe);
+    const entry = await observe_entry(iframe.src);
+    invariants.assert_tao_pass_no_redirect_http(entry);
+  }, "A cross-origin iframe with TAO enabled should report a full RT entry");
+
+  </script>
diff --git a/testing/web-platform/tests/resource-timing/cross-origin-redirects.html b/testing/web-platform/tests/resource-timing/cross-origin-redirects.html
new file mode 100644
index 0000000000..0bdc0547e5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/cross-origin-redirects.html
@@ -0,0 +1,102 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the values in resource timing for cross-origin
+redirects.</title>
+<link rel="author" title="Intel" href="http://www.intel.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/custom-cors-response.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/tao-response.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+
+const HTTP_SO_to_XO_redirect_url = url => {
+  // Make an initial request to a same-domain resource that will return a 302
+  // redirect to the given (possibly cross-origin) url.
+  return `/resource-timing/resources/redirect-cors.py?location=${url}`;
+};
+
+const HTTP_SO_resource = () => {
+  if (location.protocol != "http:") {
+    throw new Error("Can only make an HTTP SO request if this page was " +
+      "served over HTTP.");
+  }
+  return tao_response("*", ORIGIN);
+};
+
+const HTTP_XO_redirect = (url, tao) => {
+  const ret = new URL(
+    `${REMOTE_ORIGIN}/resource-timing/resources/redirect-cors.py`);
+  ret.searchParams.append("location", url);
+  ret.searchParams.append("allow_origin", "*");
+  ret.searchParams.append("timing_allow_origin", tao);
+  return ret.href;
+};
+
+attribute_test(
+  load.iframe, HTTP_SO_to_XO_redirect_url(custom_cors_response({},
+    REMOTE_ORIGIN)),
+  invariants.assert_http_to_cross_origin_redirected_resource,
+  "Verify that cross-origin resources' timings aren't exposed through HTTP " +
+  "redirects.");
+
+attribute_test(
+  load.iframe, HTTP_SO_to_XO_redirect_url(remote_tao_response("no-match")),
+  invariants.assert_cross_origin_redirected_resource,
+  "Verify that a redirected cross-origin resources' timings aren't exposed " +
+  "when the TAO check fails.");
+
+attribute_test(
+  load.iframe, HTTP_SO_to_XO_redirect_url(remote_tao_response("*")),
+  invariants.assert_http_to_tao_enabled_cross_origin_https_redirected_resource,
+  "Verify that cross-origin resources' timings are exposed when the TAO " +
+  "check succeeds. Also verify that secureConnectionStart is 0 since the " +
+  "original request was over HTTP.");
+
+attribute_test(
+  load.iframe, HTTP_XO_redirect(HTTP_XO_redirect(HTTP_SO_resource(), "*"), "*"),
+  invariants.assert_http_to_tao_enabled_cross_origin_https_redirected_resource,
+  "Verify that a redirect chain through cross-origin resources have their " +
+  "timings exposed when all TAO checks succeed. Also verify that " +
+  "secureConnectionStart is 0 since the original request was over HTTP.");
+
+const failure_permutations = [
+  ["fail", "fail", "fail"],
+  ["fail", "fail", "*"   ],
+  ["fail", "*",    "fail"],
+  ["fail", "*",    "*"   ],
+  ["*",    "fail", "fail"],
+  ["*",    "fail", "*"   ],
+  ["*",    "*",    "fail"],
+];
+const test_case = (so_tao, xo1_tao, xo2_tao) => {
+  return HTTP_XO_redirect(HTTP_XO_redirect(HTTP_SO_resource(
+    so_tao), xo2_tao), xo1_tao);
+};
+const test_label = perm => {
+  return perm.map(x => {
+    if (x == "*" ) return "PASS";
+    if (x == "fail" ) return "FAIL";
+    throw new Error(`unexpected element ${x}`);
+  }).join(" -> ");
+};
+for (const permutation of failure_permutations) {
+  attribute_test(
+    load.iframe, test_case.apply(permutation),
+    invariants.assert_tao_failure_resource,
+    `Verify that a redirect chain through cross-origin resources do not have ` +
+    `their timings exposed when any of the TAO checks fail. ` +
+    `(${test_label(permutation)})`);
+}
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/cross-origin-start-end-time-with-redirects.html b/testing/web-platform/tests/resource-timing/cross-origin-start-end-time-with-redirects.html
new file mode 100644
index 0000000000..8e368d1380
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/cross-origin-start-end-time-with-redirects.html
@@ -0,0 +1,38 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the values in resource timing for cross-origin
+redirects.</title>
+<link rel="author" title="Noam Rosenthal" href="noam@webkit.org">
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+</head>
+<body>
+<script>
+const {REMOTE_ORIGIN} = get_host_info();
+const delay = 2
+const blank_page = `/resource-timing/resources/blank_page_green.htm`;
+const destUrl = `/common/slow-redirect.py?delay=${delay}&location=${REMOTE_ORIGIN}/${blank_page}`;
+
+const timeBefore = performance.now();
+(async () => {
+  // Wait 10 ms, to ensure the difference between startTime and timeBefore is
+  // larger than 1 ms, to avoid flakiness in browsers that clamp timestamps to
+  // 1 ms.
+  await new Promise(r => step_timeout(r, 10));
+  attribute_test(load.iframe, destUrl, entry => {
+      assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
+      assert_greater_than(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
+      // See https://github.com/w3c/resource-timing/issues/264
+      assert_less_than(Math.round(entry.startTime - timeBefore), delay * 1000, 'startTime should not expose redirect delays');
+  }, "Verify that cross-origin resources don't implicitly expose their redirect timings")
+})();
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/cross-origin-status-codes.html b/testing/web-platform/tests/resource-timing/cross-origin-status-codes.html
new file mode 100644
index 0000000000..197a766339
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/cross-origin-status-codes.html
@@ -0,0 +1,70 @@
+<!doctype html>
+<html>
+<head>
+<title>Resource Timing: PerformanceResourceTiming attributes shouldn't change
+  if the HTTP status code changes</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src=/common/get-host-info.sub.js></script>
+</head>
+<body>
+<img id="img_200">
+<img id="img_307">
+<img id="img_404">
+<img id="img_502">
+<script id="script_200"></script>
+<script id="script_307"></script>
+<script id="script_404"></script>
+<script id="script_502"></script>
+<script>
+
+const listenForPerformanceEntries = num_expected => {
+  return new Promise(resolve => {
+    let results = [];
+    new PerformanceObserver(entryList => {
+      entryList.getEntries().forEach(entry => {
+        if (!entry.name.includes("status-code"))
+          return;
+
+        results.push(entry);
+        if (results.length == num_expected) {
+          resolve(results);
+        }
+      });
+    }).observe({entryTypes: ['resource']});
+  });
+}
+
+promise_test(async t => {
+  const destUrl = get_host_info().HTTP_REMOTE_ORIGIN + '/resource-timing/resources/';
+  const statusCodes = ['200', '307', '404', '502'];
+
+  let expected_entry_count = 0;
+  statusCodes.forEach(status => {
+    document.getElementById(`img_${status}`).src = `${destUrl}status-code.py?status=${status}`;
+    document.getElementById(`script_${status}`).src = `${destUrl}status-code.py?status=${status}&script=1`;
+    expected_entry_count += 2;
+  });
+
+  const entries = await listenForPerformanceEntries(expected_entry_count);
+
+  // We will check that the non-timestamp values of the entry match for all
+  // entries.
+  const keys = [
+    'entryType',
+    'nextHopProtocol',
+    'transferSize',
+    'encodedBodySize',
+    'decodedBodySize',
+  ];
+
+  const first = entries[0];
+  entries.slice(1).forEach(entry => {
+    keys.forEach(attribute => {
+      assert_equals(entry[attribute], first[attribute],
+        `There must be no discernible difference for the ${attribute} ` +
+        `attribute but found a difference for the ${entry.name} resource.`);
+  })});
+}, "Make sure cross origin resource fetch failures with different status codes are indistinguishable");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/delivery-type.tentative.any.js b/testing/web-platform/tests/resource-timing/delivery-type.tentative.any.js
new file mode 100644
index 0000000000..e2b408fdd7
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/delivery-type.tentative.any.js
@@ -0,0 +1,90 @@
+// META: global=window,worker
+// META: script=/common/get-host-info.sub.js
+// META: script=/resource-timing/resources/resource-loaders.js
+
+// TODO(crbug/1358591): Rename this file from "tentative" once
+// `w3c/resource-timing#343` is merged.
+
+const {REMOTE_ORIGIN, ORIGIN} = get_host_info();
+
+const redirectBase = new URL(
+  '/resource-timing/resources/redirect-cors.py', REMOTE_ORIGIN).href;
+const cacheAndValidatedBase = new URL(
+  '/resource-timing/resources/cacheable-and-validated.py?content=content',
+  ORIGIN).href;
+
+const mustRevalidate = {headers: {'Cache-Control': 'max-age=0'}};
+
+const fetchAndEatBody = (url, fetchOption) => {
+  return fetch(url, fetchOption).then(response => response.arrayBuffer());
+};
+
+const accumulateEntries = () => {
+  return new Promise(resolve => {
+    const po = new PerformanceObserver(list => {
+      resolve(list);
+    });
+    po.observe({type: "resource", buffered: true});
+  });
+};
+
+const checkDeliveryTypeBase =
+  (list, lookupURL, deliveryTypeForCachedResources) => {
+    const entries = list.getEntriesByName(lookupURL);
+    assert_equals(entries.length, 3, 'Wrong number of entries');
+
+    // 200 response (`cacheMode` is an empty string)
+    assert_equals(entries[0].deliveryType, "",
+      "Expect empty deliveryType for 200 response.");
+    // Cached response (`cacheMode` is "local") or 304 response (`cacheMode` is
+    // "validated").
+    assert_equals(entries[1].deliveryType, deliveryTypeForCachedResources,
+      `Expect "${deliveryTypeForCachedResources}" deliveryType for a
+        cached response.`);
+    assert_equals(entries[2].deliveryType, deliveryTypeForCachedResources,
+      `Expect "${deliveryTypeForCachedResources}" deliveryType for a
+        revalidated response.`);
+};
+
+promise_test(() => {
+  // Use a different URL every time so that the cache behaviour does not depend
+  // on execution order.
+  const initialURL = load.cache_bust(cacheAndValidatedBase);
+  const checkDeliveryType =
+    list => checkDeliveryTypeBase(list, initialURL, "cache");
+  return fetchAndEatBody(initialURL, {})                      // 200.
+    .then(() => fetchAndEatBody(initialURL, {}))              // Cached.
+    .then(() => fetchAndEatBody(initialURL, mustRevalidate))  // 304.
+    .then(accumulateEntries)
+    .then(checkDeliveryType);
+}, 'PerformanceResourceTiming deliveryType test, same origin.');
+
+promise_test(() => {
+  const cacheAndValidatedURL = load.cache_bust(
+    cacheAndValidatedBase + '&timing_allow_origin=*');
+  const redirectURL = redirectBase
+    + "?timing_allow_origin=*"
+    + `&allow_origin=${encodeURIComponent(ORIGIN)}`
+    + `&location=${encodeURIComponent(cacheAndValidatedURL)}`;
+  const checkDeliveryType =
+    list => checkDeliveryTypeBase(list, redirectURL, "cache");
+  return fetchAndEatBody(redirectURL, {})                      // 200.
+    .then(() => fetchAndEatBody(redirectURL, {}))              // Cached.
+    .then(() => fetchAndEatBody(redirectURL, mustRevalidate))  // 304.
+    .then(accumulateEntries)
+    .then(checkDeliveryType);
+}, 'PerformanceResourceTiming deliveryType test, cross origin, TAO passes.');
+
+promise_test(() => {
+  const cacheAndValidatedURL = load.cache_bust(cacheAndValidatedBase);
+  const redirectURL = redirectBase
+    + `?allow_origin=${encodeURIComponent(ORIGIN)}`
+    + `&location=${encodeURIComponent(cacheAndValidatedURL)}`;
+  const checkDeliveryType =
+    list => checkDeliveryTypeBase(list, redirectURL, "");
+  return fetchAndEatBody(redirectURL, {})                      // 200.
+    .then(() => fetchAndEatBody(redirectURL, {}))              // Cached.
+    .then(() => fetchAndEatBody(redirectURL, mustRevalidate))  // 304.
+    .then(accumulateEntries)
+    .then(checkDeliveryType);
+}, 'PerformanceResourceTiming deliveryType test, cross origin, TAO fails.');
diff --git a/testing/web-platform/tests/resource-timing/document-domain-no-impact-opener.html b/testing/web-platform/tests/resource-timing/document-domain-no-impact-opener.html
new file mode 100644
index 0000000000..69df2f27fa
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/document-domain-no-impact-opener.html
@@ -0,0 +1,16 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script>
+// Open a document on one of hosts on the web-platform test domain, so that
+// document.domain will set a valid domain, turning the frame into a
+// cross-origin frame.
+const {OTHER_ORIGIN} = get_host_info();
+const openee = window.open(OTHER_ORIGIN +
+               "/resource-timing/resources/document-domain-no-impact.html");
+fetch_tests_from_window(openee);
+</script>
diff --git a/testing/web-platform/tests/resource-timing/entries-for-network-errors.sub.https.html b/testing/web-platform/tests/resource-timing/entries-for-network-errors.sub.https.html
new file mode 100644
index 0000000000..95849d2826
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/entries-for-network-errors.sub.https.html
@@ -0,0 +1,35 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates that a failed cross-origin fetch creates an opaque network timing entry.
+</title>
+<link rel="author" title="Noam Rosenthal" href="noam@webkit.org">
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+</head>
+<body>
+<script>
+const validDataURL = 'data:,Hello%2C%20World%21'
+const {REMOTE_ORIGIN, ORIGINAL_HOST, HTTP_PORT} = get_host_info();
+const validXmlUrl = '/common/dummy.xml';
+
+network_error_entry_test(
+    `${REMOTE_ORIGIN}${validXmlUrl}`, null, `failed cross-origin requests`);
+
+network_error_entry_test(`/common/redirect.py?location=${validDataURL}`, null, "non-HTTP redirect");
+network_error_entry_test('//{{hosts[][nonexistent]}}/common/dummy.xml', null, "DNS failure");
+network_error_entry_test(`http://${ORIGINAL_HOST}:${HTTP_PORT}/commo/dummy.xml`, null, "Mixed content");
+
+network_error_entry_test('/common/dummy.xml', {cache: 'only-if-cached', mode: 'same-origin'},
+    "only-if-cached resource that was not cached");
+
+network_error_entry_test(
+    `/element-timing/resources/multiple-redirects.py?redirect_count=22&final_resource=${validXmlUrl}`,
+    null, "too many redirects");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/entry-attributes.html b/testing/web-platform/tests/resource-timing/entry-attributes.html
new file mode 100644
index 0000000000..94f219f229
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/entry-attributes.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing: PerformanceResourceTiming attributes</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help"
+  href="https://www.w3.org/TR/resource-timing-2/#timing-allow-origin"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script>
+attribute_test(
+  load.image, "resources/fake_responses.py#hash=1",
+  entry => {
+    assert_true(entry.name.includes('#hash=1'),
+      "There should be a hash in the resource name");
+    invariants.assert_tao_pass_no_redirect_http(entry);
+  },
+  "Image resources should generate conformant entries");
+
+attribute_test(
+  load.font, "/fonts/Ahem.ttf",
+  invariants.assert_tao_pass_no_redirect_http,
+  "Font resources should generate conformant entries");
+
+attribute_test(
+  load.image, "/common/redirect.py?location=resources/fake_responses.py",
+  invariants.assert_same_origin_redirected_resource,
+  "Same-origin redirects should populate redirectStart/redirectEnd");
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that PerformanceResourceTiming entries' attributes are
+populated with the correct values.</p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/event-source-timing.html b/testing/web-platform/tests/resource-timing/event-source-timing.html
new file mode 100644
index 0000000000..917e7c3495
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/event-source-timing.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>Resource Timing: EventSource timing behavior</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+</head>
+</script>
+<script>
+    async_test(t => {
+        const repetitions = 2;
+        const url = new URL(`/eventsource/resources/message.py`, location.href);
+        const eventSource = new EventSource(url);
+        let messages = 0;
+        t.add_cleanup(() => eventSource.close());
+        eventSource.addEventListener('message', () => {
+            ++messages;
+        })
+
+        new PerformanceObserver(() => {
+            const entries = performance.getEntriesByName(url);
+            assert_greater_than_equal(entries.length, messages - 1);
+            if (entries.length === repetitions)
+                t.done();
+        }).observe({type: 'resource'});
+    }, "ResourceTiming for EventSource should reflect number of re-connections to source");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/fetch-cross-origin-redirect.https.html b/testing/web-platform/tests/resource-timing/fetch-cross-origin-redirect.https.html
new file mode 100644
index 0000000000..1605e224ab
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/fetch-cross-origin-redirect.https.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test cross-origin fetch redirects have the right values.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script>
+
+const {REMOTE_ORIGIN, ORIGIN} = get_host_info();
+const redirect = "/common/redirect.py?" +
+                 "location=/resource-timing/resources/empty_script.js";
+const cross_origin_redirect = REMOTE_ORIGIN + redirect;
+const same_origin_redirect = ORIGIN + redirect;
+
+attribute_test(
+  url => fetch(url, {mode: "no-cors", credentials: "include"}),
+  new URL(cross_origin_redirect).href,
+  invariants.assert_cross_origin_redirected_resource,
+  "Test fetching through a cross-origin redirect URL"
+);
+
+attribute_test(
+  url => fetch(url, {mode: "no-cors", credentials: "include"}),
+  new URL(same_origin_redirect).href,
+  invariants.assert_same_origin_redirected_resource,
+  "Test fetching through a same-origin redirect URL"
+);
+
+</script>
diff --git a/testing/web-platform/tests/resource-timing/font-timestamps.html b/testing/web-platform/tests/resource-timing/font-timestamps.html
new file mode 100644
index 0000000000..56ecb5c4bf
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/font-timestamps.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test cross-origin fetch redirects have the right values.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<body>
+<script>
+const load_font = url => {
+  document.body.innerHTML = `
+    <style>
+    @font-face {
+        font-family: ahem;
+        src: url('${url}');
+    }
+    </style>
+    <div style="font-family: ahem;">This fetches ahem font.</div>
+  `;
+  return document.fonts.ready;
+};
+
+const run_test = async (t, url) => {
+  // Set up PerformanceObserver
+  const href = new URL(url).href;
+  const setPerformanceObserver = new Promise(resolve => {
+    const po = new PerformanceObserver(resolve);
+    po.observe({type: "resource"});
+  });
+
+  // Load the font resource and wait for it to be fetched.
+  await load_font(href);
+
+  // Wait for an entry
+  const timeout = new Promise(resolve => t.step_timeout(resolve, 3000));
+  const list = await Promise.race([setPerformanceObserver, timeout]);
+  assert_equals(typeof(list), "object", "No iframe entry was fired");
+  const entries = list.getEntriesByName(url);
+  assert_equals(entries.length, 1);
+
+  // Test entry values
+  const entry = entries[0];
+  assert_greater_than(entry.fetchStart, 0, "fetchStart should be greater than 0 in redirects.");
+  assert_greater_than_equal(entry.domainLookupStart, entry.fetchStart, "domainLookupStart should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.domainLookupEnd, entry.domainLookupStart, "domainLookupEnd should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.connectStart, entry.domainLookupEnd, "connectStart should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.secureConnectionStart, entry.connectStart, "secureConnectionStart should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.connectEnd, entry.secureConnectionStart, "connectEnd should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.requestStart, entry.connectEnd, "requestStart should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.responseStart, entry.requestStart, "responseStart should be more than 0 in same-origin redirect.");
+  assert_greater_than_equal(entry.responseEnd, entry.responseStart, "responseEnd should be greater than 0 in redirects.");
+  assert_greater_than_equal(entry.duration, 0, "duration should be greater than 0 in redirects.");
+}
+
+const {HTTPS_REMOTE_ORIGIN} = get_host_info();
+promise_test(t => {
+  return run_test(t, HTTPS_REMOTE_ORIGIN + "/fonts/Ahem.ttf");
+}, "Test a font's timestamps");
+
+promise_test(t => {
+  return run_test(t, HTTPS_REMOTE_ORIGIN + "/resource-timing/resources/cors-ahem.py?pipe=trickle(d1)");
+}, "Test a font's timestamps with delays");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/frameset-timing.html b/testing/web-platform/tests/resource-timing/frameset-timing.html
new file mode 100644
index 0000000000..1a6facbfc4
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/frameset-timing.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting timing for frames.</title>
+<frameset>
+  <frame src="resources/frameset-timing-frame.html" />
+</frameset>
diff --git a/testing/web-platform/tests/resource-timing/idlharness.any.js b/testing/web-platform/tests/resource-timing/idlharness.any.js
new file mode 100644
index 0000000000..aa860d3dd1
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/idlharness.any.js
@@ -0,0 +1,24 @@
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+// META: timeout=long
+
+'use strict';
+
+// https://w3c.github.io/resource-timing/
+
+idl_test(
+  ['resource-timing'],
+  ['performance-timeline', 'hr-time', 'dom', 'html'],
+  idl_array => {
+    try {
+      self.resource = performance.getEntriesByType('resource')[0];
+    } catch (e) {
+      // Will be surfaced when resource is undefined below.
+    }
+
+    idl_array.add_objects({
+      Performance: ['performance'],
+      PerformanceResourceTiming: ['resource']
+    });
+  }
+);
diff --git a/testing/web-platform/tests/resource-timing/iframe-failed-commit.html b/testing/web-platform/tests/resource-timing/iframe-failed-commit.html
new file mode 100644
index 0000000000..91094072a6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/iframe-failed-commit.html
@@ -0,0 +1,131 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing - test that unsuccessful iframes create entries</title>
+<meta name="timeout" content="long">
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href=
+  "https://www.w3.org/TR/resource-timing-2/#resources-included-in-the-performanceresourcetiming-interface"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<body>
+<script>
+
+// Like load.iframe but fetches the iframe under a "default-src 'none'"
+// Content-Security-Policy.
+const load_iframe_with_csp = async path => {
+  return load.iframe_with_attrs(path, {"csp": "default-src 'none'"});
+};
+
+const load_iframe_with_csp_no_navigation = async path => {
+  return load.iframe_with_attrs(path, {"csp": "default-src 'none'"}, () => {}, true);
+}
+
+// Runs a test (labeled by the given label) to verify that loading an iframe
+// with the given URL generates a PerformanceResourceTiming entry and that the
+// entry does not expose sensitive timing attributes.
+const masked_entry_test = (url, label) => {
+  return attribute_test(load.iframe, url,
+    invariants.assert_tao_failure_resource, label);
+};
+
+// Runs a test (labeled by the given label) to verify that loading an iframe
+// with the given URL generates a PerformanceResourceTiming entry and that the
+// entry does expose sensitive timing attributes.
+const unmasked_entry_with_csp_test = (url, label) => {
+  return attribute_test(load_iframe_with_csp, url,
+    invariants.assert_tao_pass_no_redirect_http, label);
+};
+
+// Runs a test (labeled by the given label) to verify that loading an iframe
+// with the given URL under a "default-src 'none' Content-Security-Policy
+// generates a PerformanceResourceTiming entry and that the entry does not
+// expose sensitive timing attributes.
+const masked_entry_with_csp_test = (url, label) => {
+  return attribute_test(load_iframe_with_csp, url,
+    invariants.assert_tao_failure_resource, label);
+};
+
+// Runs a test (labeled by the given label) to verify that loading an iframe
+// with the given URL, an empty response body and under a "default-src 'none'
+// Content-Security-Policy generates a PerformanceResourceTiming entry and that
+// the entry does expose sensitive timing attributes.
+const empty_unmasked_entry_with_csp_test = (url, label) => {
+  return attribute_test(load_iframe_with_csp, url,
+    invariants.assert_tao_pass_no_redirect_http_empty, label);
+};
+
+// Runs a test (labeled by the given label) to verify that loading an iframe
+// with the given URL under a "default-src 'none' Content-Security-Policy
+// generates a PerformanceResourceTiming entry and that the entry does not
+// expose sensitive timing attributes.
+const non_navigating_masked_entry_with_csp_test = (url, label) => {
+  return attribute_test(load_iframe_with_csp_no_navigation, url,
+    invariants.assert_tao_failure_resource, label);
+};
+
+// Runs a test (labeled by the given label) to verify that loading an iframe
+// with the given URL, an empty response body and under a "default-src 'none'
+// Content-Security-Policy generates a PerformanceResourceTiming entry and that
+// the entry does expose sensitive timing attributes.
+const non_navigating_empty_unmasked_entry_with_csp_test = (url, label) => {
+  return attribute_test(load_iframe_with_csp_no_navigation, url,
+    invariants.assert_tao_pass_no_redirect_http_empty, label);
+};
+
+const {REMOTE_ORIGIN, ORIGINAL_HOST, HTTPS_PORT} = get_host_info();
+const unhosted_url = `https://nonexistent.${ORIGINAL_HOST}:${HTTPS_PORT}/`;
+
+masked_entry_test(
+  unhosted_url,
+  "Test iframe from non-existent host gets reported");
+
+masked_entry_test(
+  "/resource-timing/resources/fake_responses.py?redirect=" + unhosted_url,
+  "Test iframe redirecting to non-existent host gets reported");
+
+unmasked_entry_with_csp_test("/resource-timing/resources/csp-default-none.html",
+  "Same-origin iframe that complies with CSP attribute gets reported");
+
+unmasked_entry_with_csp_test("/resource-timing/resources/green-frame.html",
+  "Same-origin iframe that doesn't comply with CSP attribute gets reported");
+
+masked_entry_with_csp_test(
+  new URL("/resource-timing/resources/csp-default-none.html", REMOTE_ORIGIN),
+  "Cross-origin iframe that complies with CSP attribute gets reported");
+
+masked_entry_with_csp_test(
+  new URL("/resource-timing/resources/green-frame.html", REMOTE_ORIGIN),
+  "Cross-origin iframe that doesn't comply with CSP attribute gets reported");
+
+empty_unmasked_entry_with_csp_test(
+  "/resource-timing/resources/200_empty.asis",
+  "Same-origin empty iframe with a 200 status gets reported");
+
+masked_entry_with_csp_test(
+  new URL("/resource-timing/resources/200_empty.asis", REMOTE_ORIGIN),
+  "Cross-origin empty iframe with a 200 status gets reported");
+
+non_navigating_empty_unmasked_entry_with_csp_test(
+    new URL("/resource-timing/resources/204_empty.asis", location.origin),
+    "Same-origin empty iframe with a 204 status gets reported");
+
+non_navigating_empty_unmasked_entry_with_csp_test(
+    new URL("/resource-timing/resources/205_empty.asis", location.origin),
+    "Same-origin empty iframe with a 205 status gets reported");
+
+non_navigating_masked_entry_with_csp_test(
+    new URL("/resource-timing/resources/204_empty.asis", REMOTE_ORIGIN),
+    "Cross-origin empty iframe with a 204 status gets reported");
+
+non_navigating_masked_entry_with_csp_test(
+    new URL("/resource-timing/resources/205_empty.asis", REMOTE_ORIGIN),
+    "Cross-origin empty iframe with a 205 status gets reported");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/iframe-non-html.html b/testing/web-platform/tests/resource-timing/iframe-non-html.html
new file mode 100644
index 0000000000..a5df3b0348
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/iframe-non-html.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting iframe timing.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<body>
+<script>
+    function test(href, type) {
+        promise_test(async t => {
+            await load.iframe(href);
+            const entries = performance.getEntriesByType('resource').filter(({name}) => name.includes(href));
+            assert_equals(entries.length, 1);
+            assert_equals(entries[0].initiatorType, 'iframe');
+        }, `Iframes should report resource timing for ${type} iframes`);
+    }
+
+    test('/common/square.png', 'image');
+    test('/common/dummy.xhtml', 'xhtml');
+    test('/common/dummy.xml', 'xml');
+    test('/common/text-plain.txt', 'text');
+</script>
+</body>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/iframe-redirect-without-location.html b/testing/web-platform/tests/resource-timing/iframe-redirect-without-location.html
new file mode 100644
index 0000000000..bae5f3112f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/iframe-redirect-without-location.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting iframe timing.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<body>
+<script>
+    promise_test(async t => {
+        const href = new URL('resources/redirect-without-location.py', location.href);
+        await load.iframe(href);
+        const entries = performance.getEntriesByType('resource').filter(({name}) => name.startsWith(href));
+        assert_equals(entries.length, 1);
+        assert_equals(entries[0].initiatorType, 'iframe');
+    }, 'Iframes should report resource timing for redirect responses without a location');
+</script>
+</body>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/iframe-sequence-of-events.html b/testing/web-platform/tests/resource-timing/iframe-sequence-of-events.html
new file mode 100644
index 0000000000..02d1c362c9
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/iframe-sequence-of-events.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting iframe timing.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/frame-timing.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<body>
+<script>
+  test_frame_timing_before_load_event('iframe');
+
+  const host_info = get_host_info();
+  const types = ['ORIGIN', 'HTTP_REMOTE_ORIGIN', 'HTTP_NOTSAMESITE_ORIGIN'];
+  for (const a of types) {
+    for (const b of types) {
+      for (const tao of [true, false]) {
+        test_frame_timing_change_src('iframe', host_info[a], host_info[b], tao,
+        `Changing the src of an iframe (${a}->${b}) ${tao ? "with" : "without"} TAO should result in an RT entry`);
+      }
+    }
+  }
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/iframe-with-download.html b/testing/web-platform/tests/resource-timing/iframe-with-download.html
new file mode 100644
index 0000000000..9583024dd8
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/iframe-with-download.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting iframe timing.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<body>
+<script>
+    promise_test(async t => {
+        const href = new URL('resources/download.asis', location.href);
+        const iframe = document.createElement('iframe');
+        iframe.src = href;
+        const errored = new Promise(resolve => iframe.addEventListener('error', resolve));
+        const loaded = new Promise(resolve => iframe.addEventListener('load', resolve));
+        document.body.appendChild(iframe);
+        const timeout = 2000;
+        t.add_cleanup(() => iframe.remove());
+        const expired = new Promise(resolve => t.step_timeout(resolve, timeout));
+        await Promise.any([loaded, expired, errored]);
+        const entries = performance.getEntriesByType('resource').filter(({name}) => name.startsWith(href));
+        assert_equals(entries.length, 0);
+    }, 'Iframes should not report resource timing for non-handled mime-types (downloads)');
+</script>
+</body>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/image-sequence-of-events.html b/testing/web-platform/tests/resource-timing/image-sequence-of-events.html
new file mode 100644
index 0000000000..630fed78c9
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/image-sequence-of-events.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting image timing.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+<script>
+  function test_image_sequence(src, event, t) {
+    const image = document.createElement('img');
+    const absoluteURL = new URL(src, location.href).toString();
+    document.body.appendChild(image);
+    t.add_cleanup(() => image.remove());
+    return new Promise(resolve => {
+      image.addEventListener(event, t.step_func(() => {
+        assert_equals(performance.getEntriesByName(absoluteURL).length, 1);
+        resolve();
+      }));
+      image.src = src;
+    });
+  }
+  promise_test(t => test_image_sequence('resources/blue.png', 'load', t),
+  "An image should receive its load event after the ResourceTiming entry is available");
+
+  promise_test(t => test_image_sequence('resources/nothing-at-all.png', 'error', t),
+  "A non-existent (404) image should receive its error event after the ResourceTiming entry is available");
+
+  promise_test(t => test_image_sequence('resources/invalid.png', 'error', t),
+  "An invalid image should receive its error event after the ResourceTiming entry is available");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type-for-script.html b/testing/web-platform/tests/resource-timing/initiator-type-for-script.html
new file mode 100644
index 0000000000..72173398d5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type-for-script.html
@@ -0,0 +1,67 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates that the initiatorType information for various
+Resource Timing entries is accurate for scripts.</title>
+<link rel="help"
+      href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<!-- Tested resources -->
+<script src="resources/empty_script.js?id=blocking"></script>
+<script src="resources/empty_script.js?id=async" async></script>
+<script src="resources/empty_script.js?id=async_false" async=false></script>
+<script src="resources/empty_script.js?id=defer" defer></script>
+<script>
+document.write("<script src='resources/empty_script.js?id=doc_written'></scr"
+               + "ipt>");
+
+const head = document.getElementsByTagName("head")[0];
+const s1 = document.createElement("script");
+s1.src = "empty_script.js?id=appended";
+head.appendChild(s1);
+
+const s2 = document.createElement("script");
+s2.src = "empty_script.js?id=appended_async";
+s2.async = true;
+head.appendChild(s2);
+
+const s3 = document.createElement("script");
+s3.src = "empty_script.js?id=appended_aync_false";
+s3.async = false;
+head.appendChild(s3);
+
+const s4 = document.createElement("script");
+s4.src = "empty_script.js?id=appended_defer";
+s4.defer = true;
+head.appendChild(s4);
+</script>
+</head>
+<body>
+<script>
+
+const wait_for_onload = () => {
+  return new Promise(resolve => {
+    window.addEventListener("load", resolve);
+})};
+
+promise_test(
+  async () => {
+    await wait_for_onload();
+
+    const entry_list = performance.getEntriesByType("resource");
+    for (entry of entry_list) {
+      if (entry.name.includes("empty_script.js")) {
+        assert_equals(entry.initiatorType, "script",
+                      "initiatorType should be 'script' for " + entry.name);
+      }
+    }
+}, "Validate initiatorType for scripts is 'script'");
+</script>
+</body>
+</html>
+
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/audio.html b/testing/web-platform/tests/resource-timing/initiator-type/audio.html
new file mode 100644
index 0000000000..f09fc61847
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/audio.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: audio</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<audio src="/resource-timing/resources/empty.py?id=src"></audio>
+<audio>
+  <source src="/resource-timing/resources/empty.py?id=source-wav"
+    type="audio/wav" />
+</audio>
+<audio>
+  <source src="/resource-timing/resources/empty.py?id=source-mpeg"
+    type="audio/mpeg" />
+</audio>
+<audio>
+  <source src="/resource-timing/resources/empty.py?id=source-ogg"
+    type="audio/ogg" />
+</audio>
+<script>
+  initiator_type_test("empty.py?id=src", "audio", "<audio src> without 'type' attribute");
+  initiator_type_test("empty.py?id=source-wav", "audio", "<source src> with type 'audio/wav'");
+  initiator_type_test("empty.py?id=source-mpeg", "audio", "<source src> with type 'audio/mpeg'");
+  initiator_type_test("empty.py?id=source-ogg", "audio", "<source src> with type 'audio/ogg'");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/dynamic-insertion.html b/testing/web-platform/tests/resource-timing/initiator-type/dynamic-insertion.html
new file mode 100644
index 0000000000..8ce05b3cfe
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/dynamic-insertion.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing - initiatorType with dynamic insertion</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/entry-invariants.js"></script>
+<script src="/resource-timing/resources/resource-loaders.js"></script>
+<script>
+  const dynamic_initiator_type_test = (loader, path, expected_type,
+      resource_type) => {
+    attribute_test(loader, path, entry => {
+      assert_equals(entry.initiatorType, expected_type);
+    }, `A ${resource_type} should have the '${expected_type}' initiator type.`);
+  };
+
+  dynamic_initiator_type_test(load.image, "resources/resource_timing_test0.png",
+    "img", "image");
+  // Note that, to download a font, 'load.font' uses a <style> element to
+  // construct a font-face that is then applied to a <div>. Since it's a <style>
+  // element requesting the resource, the initiator type is 'css', not 'font'.
+  dynamic_initiator_type_test(load.font, "/fonts/Ahem.ttf", "css", "font");
+  dynamic_initiator_type_test(load.stylesheet,
+    "resources/resource_timing_test0.css", "link", "stylesheet");
+  dynamic_initiator_type_test(load.iframe, "resources/green.html", "iframe",
+    "iframe");
+  dynamic_initiator_type_test(load.script, "resources/empty.js", "script",
+    "script");
+  dynamic_initiator_type_test(load.xhr_sync, "resources/empty.py",
+    "xmlhttprequest", "XMLHttpRequest");
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that the initiatorType field is correct even when an
+element is dynamically inserted.</p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/embed.html b/testing/web-platform/tests/resource-timing/initiator-type/embed.html
new file mode 100644
index 0000000000..c7a505afac
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/embed.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: embed</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<embed src="/resource-timing/resources/resource_timing_test0.css"
+    type="text/css">
+<script>
+  initiator_type_test("resource_timing_test0.css", "embed", "<embed>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/frameset.html b/testing/web-platform/tests/resource-timing/initiator-type/frameset.html
new file mode 100644
index 0000000000..697549a14d
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/frameset.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: frameset</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+<script>
+  initiator_type_test("green.html", "frame", "<frame> in a <frameset>");
+</script>
+</head>
+<!-- Although framesets were deprecated in HTML5, we still want to make sure
+  Resource Timing is emitting entries for the underlying resources' requests.
+-->
+<frameset>
+  <frame src="/resource-timing/resources/green.html">
+</frameset>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/iframe.html b/testing/web-platform/tests/resource-timing/initiator-type/iframe.html
new file mode 100644
index 0000000000..0becd86894
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/iframe.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: iframe</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<iframe src="/resource-timing/resources/green.html"></iframe>
+<script>
+  initiator_type_test("green.html", "iframe", "<iframe>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/img-srcset.html b/testing/web-platform/tests/resource-timing/initiator-type/img-srcset.html
new file mode 100644
index 0000000000..b8c81fbb25
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/img-srcset.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: img with srcset attribute</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<img src="/resource-timing/resources/resource_timing_test0.png"
+    srcset="/resource-timing/resources/resource_timing_test0.png?id=srcset 67w"
+    sizes="67px"></img>
+<script>
+  initiator_type_test("resource_timing_test0.png?id=srcset", "img", "<img srcset>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/img.html b/testing/web-platform/tests/resource-timing/initiator-type/img.html
new file mode 100644
index 0000000000..8e2d305048
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/img.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: img</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<img src="/resource-timing/resources/resource_timing_test0.png"></img>
+<script>
+  initiator_type_test("resource_timing_test0.png", "img", "<img>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/input.html b/testing/web-platform/tests/resource-timing/initiator-type/input.html
new file mode 100644
index 0000000000..a46d416671
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/input.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: input</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<input type="image" src="/resource-timing/resources/resource_timing_test0.png">
+<script>
+  initiator_type_test("resource_timing_test0.png", "input", "<input type=image>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/link.html b/testing/web-platform/tests/resource-timing/initiator-type/link.html
new file mode 100644
index 0000000000..43367ac3d5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/link.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+  <meta charset="utf-8" />
+  <title>Resource Timing initiator type: link</title>
+  <link rel="author" title="Google" href="http://www.google.com/" />
+  <link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype" />
+  <link rel="stylesheet" href="/resource-timing/resources/nested.css">
+  <link rel="prefetch" href="/resource-timing/resources/resource_timing_test0.css?id=prefetch">
+  <link rel="preload" as="style" href="/resource-timing/resources/resource_timing_test0.css?id=preload">
+  <link rel="prerender" href="/resource-timing/resources/green.html?id=prerender">
+  <link rel="manifest" href="/resource-timing/resources/manifest.json">
+  <link rel="modulepreload" href="resources/empty.js?id=modulePreload">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resource-timing/resources/observe-entry.js"></script>
+  <script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+  <script>
+    initiator_type_test("nested.css", "link", "<link>");
+
+    // Verify there are enries for each of nested.css' nested resources.
+    initiator_type_test("resource_timing_test0.css?id=n1", "css", "css resources embedded in css");
+    initiator_type_test("fonts/Ahem.ttf?id=n1", "css", "font resources embedded in css");
+    initiator_type_test("blue.png?id=n1", "css", "image resources embedded in css");
+    initiator_type_test("resource_timing_test0.css?id=prefetch", "link", "<link prefetch>");
+    initiator_type_test("resource_timing_test0.css?id=preload", "link", "<link preload>");
+    initiator_type_test("manifest.json", "link", "<link manifest>");
+    initiator_type_test("resources/empty.js?id=modulePreload", "other", "module preload");
+  </script>
+  <ol>This content forces a font to get fetched</ol>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/misc.html b/testing/web-platform/tests/resource-timing/initiator-type/misc.html
new file mode 100644
index 0000000000..02d01a1633
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/misc.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: miscellaneous elements</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body background="/resource-timing/resources/blue.png?id=body">
+<input type="image" src="/resource-timing/resources/blue.png?id=input">
+<object type="image/png" data="/resource-timing/resources/blue.png?id=object">
+</object>
+<script>
+  navigator.sendBeacon('/resource-timing/resources/empty.py?id=beacon');
+  fetch('/resource-timing/resources/empty.py?id=fetch');
+  const evtSource = new EventSource('/resource-timing/resources/eventsource.py?id=eventsource');
+</script>
+<script>
+  initiator_type_test("blue.png?id=body", "body", "<body background>");
+  initiator_type_test("blue.png?id=input", "input", "<input type='image'>");
+  initiator_type_test("blue.png?id=object", "object", "<object type='image/png'>");
+  initiator_type_test("empty.py?id=beacon", "beacon", "sendBeacon()");
+  initiator_type_test("empty.py?id=fetch", "fetch", "for fetch()");
+  initiator_type_test("eventsource.py?id=eventsource", "other", "new EventSource()");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/picture.html b/testing/web-platform/tests/resource-timing/initiator-type/picture.html
new file mode 100644
index 0000000000..e384b9e97d
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/picture.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: picture</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<picture>
+  <source srcset="blue.png?id=picture-source" type="image/png" />
+  <img src="blue.png?id=picture-img" />
+</picture>
+<picture>
+  <source srcset="blue.png?id=picture-notsupported-source" type="image/notsupported" />
+  <img src="blue.png?id=picture-notsupported-img" />
+</picture>
+<picture>
+  <img src="blue.png?id=picture-img-src"
+    srcset="blue.png?id=picture-img-srcset"
+    sizes="67px"></img>
+</picture>
+<picture>
+  <img src="blue.png?id=picture-99x-img-src"
+    srcset="blue.png?id=picture-99x-img-srcset 99x"
+    sizes="67px"></img>
+</picture>
+<script>
+  initiator_type_test("blue.png?id=picture-source", "img", "<source> in a <picture>");
+  initiator_type_test("blue.png?id=picture-notsupported-img", "img", "<img> in a <picture>");
+  initiator_type_test("blue.png?id=picture-img-srcset", "img", "<img srcset> in a <picture>");
+  initiator_type_test("blue.png?id=picture-99x-img-src", "img", "<img src> in a <picture>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/resources/initiator-type-test.js b/testing/web-platform/tests/resource-timing/initiator-type/resources/initiator-type-test.js
new file mode 100644
index 0000000000..2b1f844376
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/resources/initiator-type-test.js
@@ -0,0 +1,15 @@
+
+if (observe_entry === undefined) {
+  throw new Error("You must include resource-timing/resources/observe-entry.js "
+    + "before including this script.");
+}
+
+// Asserts that, for the given name, there is/will-be a
+// PerformanceResourceTiming entry that has the given 'initiatorType'. The test
+// is labeled according to the given descriptor.
+const initiator_type_test = (entry_name, expected_initiator, descriptor) => {
+  promise_test(async () => {
+    const entry = await observe_entry(entry_name);
+    assert_equals(entry.initiatorType, expected_initiator);
+  }, `The initiator type for ${descriptor} must be '${expected_initiator}'`);
+};
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/script.html b/testing/web-platform/tests/resource-timing/initiator-type/script.html
new file mode 100644
index 0000000000..dbd6a131de
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/script.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: script</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<script src="/resource-timing/resources/empty_script.js"></script>
+<script>
+  const async_xhr = new XMLHttpRequest;
+  async_xhr.open('GET', '/resource-timing/resources/blue.png?id=async_xhr',
+    true);
+  async_xhr.send();
+</script>
+<script>
+  initiator_type_test("empty_script.js", "script", "<script>");
+  initiator_type_test("blue.png?id=async_xhr", "xmlhttprequest", "an asynchronous XmlHTTPRequest");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/style.html b/testing/web-platform/tests/resource-timing/initiator-type/style.html
new file mode 100644
index 0000000000..051496b766
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/style.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: style</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<style>
+  iframe {
+    background: url('/resource-timing/resources/blue.png?id=background');
+  }
+  body {
+    cursor: url('/resource-timing/resources/blue.png?id=cursor'), pointer;
+  }
+  ul {
+    list-style-image: url('/resource-timing/resources/blue.png?id=list-style');
+  }
+
+  @font-face {
+    font-family: remoteFontAhem;
+    src: url('/fonts/Ahem.ttf');
+  }
+  .ahem {
+    font-family: remoteFontAhem;
+  }
+</style>
+<iframe>This iframe forces the 'background' resource to be fetched.</iframe>
+<ul>
+  <li>This content forces the 'list-style-image' resource to be fetched.</li>
+</ul>
+<div class="ahem">This content forces the '@font-face' resource to be fetched.</div>
+<script>
+  initiator_type_test("blue.png?id=background", "css", "'background' attributes in <style> elements");
+  initiator_type_test("blue.png?id=cursor", "css", "'cursor' attributes in <style> elements");
+  initiator_type_test("blue.png?id=list-style", "css", "'list-style-image' attributes in <style> elements");
+  initiator_type_test("fonts/Ahem.ttf", "css", "'@font-face' resources");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/svg.html b/testing/web-platform/tests/resource-timing/initiator-type/svg.html
new file mode 100644
index 0000000000..d92f5935d8
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/svg.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: svg</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<svg width=200 height=200
+  xmlns="http://www.w3.org/2000/svg"
+  xmlns:xlink="http://www.w3.org/1999/xlink">
+  <image href="/resource-timing/resources/blue.png" height="200" width="200"/>
+</svg>
+<script>
+  initiator_type_test("blue.png", "image", "<image> in an <svg>");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/video.html b/testing/web-platform/tests/resource-timing/initiator-type/video.html
new file mode 100644
index 0000000000..16f3b3dea5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/video.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiator type: video</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+</head>
+<body>
+<video poster="/resource-timing/resources/blue.png?id=poster"></video>
+<video src="/media/test.mp4?id=src" autoplay="true"></video>
+<video autoplay="true">
+  <source src="/media/test.mp4?id=source-mp4" type="video/mp4">
+  <track kind="subtitles" srclang="en" default
+    src="/resource-timing/resources/empty.py?id=track">
+</video>
+<video autoplay="true">
+  <source src="/media/test.ogv?id=source-ogv" type="video/ogg">
+</video>
+<script>
+  initiator_type_test("blue.png?id=poster", "video", "<video poster>");
+  initiator_type_test("media/test.mp4?id=src", "video", "<video src>");
+  initiator_type_test("media/test.mp4?id=source-mp4", "video", "<source src> with type=\"video/mp4\"");
+  initiator_type_test("empty.py?id=track", "track", "<track src>");
+  initiator_type_test("media/test.ogv?id=source-ogv", "video", "<source src> with type=\"video/ogg\"");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/initiator-type/workers.html b/testing/web-platform/tests/resource-timing/initiator-type/workers.html
new file mode 100644
index 0000000000..3a23ad71a3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/initiator-type/workers.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing initiatorType: worker resources</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+<script src="resources/initiator-type-test.js"></script>
+
+</head>
+
+<script>
+  const moduleWorkerURL = 'resources/empty.js?moduleWorker';
+  const workerURL = 'resources/empty.js?worker';
+  new Worker(moduleWorkerURL, {type: "module"});
+  new Worker(workerURL, {type: "classic"});
+  initiator_type_test(workerURL, "other", "classic worker");
+  initiator_type_test(moduleWorkerURL, "other", "module worker");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/input-sequence-of-events.html b/testing/web-platform/tests/resource-timing/input-sequence-of-events.html
new file mode 100644
index 0000000000..446e24a0bc
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/input-sequence-of-events.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting input timing.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+<script>
+  async_test(t => {
+    const input = document.createElement('input');
+    input.type = "image";
+    const absoluteURL = new URL('resources/blue.png', location.href).toString();
+    t.add_cleanup(() => input.remove());
+    input.addEventListener('load', t.step_func(() => {
+      assert_equals(performance.getEntriesByName(absoluteURL).length, 1);
+      t.done();
+    }));
+    input.src = absoluteURL;
+    document.body.appendChild(input);
+  }, "An image input element should receive its load event after the ResourceTiming entry is available");
+
+</script>
diff --git a/testing/web-platform/tests/resource-timing/interim-response-times.h2.html b/testing/web-platform/tests/resource-timing/interim-response-times.h2.html
new file mode 100644
index 0000000000..4b1ca93ff7
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/interim-response-times.h2.html
@@ -0,0 +1,74 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>Resource Timing: PerformanceResourceTiming interim resource times</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/common/utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+  const {REMOTE_HOST} = get_host_info();
+  function interim_response_time_test({origin, with100, with103}) {
+    promise_test(async t => {
+      const delay = 500;
+      const url = new URL('/resource-timing/resources/header-delay.h2.py',
+      origin == "same-origin" ?
+          location.href :
+          `${location.protocol}//${REMOTE_HOST}:${location.port}`);
+      url.searchParams.set("delay", delay);
+      if (origin === "cross-origin-with-TAO")
+        url.searchParams.set("tao", "*");
+      if (with100)
+        url.searchParams.set("with100", "true");
+      if (with103)
+        url.searchParams.set("with103", "true");
+      const response = await fetch(url.toString(), {mode: "cors"});
+      assert_equals(response.status, 200)
+      await response.text();
+      const [entry] = performance.getEntriesByName(url.toString());
+      if (origin === "cross-origin") {
+        assert_equals(entry.firstInterimResponseStart, 0);
+        return;
+      }
+      let total_delay = entry.requestStart;
+      if (with100) {
+        total_delay += delay;
+        assert_greater_than(entry.firstInterimResponseStart,
+        total_delay,
+                            "firstInterimResponseStart > 100 response");
+      }
+
+      if (with103) {
+        total_delay += delay;
+        if (with100) {
+          assert_less_than_equal(entry.firstInterimResponseStart,
+          total_delay,  "firstInterimResponseStart > 100 response");
+        } else {
+          assert_greater_than(entry.firstInterimResponseStart,
+          delay, "firstInterimResponseStart > 100 response");
+        }
+      }
+
+      total_delay += delay;
+      if (!with100 && !with103)
+        assert_equals(entry.firstInterimResponseStart, 0);
+
+      assert_greater_than(entry.responseStart, total_delay,
+                        "responseStart");
+    }, `Fetch from ${origin} ${with103 ? "with" : "without"} early hints, ${
+        with100 ? "with" : "without"} 100 response`);
+  }
+
+  for (const with103 of [true, false]) {
+    for (const with100 of [true, false]) {
+      for (origin of ['same-origin', 'cross-origin', 'cross-origin-with-TAO']) {
+        interim_response_time_test({with100, with103, origin});
+      }
+    }
+  }
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/interim-response-times.html b/testing/web-platform/tests/resource-timing/interim-response-times.html
new file mode 100644
index 0000000000..a4d03f599e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/interim-response-times.html
@@ -0,0 +1,72 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>Resource Timing: PerformanceResourceTiming interim resource times</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/common/utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+  const {REMOTE_ORIGIN} = get_host_info();
+  function interim_response_time_test({origin, with100, with103}) {
+    promise_test(async t => {
+      const delay = 500;
+      const url = new URL('/resource-timing/resources/header-delay.py',
+        origin == "same-origin" ? location.href : REMOTE_ORIGIN);
+      url.searchParams.set("delay", delay);
+      if (origin === "cross-origin-with-TAO")
+        url.searchParams.set("tao", "*");
+      if (with100)
+        url.searchParams.set("with100", "true");
+      if (with103)
+        url.searchParams.set("with103", "true");
+      const response = await fetch(url.toString(), {mode: "cors"});
+      assert_equals(response.status, 200)
+      await response.text();
+      const [entry] = performance.getEntriesByName(url.toString());
+      if (origin === "cross-origin") {
+        assert_equals(entry.firstInterimResponseStart, 0);
+        return;
+      }
+      let total_delay = entry.requestStart;
+      if (with100) {
+        total_delay += delay;
+        assert_greater_than(entry.firstInterimResponseStart,
+        total_delay,
+                            "firstInterimResponseStart > 100 response");
+      }
+
+      if (with103) {
+        total_delay += delay;
+        if (with100) {
+          assert_less_than_equal(entry.firstInterimResponseStart,
+          total_delay,  "firstInterimResponseStart > 100 response");
+        } else {
+          assert_greater_than(entry.firstInterimResponseStart,
+          delay, "firstInterimResponseStart > 100 response");
+        }
+      }
+
+      total_delay += delay;
+      if (!with100 && !with103)
+        assert_equals(entry.firstInterimResponseStart, 0);
+
+      assert_greater_than(entry.responseStart, total_delay,
+                        "responseStart");
+    }, `Fetch from ${origin} ${with103 ? "with" : "without"} early hints, ${
+        with100 ? "with" : "without"} 100 response`);
+  }
+
+  for (const with103 of [true, false]) {
+    for (const with100 of [true, false]) {
+      for (origin of ['same-origin', 'cross-origin', 'cross-origin-with-TAO']) {
+        interim_response_time_test({with100, with103, origin});
+      }
+    }
+  }
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/link-sequence-of-events.html b/testing/web-platform/tests/resource-timing/link-sequence-of-events.html
new file mode 100644
index 0000000000..be9db32cd9
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/link-sequence-of-events.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test the sequence of events when reporting link timing.</title>
+<meta name="timeout" content="long">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+<script>
+  promise_test(async t => {
+    const link = document.createElement('link');
+    const delay = 500;
+    const src = `./resources/import.sub.css?delay=${delay}`
+    const absoluteURL = new URL(src, location.href).toString();
+    new PerformanceObserver(t.step_func(() => {
+      const allPerformanceEntries = performance.getEntriesByType('resource');
+      const linkEntry = allPerformanceEntries.find(e => e.name.includes('import.sub.css'));
+      const importEntry = allPerformanceEntries.find(e => e.name.includes('delay-css'));
+      if (!linkEntry || !importEntry)
+        return;
+      const linkEndTime = linkEntry.startTime + linkEntry.duration;
+      const importEndTime = importEntry.startTime + importEntry.duration;
+      assert_greater_than_equal(importEndTime, linkEndTime + delay, "link load should be done before import load");
+      t.done();
+
+    })).observe({type: 'resource'});
+    link.href = src;
+    link.rel = 'stylesheet';
+    document.head.appendChild(link);
+  }, "test that @imports don't affect link resource timings");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/load-from-mem-cache-transfer-size.html b/testing/web-platform/tests/resource-timing/load-from-mem-cache-transfer-size.html
new file mode 100644
index 0000000000..3d2d32d6e6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/load-from-mem-cache-transfer-size.html
@@ -0,0 +1,65 @@
+<!DOCTYPE HTML>
+<html>
+
+<head>
+  <meta charset="utf-8" />
+  <title>This tests transfer size of resource timing when loaded from memory cache.</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="resources/entry-invariants.js"></script>
+</head>
+
+<body>
+  <script>
+    function getScript(url) {
+      const script = document.createElement("script");
+      const loaded = new Promise(resolve => {
+        script.onload = script.onerror = resolve;
+      });
+      script.src = url;
+      document.body.appendChild(script);
+      return loaded;
+    }
+    function add_iframe(url) {
+      return new Promise(function (resolve) {
+        var frame = document.createElement('iframe');
+        frame.src = url;
+        frame.onload = function () { resolve(frame); };
+        document.body.appendChild(frame);
+      });
+    }
+    promise_test(async t => {
+      // Add unique token to url so that each run the url is different to avoid
+      // flakiness.
+      let url = 'resources/resource_timing_test0.js?unique=' +
+        Math.random().toString().substr(2);
+      let frame;
+      return add_iframe('resources/iframe-load-from-mem-cache-transfer-size.html')
+        .then((f) => {
+          frame = f;
+          // Load script onto iframe in order to get it into the memory cache.
+          return frame.contentWindow.getScript(url.split('/')[1])
+        })
+        .then(() => {
+          // Verify that the transferSize in case of normal load is greater than
+          // 0.
+          assert_positive_(
+            frame.contentWindow.performance.getEntriesByType('resource')
+              .filter(e => e.name.includes(url))[0], ['transferSize']);
+
+          // Load the same script onto the parent document. This time the script
+          // is coming from memory cache.
+          return getScript(url);
+        })
+        .then(() => {
+          // Verify that the transferSize in case of memory cache load is 0.
+          assert_zeroed_(
+            window.performance.getEntriesByType('resource')
+              .filter(e => e.name.includes(url))[0], ['transferSize']);
+        });
+    }, "The transferSize of resource timing entries should be 0 when resource \
+    is loaded from memory cache.");
+  </script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/resource-timing/nested-context-navigations-embed.html b/testing/web-platform/tests/resource-timing/nested-context-navigations-embed.html
new file mode 100644
index 0000000000..f804adbb8a
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/nested-context-navigations-embed.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name=timeout content=long>
+<title>Resource Timing embed navigate - back button navigation</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/nested-contexts.js"></script>
+<script>
+  open_test_window("resources/embed-navigate-back.html",
+    "Test that embed navigations are not observable by the parent, even " +
+    "after history navigations by the parent");
+  open_test_window("resources/embed-navigate-back.html?crossorigin",
+    "Test that crossorigin embed navigations are not observable by the " +
+    "parent, even after history navigations by the parent");
+  open_test_window("resources/embed-navigate-back.html?cross-site",
+    "Test that cross-site embed navigations are not observable by the " +
+    "parent, even after history navigations by the parent");
+
+  open_test_window("resources/embed-navigate.html",
+    "Test that embed navigations are not observable by the parent");
+  open_test_window("resources/embed-navigate.html?crossorigin",
+    "Test that crossorigin embed navigations are not observable by the parent");
+  open_test_window("resources/embed-navigate.html?cross-site",
+    "Test that cross-site embed navigations are not observable by the parent");
+  open_test_window("resources/embed-refresh.html",
+    "Test that embed refreshes are not observable by the parent");
+  open_test_window("resources/embed-refresh.html?crossorigin",
+    "Test that crossorigin embed refreshes are not observable by the parent");
+  open_test_window("resources/embed-refresh.html?cross-site",
+    "Test that cross-site embed refreshes are not observable by the parent");
+
+</script>
+
diff --git a/testing/web-platform/tests/resource-timing/nested-context-navigations-iframe.html b/testing/web-platform/tests/resource-timing/nested-context-navigations-iframe.html
new file mode 100644
index 0000000000..32ab21633c
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/nested-context-navigations-iframe.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name=timeout content=long>
+<title>Resource Timing embed navigate - back button navigation</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/nested-contexts.js"></script>
+<script>
+  open_test_window("resources/iframe-navigate-back.html",
+    "Test that iframe navigations are not observable by the parent, even after history navigations by the parent");
+  open_test_window("resources/iframe-navigate-back.html?crossorigin",
+    "Test that crossorigin iframe navigations are not observable by the parent, even after history navigations by the parent");
+  open_test_window("resources/iframe-navigate-back.html?cross-site",
+    "Test that cross-site iframe navigations are not observable by the parent, even after history navigations by the parent");
+  open_test_window("resources/iframe-navigate.html",
+    "Test that iframe navigations are not observable by the parent");
+  open_test_window("resources/iframe-navigate.html?crossorigin",
+    "Test that crossorigin iframe navigations are not observable by the parent");
+  open_test_window("resources/iframe-navigate.html?cross-site",
+    "Test that cross-site iframe navigations are not observable by the parent");
+  open_test_window("resources/iframe-refresh.html",
+    "Test that iframe refreshes are not observable by the parent");
+  open_test_window("resources/iframe-refresh.html?crossorigin",
+    "Test that crossorigin iframe refreshes are not observable by the parent");
+  open_test_window("resources/iframe-refresh.html?cross-site",
+    "Test that cross-site iframe refreshes are not observable by the parent");
+
+</script>
+
diff --git a/testing/web-platform/tests/resource-timing/nested-context-navigations-object.html b/testing/web-platform/tests/resource-timing/nested-context-navigations-object.html
new file mode 100644
index 0000000000..1508d8829f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/nested-context-navigations-object.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta name=timeout content=long>
+<title>Resource Timing embed navigate - back button navigation</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/nested-contexts.js"></script>
+<script>
+  open_test_window("resources/object-navigate-back.html",
+    "Test that object navigations are not observable by the parent, even " +
+    "after history navigations by the parent");
+  open_test_window("resources/object-navigate-back.html?crossorigin",
+    "Test that crossorigin object navigations are not observable by the " +
+    "parent, even after history navigations by the parent");
+  open_test_window("resources/object-navigate-back.html?cross-site",
+    "Test that cross-site object navigations are not observable by the " +
+    "parent, even after history navigations by the parent");
+  open_test_window("resources/object-navigate.html",
+    "Test that object navigations are not observable by the parent");
+  open_test_window("resources/object-navigate.html?crossorigin",
+    "Test that crossorigin object navigations are not observable by the " +
+    "parent");
+  open_test_window("resources/object-navigate.html?cross-site",
+    "Test that cross-site object navigations are not observable by the " +
+    "parent");
+  open_test_window("resources/object-refresh.html",
+    "Test that object refreshes are not observable by the parent");
+  open_test_window("resources/object-refresh.html?crossorigin",
+    "Test that crossorigin object refreshes are not observable by the parent");
+  open_test_window("resources/object-refresh.html?cross-site",
+    "Test that cross-site object refreshes are not observable by the parent");
+
+</script>
+
diff --git a/testing/web-platform/tests/resource-timing/nested-nav-fallback-timing.html b/testing/web-platform/tests/resource-timing/nested-nav-fallback-timing.html
new file mode 100644
index 0000000000..b8bba5614d
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/nested-nav-fallback-timing.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test ResourceTiming reporting for cross-origin iframe.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/observe-entry.js"></script>
+</head>
+<body>
+<body>
+<script>
+  const {REMOTE_ORIGIN} = get_host_info();
+
+  promise_test(async t => {
+    const iframe = document.createElement('iframe');
+    t.add_cleanup(() => iframe.remove());
+    iframe.src = `${REMOTE_ORIGIN}/resource-timing/resources/delay-load.html`;
+    document.body.appendChild(iframe);
+    const entry = await observe_entry(iframe.src);
+    assert_greater_than(entry.duration, 1000);
+  }, "Cross-origin TAO-fail IFrame entries should report window load time");
+
+  promise_test(async t => {
+    const object = document.createElement('object');
+    object.type = "text/html";
+    t.add_cleanup(() => object.remove());
+    object.data = `${REMOTE_ORIGIN}/resource-timing/resources/delay-load.html`;
+    document.body.appendChild(object);
+    const entry = await observe_entry(object.data);
+    assert_greater_than(entry.duration, 1000);
+  }, "Cross-origin TAO-fail object entries should report window load time");
+
+  </script>
diff --git a/testing/web-platform/tests/resource-timing/nextHopProtocol-is-tao-protected.https.html b/testing/web-platform/tests/resource-timing/nextHopProtocol-is-tao-protected.https.html
new file mode 100644
index 0000000000..b16ff7af75
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/nextHopProtocol-is-tao-protected.https.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing - Check that nextHopProtocol is TAO protected</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/custom-cors-response.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/tao-response.js"></script>
+</head>
+<body>
+<script>
+
+const {HTTPS_REMOTE_ORIGIN} = get_host_info();
+
+const tao_protected_next_hop_test = (loader, item) => {
+  attribute_test(
+    loader, custom_cors_response({}, HTTPS_REMOTE_ORIGIN),
+    entry => assert_equals(entry.nextHopProtocol, "",
+      "nextHopProtocol should be the empty string."),
+    `Fetch TAO-less ${item} from remote origin. Make sure nextHopProtocol ` +
+    "is the empty string."
+  );
+
+  attribute_test(
+    loader, remote_tao_response('*'),
+    entry => assert_not_equals(entry.nextHopProtocol, "",
+      "nextHopProtocol should not be the empty string."),
+    `Fetch TAO'd ${item} from remote origin. Make sure nextHopProtocol ` +
+    "is not the empty string."
+  );
+}
+
+tao_protected_next_hop_test(load.font, "font");
+tao_protected_next_hop_test(load.iframe, "iframe");
+tao_protected_next_hop_test(load.image, "image");
+tao_protected_next_hop_test(path => load.object(path, "text/plain"), "object");
+tao_protected_next_hop_test(load.script, "script");
+tao_protected_next_hop_test(load.stylesheet, "stylesheet");
+tao_protected_next_hop_test(load.xhr_sync, "synchronous xhr");
+tao_protected_next_hop_test(load.xhr_async, "asynchronous xhr");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html b/testing/web-platform/tests/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html
new file mode 100644
index 0000000000..6b60305ded
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/no-entries-for-cross-origin-css-fetched-memory-cache.sub.html
@@ -0,0 +1,53 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Make sure that resources fetched by cross origin CSS are not in the timeline.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<!--
+  This test is mostly the same as no-entries-for-cross-origin-css-fetched.html
+  but loads the sub-resources from another Document (<iframe>) earlier before
+  they are loaded via cross-origin CSSs, so that the resources are loaded from
+  cache and therefore no resource timing entries are created.
+-->
+
+<body>
+  <script>
+    const addLink = () => {
+      return new Promise(resolve => {
+        const link = document.createElement('LINK');
+        link.rel = 'stylesheet';
+        link.id = 'cross_origin_style';
+        link.href = 'http://{{hosts[][www1]}}:{{ports[http][1]}}/resource-timing/resources/nested.css';
+        link.addEventListener('load', resolve);
+        document.body.appendChild(link);
+      });
+    }
+
+    const addFrame = () => {
+      return new Promise(resolve => {
+        const iframe = document.createElement('iframe');
+        iframe.src = 'resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html';
+        iframe.addEventListener('load', resolve);
+        document.body.appendChild(iframe);
+      });
+    }
+
+    promise_test(async t => {
+      await addFrame();
+      await addLink();
+      // Assert no resource timing entries are created when the link is attached.
+      const url = (new URL(document.getElementById('cross_origin_style').href));
+      const prefix = url.protocol + '//' + url.host;
+      assert_equals(performance.getEntriesByName(
+        prefix + '/resource-timing/resources/resource_timing_test0.css?id=n1').length, 0,
+        'Import should not be in timeline');
+      assert_equals(performance.getEntriesByName(
+        prefix + '/fonts/Ahem.ttf?id=n1').length, 0, 'Font should not be in timeline');
+      assert_equals(performance.getEntriesByName(
+        prefix + '/resource-timing/resources/blue.png?id=n1').length, 0,
+        'Image should not be in timeline');
+    }, 'Make sure that resources fetched by cross origin CSS are not in the timeline.');
+  </script>
+  <ol>Some content</ol>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/no-entries-for-cross-origin-css-fetched.sub.html b/testing/web-platform/tests/resource-timing/no-entries-for-cross-origin-css-fetched.sub.html
new file mode 100644
index 0000000000..63f9e06e19
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/no-entries-for-cross-origin-css-fetched.sub.html
@@ -0,0 +1,39 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>Make sure that resources fetched by cross origin CSS are not in the timeline.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<body>
+<script>
+    const host = get_host_info();
+
+    const link = document.createElement("LINK");
+    link.rel = "stylesheet";
+    link.id = "cross_origin_style";
+
+    /*
+        This stylesheet is fetched from one of:
+            //www1.web–platform.test:64941/resource-timing/resources/nested.css
+            //127.0.0.1:64941/resource-timing/resources/nested.css
+     */
+    link.href = "//" + host.REMOTE_HOST + ":{{ports[http][1]}}{{location[path]}}/../resources/nested.css"
+    document.currentScript.parentNode.insertBefore(link, document.currentScript);
+</script>
+<script>
+  const t = async_test("Make sure that resources fetched by cross origin CSS are not in the timeline.");
+  window.addEventListener("load", function() {
+    // A timeout is needed as entries are not guaranteed to be in the timeline before onload triggers.
+    t.step_timeout(function() {
+          const url = (new URL(document.getElementById("cross_origin_style").href));
+          const prefix = url.protocol + "//" + url.host;
+          assert_equals(performance.getEntriesByName(prefix + "/resource-timing/resources/resource_timing_test0.css?id=n1").length, 0, "Import should not be in timeline");
+          assert_equals(performance.getEntriesByName(prefix + "/fonts/Ahem.ttf?id=n1").length, 0, "Font should not be in timeline");
+          assert_equals(performance.getEntriesByName(prefix + "/resource-timing/resources/blue.png?id=n1").length, 0, "Image should not be in timeline");
+          t.done();
+    }, 200);
+  });
+</script>
+<ol>Some content</ol>
+</body>
+
diff --git a/testing/web-platform/tests/resource-timing/object-not-found-adds-entry.html b/testing/web-platform/tests/resource-timing/object-not-found-adds-entry.html
new file mode 100644
index 0000000000..d11823dd9d
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/object-not-found-adds-entry.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates that object resource emit resource timing entries.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+</head>
+<body>
+<script>
+const load_image_object = async path => {
+  return load.object(path, "image/png");
+}
+
+const load_null_object = async path => {
+  return load.object(path, null);
+}
+
+attribute_test(
+  load_null_object, "resources/status-code.py?status=200&type=none",
+  invariants.assert_tao_pass_no_redirect_http,
+  "Verify that a 200 null-typed object emits an entry.");
+
+attribute_test(
+  load_null_object, "resources/status-code.py?status=404&type=none",
+  invariants.assert_tao_pass_no_redirect_http,
+  "Verify that a 404 null-typed object emits an entry.");
+
+attribute_test(
+  load_image_object, "resources/status-code.py?status=404&type=img",
+  invariants.assert_tao_pass_no_redirect_http,
+  "Verify that a 404 img-typed object emits an entry.");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/object-not-found-after-TAO-cross-origin-redirect.html b/testing/web-platform/tests/resource-timing/object-not-found-after-TAO-cross-origin-redirect.html
new file mode 100644
index 0000000000..d0dad9381b
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/object-not-found-after-TAO-cross-origin-redirect.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates resource timing information for a timing allowed cross-origin redirect chain.</title>
+<link rel="help" href="http://www.w3.org/TR/resource-timing/#performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src=/common/get-host-info.sub.js></script>
+<script src="resources/webperftestharness.js"></script>
+<script src="resources/webperftestharnessextension.js"></script>
+
+<script>
+    setup({explicit_done: true});
+    test_namespace('getEntriesByName');
+
+    function onload_test()
+    {
+        const context = new PerformanceContext(performance);
+        const entries = context.getEntriesByName(document.querySelector('object').data, 'resource');
+        test_equals(entries.length, 1, 'There should be one entry.');
+        const entry = entries[0];
+
+        test_greater_than(entry.redirectStart, 0, 'redirectStart > 0 in timing allowed cross-origin redirect.');
+        test_equals(entry.redirectStart, entry.startTime, 'redirectStart == startTime in timing allowed cross-origin redirect.');
+        test_greater_than(entry.redirectEnd, entry.redirectStart, 'redirectEnd > redirectStart in timing allowed cross-origin redirect.');
+        test_greater_or_equals(entry.fetchStart, entry.redirectEnd, 'fetchStart >= redirectEnd in timing allowed cross-origin redirect.');
+        done();
+    }
+</script>
+
+</head>
+<body>
+<script>
+    let destUrl = get_host_info().HTTP_REMOTE_ORIGIN + '/resource-timing/resources/multi_redirect.py?';
+    destUrl += 'page_origin=' + 'http://' + document.location.host;
+    destUrl += '&cross_origin=' + get_host_info().HTTP_REMOTE_ORIGIN;
+    destUrl += '&final_resource=' + encodeURIComponent("/resource-timing/resources/status-code.py?status=404&tao_value=*");
+    destUrl += '&tao_steps=3';
+    const objElement = document.createElement('object');
+    objElement.style = 'width: 0px; height: 0px;';
+    objElement.data = destUrl;
+    objElement.onerror = onload_test;
+    document.body.appendChild(objElement);
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/object-not-found-after-cross-origin-redirect.html b/testing/web-platform/tests/resource-timing/object-not-found-after-cross-origin-redirect.html
new file mode 100644
index 0000000000..6990c6c060
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/object-not-found-after-cross-origin-redirect.html
@@ -0,0 +1,42 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the values in resource timing for cross-origin
+redirects.</title>
+<meta name="timeout" content="long">
+<link rel="author" title="Noam Rosenthal" href="noam@webkit.org">
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+</head>
+<body>
+<script>
+const {REMOTE_ORIGIN} = get_host_info();
+const delay = 1;
+const not_found_page = encodeURIComponent("/resource-timing/resources/status-code.py?status=404");
+const load_null_object = async path => {
+  return load.object(path, null);
+}
+const destUrl = `/common/slow-redirect.py?delay=${delay}&location=${REMOTE_ORIGIN}${not_found_page}`;
+
+const timeBefore = performance.now();
+(async () => {
+  // Wait 10 ms, to ensure the difference between startTime and timeBefore is
+  // larger than 1 ms, to avoid flakiness in browsers that clamp timestamps to
+  // 1 ms.
+  await new Promise(r => step_timeout(r, 10));
+  attribute_test(load_null_object, destUrl, entry => {
+      assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
+      assert_greater_than(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
+      // See https://github.com/w3c/resource-timing/issues/264
+      assert_less_than(Math.round(entry.startTime - timeBefore), delay * 1000, 'startTime should not expose redirect delays');
+  }, "Verify that cross-origin object resources don't implicitly expose their redirect timings")
+})();
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/opaque-origin.html b/testing/web-platform/tests/resource-timing/opaque-origin.html
new file mode 100644
index 0000000000..598ee50a59
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/opaque-origin.html
@@ -0,0 +1,46 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing TAO - "null" and opaque origin</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#timing-allow-origin"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that, for a cross origin resource, the timing allow
+check algorithm will correctly distinguish between 'null' and 'Null' values in
+the Timing-Allow-Origin header. An opaque origin's serialization is the string
+"null" and the timing allow origin check needs to do a case-sensitive comparison
+to the Timing-Allow-Origin header.
+</p>
+<iframe id="frameContext"></iframe>
+<script>
+const {ORIGIN} = get_host_info();
+const url = `${ORIGIN}/resource-timing/resources/TAOResponse.py`;
+const frame_content = `data:text/html;utf8,<body>
+  <script src="${ORIGIN}/resources/testharness.js"></` + `script>
+  <script src="${ORIGIN}/resource-timing/resources/entry-invariants.js">
+  </` + `script>
+  <script>
+    attribute_test(fetch, "${url}?tao=null",
+      invariants.assert_tao_pass_no_redirect_http,
+      "An opaque origin should be authorized to see resource timings when the" +
+      "TAO header is the string 'null'");
+    attribute_test(fetch, "${url}?tao=Null",
+      invariants.assert_tao_failure_resource,
+      "An opaque origin must not be authorized to see resource timings when " +
+      "the TAO header is the string 'Null'. (The check for 'null' must be " +
+      "case-sensitive)");
+  </` + `script>
+</body>`;
+
+frameContext.style = "display:none";
+frameContext.src = frame_content;
+fetch_tests_from_window(frameContext.contentWindow);
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/ping-rt-entries.html b/testing/web-platform/tests/resource-timing/ping-rt-entries.html
new file mode 100644
index 0000000000..34dad10b9f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/ping-rt-entries.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing Entry For hyperlink audit (ping)</title>
+<link rel="help" href="https://w3c.github.io/resource-timing/"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resource-timing/resources/observe-entry.js"></script>
+</head>
+<body>
+<script>
+    promise_test(async t => {
+        const link = document.createElement('a');
+        const delay = 500;
+        const ping = `/xhr/resources/delay.py?ms=${delay}`;
+        link.setAttribute('href', 'resources/close.html');
+        link.setAttribute('target', '_blank');
+        link.setAttribute('ping', ping);
+        link.innerText = 'Link';
+        document.body.appendChild(link);
+        link.click();
+        const entry = await observe_entry(ping);
+        assert_equals(entry.initiatorType, 'ping');
+        assert_greater_than(entry.duration, delay);
+    }, "Hyperlink auditing (<a ping>) should have a resource timing entry");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/queue-entry-regardless-buffer-size.html b/testing/web-platform/tests/resource-timing/queue-entry-regardless-buffer-size.html
new file mode 100644
index 0000000000..ea47ae3a79
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/queue-entry-regardless-buffer-size.html
@@ -0,0 +1,38 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<link rel="help" href="https://w3c.github.io/resource-timing/#dfn-mark-resource-timing">
+<title>This test validates that resource timing entires should always be queued regardless the size of the buffer.</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/buffer-full-utilities.js"></script>
+</head>
+<body>
+<script>
+promise_test(async t => {
+    clearBufferAndSetSize(1);
+    let count = 0;
+    const allEntriesReceived =  new Promise(resolve => {
+      new PerformanceObserver(t.step_func((list) => {
+        for (const entry of list.getEntries()) {
+          if (entry.name.includes(scriptResources[0])) {
+            count += 1;
+          } else if (entry.name.includes(scriptResources[1])) {
+            count += 1;
+          }
+        }
+        if (count == 2) {
+          resolve();
+        }
+      })).observe({type: 'resource'});
+    });
+    load.script(scriptResources[0]);
+    load.script(scriptResources[1]);
+
+    // Two resource timing entries should be observed regardless the
+    // fact that we've set the buffer size to 1.
+    await allEntriesReceived;
+}, "Test that buffer size has no impact to whether an entry is queued or not");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/redirects.html b/testing/web-platform/tests/resource-timing/redirects.html
new file mode 100644
index 0000000000..ba69907a5f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/redirects.html
@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing: resources fetched through same-origin redirects</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script>
+const {HTTPS_NOTSAMESITE_ORIGIN} = get_host_info();
+const redirect_url = `/common/redirect.py`;
+const url_prefix = `${redirect_url}?location=/resource-timing/resources/`;
+const https_url_prefix = `${redirect_url}?location=${HTTPS_NOTSAMESITE_ORIGIN}/resource-timing/resources/`;
+
+attribute_test(
+  load.stylesheet, url_prefix + "resource_timing_test0.css",
+  invariants.assert_same_origin_redirected_resource,
+  "Verify attributes of a redirected stylesheet's PerformanceResourceTiming");
+
+attribute_test(
+  load.image, url_prefix + "blue.png",
+  invariants.assert_same_origin_redirected_resource,
+  "Verify attributes of a redirected image's PerformanceResourceTiming");
+
+attribute_test(
+  load.iframe, url_prefix + "green.html",
+  invariants.assert_same_origin_redirected_resource,
+  "Verify attributes of a redirected iframe's PerformanceResourceTiming");
+
+attribute_test(
+  load.script, url_prefix + "empty_script.js",
+  invariants.assert_same_origin_redirected_resource,
+  "Verify attributes of a redirected script's PerformanceResourceTiming");
+
+attribute_test(
+  load.xhr_sync, url_prefix + "green.html?id=xhr",
+  invariants.assert_same_origin_redirected_resource,
+  "Verify attributes of a redirected synchronous XMLHttpRequest's " +
+  "PerformanceResourceTiming");
+
+attribute_test(
+  load.xhr_sync, https_url_prefix + "green.html?id=xhr",
+  invariants.assert_cross_origin_redirected_resource,
+  "Verify attributes of a synchronous XMLHttpRequest's " +
+  "PerformanceResourceTiming where the initial HTTP request is redirected " +
+  "to a cross-origin HTTPS resource."
+);
+
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that, when a fetching resources that encounter
+same-origin redirects, attributes of the PerformanceResourceTiming entry
+conform to the specification.</p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/render-blocking-status-link.html b/testing/web-platform/tests/resource-timing/render-blocking-status-link.html
new file mode 100644
index 0000000000..8c6544db48
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/render-blocking-status-link.html
@@ -0,0 +1,222 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the render blocking status of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<!-- Start of test cases -->
+<script>
+    // Dynamic style using document.write in head
+    document.write(`
+        <link rel=stylesheet
+              href='resources/empty_style.css?stylesheet-head-dynamic-docWrite'>
+    `);
+    document.write(`
+        <link rel=stylesheet
+              href='resources/empty_style.css?stylesheet-head-dynamic-docWrite-print'
+              media=print>
+    `);
+</script>
+
+<link rel=stylesheet href="resources/empty_style.css?stylesheet-head">
+<link rel=stylesheet href="resources/empty_style.css?stylesheet-head-media-print"
+      media=print>
+<link rel="alternate stylesheet"
+      href="resources/empty_style.css?stylesheet-head-alternate">
+<link rel=preload as=style href="resources/empty_style.css?link-style-head-preload">
+<link rel=preload as=style href="resources/empty_style.css?link-style-preload-used">
+<link rel=stylesheet href="resources/importer.css?stylesheet-importer-head">
+<link rel=stylesheet id="link-head-remove-attr" blocking="render"
+    href="resources/empty_style.css?stylesheet-head-blocking-render-remove-attr">
+<link rel=modulepreload href="resources/empty_script.js?link-head-modulepreload">
+
+<style>@import url(resources/empty_style.css?stylesheet-inline-imported);</style>
+<style media=print>
+    @import url(resources/empty_style.css?stylesheet-inline-imported-print);
+</style>
+</head>
+
+<body>
+
+<link rel=stylesheet href="resources/empty_style.css?stylesheet-body">
+<link rel=stylesheet href="resources/importer.css?stylesheet-importer-body">
+<link rel=stylesheet href="resources/empty_style.css?stylesheet-body-media-print"
+      media=print>
+<link rel=stylesheet blocking="render"
+    href="resources/empty_style.css?stylesheet-body-blocking-render">
+
+<!-- https://html.spec.whatwg.org/multipage/urls-and-fetching.html#blocking-attributes
+     mentions that an element is potentially render-blocking if its blocking
+     tokens set contains "render", or if it is implicitly potentially
+     render-blocking. By default, an element is not implicitly potentially
+     render-blocking.
+     https://html.spec.whatwg.org/multipage/links.html#link-type-stylesheet
+     specifies that a link element of type stylesheet is implicitly potentially
+     render-blocking only if the element was created by its node document's parser. -->
+<script>
+    // Dynamic style using document.write in body
+    document.write(`
+        <link rel=stylesheet
+              href='resources/empty_style.css?stylesheet-body-dynamic-docWrite'>
+    `);
+    document.write(`
+        <link rel=stylesheet
+              href='resources/empty_style.css?stylesheet-body-dynamic-docWrite-print'
+              media=print>
+    `);
+
+    // Dynamic style using innerHTML
+    document.head.innerHTML += `
+        <link rel=stylesheet
+              href='resources/empty_style.css?stylesheet-head-dynamic-innerHTML'>
+    `;
+    document.head.innerHTML += `
+        <link rel=stylesheet
+              href='resources/empty_style.css?stylesheet-head-dynamic-innerHTML-print'
+              media=print>
+    `;
+    document.head.innerHTML += `
+        <link rel=stylesheet blocking=render
+              href='resources/empty_style.css?stylesheet-head-blocking-render-dynamic-innerHTML'>
+    `;
+
+    // Dynamic style using DOM API
+    var link = document.createElement("link");
+    link.href = "resources/empty_style.css?stylesheet-head-dynamic-dom";
+    link.rel = "stylesheet";
+    document.head.appendChild(link);
+
+    // Add a dynamic render-blocking style with DOM API
+    link = document.createElement("link");
+    link.href = "resources/empty_style.css?stylesheet-head-blocking-render-dynamic-dom";
+    link.rel = "stylesheet";
+    link.blocking = "render";
+    document.head.appendChild(link);
+
+    // Dynamic style preload using DOM API
+    link = document.createElement("link");
+    link.href = "resources/empty_style.css?link-style-head-preload-dynamic-dom";
+    link.rel = "preload";
+    link.as = "style";
+    document.head.appendChild(link);
+
+    // Dynamic module via modulepreload using DOM API
+    link = document.createElement("link");
+    link.href = "resources/empty_script.js?link-head-modulepreload-dynamic-dom";
+    link.rel = "modulepreload";
+    document.head.appendChild(link);
+
+    // Add a style preload with DOM API to be used later
+    link = document.createElement("link");
+    link.href = "resources/empty_style.css?link-style-preload-used-dynamic";
+    link.rel = "preload";
+    link.as = "style";
+    document.head.appendChild(link);
+    // Use the preload
+    link = document.createElement("link");
+    link.href = "resources/empty_style.css?link-style-preload-used-dynamic";
+    link.rel = "stylesheet";
+    document.head.appendChild(link);
+
+    // Dynamic inline CSS
+    // Add an inline CSS importer
+    document.write(`
+        <style>
+            @import url('resources/empty_style.css?stylesheet-inline-imported-dynamic-docwrite')
+        </style>
+    `);
+    document.write(`
+        <style media=print>
+            @import url('resources/empty_style.css?stylesheet-inline-imported-dynamic-docwrite-print')
+        </style>
+    `);
+
+    // Add a dynamic inline CSS importer using DOM API
+    let style = document.createElement("style");
+    style.textContent = "@import url('resources/empty_style.css?stylesheet-inline-imported-dynamic-dom')";
+    document.head.appendChild(style);
+
+    // Add a dynamic render-blocking inline CSS importer
+    style = document.createElement("style");
+    style.textContent = "@import url('resources/empty_style.css?stylesheet-inline-imported-blocking-render-dynamic-dom')";
+    style.blocking = "render";
+    document.head.appendChild(style);
+
+    // Dynamic CSS importer
+    document.write(`
+        <link rel=stylesheet href='resources/importer_dynamic.css'>
+    `);
+    document.write(`
+        <link rel=stylesheet href='resources/importer_print.css' media=print>
+    `);
+
+    // Removing blocking render attribute after request is made
+    const sheet = document.getElementById("link-head-remove-attr");
+    sheet.blocking = "";
+</script>
+
+<link rel=stylesheet href="resources/empty_style.css?link-style-preload-used">
+
+<script>
+
+const wait_for_onload = () => {
+  return new Promise(resolve => {
+    window.addEventListener("load", resolve);
+})};
+
+promise_test(
+  async () => {
+    const expectedRenderBlockingStatus = {
+        'stylesheet-head-dynamic-docWrite': 'blocking',
+        'stylesheet-head-dynamic-docWrite-print': 'non-blocking',
+        'stylesheet-head': 'blocking',
+        'stylesheet-head-media-print' : 'non-blocking',
+        'stylesheet-head-alternate' : 'non-blocking',
+        'link-style-head-preload' : 'non-blocking',
+        'stylesheet-importer-head' : 'blocking',
+        'stylesheet-head-blocking-render-remove-attr' : 'blocking',
+        'link-head-modulepreload' : 'non-blocking',
+        'stylesheet-inline-imported' : 'blocking',
+        'stylesheet-inline-imported-print' : 'non-blocking',
+        'stylesheet-body': 'non-blocking',
+        'stylesheet-importer-body' : 'non-blocking',
+        'stylesheet-body-media-print' : 'non-blocking',
+        'stylesheet-body-blocking-render' : 'non-blocking',
+        'stylesheet-body-dynamic-docWrite' : 'non-blocking',
+        'stylesheet-body-dynamic-docWrite-print': 'non-blocking',
+        'stylesheet-head-dynamic-innerHTML' : 'non-blocking',
+        'stylesheet-head-dynamic-innerHTML-print' : 'non-blocking',
+        'stylesheet-head-blocking-render-dynamic-innerHTML' : 'blocking',
+        'stylesheet-head-dynamic-dom' : 'non-blocking',
+        'stylesheet-head-blocking-render-dynamic-dom' : 'blocking',
+        'link-style-head-preload-dynamic-dom' : 'non-blocking',
+        'link-head-modulepreload-dynamic-dom' : 'non-blocking',
+        'link-style-preload-used' : 'non-blocking',
+        'link-style-preload-used-dynamic' : 'non-blocking',
+        'stylesheet-inline-imported-dynamic-docwrite': 'blocking',
+        'stylesheet-inline-imported-dynamic-docwrite-print' : 'non-blocking',
+        'stylesheet-inline-imported-dynamic-dom' : 'non-blocking',
+        'stylesheet-inline-imported-blocking-render-dynamic-dom' : 'blocking',
+        'stylesheet-imported' : 'blocking',
+        'stylesheet-imported-print' : 'non-blocking',
+        'stylesheet-imported-dynamic' : 'non-blocking'
+    };
+
+    await wait_for_onload();
+
+    const entry_list = performance.getEntriesByType("resource");
+    for (entry of entry_list) {
+        if (entry.name.includes("empty_style.css") ||
+                entry.name.includes("importer.css") ||
+                entry.name.includes("empty_script.js")) {
+            key = entry.name.split("?").pop();
+            expectedStatus = expectedRenderBlockingStatus[key];
+            assert_equals(entry.renderBlockingStatus, expectedStatus,
+                `render blocking status for ${entry.name} should be ${expectedStatus}`);
+        }
+    }
+}, "Validate render blocking status of link resources in PerformanceResourceTiming");
+
+</script>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/render-blocking-status-script.html b/testing/web-platform/tests/resource-timing/render-blocking-status-script.html
new file mode 100644
index 0000000000..bcd55b8994
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/render-blocking-status-script.html
@@ -0,0 +1,196 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the render blocking status of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<!-- Start of test cases -->
+<script src="resources/empty_script.js?script-head"></script>
+<script type="module" src="resources/empty_script.js?script-head-module"></script>
+<script async type=module
+        src="resources/empty_script.js?script-head-async-module">
+</script>
+<script async src="resources/empty_script.js?script-head-async"></script>
+<script defer src="resources/empty_script.js?script-head-defer"></script>
+<script blocking=render
+        src="resources/empty_script.js?script-head-blocking-render">
+</script>
+<script async blocking=render
+        src="resources/empty_script.js?script-head-async-blocking-render">
+</script>
+<script type=module blocking=render
+        src="resources/empty_script.js?script-head-module-blocking-render">
+</script>
+<script async type=module blocking=render
+        src="resources/empty_script.js?script-head-async-module-blocking-render">
+</script>
+<script defer blocking=render
+        src="resources/empty_script.js?script-head-defer-blocking-render">
+</script>
+
+<script id="script-head-remove-attr" blocking=render
+        src="resources/empty_script.js?script-head-blocking-render-remove-attr">
+</script>
+
+<script>
+    document.write(`
+        <script defer
+            src="resources/empty_script.js?script-head-defer-dynamic-docwrite">
+        <\/script>`);
+</script>
+</head>
+
+<body>
+
+<script src="resources/empty_script.js?script-body"></script>
+<script type="module" src="resources/empty_script.js?script-body-module"></script>
+<script async type=module
+        src="resources/empty_script.js?script-body-async-module">
+</script>
+<script async src="resources/empty_script.js?script-body-async"></script>
+<script defer src="resources/empty_script.js?script-body-defer"></script>
+
+<script>
+    const script = document.createElement("script");
+    script.src = "resources/empty_script.js?script-head-dynamic-dom";
+    document.head.appendChild(script);
+
+    // Dynamic explicitly async script
+    const async_script = document.createElement("script");
+    async_script.src = "resources/empty_script.js?script-head-async-dynamic-dom";
+    async_script.async = true;
+    document.head.appendChild(async_script);
+
+    // Dynamic non-async script
+    // https://html.spec.whatwg.org/multipage/scripting.html#script-processing-model
+    // mentions that a script element has to be parser-inserted to be
+    // implicitly potentially render-blocking
+    const non_async_script = document.createElement("script");
+    non_async_script.src = "resources/empty_script.js?script-head-non-async-dynamic-dom";
+    non_async_script.async = false;
+    document.head.appendChild(non_async_script);
+
+    // Dynamic defer script
+    const defer_script = document.createElement("script");
+    defer_script.src = "resources/empty_script.js?script-head-defer-dynamic-dom";
+    defer_script.defer = true;
+    document.head.appendChild(defer_script);
+
+    // Dynamic explicitly render-blocking script
+    const blocking_script = document.createElement("script");
+    blocking_script.src = "resources/empty_script.js?script-head-blocking-render-dynamic-dom";
+    blocking_script.blocking = "render";
+    document.head.appendChild(blocking_script);
+
+    // Dynamic explicitly render-blocking module script
+    const blocking_module_script = document.createElement("script");
+    blocking_module_script.src = "resources/empty_script.js?script-head-module-blocking-render-dynamic-dom";
+    blocking_module_script.type = "module";
+    blocking_module_script.blocking = "render";
+    document.head.appendChild(blocking_module_script);
+
+    // Dynamic async module script
+    const async_module_script = document.createElement("script");
+    async_module_script.src = "resources/empty_script.js?script-head-async-module-dynamic-dom";
+    async_module_script.type = "module";
+    async_module_script.async = true;
+    document.head.appendChild(async_module_script);
+
+    // Dynamic async render-blocking module script
+    const async_blocking_module_script = document.createElement("script");
+    async_blocking_module_script.src = "resources/empty_script.js?script-head-async-module-blocking-render-dynamic-dom";
+    async_blocking_module_script.type = "module";
+    async_blocking_module_script.async = true;
+    async_blocking_module_script.blocking = "render"
+    document.head.appendChild(async_blocking_module_script);
+
+    // Add a module that imports more modules
+    const importer_script = document.createElement("script");
+    importer_script.src = "resources/fake_responses.py?url=importer.js";
+    importer_script.type = "module";
+    document.head.appendChild(importer_script);
+
+    // Add an async module that imports more modules
+    const importer_async_script = document.createElement("script");
+    importer_async_script.src = "resources/fake_responses.py?url=importer_async.js";
+    importer_async_script.type = "module";
+    importer_async_script.async = true;
+    document.head.appendChild(importer_async_script);
+
+    // Removing blocking render attribute after request is made
+    const script_element = document.getElementById("script-head-remove-attr");
+    script_element.blocking = "";
+</script>
+
+
+<script>
+
+const wait_for_onload = () => {
+  return new Promise(resolve => {
+    window.addEventListener("load", resolve);
+})};
+
+promise_test(
+  async () => {
+    const expectedRenderBlockingStatus = {
+        'script-head': 'blocking',
+        'script-head-module' : 'non-blocking',
+        'script-head-async-module' : 'non-blocking',
+        'script-head-async' : 'non-blocking',
+        'script-head-defer' : 'non-blocking',
+        'script-head-blocking-render' : 'blocking',
+        'script-head-async-blocking-render' : 'blocking',
+        'script-head-module-blocking-render' : 'blocking',
+        'script-head-async-module-blocking-render' : 'blocking',
+        'script-head-defer-blocking-render' : 'blocking',
+        'script-head-blocking-render-remove-attr' : 'blocking',
+        'script-head-defer-dynamic-docwrite' : 'non-blocking',
+        'script-body' : 'non-blocking',
+        'script-body-module' : 'non-blocking',
+        'script-body-async-module' : 'non-blocking',
+        'script-body-async' : 'non-blocking',
+        'script-body-defer' : 'non-blocking',
+        'script-head-dynamic-dom': 'non-blocking',
+        'script-head-async-dynamic-dom' : 'non-blocking',
+        'script-head-non-async-dynamic-dom': 'non-blocking',
+        'script-head-defer-dynamic-dom' : 'non-blocking',
+        'script-head-blocking-render-dynamic-dom' : 'blocking',
+        'script-head-module-blocking-render-dynamic-dom' : 'blocking',
+        'script-head-async-module-dynamic-dom' : 'non-blocking',
+        'script-head-async-module-blocking-render-dynamic-dom' : 'blocking',
+        'script-head-import-defer' : 'non-blocking',
+        'script-head-import-defer-dynamic' : 'non-blocking',
+        'script-head-import-async' : 'non-blocking',
+        'script-head-import-async-dynamic' : 'non-blocking',
+        'script-importer' : 'non-blocking',
+        'script-importer-async' : 'non-blocking'
+    };
+
+    await wait_for_onload();
+
+    const entry_list = performance.getEntriesByType("resource");
+    for (entry of entry_list) {
+        if (entry.name.includes("empty_script.js")) {
+            key = entry.name.split("?").pop();
+            expectedStatus = expectedRenderBlockingStatus[key];
+            assert_equals(entry.renderBlockingStatus, expectedStatus,
+                `render blocking status for ${entry.name} should be ${expectedStatus}`);
+        }
+        else if (entry.name.includes("importer.js")){
+            key = 'script-importer';
+            expectedStatus = expectedRenderBlockingStatus[key];
+            assert_equals(entry.renderBlockingStatus, expectedStatus,
+                `render blocking status for ${entry.name} should be ${expectedStatus}`);
+        }
+        else if (entry.name.includes("importer_async.js")){
+            key = 'script-importer-async';
+            expectedStatus = expectedRenderBlockingStatus[key];
+            assert_equals(entry.renderBlockingStatus, expectedStatus,
+                `render blocking status for ${entry.name} should be ${expectedStatus}`);
+        }
+    }
+}, "Validate render blocking status of script resources in PerformanceResourceTiming");
+
+</script>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resource-ignore-data-url.html b/testing/web-platform/tests/resource-timing/resource-ignore-data-url.html
new file mode 100644
index 0000000000..a7056a8080
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource-ignore-data-url.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing ignores resources with data: URIs</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#resources-included-in-the-performanceresourcetiming-interface"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+</head>
+<body>
+<img src="data:image/gif;base64,R0lGODlhAQABAIAAAOTm7AAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw=="></img>
+<script>
+  promise_test(async t => {
+    const promise = new Promise(resolve => {
+      new PerformanceObserver(t.step_func(list => {
+        const entries = list.getEntries();
+        const dataEntries = entries.filter(e => e.name.includes('data:'));
+        assert_equals(dataEntries.length, 0, 'There must be no entry for `data: URL`.');
+        const blueEntries = entries.filter(e => e.name.includes('blue.png'));
+        if (blueEntries.length) {
+          // We can finish the test once we see the entry with blue.png.
+          resolve();
+        }
+      })).observe({entryTypes: ['resource']});
+    });
+    // Wait until the document is loaded.
+    await new Promise(resolve => {
+      window.addEventListener('load', resolve);
+    });
+    // Add the blue.png image after document is loaded to ensure we've received
+    // all of the previous Resource Timing entries.
+    load.image('blue.png');
+    return promise;
+  }, 'Resources with data: URIs must not be surfaced in Resource Timing');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resource-reload-TAO.html b/testing/web-platform/tests/resource-timing/resource-reload-TAO.html
new file mode 100644
index 0000000000..83a1e921bb
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource-reload-TAO.html
@@ -0,0 +1,18 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing - TAO on reload</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-timing-allow-origin"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<iframe id="test_iframe" src="resources/iframe-reload-TAO.html"></iframe>
+<script>
+window.onload = () => {
+  fetch_tests_from_window(test_iframe.contentWindow);
+};
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resource-timing-level1.js b/testing/web-platform/tests/resource-timing/resource-timing-level1.js
new file mode 100644
index 0000000000..6167777fe6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource-timing-level1.js
@@ -0,0 +1,476 @@
+"use strict";
+
+window.onload =
+    function () {
+        setup({ explicit_timeout: true });
+
+        /** Number of milliseconds to delay when the server injects pauses into the response.
+
+            This should be large enough that we can distinguish it from noise with high confidence,
+            but small enough that tests complete quickly. */
+        var serverStepDelay = 250;
+
+        var mimeHtml    = "text/html";
+        var mimeText    = "text/plain";
+        var mimePng     = "image/png";
+        var mimeScript  = "application/javascript";
+        var mimeCss     = "text/css";
+
+        /** Hex encoding of a a 150x50px green PNG. */
+        var greenPng = "0x89504E470D0A1A0A0000000D494844520000006400000032010300000090FBECFD00000003504C544500FF00345EC0A80000000F49444154281563601805A36068020002BC00011BDDE3900000000049454E44AE426082";
+
+        /** Array containing test cases to run.  Initially, it contains the one-off 'about:blank" test,
+            but additional cases are pushed below by expanding templates. */
+        var testCases = [
+            {
+                description: "No timeline entry for about:blank",
+                test:
+                    function (test) {
+                        // Insert an empty IFrame.
+                        var frame = document.createElement("iframe");
+
+                        // Wait for the IFrame to load and ensure there is no resource entry for it on the timeline.
+                        //
+                        // We use the 'createOnloadCallbackFn()' helper which is normally invoked by 'initiateFetch()'
+                        // to avoid setting the IFrame's src.  It registers a test step for us, finds our entry on the
+                        // resource timeline, and wraps our callback function to automatically vet invariants.
+                        frame.onload = createOnloadCallbackFn(test, frame, "about:blank",
+                            function (initiator, entry) {
+                                assert_equals(entry, undefined, "Inserting an IFrame with a src of 'about:blank' must not add an entry to the timeline.");
+                                assertInvariants(
+                                    test,
+                                    function () {
+                                        test.done();
+                                    });
+                            });
+
+                        document.body.appendChild(frame);
+
+                        // Paranoid check that the new IFrame has loaded about:blank.
+                        assert_equals(
+                            frame.contentWindow.location.href,
+                            "about:blank",
+                            "'Src' of new <iframe> must be 'about:blank'.");
+                    }
+            },
+        ];
+
+        // Create cached/uncached tests from the following array of templates.  For each template entry,
+        // we add two identical test cases to 'testCases'.  The first case initiates a fetch to populate the
+        // cache.  The second request initiates a fetch with the same URL to cover the case where we hit
+        // the cache (if the caching policy permits caching).
+        [
+            { initiator: "iframe",         response: "(done)",      mime: mimeHtml },
+            { initiator: "xmlhttprequest", response: "(done)",      mime: mimeText },
+            // Multiple browsers seem to cheat a bit and race onLoad of images.  Microsoft https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/2379187
+            // { initiator: "img",            response: greenPng,      mime: mimePng },
+            { initiator: "script",         response: '"";',         mime: mimeScript },
+            { initiator: "link",           response: ".unused{}",   mime: mimeCss },
+        ]
+        .forEach(function (template) {
+            testCases.push({
+                description: "'" + template.initiator + " (Populate cache): The initial request populates the cache (if appropriate).",
+                test: function (test) {
+                    initiateFetch(
+                        test,
+                        template.initiator,
+                        getSyntheticUrl(
+                            "mime:" + encodeURIComponent(template.mime)
+                                + "&send:" + encodeURIComponent(template.response),
+                            /* allowCaching = */ true),
+                        function (initiator, entry) {
+                            test.done();
+                        });
+                    }
+                });
+
+            testCases.push({
+                description: "'" + template.initiator + " (Potentially Cached): Immediately fetch the same URL, exercising the cache hit path (if any).",
+                test: function (test) {
+                    initiateFetch(
+                        test,
+                        template.initiator,
+                        getSyntheticUrl(
+                            "mime:" + encodeURIComponent(template.mime)
+                                + "&send:" + encodeURIComponent(template.response),
+                            /* allowCaching = */ true),
+                        function (initiator, entry) {
+                            test.done();
+                        });
+                    }
+                });
+            });
+
+        // Create responseStart/responseEnd tests from the following array of templates.  In this test, the server delays before
+        // responding with responsePart1, then delays again before completing with responsePart2.  The test looks for the expected
+        // pauses before responseStart and responseEnd.
+        [
+            { initiator: "iframe",         responsePart1: serverStepDelay + "ms;", responsePart2: (serverStepDelay * 2) + "ms;(done)",                                                      mime: mimeHtml },
+            { initiator: "xmlhttprequest", responsePart1: serverStepDelay + "ms;", responsePart2: (serverStepDelay * 2) + "ms;(done)",                                                      mime: mimeText },
+            // Multiple browsers seem to cheat a bit and race img.onLoad and setting responseEnd.  Microsoft https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/2379187
+            // { initiator: "img",            responsePart1: greenPng.substring(0, greenPng.length / 2), responsePart2: "0x" + greenPng.substring(greenPng.length / 2, greenPng.length),       mime: mimePng },
+            { initiator: "script",         responsePart1: '"', responsePart2: '";',                                                                                                         mime: mimeScript },
+            { initiator: "link",           responsePart1: ".unused{", responsePart2: "}",                                                                                                   mime: mimeCss },
+        ]
+        .forEach(function (template) {
+            testCases.push({
+                description: "'" + template.initiator + ": " + serverStepDelay + "ms delay before 'responseStart', another " + serverStepDelay + "ms delay before 'responseEnd'.",
+                test: function (test) {
+                    initiateFetch(
+                        test,
+                        template.initiator,
+                        getSyntheticUrl(serverStepDelay + "ms"                          // Wait, then echo back responsePart1
+                            + "&mime:" + encodeURIComponent(template.mime)
+                            + "&send:" + encodeURIComponent(template.responsePart1)
+                            + "&" + serverStepDelay + "ms"                              // Wait, then echo back responsePart2
+                            + "&send:" + encodeURIComponent(template.responsePart2)),
+
+                        function (initiator, entry) {
+                            // Per https://w3c.github.io/resource-timing/#performanceresourcetiming:
+                            // If no redirects (or equivalent) occur, this redirectStart/End must return zero.
+                            assert_equals(entry.redirectStart, 0, "When no redirect occurs, redirectStart must be 0.");
+                            assert_equals(entry.redirectEnd, 0, "When no redirect occurs, redirectEnd must be 0.");
+
+                            // Server creates a gap between 'requestStart' and 'responseStart'.
+                            assert_greater_than_equal(
+                                entry.responseStart,
+                                entry.requestStart + serverStepDelay,
+                                "'responseStart' must be " + serverStepDelay + "ms later than 'requestStart'.");
+
+                            // Server creates a gap between 'responseStart' and 'responseEnd'.
+                            assert_greater_than_equal(
+                                entry.responseEnd,
+                                entry.responseStart + serverStepDelay,
+                                "'responseEnd' must be " + serverStepDelay + "ms later than 'responseStart'.");
+
+                            test.done();
+                        });
+                    }
+                });
+            });
+
+        // Create redirectEnd/responseStart tests from the following array of templates.  In this test, the server delays before
+        // redirecting to a new synthetic response, then delays again before responding with 'response'.  The test looks for the
+        // expected pauses before redirectEnd and responseStart.
+        [
+            { initiator: "iframe",         response: serverStepDelay + "ms;redirect;" + (serverStepDelay * 2) + "ms;(done)",        mime: mimeHtml },
+            { initiator: "xmlhttprequest", response: serverStepDelay + "ms;redirect;" + (serverStepDelay * 2) + "ms;(done)",        mime: mimeText },
+            // Multiple browsers seem to cheat a bit and race img.onLoad and setting responseEnd.  Microsoft https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/2379187
+            // { initiator: "img",            response: greenPng,                                                                      mime: mimePng },
+            { initiator: "script",         response: '"";',                                                                         mime: mimeScript },
+            { initiator: "link",           response: ".unused{}",                                                                   mime: mimeCss },
+        ]
+        .forEach(function (template) {
+            testCases.push({
+                description: "'" + template.initiator + " (Redirected): " + serverStepDelay + "ms delay before 'redirectEnd', another " + serverStepDelay + "ms delay before 'responseStart'.",
+                test: function (test) {
+                    initiateFetch(
+                        test,
+                        template.initiator,
+                        getSyntheticUrl(serverStepDelay + "ms"      // Wait, then redirect to a second page that waits
+                            + "&redirect:"                          // before echoing back the response.
+                                + encodeURIComponent(
+                                    getSyntheticUrl(serverStepDelay + "ms"
+                                        + "&mime:" + encodeURIComponent(template.mime)
+                                        + "&send:" + encodeURIComponent(template.response)))),
+                        function (initiator, entry) {
+                            // Per https://w3c.github.io/resource-timing/#performanceresourcetiming:
+                            //      "[If redirected, startTime] MUST return the same value as redirectStart.
+                            assert_equals(entry.startTime, entry.redirectStart, "startTime must be equal to redirectStart.");
+
+                            // Server creates a gap between 'redirectStart' and 'redirectEnd'.
+                            assert_greater_than_equal(
+                                entry.redirectEnd,
+                                entry.redirectStart + serverStepDelay,
+                                "'redirectEnd' must be " + serverStepDelay + "ms later than 'redirectStart'.");
+
+                            // Server creates a gap between 'requestStart' and 'responseStart'.
+                            assert_greater_than_equal(
+                                entry.responseStart,
+                                entry.requestStart + serverStepDelay,
+                                "'responseStart' must be " + serverStepDelay + "ms later than 'requestStart'.");
+
+                            test.done();
+                        });
+                    }
+                });
+            });
+
+        // Ensure that responseStart only measures the time up to the first few
+        // bytes of the header response. This is tested by writing an HTTP 1.1
+        // status line, followed by a flush, then a pause before the end of the
+        // headers. The test makes sure that responseStart is not delayed by
+        // this pause.
+        [
+            { initiator: "iframe",         response: "(done)",    mime: mimeHtml },
+            { initiator: "xmlhttprequest", response: "(done)",    mime: mimeText },
+            { initiator: "script",         response: '"";',       mime: mimeScript },
+            { initiator: "link",           response: ".unused{}", mime: mimeCss },
+        ]
+        .forEach(function (template) {
+            testCases.push({
+                description: "'" + template.initiator + " " + serverStepDelay + "ms delay in headers does not affect responseStart'",
+                test: function (test) {
+                    initiateFetch(
+                        test,
+                        template.initiator,
+                        getSyntheticUrl("status:200"
+                                        + "&flush"
+                                        + "&" + serverStepDelay + "ms"
+                                        + "&mime:" + template.mime
+                                        + "&send:" + encodeURIComponent(template.response)),
+                        function (initiator, entry) {
+                            // Test that the delay between 'responseStart' and
+                            // 'responseEnd' includes the delay, which implies
+                            // that 'responseStart' was measured at the time of
+                            // status line receipt.
+                            assert_greater_than_equal(
+                                entry.responseEnd,
+                                entry.responseStart + serverStepDelay,
+                                "Delay after HTTP/1.1 status should not affect 'responseStart'.");
+
+                            test.done();
+                        });
+                    }
+                });
+            });
+
+        // Function to run the next case in the queue.
+        var currentTestIndex = -1;
+        function runNextCase() {
+            var testCase = testCases[++currentTestIndex];
+            if (testCase !== undefined) {
+                async_test(testCase.test, testCase.description);
+            }
+        }
+
+        // When a test completes, run the next case in the queue.
+        add_result_callback(runNextCase);
+
+        // Start the first test.
+        runNextCase();
+
+        /** Iterates through all resource entries on the timeline, vetting all invariants. */
+        function assertInvariants(test, done) {
+            // Multiple browsers seem to cheat a bit and race img.onLoad and setting responseEnd.  Microsoft https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/2379187
+            // Yield for 100ms to workaround a suspected race where window.onload fires before
+            //     script visible side-effects from the wininet/urlmon thread have finished.
+            test.step_timeout(
+                test.step_func(
+                    function () {
+                        performance
+                            .getEntriesByType("resource")
+                            .forEach(
+                                function (entry, index, entries) {
+                                    assertResourceEntryInvariants(entry);
+                                });
+
+                        done();
+                    }),
+                    100);
+        }
+
+        /** Assets the invariants for a resource timeline entry. */
+        function assertResourceEntryInvariants(actual) {
+            // Example from http://w3c.github.io/resource-timing/#resources-included:
+            //     "If an HTML IFRAME element is added via markup without specifying a src attribute,
+            //      the user agent may load the about:blank document for the IFRAME. If at a later time
+            //      the src attribute is changed dynamically via script, the user agent may fetch the new
+            //      URL resource for the IFRAME. In this case, only the fetch of the new URL would be
+            //      included as a PerformanceResourceTiming object in the Performance Timeline."
+            assert_not_equals(
+                actual.name,
+                "about:blank",
+                "Fetch for 'about:blank' must not appear in timeline.");
+
+            assert_not_equals(actual.startTime, 0, "startTime");
+
+            // Per https://w3c.github.io/resource-timing/#performanceresourcetiming:
+            //      "[If redirected, startTime] MUST return the same value as redirectStart. Otherwise,
+            //      [startTime] MUST return the same value as fetchStart."
+            assert_in_array(actual.startTime, [actual.redirectStart, actual.fetchStart],
+                "startTime must be equal to redirectStart or fetchStart.");
+
+            // redirectStart <= redirectEnd <= fetchStart <= domainLookupStart <= domainLookupEnd <= connectStart
+            assert_less_than_equal(actual.redirectStart, actual.redirectEnd, "redirectStart <= redirectEnd");
+            assert_less_than_equal(actual.redirectEnd, actual.fetchStart, "redirectEnd <= fetchStart");
+            assert_less_than_equal(actual.fetchStart, actual.domainLookupStart, "fetchStart <= domainLookupStart");
+            assert_less_than_equal(actual.domainLookupStart, actual.domainLookupEnd, "domainLookupStart <= domainLookupEnd");
+            assert_less_than_equal(actual.domainLookupEnd, actual.connectStart, "domainLookupEnd <= connectStart");
+
+            // Per https://w3c.github.io/resource-timing/#performanceresourcetiming:
+            //      "This attribute is optional. User agents that don't have this attribute available MUST set it
+            //      as undefined.  [...]  If the secureConnectionStart attribute is available but HTTPS is not used,
+            //      this attribute MUST return zero."
+            assert_true(actual.secureConnectionStart == undefined ||
+                        actual.secureConnectionStart == 0 ||
+                        actual.secureConnectionStart >= actual.connectEnd, "secureConnectionStart time");
+
+            // connectStart <= connectEnd <= requestStart <= responseStart <= responseEnd
+            assert_less_than_equal(actual.connectStart, actual.connectEnd, "connectStart <= connectEnd");
+            assert_less_than_equal(actual.connectEnd, actual.requestStart, "connectEnd <= requestStart");
+            assert_less_than_equal(actual.requestStart, actual.responseStart, "requestStart <= responseStart");
+            assert_less_than_equal(actual.responseStart, actual.responseEnd, "responseStart <= responseEnd");
+        }
+
+        /** Helper function to resolve a relative URL */
+        function canonicalize(url) {
+            var div = document.createElement('div');
+            div.innerHTML = "<a></a>";
+            div.firstChild.href = url;
+            div.innerHTML = div.innerHTML;
+            return div.firstChild.href;
+        }
+
+        /** Generates a unique string, used by getSyntheticUrl() to avoid hitting the cache. */
+        function createUniqueQueryArgument() {
+            var result =
+                "ignored_"
+                    + Date.now()
+                    + "-"
+                    + ((Math.random() * 0xFFFFFFFF) >>> 0)
+                    + "-"
+                    + syntheticRequestCount;
+
+            return result;
+        }
+
+        /** Count of the calls to getSyntheticUrl().  Used by createUniqueQueryArgument() to generate unique strings. */
+        var syntheticRequestCount = 0;
+
+        /** Return a URL to a server that will synthesize an HTTP response using the given
+            commands. (See SyntheticResponse.aspx). */
+        function getSyntheticUrl(commands, allowCache) {
+            syntheticRequestCount++;
+
+            var url =
+                canonicalize("./SyntheticResponse.py")    // ASP.NET page that will synthesize the response.
+                    + "?" + commands;                       // Commands that will be used.
+
+            if (allowCache !== true) {                      // If caching is disallowed, append a unique argument
+                url += "&" + createUniqueQueryArgument();   // to the URL's query string.
+            }
+
+            return url;
+        }
+
+        /** Given an 'initiatorType' (e.g., "img") , it triggers the appropriate type of fetch for the specified
+            url and invokes 'onloadCallback' when the fetch completes.  If the fetch caused an entry to be created
+            on the resource timeline, the entry is passed to the callback. */
+        function initiateFetch(test, initiatorType, url, onloadCallback) {
+            assertInvariants(
+                test,
+                function () {
+                    log("--- Begin: " + url);
+
+                    switch (initiatorType) {
+                        case "script":
+                        case "img":
+                        case "iframe": {
+                            var element = document.createElement(initiatorType);
+                            document.body.appendChild(element);
+                            element.onload = createOnloadCallbackFn(test, element, url, onloadCallback);
+                            element.src = url;
+                            break;
+                        }
+                        case "link": {
+                            var element = document.createElement(initiatorType);
+                            element.rel = "stylesheet";
+                            document.body.appendChild(element);
+                            element.onload = createOnloadCallbackFn(test, element, url, onloadCallback);
+                            element.href = url;
+                            break;
+                        }
+                        case "xmlhttprequest": {
+                            var xhr = new XMLHttpRequest();
+                            xhr.open('GET', url, true);
+                            xhr.onreadystatechange = createOnloadCallbackFn(test, xhr, url, onloadCallback);
+                            xhr.send();
+                            break;
+                        }
+                        default:
+                            assert_unreached("Unsupported initiatorType '" + initiatorType + "'.");
+                            break;
+                    }});
+        }
+
+        /** Used by 'initiateFetch' to register a test step for the asynchronous callback, vet invariants,
+            find the matching resource timeline entry (if any), and pass it to the given 'onloadCallback'
+            when invoked. */
+        function createOnloadCallbackFn(test, initiator, url, onloadCallback) {
+            // Remember the number of entries on the timeline prior to initiating the fetch:
+            var beforeEntryCount = performance.getEntriesByType("resource").length;
+
+            return test.step_func(
+                function() {
+                    // If the fetch was initiated by XHR, we're subscribed to the 'onreadystatechange' event.
+                    // Ignore intermediate callbacks and wait for the XHR to complete.
+                    if (Object.getPrototypeOf(initiator) === XMLHttpRequest.prototype) {
+                        if (initiator.readyState != 4) {
+                            return;
+                        }
+                    }
+
+                    var entries = performance.getEntriesByType("resource");
+                    var candidateEntry = entries[entries.length - 1];
+
+                    switch (entries.length - beforeEntryCount)
+                    {
+                        case 0:
+                            candidateEntry = undefined;
+                            break;
+                        case 1:
+                            // Per https://w3c.github.io/resource-timing/#performanceresourcetiming:
+                            //     "This attribute MUST return the resolved URL of the requested resource. This attribute
+                            //      MUST NOT change even if the fetch redirected to a different URL."
+                            assert_equals(candidateEntry.name, url, "'name' did not match expected 'url'.");
+                            logResourceEntry(candidateEntry);
+                            break;
+                        default:
+                            assert_unreached("At most, 1 entry should be added to the performance timeline during a fetch.");
+                            break;
+                    }
+
+                    assertInvariants(
+                        test,
+                        function () {
+                            onloadCallback(initiator, candidateEntry);
+                        });
+                });
+        }
+
+        /** Log the given text to the document element with id='output' */
+        function log(text) {
+            var output = document.getElementById("output");
+            output.textContent += text + "\r\n";
+        }
+
+        add_completion_callback(function () {
+            var output = document.getElementById("output");
+            var button = document.createElement('button');
+            output.parentNode.insertBefore(button, output);
+            button.onclick = function () {
+                var showButton = output.style.display == 'none';
+                output.style.display = showButton ? null : 'none';
+                button.textContent = showButton ? 'Hide details' : 'Show details';
+            }
+            button.onclick();
+            var iframes = document.querySelectorAll('iframe');
+            for (var i = 0; i < iframes.length; i++)
+                iframes[i].parentNode.removeChild(iframes[i]);
+        });
+
+        /** pretty print a resource timeline entry. */
+        function logResourceEntry(entry) {
+            log("[" + entry.entryType + "] " + entry.name);
+
+            ["startTime", "redirectStart", "redirectEnd", "fetchStart", "domainLookupStart", "domainLookupEnd", "connectStart", "secureConnectionStart", "connectEnd", "requestStart", "responseStart", "responseEnd"]
+                .forEach(
+                    function (property, index, array) {
+                        var value = entry[property];
+                        log(property + ":\t" + value);
+                    });
+
+            log("\r\n");
+        }
+    };
diff --git a/testing/web-platform/tests/resource-timing/resource-timing-level1.sub.html b/testing/web-platform/tests/resource-timing/resource-timing-level1.sub.html
new file mode 100644
index 0000000000..093d254221
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource-timing-level1.sub.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Resource-Timing Level 1</title>
+  <meta name="timeout" content="long">
+  <!-- To aid debugability, explicitly link the testharness's CSS to avoid demand
+       loading it while the test executes. -->
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+
+  <link rel="author" title="Microsoft" href="http://www.microsoft.com/">
+  <link rel="help" href="https://w3c.github.io/resource-timing/">
+</head>
+<body>
+  <div id="log"></div>
+  <pre id="output"></pre>
+  <script src="resource-timing-level1.js"></script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resource_connection_reuse_mixed_content.html b/testing/web-platform/tests/resource-timing/resource_connection_reuse_mixed_content.html
new file mode 100644
index 0000000000..51c04ee604
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_connection_reuse_mixed_content.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing connection reuse</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/webperftestharness.js"></script>
+<script src="resources/webperftestharnessextension.js"></script>
+<script>
+setup({explicit_done: true});
+let iframe;
+let d;
+let body;
+
+// Explicitly test the namespace before we start testing.
+test_namespace('getEntriesByType');
+
+function setup_iframe() {
+    iframe = document.getElementById('frameContext');
+    d = iframe.contentWindow.document;
+    iframe.addEventListener('load', onload_test, false);
+}
+
+function onload_test() {
+    const entries = iframe.contentWindow.performance.getEntriesByType('resource');
+
+    // When a persistent connection is used, follow-on resources should be included as PerformanceResourceTiming objects.
+    test_equals(entries.length, 2, 'There should be 2 PerformanceEntries');
+
+    if (entries.length >= 2) {
+        // When a persistent connection is used, for the resource that reuses the socket, connectStart and connectEnd should have the same value as fetchStart.
+        const entry = entries[1];
+        test_equals(entry.fetchStart, entry.connectStart, 'connectStart and fetchStart should be the same');
+        test_equals(entry.fetchStart, entry.connectEnd, 'connectEnd and fetchStart should be the same');
+        // secureConnectionStart is the same as fetchStart since the subresource is fetched over https
+        test_equals(entry.fetchStart, entry.secureConnectionStart, 'secureConnectionStart and fetchStart should be the same');
+        test_equals(entry.fetchStart, entry.domainLookupStart, 'domainLookupStart and fetchStart should be the same')
+        test_equals(entry.fetchStart, entry.domainLookupEnd, 'domainLookupEnd and fetchStart should be the same')
+    }
+
+    done();
+}
+
+window.setup_iframe = setup_iframe;
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that connectStart and connectEnd are the same when a connection is reused (e.g. when a persistent connection is used).</p>
+<div id="log"></div>
+<iframe id="frameContext" src="resources/fake_responses_https.sub.html"></iframe>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resource_connection_reuse_mixed_content_redirect.html b/testing/web-platform/tests/resource-timing/resource_connection_reuse_mixed_content_redirect.html
new file mode 100644
index 0000000000..a46d14c9f1
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_connection_reuse_mixed_content_redirect.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing connection reuse</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/webperftestharness.js"></script>
+<script src="resources/webperftestharnessextension.js"></script>
+<script>
+setup({explicit_done: true});
+let iframe;
+let d;
+let body;
+
+// Explicitly test the namespace before we start testing.
+test_namespace('getEntriesByType');
+
+function setup_iframe() {
+    iframe = document.getElementById('frameContext');
+    d = iframe.contentWindow.document;
+    iframe.addEventListener('load', onload_test, false);
+}
+
+function onload_test() {
+    const entries = iframe.contentWindow.performance.getEntriesByType('resource');
+
+    // When a persistent connection is used, follow-on resources should be included as PerformanceResourceTiming objects.
+    test_equals(entries.length, 2, 'There should be 2 PerformanceEntries');
+
+    if (entries.length >= 2) {
+        // When a persistent connection is used, for the resource that reuses the socket, connectStart and connectEnd should have the same value as fetchStart.
+        const entry = entries[1];
+        test_equals(entry.fetchStart, entry.connectStart, 'connectStart and fetchStart should be the same');
+        test_equals(entry.fetchStart, entry.connectEnd, 'connectEnd and fetchStart should be the same');
+        // secureConnectionStart is the same as fetchStart since the subresource is eventually redirected to https.
+        test_equals(entry.fetchStart, entry.secureConnectionStart, 'secureConnectionStart and fetchStart should be the same');
+        test_equals(entry.fetchStart, entry.domainLookupStart, 'domainLookupStart and fetchStart should be the same')
+        test_equals(entry.fetchStart, entry.domainLookupEnd, 'domainLookupEnd and fetchStart should be the same')
+    }
+
+    done();
+}
+
+window.setup_iframe = setup_iframe;
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that connectStart and connectEnd are the same when a connection is reused (e.g. when a persistent connection is used).</p>
+<div id="log"></div>
+<iframe id="frameContext" src="resources/fake_responses_https_redirect.sub.html"></iframe>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resource_dedicated_worker.html b/testing/web-platform/tests/resource-timing/resource_dedicated_worker.html
new file mode 100644
index 0000000000..6d27245ab9
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_dedicated_worker.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing in dedicated workers</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="http://www.w3.org/TR/resource-timing/"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/webperftestharness.js"></script>
+<script src="resources/webperftestharnessextension.js"></script>
+<link rel="stylesheet" href="resources/resource_timing_test0.css" />
+<script>
+setup({explicit_done: true});
+const worker = new Worker("resources/worker_with_images.js");
+worker.onmessage = function(event) {
+  const context = new PerformanceContext(window.performance);
+  const entries = context.getEntriesByType('resource');
+  test_equals(entries.length, 6, "There should be six entries: 4 scripts, 1 stylesheet, and the worker itself");
+  done();
+}
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that resources requested by dedicated workers don't appear in the main document.</p>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resource_nested_dedicated_worker.worker.js b/testing/web-platform/tests/resource-timing/resource_nested_dedicated_worker.worker.js
new file mode 100644
index 0000000000..2c9f5f9542
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_nested_dedicated_worker.worker.js
@@ -0,0 +1,17 @@
+importScripts("/resources/testharness.js");
+
+async_test(function() {
+  const worker = new Worker('resources/worker_with_images.js');
+  worker.onmessage = this.step_func_done((event) => {
+    const childNumEntries = event.data;
+    assert_equals(2, childNumEntries,
+      "There should be two resource timing entries: 2 image XHRs");
+
+    const parentNumEntries = performance.getEntries().length;
+    assert_equals(2, parentNumEntries,
+      "There should be two resource timing entries: " +
+      "one is for importScripts() and the another is for a nested worker");
+    worker.terminate();
+  });
+}, "Resource timing for nested dedicated workers");
+done();
diff --git a/testing/web-platform/tests/resource-timing/resource_reparenting.html b/testing/web-platform/tests/resource-timing/resource_reparenting.html
new file mode 100644
index 0000000000..7d4947fa77
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_reparenting.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing reparenting elements</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help" href="http://www.w3.org/TR/resource-timing/#dom-performanceresourcetiming-initiatortype"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/webperftestharness.js"></script>
+<script src="resources/webperftestharnessextension.js"></script>
+<script>
+let iframe;
+function setup_iframe() {
+    iframe = document.getElementById('frameContext');
+    const d = iframe.contentWindow.document;
+    const iframeBody = d.createElement('body');
+
+    const move_to_parent = d.createElement('img');
+    move_to_parent.src = 'blue.png?id=move_to_parent';
+    iframeBody.appendChild(move_to_parent);
+    iframeBody.removeChild(move_to_parent);
+
+    const parentBody = document.getElementsByTagName('body')[0];
+    parentBody.appendChild(move_to_parent);
+
+    const move_to_child = document.createElement('img');
+    move_to_child.src = 'blue.png?id=move_to_child';
+    parentBody.appendChild(move_to_child);
+    parentBody.removeChild(move_to_child);
+    iframeBody.appendChild(move_to_child);
+}
+function onload_test() {
+    const context = new PerformanceContext(iframe.contentWindow.performance);
+    const entries = context.getEntriesByType('resource');
+
+    const index = window.location.pathname.lastIndexOf('/');
+    const pathname = window.location.pathname.substring(0, index);
+    let expected_entries = {};
+    expected_entries[pathname + '/resources/blue.png?id=move_to_child'] = 'img';
+
+    test_resource_entries(entries, expected_entries);
+}
+window.setup_iframe = setup_iframe;
+</script>
+</head>
+<body>
+<h1>Description</h1>
+<p>This test validates that reparenting an element doesn't change the initiator document.</p>
+<div id="log"></div>
+<iframe id="frameContext" onload="onload_test();" src="resources/inject_resource_test.html"></iframe>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resource_subframe_self_navigation.html b/testing/web-platform/tests/resource-timing/resource_subframe_self_navigation.html
new file mode 100644
index 0000000000..5843f88307
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_subframe_self_navigation.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+<script>
+function numberOfDownloads(url) {
+    let absoluteURL = new URL(url, location.href).href;
+    return performance.getEntriesByName(absoluteURL).length;
+}
+
+function waitForSubFrameLoad() {
+    return new Promise((resolve) => {
+        window.subFrameLoaded = () => {
+            window.subFrameLoaded = null;
+            resolve();
+        };
+    });
+}
+
+function runTest(type) {
+    performance.clearResourceTimings();
+    let elem = document.createElement(type);
+    if (type === 'object')
+        elem.data = 'resources/self_navigation.html?' + type;
+    else
+        elem.src = 'resources/self_navigation.html?' + type;
+    document.body.appendChild(elem);
+    return waitForSubFrameLoad().then(() => {
+        let resources = performance.getEntriesByType('resource');
+        assert_equals(numberOfDownloads('resources/self_navigation.html?' + type), 1);
+        assert_equals(numberOfDownloads('resources/notify_parent.html?redirected'), 0);
+        document.body.removeChild(elem);
+    });
+}
+
+promise_test(
+    () => runTest('iframe'),
+    "Subsequent <iframe> navigations don't appear in the resource-timing buffer.");
+
+promise_test(
+    () => runTest('frame'),
+    "Subsequent <frame> navigations don't appear in the resource-timing buffer.");
+
+promise_test(
+    () => runTest('embed'),
+    "Subsequent <embed> navigations don't appear in the resource-timing buffer.");
+
+promise_test(
+    () => runTest('object'),
+    "Subsequent <object> navigations don't appear in the resource-timing buffer.");
+
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resource_timing.worker.js b/testing/web-platform/tests/resource-timing/resource_timing.worker.js
new file mode 100644
index 0000000000..dafd2e9af6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_timing.worker.js
@@ -0,0 +1,64 @@
+importScripts("/resources/testharness.js");
+
+function check(initiatorType, protocol) {
+  let entries = performance.getEntries();
+  assert_equals(entries.length, 1);
+
+  assert_true(entries[0] instanceof PerformanceEntry);
+  assert_equals(entries[0].entryType, "resource");
+  assert_true(entries[0].startTime > 0);
+  assert_true(entries[0].duration > 0);
+
+  assert_true(entries[0] instanceof PerformanceResourceTiming);
+  assert_equals(entries[0].initiatorType, initiatorType);
+  assert_equals(entries[0].nextHopProtocol, protocol);
+}
+
+async_test(t => {
+  performance.clearResourceTimings();
+
+  // Fetch
+  fetch("resources/empty.js")
+  .then(r => r.blob())
+  .then(blob => {
+    check("fetch", "http/1.1");
+  })
+
+  // XMLHttpRequest
+  .then(() => {
+    return new Promise(resolve => {
+      performance.clearResourceTimings();
+      let xhr = new XMLHttpRequest();
+      xhr.onload = () => {
+        check("xmlhttprequest", "http/1.1");
+        resolve();
+      };
+      xhr.open("GET", "resources/empty.js");
+      xhr.send();
+    });
+  })
+
+  // Sync XMLHttpREquest
+  .then(() => {
+    performance.clearResourceTimings();
+    let xhr = new XMLHttpRequest();
+    xhr.open("GET", "resources/empty.js", false);
+    xhr.send();
+
+    check("xmlhttprequest", "http/1.1");
+  })
+
+  // ImportScripts
+  .then(() => {
+    performance.clearResourceTimings();
+    importScripts(["resources/empty.js"]);
+    check("other", "http/1.1");
+  })
+
+  // All done.
+  .then(() => {
+    t.done();
+  });
+}, "Performance Resource Entries in workers");
+
+done();
diff --git a/testing/web-platform/tests/resource-timing/resource_timing_content_length.html b/testing/web-platform/tests/resource-timing/resource_timing_content_length.html
new file mode 100644
index 0000000000..32bd8a97e0
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resource_timing_content_length.html
@@ -0,0 +1,35 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates the value of encodedBodySize in certain situations.</title>
+<link rel="help" href="http://www.w3.org/TR/resource-timing/#performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+    function test_resource_timing_for_content_length({actualContentLength, lengthHeader}, title) {
+        promise_test(async t => {
+            const content = new Array(actualContentLength).fill('x').join('')
+            const url = `resources/resource-timing-content-length.py?content=${content}&length=${lengthHeader}`
+            fetch(url)
+            const entry = await new Promise(resolve => new PerformanceObserver((entryList, observer) => {
+                observer.disconnect()
+                resolve(entryList.getEntries()[0])
+            }).observe({entryTypes: ['resource']}))
+
+            const expectedContentLength = Number.isInteger(lengthHeader) ? Math.min(actualContentLength, lengthHeader) : actualContentLength
+            assert_equals(entry.encodedBodySize, expectedContentLength)
+        }, title);
+    }
+
+    test_resource_timing_for_content_length({actualContentLength: 3, lengthHeader: 'auto'},
+        "encodedBodySize should be equal to the actual byte size of the content")
+    test_resource_timing_for_content_length({actualContentLength: 13, lengthHeader: 'none'},
+        "encodedBodySize should be equal to the actual byte size of the content when no header present")
+    test_resource_timing_for_content_length({actualContentLength: 7, lengthHeader: 3},
+        "encodedBodySize should be equal to the actual byte size of the content when header value is lower than actual content")
+    test_resource_timing_for_content_length({actualContentLength: 8, lengthHeader: 40},
+        "encodedBodySize should be equal to the actual byte size of the content when header value is higher than actual content")
+</script>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/200.https.asis b/testing/web-platform/tests/resource-timing/resources/200.https.asis
new file mode 100644
index 0000000000..5b7c25f4ca
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/200.https.asis
@@ -0,0 +1,5 @@
+HTTP/1.0 200 OK
+Content-Length: 0
+Timing-Allow-Origin: *
+
+
diff --git a/testing/web-platform/tests/resource-timing/resources/200_empty.asis b/testing/web-platform/tests/resource-timing/resources/200_empty.asis
new file mode 100644
index 0000000000..b5d10bda32
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/200_empty.asis
@@ -0,0 +1,3 @@
+HTTP/1.0 200 OK
+Content-Length: 0
+
diff --git a/testing/web-platform/tests/resource-timing/resources/204_empty.asis b/testing/web-platform/tests/resource-timing/resources/204_empty.asis
new file mode 100644
index 0000000000..3d9151326b
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/204_empty.asis
@@ -0,0 +1,3 @@
+HTTP/1.0 204 OK
+Content-Length: 0
+
diff --git a/testing/web-platform/tests/resource-timing/resources/205_empty.asis b/testing/web-platform/tests/resource-timing/resources/205_empty.asis
new file mode 100644
index 0000000000..2c06998c1e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/205_empty.asis
@@ -0,0 +1,3 @@
+HTTP/1.0 205 OK
+Content-Length: 0
+
diff --git a/testing/web-platform/tests/resource-timing/resources/TAOResponse.py b/testing/web-platform/tests/resource-timing/resources/TAOResponse.py
new file mode 100644
index 0000000000..60392b8e10
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/TAOResponse.py
@@ -0,0 +1,64 @@
+import os
+
+def main(request, response):
+    if b'origin' in request.headers:
+      origin = request.headers[b'origin']
+      response.headers.set(b'Access-Control-Allow-Origin', origin)
+
+    tao = request.GET.first(b'tao')
+    img = request.GET.first(b'img') if b'img' in request.GET else None
+
+    if tao == b'zero':
+    # zero TAO value, fail
+        pass
+    elif tao == b'wildcard':
+    # wildcard, pass
+        response.headers.set(b'Timing-Allow-Origin', b'*')
+    elif tao == b'null':
+    # null, fail unless it's an opaque origin
+        response.headers.set(b'Timing-Allow-Origin', b'null')
+    elif tao == b'Null':
+    # case-insensitive null, fail
+        response.headers.set(b'Timing-Allow-Origin', b'Null')
+    elif tao == b'origin':
+    # case-sensitive match for origin, pass
+        response.headers.set(b'Timing-Allow-Origin', origin)
+    elif tao.startswith(b'origin_port'):
+    # case-sensitive match for origin and port, pass
+        origin_parts = origin.split(b':')
+        host = origin_parts[0] + b':' + origin_parts[1]
+        port = tao.split(b'origin_port_')[1]
+        response.headers.set(b'Timing-Allow-Origin', host + b':' + port)
+    elif tao == b'space':
+    # space separated list of origin and wildcard, fail
+        response.headers.set(b'Timing-Allow-Origin', (origin + b' *'))
+    elif tao == b'multi':
+    # more than one TAO values, separated by comma, pass
+        response.headers.set(b'Timing-Allow-Origin', origin)
+        response.headers.append(b'Timing-Allow-Origin', b'*')
+    elif tao == b'multi_wildcard':
+    # multiple wildcards, separated by comma, pass
+        response.headers.set(b'Timing-Allow-Origin', b'*')
+        response.headers.append(b'Timing-Allow-Origin', b'*')
+    elif tao == b'match_origin':
+    # contains a match of origin, separated by comma, pass
+        response.headers.set(b'Timing-Allow-Origin', origin)
+        response.headers.append(b'Timing-Allow-Origin', b"fake")
+    elif tao == b'match_wildcard':
+    # contains a wildcard, separated by comma, pass
+        response.headers.set(b'Timing-Allow-Origin', b"fake")
+        response.headers.append(b'Timing-Allow-Origin', b'*')
+    elif tao == b'uppercase':
+    # non-case-sensitive match for origin, fail
+        response.headers.set(b'Timing-Allow-Origin', origin.upper())
+    else:
+        pass
+    response.status = 200
+    if img:
+      response.headers.set(b"Content-Type", b"image/png")
+      with open(request.doc_root + "/resource-timing/resources/blue.png", "rb") as f:
+        response.content = f.read()
+        f.close()
+    else:
+      response.headers.set(b"Content-Type", b"text/plain")
+      response.content = "TEST"
diff --git a/testing/web-platform/tests/resource-timing/resources/blank-with-tao.html b/testing/web-platform/tests/resource-timing/resources/blank-with-tao.html
new file mode 100644
index 0000000000..b8a1947b77
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/blank-with-tao.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML>
+<html>
+    <head>
+        <meta content="text/html; charset=utf-8" http-equiv="Content-Type" />
+        <title>Green Test Page</title>
+    </head>
+    <body style="background-color:#00FF00;">
+        <h1>Placeholder</h1>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/blank-with-tao.html.headers b/testing/web-platform/tests/resource-timing/resources/blank-with-tao.html.headers
new file mode 100644
index 0000000000..7296361df3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/blank-with-tao.html.headers
@@ -0,0 +1 @@
+Timing-Allow-Origin: *
diff --git a/testing/web-platform/tests/resource-timing/resources/blue-with-tao.png b/testing/web-platform/tests/resource-timing/resources/blue-with-tao.png
new file mode 100644
index 0000000000..820f8cace2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/blue-with-tao.png
diff --git a/testing/web-platform/tests/resource-timing/resources/blue-with-tao.png.headers b/testing/web-platform/tests/resource-timing/resources/blue-with-tao.png.headers
new file mode 100644
index 0000000000..7296361df3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/blue-with-tao.png.headers
@@ -0,0 +1 @@
+Timing-Allow-Origin: *
diff --git a/testing/web-platform/tests/resource-timing/resources/blue.png b/testing/web-platform/tests/resource-timing/resources/blue.png
new file mode 100644
index 0000000000..820f8cace2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/blue.png
diff --git a/testing/web-platform/tests/resource-timing/resources/buffer-full-utilities.js b/testing/web-platform/tests/resource-timing/resources/buffer-full-utilities.js
new file mode 100644
index 0000000000..6cb1753b2e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/buffer-full-utilities.js
@@ -0,0 +1,75 @@
+// This script relies on resources/resource-loaders.js. Include it before in order for the below
+// methods to work properly.
+
+// The resources used to trigger new entries.
+const scriptResources = [
+    'resources/empty.js',
+    'resources/empty_script.js',
+    'resources/empty.js?id'
+];
+
+const waitForNextTask = () => {
+    return new Promise(resolve => {
+        step_timeout(resolve, 0);
+    });
+};
+
+const clearBufferAndSetSize = size => {
+  performance.clearResourceTimings();
+  performance.setResourceTimingBufferSize(size);
+}
+
+const forceBufferFullEvent = async () => {
+  clearBufferAndSetSize(1);
+  return new Promise(async resolve => {
+    performance.addEventListener('resourcetimingbufferfull', resolve);
+    // Load 2 resources to ensure onresourcetimingbufferfull is fired.
+    // Load them in order in order to get the entries in that order!
+    await load.script(scriptResources[0]);
+    await load.script(scriptResources[1]);
+  });
+};
+
+const fillUpTheBufferWithSingleResource = async (src = scriptResources[0]) => {
+  clearBufferAndSetSize(1);
+  await load.script(src);
+};
+
+const fillUpTheBufferWithTwoResources = async () => {
+    clearBufferAndSetSize(2);
+    // Load them in order in order to get the entries in that order!
+    await load.script(scriptResources[0]);
+    await load.script(scriptResources[1]);
+};
+
+const addAssertUnreachedBufferFull = t => {
+  performance.addEventListener('resourcetimingbufferfull', t.step_func(() => {
+    assert_unreached("resourcetimingbufferfull should not fire")
+  }));
+};
+
+const checkEntries = numEntries => {
+  const entries = performance.getEntriesByType('resource');
+  assert_equals(entries.length, numEntries,
+      'Number of entries does not match the expected value.');
+  assert_true(entries[0].name.includes(scriptResources[0]),
+      scriptResources[0] + " is in the entries buffer");
+  if (entries.length > 1) {
+    assert_true(entries[1].name.includes(scriptResources[1]),
+        scriptResources[1] + " is in the entries buffer");
+  }
+  if (entries.length > 2) {
+    assert_true(entries[2].name.includes(scriptResources[2]),
+        scriptResources[2] + " is in the entries buffer");
+  }
+}
+
+const bufferFullFirePromise = new Promise(resolve => {
+  performance.addEventListener('resourcetimingbufferfull', async () => {
+    // Wait for the next task just to ensure that all bufferfull events have fired, and to ensure
+    // that the secondary buffer is copied (as this is an event, there may be microtask checkpoints
+    // right after running an event handler).
+    await waitForNextTask();
+    resolve();
+  });
+});
diff --git a/testing/web-platform/tests/resource-timing/resources/cacheable-and-validated.py b/testing/web-platform/tests/resource-timing/resources/cacheable-and-validated.py
new file mode 100644
index 0000000000..97de866277
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/cacheable-and-validated.py
@@ -0,0 +1,30 @@
+def main(request, response):
+    # Headers need to be set before `response.writer` writes out the response.
+    tao = request.GET.get(b'timing_allow_origin')
+    if tao:
+      response.headers.set(b"Timing-Allow-Origin", tao)
+
+    if b'origin' in request.headers:
+      origin = request.headers[b'origin']
+      response.headers.set(b'Access-Control-Allow-Origin', origin)
+
+    content = request.GET.first(b'content')
+    response.headers.set(b'Cache-Control', b'max-age=60')
+    response.headers.set(b'ETag', b'assdfsdfe')
+
+    # Handle CORS-preflights of non-simple requests.
+    if request.method == 'OPTIONS':
+      response.status = 204
+      requested_method = request.headers.get(b"Access-Control-Request-Method")
+      if requested_method:
+        response.headers.set(b"Access-Control-Allow-Methods", requested_method)
+      requested_headers = request.headers.get(b"Access-Control-Request-Headers")
+      if requested_headers:
+        response.headers.set(b"Access-Control-Allow-Headers", requested_headers)
+    else:
+      if 'Cache-Control' in request.headers:
+        response.status = (304, b'NotModified')
+      else:
+        response.status = (200, b'OK')
+        response.write_status_headers()
+        response.writer.write(content)
diff --git a/testing/web-platform/tests/resource-timing/resources/close.html b/testing/web-platform/tests/resource-timing/resources/close.html
new file mode 100644
index 0000000000..02c275f37b
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/close.html
@@ -0,0 +1 @@
+<script>window.close()</script>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/connection-reuse-test.js b/testing/web-platform/tests/resource-timing/resources/connection-reuse-test.js
new file mode 100644
index 0000000000..453fbd3405
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/connection-reuse-test.js
@@ -0,0 +1,63 @@
+// This script is loaded in HTTP and HTTPS contexts to validate
+// PerformanceResourceTiming entries' attributes when reusing connections.
+//
+// Note: to ensure that we reuse the connection to fetch multiple resources, we
+// use the same XMLHttpRequest object throughout an individual test. Although
+// it doesn't seem to be specified, each browser tested by WPT will reuse the
+// underlying TCP connection with this approach. Pre-establishing the XHR's
+// connection helps us to test connection reuse also in browsers that may key
+// their connections on the related request's credentials mode.
+
+const connection_reuse_test = (path, follow_on_assertions, test_label) => {
+  const {on_200, on_304} = follow_on_assertions;
+
+  // Make the first request before calling 'attribute_test' so that only the
+  // second request's PerformanceResourceTiming entry will be interrogated. We
+  // don't check the first request's PerformanceResourceTiming entry because
+  // that's not what this test is trying to validate.
+  const client = new XMLHttpRequest();
+  const identifier = Math.random();
+  path = `${path}?tag=${identifier}`;
+  client.open("GET", path, false);
+  client.send();
+
+  attribute_test(
+    async () => {
+      client.open("GET", path + "&same_resource=false", false);
+      client.send();
+
+      // We expect to get a 200 Ok response because we've requested a different
+      // resource than previous requests.
+      if (client.status != 200) {
+        throw new Error(`Got something other than a 200 response. ` +
+                        `client.status: ${client.status}`);
+      }
+    }, path, entry => {
+      invariants.assert_connection_reused(entry);
+      on_200(entry);
+    },
+    `PerformanceResrouceTiming entries need to conform to the spec when a ` +
+    `distinct resource is fetched over a persistent connection ` +
+    `(${test_label})`);
+
+  attribute_test(
+    async () => {
+      client.open("GET", path, false);
+      client.setRequestHeader("If-None-Match", identifier);
+      client.send();
+
+      // We expect to get a 304 Not Modified response because we've used a
+      // matching 'identifier' for the If-None-Match header.
+      if (client.status != 304) {
+        throw new Error(`Got something other than a 304 response. ` +
+                        `client.status: ${client.status}, response: ` +
+                        `'${client.responseText}'`);
+      }
+    }, path, entry => {
+      invariants.assert_connection_reused(entry);
+      on_304(entry);
+    },
+    `PerformanceResrouceTiming entries need to conform to the spec when the ` +
+    `resource is cache-revalidated over a persistent connection ` +
+    `(${test_label})`);
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/content-type.py b/testing/web-platform/tests/resource-timing/resources/content-type.py
new file mode 100644
index 0000000000..23a4f0dbc6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/content-type.py
@@ -0,0 +1,5 @@
+def main(request, response):
+    if b'content_type' in request.GET:
+      response.headers.set(b'content-type', request.GET.first(b'content_type'))
+    if b'allow_origin' in request.GET:
+      response.headers.set(b'access-control-allow-origin', request.GET.first(b'allow_origin'))
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/cors-ahem.py b/testing/web-platform/tests/resource-timing/resources/cors-ahem.py
new file mode 100644
index 0000000000..dee5b62f00
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/cors-ahem.py
@@ -0,0 +1,19 @@
+import os.path
+
+from wptserve.utils import isomorphic_decode
+
+def main(request, response):
+    etag = b"123abc"
+    if etag == request.headers.get(b"If-None-Match", None):
+        response.headers.set(b"X-HTTP-STATUS", 304)
+        response.status = (304, b"Not Modified")
+        return u""
+
+    response.headers.set(b"Cache-Control", b"public, max-age=86400")
+    response.headers.set(b"Content-Type", b"font/truetype")
+    response.headers.set(b"Access-Control-Allow-Origin", b"*")
+    response.headers.set(b"Timing-Allow-Origin", b"*")
+    response.headers.set(b"ETag", etag)
+    font = u"../../fonts/Ahem.ttf"
+    path = os.path.join(os.path.dirname(isomorphic_decode(__file__)), font)
+    response.content = open(path, u"rb").read()
diff --git a/testing/web-platform/tests/resource-timing/resources/csp-default-none.html b/testing/web-platform/tests/resource-timing/resources/csp-default-none.html
new file mode 100644
index 0000000000..1f59d8c225
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/csp-default-none.html
@@ -0,0 +1,3 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>empty page</title>
diff --git a/testing/web-platform/tests/resource-timing/resources/csp-default-none.html.headers b/testing/web-platform/tests/resource-timing/resources/csp-default-none.html.headers
new file mode 100644
index 0000000000..d66f886dd2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/csp-default-none.html.headers
@@ -0,0 +1,2 @@
+Content-Security-Policy: default-src 'none'
+
diff --git a/testing/web-platform/tests/resource-timing/resources/delay-css.py b/testing/web-platform/tests/resource-timing/resources/delay-css.py
new file mode 100644
index 0000000000..9a905960ee
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/delay-css.py
@@ -0,0 +1,6 @@
+import time
+
+def main(request, response):
+    time.sleep(float(request.GET.first(b"delay", 1000)) / 1000)
+    response.headers.set('Content-Type', 'text/css')
+    return "/* */"
diff --git a/testing/web-platform/tests/resource-timing/resources/delay-load.html b/testing/web-platform/tests/resource-timing/resources/delay-load.html
new file mode 100644
index 0000000000..4898c1be8e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/delay-load.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<body>
+<img src="/images/blue.png?pipe=trickle(d1)">
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/document-domain-no-impact.html b/testing/web-platform/tests/resource-timing/resources/document-domain-no-impact.html
new file mode 100644
index 0000000000..64cdd8a870
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/document-domain-no-impact.html
@@ -0,0 +1,28 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8">
+<script src="/resources/testharness.js"></script>
+<script src="resource-loaders.js"></script>
+<script src="entry-invariants.js"></script>
+<body>
+<script>
+const path = location.origin +
+             "/resource-timing/resources/iframe-setdomain.sub.html";
+attribute_test_with_validator(load.iframe, path,
+  el => {
+    try {
+      el.contentWindow.document;
+      throw new Error("iframe document.domain was not set");
+    } catch(error) {
+      if (error.name != "SecurityError") {
+        throw(error);
+      }
+    }
+  },
+  invariants.assert_tao_pass_no_redirect_http,
+  "test that document.domain being set doesn't have an impact on the " +
+  "resource timing entry."
+);
+</script>
+
diff --git a/testing/web-platform/tests/resource-timing/resources/document-navigated.html b/testing/web-platform/tests/resource-timing/resources/document-navigated.html
new file mode 100644
index 0000000000..bedae77082
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/document-navigated.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+</head>
+<body>
+  Navigated document!
+<script>
+  top.postMessage("navigated", "*");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/document-refreshed.html b/testing/web-platform/tests/resource-timing/resources/document-refreshed.html
new file mode 100644
index 0000000000..568f7f27c7
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/document-refreshed.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+</head>
+<body>
+  Refreshed document!
+<script>
+  top.postMessage("refreshed", "*");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/document-that-navigates.html b/testing/web-platform/tests/resource-timing/resources/document-that-navigates.html
new file mode 100644
index 0000000000..a59e9f3ab2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/document-that-navigates.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+</head>
+<body>
+<script>
+  location.href="document-navigated.html";
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/document-that-refreshes.html b/testing/web-platform/tests/resource-timing/resources/document-that-refreshes.html
new file mode 100644
index 0000000000..659513a642
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/document-that-refreshes.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<meta http-equiv="refresh" content="0;document-refreshed.html">
+</head>
+<body>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/download.asis b/testing/web-platform/tests/resource-timing/resources/download.asis
new file mode 100644
index 0000000000..167386d7a5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/download.asis
@@ -0,0 +1,6 @@
+HTTP/1.0 200 OK
+Content-Type: application/octet-stream
+
+12312313
+
+
diff --git a/testing/web-platform/tests/resource-timing/resources/embed-navigate-back.html b/testing/web-platform/tests/resource-timing/resources/embed-navigate-back.html
new file mode 100644
index 0000000000..c9c7340f53
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/embed-navigate-back.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing embed navigate - back button navigation</title>
+</head>
+<body onunload="/*disable bfcache*/">
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_back_navigation("embed-navigate-back.html");
+</script>
+<embed id="target" type="text/html">
+<script>
+  target.src = pre_navigate_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/embed-navigate.html b/testing/web-platform/tests/resource-timing/resources/embed-navigate.html
new file mode 100644
index 0000000000..24c9d3c462
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/embed-navigate.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing embed navigate</title>
+</head>
+<body>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_navigate_test();
+</script>
+<embed id="target" type="text/html">
+<script>
+  target.src = pre_navigate_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/embed-refresh.html b/testing/web-platform/tests/resource-timing/resources/embed-refresh.html
new file mode 100644
index 0000000000..bd4b5a14de
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/embed-refresh.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing embed refresh</title>
+</head>
+<body>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_refresh_test();
+</script>
+<embed id="target" type="text/html">
+<script>
+  target.src = pre_refresh_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/empty.js b/testing/web-platform/tests/resource-timing/resources/empty.js
new file mode 100644
index 0000000000..3b44754e30
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/empty.js
@@ -0,0 +1 @@
+/* Nothing here */
diff --git a/testing/web-platform/tests/resource-timing/resources/empty.py b/testing/web-platform/tests/resource-timing/resources/empty.py
new file mode 100644
index 0000000000..cae83c146e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/empty.py
@@ -0,0 +1,3 @@
+def main(request, response):
+    response.headers.set(b"Content-Type", b"text/plain")
+    return u""
diff --git a/testing/web-platform/tests/resource-timing/resources/empty_script.js b/testing/web-platform/tests/resource-timing/resources/empty_script.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/empty_script.js
diff --git a/testing/web-platform/tests/resource-timing/resources/empty_style.css b/testing/web-platform/tests/resource-timing/resources/empty_style.css
new file mode 100644
index 0000000000..eb90b432e8
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/empty_style.css
@@ -0,0 +1 @@
+/*Nothing here*/
diff --git a/testing/web-platform/tests/resource-timing/resources/entry-invariants.js b/testing/web-platform/tests/resource-timing/resources/entry-invariants.js
new file mode 100644
index 0000000000..bbc913b722
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/entry-invariants.js
@@ -0,0 +1,510 @@
+const await_with_timeout = async (delay, message, promise, cleanup = ()=>{}) => {
+  let timeout_id;
+  const timeout = new Promise((_, reject) => {
+    timeout_id = step_timeout(() =>
+      reject(new DOMException(message, "TimeoutError")), delay)
+  });
+  let result = null;
+  try {
+    result = await Promise.race([promise, timeout]);
+    clearTimeout(timeout_id);
+  } finally {
+    cleanup();
+  }
+  return result;
+};
+
+// Asserts that the given attributes are present in 'entry' and hold equal
+// values.
+const assert_all_equal_ = (entry, attributes) => {
+  let first = attributes[0];
+  attributes.slice(1).forEach(other => {
+    assert_equals(entry[first], entry[other],
+      `${first} should be equal to ${other}`);
+  });
+}
+
+// Asserts that the given attributes are present in 'entry' and hold values
+// that are sorted in the same order as given in 'attributes'.
+const assert_ordered_ = (entry, attributes) => {
+  let before = attributes[0];
+  attributes.slice(1).forEach(after => {
+    assert_greater_than_equal(entry[after], entry[before],
+      `${after} should be greater than ${before}`);
+    before = after;
+  });
+}
+
+// Asserts that the given attributes are present in 'entry' and hold a value of
+// 0.
+const assert_zeroed_ = (entry, attributes) => {
+  attributes.forEach(attribute => {
+    assert_equals(entry[attribute], 0, `${attribute} should be 0`);
+  });
+}
+
+// Asserts that the given attributes are present in 'entry' and hold a value of
+// 0 or more.
+const assert_not_negative_ = (entry, attributes) => {
+  attributes.forEach(attribute => {
+    assert_greater_than_equal(entry[attribute], 0,
+      `${attribute} should be greater than or equal to 0`);
+  });
+}
+
+// Asserts that the given attributes are present in 'entry' and hold a value
+// greater than 0.
+const assert_positive_ = (entry, attributes) => {
+  attributes.forEach(attribute => {
+    assert_greater_than(entry[attribute], 0,
+      `${attribute} should be greater than 0`);
+  });
+}
+
+const invariants = {
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates for any resource fetched over HTTP without
+  // redirects but passing the Timing-Allow-Origin checks.
+  assert_tao_pass_no_redirect_http: entry => {
+    assert_ordered_(entry, [
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+
+    assert_zeroed_(entry, [
+      "workerStart",
+      "secureConnectionStart",
+      "redirectStart",
+      "redirectEnd",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "transferSize",
+    ]);
+  },
+
+  // Like assert_tao_pass_no_redirect_http but for empty response bodies.
+  assert_tao_pass_no_redirect_http_empty: entry => {
+    assert_ordered_(entry, [
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+
+    assert_zeroed_(entry, [
+      "workerStart",
+      "secureConnectionStart",
+      "redirectStart",
+      "redirectEnd",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "transferSize",
+    ]);
+  },
+
+  // Like assert_tao_pass_no_redirect_http but for resources fetched over HTTPS
+  assert_tao_pass_no_redirect_https: entry => {
+    assert_ordered_(entry, [
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "secureConnectionStart",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+
+    assert_zeroed_(entry, [
+      "workerStart",
+      "redirectStart",
+      "redirectEnd",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "transferSize",
+    ]);
+  },
+
+  // Like assert_tao_pass_no_redirect_https but for resources that did encounter
+  // at least one HTTP redirect.
+  assert_tao_pass_with_redirect_https: entry => {
+    assert_ordered_(entry, [
+      "fetchStart",
+      "redirectStart",
+      "redirectEnd",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "secureConnectionStart",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+
+    assert_zeroed_(entry, [
+      "workerStart",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "transferSize",
+    ]);
+  },
+
+  // Like assert_tao_pass_no_redirect_http but, since the resource's bytes
+  // won't be retransmitted, the encoded and decoded sizes must be zero.
+  assert_tao_pass_304_not_modified_http: entry => {
+    assert_ordered_(entry, [
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+
+    assert_zeroed_(entry, [
+      "workerStart",
+      "secureConnectionStart",
+      "redirectStart",
+      "redirectEnd",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "transferSize",
+    ]);
+  },
+
+  // Like assert_tao_pass_304_not_modified_http but for resources fetched over
+  // HTTPS.
+  assert_tao_pass_304_not_modified_https: entry => {
+    assert_ordered_(entry, [
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "secureConnectionStart",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+
+    assert_zeroed_(entry, [
+      "workerStart",
+      "redirectStart",
+      "redirectEnd",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "transferSize",
+    ]);
+  },
+
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates for any resource subsequently fetched over a
+  // persistent connection. When this happens, we expect that certain
+  // attributes describing transport layer behaviour will be equal.
+  assert_connection_reused: entry => {
+    assert_all_equal_(entry, [
+      "fetchStart",
+      "connectStart",
+      "connectEnd",
+      "domainLookupStart",
+      "domainLookupEnd",
+    ]);
+  },
+
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates for any resource fetched over HTTP through an HTTP
+  // redirect.
+  assert_same_origin_redirected_resource: entry => {
+    assert_positive_(entry, [
+      "redirectStart",
+    ]);
+
+    assert_equals(entry.redirectStart, entry.startTime,
+      "redirectStart should be equal to startTime");
+
+    assert_ordered_(entry, [
+      "redirectStart",
+      "redirectEnd",
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+    ]);
+  },
+
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates for any resource fetched over HTTPS through a
+  // cross-origin redirect.
+  // (e.g. GET http://remote.com/foo => 302 Location: https://remote.com/foo)
+  assert_cross_origin_redirected_resource: entry => {
+    assert_zeroed_(entry, [
+      "redirectStart",
+      "redirectEnd",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "secureConnectionStart",
+      "requestStart",
+      "responseStart",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "responseEnd",
+    ]);
+
+    assert_ordered_(entry, [
+      "fetchStart",
+      "responseEnd",
+    ]);
+  },
+
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates when
+  // 1. An HTTP request is made for a same-origin resource.
+  // 2. The response to 1 is an HTTP redirect (like a 302).
+  // 3. The location from 2 is a cross-origin HTTPS URL.
+  // 4. The response to fetching the URL from 3 does not set a matching TAO header.
+  assert_http_to_cross_origin_redirected_resource: entry => {
+    assert_zeroed_(entry, [
+      "redirectStart",
+      "redirectEnd",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "secureConnectionStart",
+      "requestStart",
+      "responseStart",
+    ]);
+
+    assert_positive_(entry, [
+      "fetchStart",
+      "responseEnd",
+    ]);
+
+    assert_ordered_(entry, [
+      "fetchStart",
+      "responseEnd",
+    ]);
+  },
+
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates when
+  // 1. An HTTPS request is made for a same-origin resource.
+  // 2. The response to 1 is an HTTP redirect (like a 302).
+  // 3. The location from 2 is a cross-origin HTTPS URL.
+  // 4. The response to fetching the URL from 3 sets a matching TAO header.
+  assert_tao_enabled_cross_origin_redirected_resource: entry => {
+    assert_positive_(entry, [
+      "redirectStart",
+    ]);
+    assert_ordered_(entry, [
+      "redirectStart",
+      "redirectEnd",
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "secureConnectionStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+  },
+
+  // Asserts that attributes of the given PerformanceResourceTiming entry match
+  // what the spec dictates when
+  // 1. An HTTP request is made for a same-origin resource
+  // 2. The response to 1 is an HTTP redirect (like a 302).
+  // 3. The location from 2 is a cross-origin HTTPS URL.
+  // 4. The response to fetching the URL from 3 sets a matching TAO header.
+  assert_http_to_tao_enabled_cross_origin_https_redirected_resource: entry => {
+    assert_zeroed_(entry, [
+      // Note that, according to the spec, the secureConnectionStart attribute
+      // should describe the connection for the first resource request when
+      // there are redirects. Since the initial request is over HTTP,
+      // secureConnectionStart must be 0.
+      "secureConnectionStart",
+    ]);
+    assert_positive_(entry, [
+      "redirectStart",
+    ]);
+    assert_ordered_(entry, [
+      "redirectStart",
+      "redirectEnd",
+      "fetchStart",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "requestStart",
+      "responseStart",
+      "responseEnd",
+    ]);
+  },
+
+  assert_same_origin_redirected_from_cross_origin_resource: entry => {
+    assert_zeroed_(entry, [
+      "workerStart",
+      "redirectStart",
+      "redirectEnd",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "secureConnectionStart",
+      "requestStart",
+      "responseStart",
+      "transferSize",
+    ]);
+
+    assert_ordered_(entry, [
+      "fetchStart",
+      "responseEnd",
+    ]);
+
+    assert_equals(entry.fetchStart, entry.startTime,
+      "fetchStart must equal startTime");
+  },
+
+  assert_tao_failure_resource: entry => {
+    assert_equals(entry.entryType, "resource", "entryType must always be 'resource'");
+
+    assert_positive_(entry, [
+      "startTime",
+    ]);
+
+    assert_not_negative_(entry, [
+      "duration",
+    ]);
+
+    assert_zeroed_(entry, [
+      "redirectStart",
+      "redirectEnd",
+      "domainLookupStart",
+      "domainLookupEnd",
+      "connectStart",
+      "connectEnd",
+      "secureConnectionStart",
+      "requestStart",
+      "responseStart",
+      "transferSize",
+    ]);
+  }
+
+};
+
+const attribute_test_internal = (loader, path, validator, run_test, test_label) => {
+  promise_test(
+    async () => {
+      let loaded_entry = new Promise((resolve, reject) => {
+        new PerformanceObserver((entry_list, self) => {
+          try {
+            const name_matches = entry_list.getEntries().forEach(entry => {
+              if (entry.name.includes(path)) {
+                resolve(entry);
+              }
+            });
+          } catch(e) {
+            // By surfacing exceptions through the Promise interface, tests can
+            // fail fast with a useful message instead of timing out.
+            reject(e);
+          }
+        }).observe({"type": "resource"});
+      });
+
+      await loader(path, validator);
+      const entry = await await_with_timeout(2000,
+        "Timeout was reached before entry fired",
+        loaded_entry);
+      assert_not_equals(entry, null, 'No entry was received');
+      run_test(entry);
+  }, test_label);
+};
+
+// Given a resource-loader, a path (a relative path or absolute URL), and a
+// PerformanceResourceTiming test, applies the loader to the resource path
+// and tests the resulting PerformanceResourceTiming entry.
+const attribute_test = (loader, path, run_test, test_label) => {
+  attribute_test_internal(loader, path, () => {}, run_test, test_label);
+};
+
+// Similar to attribute test, but on top of that, validates the added element,
+// to ensure the test does what it intends to do.
+const attribute_test_with_validator = (loader, path, validator, run_test, test_label) => {
+  attribute_test_internal(loader, path, validator, run_test, test_label);
+};
+
+const network_error_entry_test = (originalURL, args, label) => {
+  const url = new URL(originalURL, location.href);
+  const search = new URLSearchParams(url.search.substr(1));
+  const timeBefore = performance.now();
+  loader = () => new Promise(resolve => fetch(url, args).catch(resolve));
+
+  attribute_test(
+    loader, url,
+    () => {
+      const timeAfter = performance.now();
+      const names = performance.getEntriesByType('resource').filter(e => e.initiatorType === 'fetch').map(e => e.name);
+      const entries = performance.getEntriesByName(url.toString());
+      assert_equals(entries.length, 1, 'resource timing entry for network error');
+      const entry = entries[0]
+      assert_equals(entry.startTime, entry.fetchStart, 'startTime and fetchStart should be equal');
+      assert_greater_than_equal(entry.startTime, timeBefore, 'startTime and fetchStart should be greater than the time before fetching');
+      assert_greater_than_equal(timeAfter, entry.responseEnd, 'endTime should be less than the time right after returning from the fetch');
+      invariants.assert_tao_failure_resource(entry);
+  }, `A ResourceTiming entry should be created for network error of type ${label}`);
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/eventsource.py b/testing/web-platform/tests/resource-timing/resources/eventsource.py
new file mode 100644
index 0000000000..e3a2355730
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/eventsource.py
@@ -0,0 +1,3 @@
+def main(request, response):
+    response.headers.set(b"Content-Type", b"text/event-stream")
+    return u""
diff --git a/testing/web-platform/tests/resource-timing/resources/fake_responses.html b/testing/web-platform/tests/resource-timing/resources/fake_responses.html
new file mode 100644
index 0000000000..52cad6c415
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/fake_responses.html
@@ -0,0 +1,19 @@
+<body>
+<script>
+function request(type) {
+  var client = new XMLHttpRequest,
+    identifier = type == "tag" ? Math.random() : new Date().toGMTString(),
+    url = "fake_responses.py?" + type + "=" + identifier
+    client.open("GET", url, false)
+    client.send(null)
+    client.open("GET", url, false)
+    client.setRequestHeader(type == "tag" ? "If-None-Match" : "If-Modified-Since", identifier)
+    client.send(null)
+}
+
+if(window.parent.setup_iframe) {
+  window.parent.setup_iframe();
+  request("tag");
+}
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/fake_responses.py b/testing/web-platform/tests/resource-timing/resources/fake_responses.py
new file mode 100644
index 0000000000..cc6aba6efa
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/fake_responses.py
@@ -0,0 +1,42 @@
+# /xhr/resources/conditional.py -- to fake a 304 response
+
+def main(request, response):
+    if request.method == "OPTIONS":
+        # Assume this is a CORS preflight
+        response.headers.set(b"Access-Control-Allow-Headers", "*")
+        response.headers.set(b"Access-Control-Allow-Origin", "*")
+        response.status = (204, "No Content")
+        return b""
+    tag = request.GET.first(b"tag", None)
+    redirect = request.GET.first(b"redirect", None)
+    match = request.headers.get(b"If-None-Match", None)
+    date = request.GET.first(b"date", b"")
+    modified = request.headers.get(b"If-Modified-Since", None)
+    url = request.GET.first(b"url", None)
+    response.headers.set(b"Access-Control-Allow-Origin", b"*")
+    response.headers.set(b"Timing-Allow-Origin", b"*")
+    if tag:
+        response.headers.set(b"ETag", b'"%s"' % tag)
+    elif date:
+        response.headers.set(b"Last-Modified", date)
+    if redirect:
+        response.headers.set(b"Location", redirect)
+        response.status = (302, b"Moved")
+        return b""
+
+    if url:
+        filename = url.decode('utf-8').split("?")[0]
+        filepath = "./resource-timing/resources/{}".format(filename)
+        response.headers.set(b"Content-Type", b"text/javascript")
+        with open(filepath, 'rb') as f:
+            filedata = f.read()
+
+        return filedata
+
+    if ((match is not None and match == tag) or
+        (modified is not None and modified == date)):
+        response.status = (304, b"SUPERCOOL")
+        return b""
+    else:
+        response.headers.set(b"Content-Type", b"text/plain")
+        return b"MAYBE NOT"
diff --git a/testing/web-platform/tests/resource-timing/resources/fake_responses_https.sub.html b/testing/web-platform/tests/resource-timing/resources/fake_responses_https.sub.html
new file mode 100644
index 0000000000..21f1f02a67
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/fake_responses_https.sub.html
@@ -0,0 +1,18 @@
+<body>
+<script>
+function request() {
+  var client = new XMLHttpRequest,
+      baseurl = "https://{{hosts[alt][]}}:{{ports[https][0]}}{{location[pathname]}}",
+      url = new URL("fake_responses.py", baseurl).href;
+    client.open("GET", url, false)
+    client.send(null)
+    client.open("GET", url, false)
+    client.send(null)
+}
+
+if(window.parent.setup_iframe) {
+  window.parent.setup_iframe();
+  request();
+}
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/fake_responses_https_redirect.sub.html b/testing/web-platform/tests/resource-timing/resources/fake_responses_https_redirect.sub.html
new file mode 100644
index 0000000000..2ee92b2a55
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/fake_responses_https_redirect.sub.html
@@ -0,0 +1,20 @@
+<body>
+<script>
+function request() {
+  var client = new XMLHttpRequest,
+      baseurl = "http://{{hosts[alt][]}}:{{ports[http][0]}}{{location[pathname]}}",
+      subresource = "fake_responses.py",
+      redirecturl = new URL(subresource, "https://{{hosts[][www]}}:{{ports[https][0]}}{{location[pathname]}}").href,
+      url = new URL(subresource + "?redirect=" + redirecturl, baseurl).href;
+    client.open("GET", url, false)
+    client.send(null)
+    client.open("GET", url, false)
+    client.send(null)
+}
+
+if(window.parent.setup_iframe) {
+  window.parent.setup_iframe();
+  request();
+}
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/frame-timing.js b/testing/web-platform/tests/resource-timing/resources/frame-timing.js
new file mode 100644
index 0000000000..019bd424b5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/frame-timing.js
@@ -0,0 +1,63 @@
+function test_frame_timing_before_load_event(type) {
+  promise_test(async t => {
+    const {document, performance} = type === 'frame' ? window.parent : window;
+    const delay = 500;
+    const frame = document.createElement(type);
+    t.add_cleanup(() => frame.remove());
+    await new Promise(resolve => {
+      frame.addEventListener('load', resolve);
+      frame.src = `/resource-timing/resources/iframe-with-delay.sub.html?delay=${delay}`;
+      (type === 'frame' ? document.querySelector('frameset') : document.body).appendChild(frame);
+    });
+
+    const entries = performance.getEntriesByName(frame.src);
+    const navigationEntry = frame.contentWindow.performance.getEntriesByType('navigation')[0];
+    assert_equals(entries.length, 1);
+    assert_equals(entries[0].initiatorType, type);
+    assert_greater_than(performance.now(), entries[0].responseEnd + delay);
+    const domContentLoadedEventAbsoluteTime =
+      navigationEntry.domContentLoadedEventStart +
+      frame.contentWindow.performance.timeOrigin;
+    const frameResponseEndAbsoluteTime = entries[0].responseEnd + performance.timeOrigin;
+    assert_greater_than(domContentLoadedEventAbsoluteTime, frameResponseEndAbsoluteTime);
+  }, `A ${type} should report its RT entry when the response is done and before it is completely loaded`);
+}
+
+
+function test_frame_timing_change_src(type,
+                                      origin1 = document.origin,
+                                      origin2 = document.origin,
+                                      tao = false, label = '') {
+  const uid = token();
+  promise_test(async t => {
+    const {document, performance} = type === 'frame' ? window.parent : window;
+    const frame = document.createElement(type);
+    t.add_cleanup(() => frame.remove());
+    function createURL(origin) {
+      const url = new URL(`${origin}/resource-timing/resources/green.html`, location.href);
+      url.searchParams.set("uid", uid);
+      if (tao)
+        url.searchParams.set("pipe", "header(Timing-Allow-Origin, *)");
+      return url.toString();
+    }
+
+    await new Promise(resolve => {
+      const done = () => {
+        resolve();
+        frame.removeEventListener('load', done);
+      }
+      frame.addEventListener('load', done);
+      frame.src = createURL(origin1);
+      const root = type === 'frame' ? document.querySelector('frameset') : document.body;
+      root.appendChild(frame);
+    });
+
+    await new Promise(resolve => {
+      frame.addEventListener('load', resolve);
+      frame.src = createURL(origin2);
+    });
+
+    const entries = performance.getEntries().filter(e => e.name.includes(uid));
+    assert_equals(entries.length, 2);
+  }, label || `A ${type} should report separate RT entries if its src changed from the outside`);
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/frameset-timing-frame.html b/testing/web-platform/tests/resource-timing/resources/frameset-timing-frame.html
new file mode 100644
index 0000000000..e260f57526
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/frameset-timing-frame.html
@@ -0,0 +1,8 @@
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="./frame-timing.js"></script>
+
+<script>
+  test_frame_timing_before_load_event('frame');
+  test_frame_timing_change_src('frame');
+</script>
diff --git a/testing/web-platform/tests/resource-timing/resources/green-frame.html b/testing/web-platform/tests/resource-timing/resources/green-frame.html
new file mode 100644
index 0000000000..9613240ae3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/green-frame.html
@@ -0,0 +1,7 @@
+<html>
+  <head>
+    <frameset>
+      <frame src="green.html?id=frame">
+    </frameset>
+  </head>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/green.html b/testing/web-platform/tests/resource-timing/resources/green.html
new file mode 100644
index 0000000000..b8a1947b77
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/green.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML>
+<html>
+    <head>
+        <meta content="text/html; charset=utf-8" http-equiv="Content-Type" />
+        <title>Green Test Page</title>
+    </head>
+    <body style="background-color:#00FF00;">
+        <h1>Placeholder</h1>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/green.html.headers b/testing/web-platform/tests/resource-timing/resources/green.html.headers
new file mode 100644
index 0000000000..cb762eff80
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/green.html.headers
@@ -0,0 +1 @@
+Access-Control-Allow-Origin: *
diff --git a/testing/web-platform/tests/resource-timing/resources/gzip_xml.py b/testing/web-platform/tests/resource-timing/resources/gzip_xml.py
new file mode 100644
index 0000000000..7debc9ce3f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/gzip_xml.py
@@ -0,0 +1,23 @@
+import gzip as gzip_module
+import os
+
+from io import BytesIO
+
+from wptserve.utils import isomorphic_decode
+
+def main(request, response):
+    dir_path = os.path.dirname(os.path.realpath(isomorphic_decode(__file__)))
+    file_path = os.path.join(dir_path, u'resource_timing_test0.xml')
+    f = open(file_path, u'rb')
+    output = f.read()
+
+    out = BytesIO()
+    with gzip_module.GzipFile(fileobj=out, mode="w") as f:
+        f.write(output)
+    output = out.getvalue()
+
+    headers = [(b"Content-type", b"text/plain"),
+               (b"Content-Encoding", b"gzip"),
+               (b"Content-Length", len(output))]
+
+    return headers, output
diff --git a/testing/web-platform/tests/resource-timing/resources/header-delay.h2.py b/testing/web-platform/tests/resource-timing/resources/header-delay.h2.py
new file mode 100644
index 0000000000..27b6fd5bfb
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/header-delay.h2.py
@@ -0,0 +1,25 @@
+from time import sleep
+
+def handle_headers(frame, request, response):
+    delay = int(request.GET.first(b"delay")) / 1000
+
+    if b"with100" in request.GET:
+        sleep(delay)
+        response.writer.write_raw_header_frame(headers=[(b":status", b"103")], end_headers=True)
+
+    if b"with103" in request.GET:
+        sleep(delay)
+        response.writer.write_raw_header_frame(headers=[(b":status", b"103")], end_headers=True)
+
+    sleep(delay)
+    response.status = 200
+
+    if b"tao" in request.GET:
+        response.headers[b"timing-allow-origin"] = "*"
+
+    response.headers[b"content-type"] = "text/plain"
+    response.headers[b"access-control-allow-origin"] = "*"
+    response.write_status_headers()
+
+def main(request, response):
+    response.writer.write_data(item="Hello World", last=True)
diff --git a/testing/web-platform/tests/resource-timing/resources/header-delay.py b/testing/web-platform/tests/resource-timing/resources/header-delay.py
new file mode 100644
index 0000000000..631f7855f8
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/header-delay.py
@@ -0,0 +1,29 @@
+from time import sleep
+
+def main(request, response):
+    delay = int(request.GET.first(b"delay")) / 1000
+
+    # TODO: make this exported from ResponseWriter
+    handler = response.writer._handler
+    if b"with100" in request.GET:
+        sleep(delay)
+        handler.send_response(100)
+        handler.end_headers()
+
+    if b"with103" in request.GET:
+        sleep(delay)
+        handler.send_response(103)
+        handler.send_header("Link", "<resources/empty.js>;rel=preload;as=script")
+        handler.end_headers()
+
+    sleep(delay)
+
+    handler.send_response(200)
+
+    if b"tao" in request.GET:
+        handler.send_header("timing-allow-origin", "*")
+
+    handler.send_header("content-type", "text/plain")
+    handler.send_header("access-control-allow-origin", "*")
+    handler.end_headers()
+    handler.wfile.write(bytes("Hello World", "utf8"))
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-TAO-crossorigin-port.sub.html b/testing/web-platform/tests/resource-timing/resources/iframe-TAO-crossorigin-port.sub.html
new file mode 100644
index 0000000000..97d77fcc58
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-TAO-crossorigin-port.sub.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html>
+<body>
+<script>
+    const url = '{{location[scheme]}}://{{host}}:{{ports[http][1]}}/resource-timing/resources/TAOResponse.py?tao=origin_port_{{ports[http][1]}}';
+    const observe = (list, observer) => {
+        const entry = list.getEntries()[0];
+        const sum = entry.redirectStart +
+                  entry.redirectEnd +
+                  entry.domainLookupStart +
+                  entry.domainLookupEnd +
+                  entry.connectStart +
+                  entry.connectEnd +
+                  entry.secureConnectionStart +
+                  entry.requestStart +
+                  entry.responseStart +
+                  entry.transferSize +
+                  entry.encodedBodySize +
+                  entry.decodedBodySize;
+
+        const result = sum == 0 ? 'PASS' : 'FAIL';
+        window.top.postMessage(result, '*');
+    }
+    let observer = new PerformanceObserver(observe);
+    observer.observe({ entryTypes: ["resource"] });
+    fetch(url).then(r => r.text());
+</script>
+</body>
+</html>
+
+
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-load-from-mem-cache-transfer-size.html b/testing/web-platform/tests/resource-timing/resources/iframe-load-from-mem-cache-transfer-size.html
new file mode 100644
index 0000000000..6f37a33e8c
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-load-from-mem-cache-transfer-size.html
@@ -0,0 +1,24 @@
+<!DOCTYPE HTML>
+<html>
+
+<head>
+  <meta charset="utf-8" />
+  <title>transfer size of resource timing when loaded from memory cache.</title>
+</head>
+
+<body>
+  <script>
+    // This function is called from the test in the parent document.
+    function getScript(url) {
+      const script = document.createElement("script");
+      const loaded = new Promise(resolve => {
+        script.onload = script.onerror = resolve;
+      });
+      script.src = url;
+      document.body.appendChild(script);
+      return loaded;
+    }
+  </script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-navigate-back.html b/testing/web-platform/tests/resource-timing/resources/iframe-navigate-back.html
new file mode 100644
index 0000000000..f944b633e2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-navigate-back.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing iframe navigate - back button navigation</title>
+</head>
+<body onunload="/*disable bfcache*/">
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_back_navigation("iframe-navigate-back.html");
+</script>
+<iframe id="target"></iframe>
+<script>
+  target.src = pre_navigate_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-navigate.html b/testing/web-platform/tests/resource-timing/resources/iframe-navigate.html
new file mode 100644
index 0000000000..0286884021
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-navigate.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing iframe navigate</title>
+</head>
+<body>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_navigate_test();
+</script>
+<iframe id="target"></iframe>
+<script>
+  target.src = pre_navigate_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-refresh.html b/testing/web-platform/tests/resource-timing/resources/iframe-refresh.html
new file mode 100644
index 0000000000..862b96da9d
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-refresh.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing iframe refresh</title>
+</head>
+<body>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_refresh_test();
+</script>
+<iframe id="target"></iframe>
+<script>
+  target.src = pre_refresh_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-reload-TAO.html b/testing/web-platform/tests/resource-timing/resources/iframe-reload-TAO.html
new file mode 100644
index 0000000000..461f43bf8e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-reload-TAO.html
@@ -0,0 +1,25 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf-8" />
+<script src="/resources/testharness.js"></script>
+<script src="resource-loaders.js"></script>
+<script src="entry-invariants.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<body>
+<script>
+  const {HTTP_NOTSAMESITE_ORIGIN} = get_host_info();
+  const font_url = `${HTTP_NOTSAMESITE_ORIGIN}/resource-timing/resources/cors-ahem.py`;
+  if (location.hash === '#check') {
+    attribute_test(
+      load.font, font_url,
+      invariants.assert_tao_pass_no_redirect_http,
+      "Test that TAO headers are reused on reloads.");
+  } else {
+    window.onload = () => {
+      location.hash = 'check';
+      location.reload();
+    };
+  }
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-setdomain.sub.html b/testing/web-platform/tests/resource-timing/resources/iframe-setdomain.sub.html
new file mode 100644
index 0000000000..4a2f609aa4
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-setdomain.sub.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>domain: {{domains[]}}</title>
+</head>
+<body>
+  <script>
+    // The purpose of this IFrame is to change the 'document.domain'
+    document.domain = "{{domains[]}}";
+  </script>
+  The resource-timings-level1.sub.html test loads this document into an IFrame to vet that setting
+  'document.domain' does not effect the timing allowed.
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe-with-delay.sub.html b/testing/web-platform/tests/resource-timing/resources/iframe-with-delay.sub.html
new file mode 100644
index 0000000000..fe50aa7e47
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe-with-delay.sub.html
@@ -0,0 +1,3 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<img src="/xhr/resources/delay.py?ms={{GET[delay]}}" />
diff --git a/testing/web-platform/tests/resource-timing/resources/iframe_TAO_match_origin.html b/testing/web-platform/tests/resource-timing/resources/iframe_TAO_match_origin.html
new file mode 100644
index 0000000000..cf68aade79
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/iframe_TAO_match_origin.html
@@ -0,0 +1,21 @@
+<body>
+<script>
+function dirname(path) {
+    return path.replace(/\/[^\/]*$/, '/');
+}
+
+function request() {
+  var dirName = dirname(location.href);
+  var client = new XMLHttpRequest,
+  // create a cross-origin request
+    url = dirName.replace('://', '://www.') + 'TAOResponse.py?tao=match_origin';
+    client.open("GET", url, false);
+    client.send(null);
+}
+
+if(window.parent.setup_iframe) {
+  window.parent.setup_iframe();
+  request();
+}
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/import.sub.css b/testing/web-platform/tests/resource-timing/resources/import.sub.css
new file mode 100644
index 0000000000..618c568d2a
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/import.sub.css
@@ -0,0 +1 @@
+@import "delay-css.py?delay={{GET[delay]}}"
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/importer.css b/testing/web-platform/tests/resource-timing/resources/importer.css
new file mode 100644
index 0000000000..771204cdd1
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/importer.css
@@ -0,0 +1 @@
+@import 'empty_style.css?stylesheet-imported'
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/importer.js b/testing/web-platform/tests/resource-timing/resources/importer.js
new file mode 100644
index 0000000000..e73d45da29
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/importer.js
@@ -0,0 +1,2 @@
+import './fake_responses.py?url=empty_script.js?script-head-import-defer';
+import('./fake_responses.py?url=empty_script.js?script-head-import-defer-dynamic').then(module => {});
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/importer_async.js b/testing/web-platform/tests/resource-timing/resources/importer_async.js
new file mode 100644
index 0000000000..4b1cd4ddae
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/importer_async.js
@@ -0,0 +1,2 @@
+import './fake_responses.py?url=empty_script.js?script-head-import-async';
+import('./fake_responses.py?url=empty_script.js?script-head-import-async-dynamic').then(module => {});
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/importer_dynamic.css b/testing/web-platform/tests/resource-timing/resources/importer_dynamic.css
new file mode 100644
index 0000000000..f0ba069f0c
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/importer_dynamic.css
@@ -0,0 +1 @@
+@import 'empty_style.css?stylesheet-imported-dynamic'
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/importer_print.css b/testing/web-platform/tests/resource-timing/resources/importer_print.css
new file mode 100644
index 0000000000..aac191635e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/importer_print.css
@@ -0,0 +1 @@
+@import 'empty_style.css?stylesheet-imported-print'
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/inject_resource_test.html b/testing/web-platform/tests/resource-timing/resources/inject_resource_test.html
new file mode 100644
index 0000000000..44d09675d3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/inject_resource_test.html
@@ -0,0 +1,7 @@
+<body>
+<script>
+if(window.parent.setup_iframe) {
+  window.parent.setup_iframe();
+}
+</script>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/invalid.jpg b/testing/web-platform/tests/resource-timing/resources/invalid.jpg
new file mode 100644
index 0000000000..81c545efeb
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/invalid.jpg
@@ -0,0 +1 @@
+1234
diff --git a/testing/web-platform/tests/resource-timing/resources/manifest.json b/testing/web-platform/tests/resource-timing/resources/manifest.json
new file mode 100644
index 0000000000..e107c044d5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/manifest.json
@@ -0,0 +1,4 @@
+{
+    "name": "Dummy manifest",
+    "start_url": "/start.html"
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/multi_redirect.py b/testing/web-platform/tests/resource-timing/resources/multi_redirect.py
new file mode 100644
index 0000000000..a5fc5db4ac
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/multi_redirect.py
@@ -0,0 +1,59 @@
+import urllib.parse
+from wptserve.utils import isomorphic_encode
+
+def main(request, response):
+    """Handler that causes multiple redirections. Redirect chain is as follows:
+        1. Initial URL containing multi-redirect.py
+        2. Redirect to cross-origin URL
+        3. Redirect to same-origin URL
+        4. Final URL containing the final same-origin resource.
+    Mandatory parameters:
+    page_origin - The page origin, used for redirection and to set TAO. This is a mandatory parameter.
+    cross_origin - The cross origin used to make this a cross-origin redirect. This is a mandatory parameter.
+    final_resource - Path of the final resource, without origin. This is a mandatory parameter.
+    Optional parameters:
+    tao_steps - Number of redirects for which the TAO header will be present (a number 0 - 3 makes the most sense). Default value is 0.
+    tao_value - The value of the TAO header, when present. Default value is "*".
+    Note that |step| is a parameter used internally for the multi-redirect. It's the step we're at in the redirect chain.
+    """
+    step = 1
+    if b"step" in request.GET:
+        try:
+            step = int(request.GET.first(b"step"))
+        except ValueError:
+            pass
+
+    page_origin = request.GET.first(b"page_origin")
+    cross_origin = request.GET.first(b"cross_origin")
+    final_resource = request.GET.first(b"final_resource")
+
+    tao_value = b"*"
+    if b"tao_value" in request.GET:
+        tao_value = request.GET.first(b"tao_value")
+    tao_steps = 0
+    if b"tao_steps" in request.GET:
+        tao_steps = int(request.GET.first(b"tao_steps"))
+
+    next_tao_steps = tao_steps - 1
+    redirect_url_path = b"/resource-timing/resources/multi_redirect.py?"
+    redirect_url_path += b"page_origin=" + page_origin
+    redirect_url_path += b"&cross_origin=" + cross_origin
+    redirect_url_path += b"&final_resource=" + urllib.parse.quote(final_resource).encode('ascii')
+    redirect_url_path += b"&tao_value=" + tao_value
+    redirect_url_path += b"&tao_steps=" + isomorphic_encode(str(next_tao_steps))
+    redirect_url_path += b"&step="
+    if tao_steps > 0:
+        response.headers.set(b"timing-allow-origin", tao_value)
+
+    if step == 1:
+        # On the first request, redirect to a cross origin URL
+        redirect_url = cross_origin + redirect_url_path + b"2"
+    elif step == 2:
+        # On the second request, redirect to a same origin URL
+        redirect_url = page_origin + redirect_url_path + b"3"
+    else:
+        # On the third request, redirect to a static response
+        redirect_url = page_origin + final_resource
+
+    response.status = 302
+    response.headers.set(b"Location", redirect_url)
diff --git a/testing/web-platform/tests/resource-timing/resources/navigate_back.html b/testing/web-platform/tests/resource-timing/resources/navigate_back.html
new file mode 100644
index 0000000000..345eee1fcc
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/navigate_back.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<script>
+window.onload = function() {history.back();}
+</script>
diff --git a/testing/web-platform/tests/resource-timing/resources/nested-contexts.js b/testing/web-platform/tests/resource-timing/resources/nested-contexts.js
new file mode 100644
index 0000000000..31337ae5da
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/nested-contexts.js
@@ -0,0 +1,87 @@
+let destination = location;
+
+if (location.search == "?cross-site") {
+    const https = destination.protocol.startsWith("https");
+    destination = get_host_info()[https ? 'HTTPS_NOTSAMESITE_ORIGIN' : 'HTTP_NOTSAMESITE_ORIGIN'];
+} else if (location.search == "?crossorigin") {
+    destination =  get_host_info().REMOTE_ORIGIN;
+}
+
+const pre_navigate_url =
+  new URL("/resource-timing/resources/document-that-navigates.html",
+    destination).href;
+const post_navigate_url =
+  new URL("/resource-timing/resources/document-navigated.html",
+    destination).href;
+const pre_refresh_url =
+  new URL("/resource-timing/resources/document-that-refreshes.html",
+    destination).href;
+const post_refresh_url =
+  new URL("/resource-timing/resources/document-refreshed.html",
+    destination).href;
+
+const setup_navigate_or_refresh = (type, pre, post) => {
+  const verify_document_navigate_not_observable = () => {
+    if (performance.getEntriesByName(post).length) {
+      opener.postMessage(`FAIL - ${type} document should not be observable`,
+      `*`);
+
+    }
+
+    opener.postMessage("PASS", "*");
+  }
+  window.addEventListener("message", e => {
+    if (e.data == type) {
+      verify_document_navigate_not_observable();
+    }
+  });
+}
+
+const setup_navigate_test = () => {
+  setup_navigate_or_refresh("navigated", pre_navigate_url, post_navigate_url);
+}
+
+const setup_refresh_test = () => {
+  setup_navigate_or_refresh("refreshed", pre_refresh_url, post_refresh_url);
+}
+
+const setup_back_navigation = pushed_url => {
+  const verify_document_navigate_not_observable = navigated_back => {
+    if (performance.getEntriesByName(post_navigate_url).length) {
+      opener.postMessage("FAIL - navigated document exposed", "*");
+    }
+    if (navigated_back) {
+      opener.postMessage("PASS", "*");
+    }
+  }
+  window.addEventListener("message", e => {
+    if (e.data == "navigated") {
+      verify_document_navigate_not_observable(sessionStorage.navigated);
+      if (sessionStorage.navigated) {
+        delete sessionStorage.navigated;
+      } else {
+        sessionStorage.navigated = true;
+        setTimeout(() => {
+          history.pushState({}, "", pushed_url);
+          location.href="navigate_back.html";
+        }, 0);
+      }
+    }
+  });
+}
+
+const open_test_window = (url, message) => {
+  promise_test(() => {
+    return new Promise((resolve, reject) => {
+      const openee = window.open(url);
+      addEventListener("message", e => {
+        openee.close();
+        if (e.data == "PASS") {
+          resolve();
+        } else {
+          reject(e.data);
+        }
+      });
+    });
+  }, message);
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/nested.css b/testing/web-platform/tests/resource-timing/resources/nested.css
new file mode 100644
index 0000000000..90d61b04ac
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/nested.css
@@ -0,0 +1,10 @@
+@import "resource_timing_test0.css?id=n1";
+
+@font-face {
+    font-family: remoteFont;
+    src: url('/fonts/Ahem.ttf?id=n1');
+}
+ol {
+    font-family: remoteFont;
+    list-style-image: url('blue.png?id=n1');
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html b/testing/web-platform/tests/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html
new file mode 100644
index 0000000000..f47913468b
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/no-entries-for-cross-origin-css-fetched-memory-cache-iframe.sub.html
@@ -0,0 +1,8 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<link rel="stylesheet" href="http://{{hosts[][www1]}}:{{ports[http][1]}}/resource-timing/resources/nested.css">
+</head>
+<body>
+<ol>Some content</ol>
+</body>
diff --git a/testing/web-platform/tests/resource-timing/resources/notify_parent.html b/testing/web-platform/tests/resource-timing/resources/notify_parent.html
new file mode 100644
index 0000000000..c104f3c8f0
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/notify_parent.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<script>
+window.parent.subFrameLoaded();
+</script>
diff --git a/testing/web-platform/tests/resource-timing/resources/object-navigate-back.html b/testing/web-platform/tests/resource-timing/resources/object-navigate-back.html
new file mode 100644
index 0000000000..a746947818
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/object-navigate-back.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing object navigate - back button navigation</title>
+</head>
+<body onunload="/*disable bfcache*/">
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_back_navigation("object-navigate-back.html");
+</script>
+<object id="target" type="text/html"></object>
+<script>
+  target.data = pre_navigate_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/object-navigate.html b/testing/web-platform/tests/resource-timing/resources/object-navigate.html
new file mode 100644
index 0000000000..6b4bb3128e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/object-navigate.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing object navigate</title>
+</head>
+<body>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_navigate_test();
+</script>
+<object id="target" type="text/html"></object>
+<script>
+  target.data = pre_navigate_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/object-refresh.html b/testing/web-platform/tests/resource-timing/resources/object-refresh.html
new file mode 100644
index 0000000000..5c5f60fb06
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/object-refresh.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing object refresh</title>
+</head>
+<body>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="nested-contexts.js"></script>
+<script>
+  setup_refresh_test();
+</script>
+<object id="target" type="text/html"></object>
+<script>
+  target.data = pre_refresh_url;
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/resources/observe-entry.js b/testing/web-platform/tests/resource-timing/resources/observe-entry.js
new file mode 100644
index 0000000000..260b5929a5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/observe-entry.js
@@ -0,0 +1,25 @@
+// Given a resource name, returns a promise that will resolve to the
+// corresponding PerformanceResourceTiming entry. The promise will reject,
+// however, if the PerformanceResourceTiming entry isn't observed within ~2
+// seconds (scaled according to WPT timeout scaling).
+const observe_entry = entry_name => {
+  const entry = new Promise(resolve => {
+    new PerformanceObserver((entry_list, observer) => {
+      for (const entry of entry_list.getEntries()) {
+        if (entry.name.endsWith(entry_name)) {
+          resolve(entry);
+          observer.disconnect();
+          return;
+        }
+      }
+    }).observe({"type": "resource", "buffered": true});
+  });
+  const timeout = new Promise((resolve, reject) => {
+    step_timeout(() => {
+      reject(new Error("observe_entry: timeout"));
+    }, 2000);
+  });
+  // If the entry isn't observed within 2 seconds, assume it will never show
+  // up.
+  return Promise.race([entry, timeout]);
+};
diff --git a/testing/web-platform/tests/resource-timing/resources/preflight.py b/testing/web-platform/tests/resource-timing/resources/preflight.py
new file mode 100644
index 0000000000..f0f6017b47
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/preflight.py
@@ -0,0 +1,9 @@
+def main(request, response):
+  response.headers.set(b"Access-Control-Allow-Origin", b"*")
+  response.headers.set(b"Access-Control-Max-Age", b"0")
+  response.headers.set(b"Timing-Allow-Origin", b"*")
+  # If this script is accessed with the header X-Require-Preflight then the
+  # browser will send a preflight request. Otherwise it won't.
+  if request.method == u'OPTIONS':
+    response.headers.set(b"Access-Control-Allow-Headers",
+        b"X-Require-Preflight")
diff --git a/testing/web-platform/tests/resource-timing/resources/redirect-cors.py b/testing/web-platform/tests/resource-timing/resources/redirect-cors.py
new file mode 100644
index 0000000000..655b862fcd
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/redirect-cors.py
@@ -0,0 +1,22 @@
+def main(request, response):
+    if b"allow_origin" in request.GET:
+      response.headers.set(b"Access-Control-Allow-Origin",
+        request.GET.first(b"allow_origin"))
+
+    if b"timing_allow_origin" in request.GET:
+        response.headers.set(b"Timing-Allow-Origin",
+          request.GET.first(b"timing_allow_origin"))
+
+    # Handle CORS-preflights of non-simple requests.
+    if request.method == 'OPTIONS':
+      response.status = 204
+      requested_method = request.headers.get(b"Access-Control-Request-Method")
+      if requested_method:
+        response.headers.set(b"Access-Control-Allow-Methods", requested_method)
+      requested_headers = request.headers.get(b"Access-Control-Request-Headers")
+      if requested_headers:
+        response.headers.set(b"Access-Control-Allow-Headers", requested_headers)
+    else:
+      location = request.GET.first(b"location")
+      response.status = 302
+      response.headers.set(b"Location", location)
diff --git a/testing/web-platform/tests/resource-timing/resources/redirect-without-location.py b/testing/web-platform/tests/resource-timing/resources/redirect-without-location.py
new file mode 100644
index 0000000000..eef1df858b
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/redirect-without-location.py
@@ -0,0 +1,2 @@
+def main(request, response):
+      response.status = 302
diff --git a/testing/web-platform/tests/resource-timing/resources/resource-loaders.js b/testing/web-platform/tests/resource-timing/resources/resource-loaders.js
new file mode 100644
index 0000000000..37fea16b17
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource-loaders.js
@@ -0,0 +1,174 @@
+const load = {
+
+  cache_bust: path => {
+    let url = new URL(path, location.origin);
+    url.href += (url.href.includes("?")) ? '&' : '?';
+    // The `Number` type in Javascript, when interpreted as an integer, can only
+    // safely represent [-2^53 + 1, 2^53 - 1] without the loss of precision [1].
+    // We do not generate a global value and increment from it, as the increment
+    // might not have enough precision to be reflected.
+    //
+    // [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number
+    url.href += "unique=" + Math.random().toString().substring(2);
+    return url.href;
+  },
+
+  image_with_attrs: async (path, attribute_map) => {
+    return new Promise(resolve => {
+      const img = new Image();
+      for (const key in attribute_map)
+          img[key] = attribute_map[key];
+      img.onload = img.onerror = resolve;
+      img.src = load.cache_bust(path);
+    });
+  },
+
+  // Returns a promise that settles once the given path has been fetched as an
+  // image resource.
+  image: path => {
+    return load.image_with_attrs(path, undefined);
+  },
+
+  // Returns a promise that settles once the given path has been fetched as an
+  // image resource.
+  image_cors: path => load.image_with_attrs(path, {crossOrigin: "anonymous"}),
+
+  // Returns a promise that settles once the given path has been fetched as a
+  // font resource.
+  font: path => {
+    const div = document.createElement('div');
+    div.innerHTML = `
+      <style>
+      @font-face {
+          font-family: ahem;
+          src: url('${load.cache_bust(path)}');
+      }
+      </style>
+      <div style="font-family: ahem;">This fetches ahem font.</div>
+    `;
+    document.body.appendChild(div);
+    return document.fonts.ready.then(() => {
+      document.body.removeChild(div);
+    });
+  },
+
+  stylesheet_with_attrs: async (path, attribute_map) => {
+    const link = document.createElement("link");
+    if (attribute_map instanceof Object) {
+      for (const [key, value] of Object.entries(attribute_map)) {
+        link[key] = value;
+      }
+    }
+    link.rel = "stylesheet";
+    link.type = "text/css";
+    link.href = load.cache_bust(path);
+
+    const loaded = new Promise(resolve => {
+      link.onload = link.onerror = resolve;
+    });
+
+    document.head.appendChild(link);
+    await loaded;
+    document.head.removeChild(link);
+  },
+
+  // Returns a promise that settles once the given path has been fetched as a
+  // stylesheet resource.
+  stylesheet: async path => {
+    return load.stylesheet_with_attrs(path, undefined);
+  },
+
+  iframe_with_attrs: async (path, attribute_map, validator, skip_wait_for_navigation) => {
+    const frame = document.createElement("iframe");
+    if (attribute_map instanceof Object) {
+      for (const [key, value] of Object.entries(attribute_map)) {
+        frame[key] = value;
+      }
+    }
+    const loaded = new Promise(resolve => {
+      frame.onload = frame.onerror = resolve;
+    });
+    frame.src = load.cache_bust(path);
+    document.body.appendChild(frame);
+    if ( !skip_wait_for_navigation ) {
+      await loaded;
+    }
+    if (validator instanceof Function) {
+      validator(frame);
+    }
+    // since we skipped the wait for load animation, we cannot
+    // remove the iframe here since the request could get cancelled
+    if ( !skip_wait_for_navigation ) {
+      document.body.removeChild(frame);
+    }
+  },
+
+  // Returns a promise that settles once the given path has been fetched as an
+  // iframe.
+  iframe: async (path, validator) => {
+    return load.iframe_with_attrs(path, undefined, validator);
+  },
+
+  script_with_attrs: async (path, attribute_map) => {
+    const script = document.createElement("script");
+    if (attribute_map instanceof Object) {
+      for (const [key, value] of Object.entries(attribute_map)) {
+        script[key] = value;
+      }
+    }
+    const loaded = new Promise(resolve => {
+      script.onload = script.onerror = resolve;
+    });
+    script.src = load.cache_bust(path);
+    document.body.appendChild(script);
+    await loaded;
+    document.body.removeChild(script);
+  },
+
+  // Returns a promise that settles once the given path has been fetched as a
+  // script.
+  script: async path => {
+    return load.script_with_attrs(path, undefined);
+  },
+
+  // Returns a promise that settles once the given path has been fetched as an
+  // object.
+  object: async (path, type) => {
+    const object = document.createElement("object");
+    const object_load_settled = new Promise(resolve => {
+      object.onload = object.onerror = resolve;
+    });
+    object.data = load.cache_bust(path);
+    if (type) {
+      object.type = type;
+    }
+    document.body.appendChild(object);
+    await await_with_timeout(2000,
+      "Timeout was reached before load or error events fired",
+      object_load_settled,
+      () => { document.body.removeChild(object) }
+    );
+  },
+
+  // Returns a promise that settles once the given path has been fetched
+  // through a synchronous XMLHttpRequest.
+  xhr_sync: async (path, headers) => {
+    const xhr = new XMLHttpRequest;
+    xhr.open("GET", path, /* async = */ false);
+    if (headers instanceof Object) {
+      for (const [key, value] of Object.entries(headers)) {
+        xhr.setRequestHeader(key, value);
+      }
+    }
+    xhr.send();
+  },
+
+  xhr_async: path => {
+    const xhr = new XMLHttpRequest();
+    xhr.open("GET", path)
+    xhr.send();
+    return new Promise(resolve => {
+      xhr.onload = xhr.onerror = resolve;
+    });
+  }
+};
diff --git a/testing/web-platform/tests/resource-timing/resources/resource-timing-content-length.py b/testing/web-platform/tests/resource-timing/resources/resource-timing-content-length.py
new file mode 100644
index 0000000000..687689e272
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource-timing-content-length.py
@@ -0,0 +1,20 @@
+def main(request, response):
+    content = request.GET.first(b"content")
+    length = request.GET.first(b"length").decode("ascii")
+    response.add_required_headers = False
+
+    output =  b"HTTP/1.1 200 OK\r\n"
+    output += b"Content-Type: text/plain;charset=UTF-8\r\n"
+    output += b"Connection: close\r\n"
+    if length == b"auto" :
+        output += b"Content-Length:"
+        output += "{0}".format(len(content)).encode("ascii")
+        output += b"\r\n"
+    elif length != b"none" :
+        output += b"Content-Length:"
+        output += "{0}".format(length).encode("ascii")
+        output += b"\r\n"
+    output += b"\r\n"
+    output += content
+    response.writer.write(output)
+    response.close_connection = True
diff --git a/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.css b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.css
new file mode 100644
index 0000000000..8bc8326ba6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.css
@@ -0,0 +1,4 @@
+div#resource_link_css
+{
+    color:hotpink;
+}
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.html b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.html
new file mode 100644
index 0000000000..167c65c5c4
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>
+        Child Frame
+        </title>
+    </head>
+    <body style="background-color: #C0C0C0">
+
+        <h1>
+        Child Document
+        </h1>
+
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.js b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.js
new file mode 100644
index 0000000000..cf1c1df392
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.js
@@ -0,0 +1,3 @@
+// This is a test script for purposes of testing the
+// script initiator type in the Resource Timing feature
+var testDummyValue = 0;
diff --git a/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.js.headers b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.js.headers
new file mode 100644
index 0000000000..308bee94d0
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.js.headers
@@ -0,0 +1,2 @@
+Content-Type: text/javascript
+Cache-Control: max-age=36000
diff --git a/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.png b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.png
new file mode 100644
index 0000000000..be211bc377
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.png
diff --git a/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.xml b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.xml
new file mode 100644
index 0000000000..91cd676be6
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/resource_timing_test0.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<TESTDATA>
+    <ITEM>
+        <DATA>Test XML Data</DATA>
+    </ITEM>
+</TESTDATA>
diff --git a/testing/web-platform/tests/resource-timing/resources/self_navigation.html b/testing/web-platform/tests/resource-timing/resources/self_navigation.html
new file mode 100644
index 0000000000..beb12f5da5
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/self_navigation.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=notify_parent.html?redirected">
diff --git a/testing/web-platform/tests/resource-timing/resources/shared-worker.js b/testing/web-platform/tests/resource-timing/resources/shared-worker.js
new file mode 100644
index 0000000000..f3ef3feb96
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/shared-worker.js
@@ -0,0 +1,3 @@
+self.onconnect = e => {
+  e.ports[0].postMessage(performance.timeOrigin);
+}
+\ No newline at end of file
diff --git a/testing/web-platform/tests/resource-timing/resources/sizes-helper.js b/testing/web-platform/tests/resource-timing/resources/sizes-helper.js
new file mode 100644
index 0000000000..86336686b3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/sizes-helper.js
@@ -0,0 +1,16 @@
+// Header size is a fixed constant.
+// https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-transfersize
+const headerSize = 300;
+
+const cacheBustUrl = url => {
+  return url + '&unique=' + Math.random().toString().substring(2);
+}
+
+const checkSizeFields = (entry, bodySize, transferSize) => {
+  assert_equals(entry.decodedBodySize, bodySize,
+                'decodedBodySize');
+  assert_equals(entry.encodedBodySize, bodySize,
+                'encodedBodySize');
+  assert_equals(entry.transferSize, transferSize,
+                'transferSize');
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/status-code.py b/testing/web-platform/tests/resource-timing/resources/status-code.py
new file mode 100644
index 0000000000..1c6a021633
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/status-code.py
@@ -0,0 +1,8 @@
+def main(request, response):
+    status = request.GET.first(b'status')
+    response.status = (status, b"");
+    if b'tao_value' in request.GET:
+      response.headers.set(b'timing-allow-origin', request.GET.first(b'tao_value'))
+    if b'allow_origin' in request.GET:
+      response.headers.set(b'access-control-allow-origin', request.GET.first(b'allow_origin'))
+
diff --git a/testing/web-platform/tests/resource-timing/resources/sw-install.html b/testing/web-platform/tests/resource-timing/resources/sw-install.html
new file mode 100644
index 0000000000..3d1407e831
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/sw-install.html
@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<script>
+const service_worker_unregister = async scope => {
+  const absoluteScope = new URL(scope, window.location).href;
+  const registration = await navigator.serviceWorker.getRegistration(scope);
+  if (registration && registration.scope === absoluteScope) {
+    return registration.unregister();
+  }
+};
+
+const service_worker_reregister = async (url, scope) => {
+  if (!scope || scope.length == 0) {
+    return Promise.reject(new Error('tests must define a scope'));
+  }
+
+  await service_worker_unregister(scope);
+  return navigator.serviceWorker.register(url, {'scope': scope});
+};
+
+const wait_for_state_activated = worker => {
+  if (worker.state === 'activated')
+    return Promise.resolve();
+
+  if (worker.state === 'redundant') {
+    return Promise.reject(new Error('worker is redundant'));
+  }
+
+  return new Promise(function(resolve) {
+    worker.addEventListener('statechange', () => {
+      if (worker.state === 'activated') {
+        resolve();
+      }
+    });
+  });
+};
+
+(async () => {
+  const script = '/resource-timing/resources/sw.js';
+  const scope = '/resource-timing/resources/';
+  const registration = await service_worker_reregister(script, scope);
+  await wait_for_state_activated(registration.installing);
+
+  const opener = window.opener;
+  if (!opener) {
+    return;
+  }
+
+  opener.postMessage("installed", "*");
+  window.addEventListener("message", async e => {
+    if (e.data === "unregister") {
+      await registration.unregister();
+      opener.postMessage("unregistered", "*");
+    }
+  });
+
+})();
+
+</script>
diff --git a/testing/web-platform/tests/resource-timing/resources/sw.js b/testing/web-platform/tests/resource-timing/resources/sw.js
new file mode 100644
index 0000000000..4e4fe1e1f0
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/sw.js
@@ -0,0 +1,3 @@
+self.addEventListener('fetch', function(event) {
+  event.respondWith(fetch(event.request));
+});
diff --git a/testing/web-platform/tests/resource-timing/resources/tao-response.js b/testing/web-platform/tests/resource-timing/resources/tao-response.js
new file mode 100644
index 0000000000..2194c5d43a
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/tao-response.js
@@ -0,0 +1,13 @@
+const tao_response = (tao_value, base_url) => {
+  const payload = {
+    'headers': {
+      'Timing-Allow-Origin': tao_value
+    }
+  };
+  return custom_cors_response(payload, base_url);
+};
+
+const remote_tao_response = tao_value => {
+  const {REMOTE_ORIGIN} = get_host_info();
+  return tao_response(tao_value, REMOTE_ORIGIN);
+};
diff --git a/testing/web-platform/tests/resource-timing/resources/webperftestharness.js b/testing/web-platform/tests/resource-timing/resources/webperftestharness.js
new file mode 100644
index 0000000000..869ef3d74f
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/webperftestharness.js
@@ -0,0 +1,166 @@
+/*
+author: W3C http://www.w3.org/
+help: http://www.w3.org/TR/navigation-timing/#sec-window.performance-attribute
+*/
+//
+// Helper Functions for ResourceTiming W3C tests
+//
+
+var performanceNamespace = window.performance;
+var timingAttributes = [
+    'connectEnd',
+    'connectStart',
+    'domComplete',
+    'domContentLoadedEventEnd',
+    'domContentLoadedEventStart',
+    'domInteractive',
+    'domLoading',
+    'domainLookupEnd',
+    'domainLookupStart',
+    'fetchStart',
+    'loadEventEnd',
+    'loadEventStart',
+    'navigationStart',
+    'redirectEnd',
+    'redirectStart',
+    'requestStart',
+    'responseEnd',
+    'responseStart',
+    'unloadEventEnd',
+    'unloadEventStart'
+];
+
+var namespace_check = false;
+
+//
+// All test() functions in the WebPerf test suite should use wp_test() instead.
+//
+// wp_test() validates the window.performance namespace exists prior to running tests and
+// immediately shows a single failure if it does not.
+//
+
+function wp_test(func, msg, properties)
+{
+    // only run the namespace check once
+    if (!namespace_check)
+    {
+        namespace_check = true;
+
+        if (performanceNamespace === undefined || performanceNamespace == null)
+        {
+            // show a single error that window.performance is undefined
+            // The window.performance attribute provides a hosting area for performance related attributes.
+            test(function() { assert_true(performanceNamespace !== undefined && performanceNamespace != null, "window.performance is defined and not null"); }, "window.performance is defined and not null.");
+        }
+    }
+
+    test(func, msg, properties);
+}
+
+function test_namespace(child_name, skip_root)
+{
+    if (skip_root === undefined) {
+        var msg = 'window.performance is defined';
+        // The window.performance attribute provides a hosting area for performance related attributes.
+        wp_test(function () { assert_not_equals(performanceNamespace, undefined, msg); }, msg);
+    }
+
+    if (child_name !== undefined) {
+        var msg2 = 'window.performance.' + child_name + ' is defined';
+        // The window.performance attribute provides a hosting area for performance related attributes.
+        wp_test(function() { assert_not_equals(performanceNamespace[child_name], undefined, msg2); }, msg2);
+    }
+}
+
+function test_attribute_exists(parent_name, attribute_name, properties)
+{
+    var msg = 'window.performance.' + parent_name + '.' + attribute_name + ' is defined.';
+    wp_test(function() { assert_not_equals(performanceNamespace[parent_name][attribute_name], undefined, msg); }, msg, properties);
+}
+
+function test_enum(parent_name, enum_name, value, properties)
+{
+    var msg = 'window.performance.' + parent_name + '.' + enum_name + ' is defined.';
+    wp_test(function() { assert_not_equals(performanceNamespace[parent_name][enum_name], undefined, msg); }, msg, properties);
+
+    msg = 'window.performance.' + parent_name + '.' + enum_name + ' = ' + value;
+    wp_test(function() { assert_equals(performanceNamespace[parent_name][enum_name], value, msg); }, msg, properties);
+}
+
+function test_timing_order(attribute_name, greater_than_attribute, properties)
+{
+    // ensure it's not 0 first
+    var msg = "window.performance.timing." + attribute_name + " > 0";
+    wp_test(function() { assert_true(performanceNamespace.timing[attribute_name] > 0, msg); }, msg, properties);
+
+    // ensure it's in the right order
+    msg = "window.performance.timing." + attribute_name + " >= window.performance.timing." + greater_than_attribute;
+    wp_test(function() { assert_true(performanceNamespace.timing[attribute_name] >= performanceNamespace.timing[greater_than_attribute], msg); }, msg, properties);
+}
+
+function test_timing_greater_than(attribute_name, greater_than, properties)
+{
+    var msg = "window.performance.timing." + attribute_name + " > " + greater_than;
+    test_greater_than(performanceNamespace.timing[attribute_name], greater_than, msg, properties);
+}
+
+function test_timing_equals(attribute_name, equals, msg, properties)
+{
+    var test_msg = msg || "window.performance.timing." + attribute_name + " == " + equals;
+    test_equals(performanceNamespace.timing[attribute_name], equals, test_msg, properties);
+}
+
+//
+// Non-test related helper functions
+//
+
+function sleep_milliseconds(n)
+{
+    var start = new Date().getTime();
+    while (true) {
+        if ((new Date().getTime() - start) >= n) break;
+    }
+}
+
+//
+// Common helper functions
+//
+
+function test_true(value, msg, properties)
+{
+    wp_test(function () { assert_true(value, msg); }, msg, properties);
+}
+
+function test_equals(value, equals, msg, properties)
+{
+    wp_test(function () { assert_equals(value, equals, msg); }, msg, properties);
+}
+
+function test_greater_than(value, greater_than, msg, properties)
+{
+    wp_test(function () { assert_true(value > greater_than, msg); }, msg, properties);
+}
+
+function test_greater_or_equals(value, greater_than, msg, properties)
+{
+    wp_test(function () { assert_true(value >= greater_than, msg); }, msg, properties);
+}
+
+function test_not_equals(value, notequals, msg, properties)
+{
+    wp_test(function() { assert_not_equals(value, notequals, msg); }, msg, properties);
+}
+
+function test_tao_pass(entry) {
+    test_greater_than(entry.redirectStart, 0, 'redirectStart > 0 in cross-origin redirect with Timing-Allow-Origin.');
+    test_greater_than(entry.redirectEnd, 0, 'redirectEnd > 0 in cross-origin redirect with Timing-Allow-Origin.');
+    test_greater_than(entry.fetchStart, 0, 'fetchStart > 0 in cross-origin redirect with Timing-Allow-Origin.');
+    test_greater_than(entry.fetchStart, entry.startTime, 'startTime < fetchStart in cross-origin redirect with Timing-Allow-Origin.');
+}
+
+function test_tao_fail(entry) {
+    test_equals(entry.redirectStart, 0, 'redirectStart == 0 in cross-origin redirect with failing Timing-Allow-Origin.');
+    test_equals(entry.redirectEnd, 0, 'redirectEnd == 0 in cross-origin redirect with failing Timing-Allow-Origin.');
+    test_greater_than(entry.fetchStart, 0, 'fetchStart > 0 in cross-origin redirect with failing Timing-Allow-Origin.');
+    test_equals(entry.fetchStart, entry.startTime, 'startTime == fetchStart in cross-origin redirect with failing Timing-Allow-Origin.');
+}
diff --git a/testing/web-platform/tests/resource-timing/resources/webperftestharnessextension.js b/testing/web-platform/tests/resource-timing/resources/webperftestharnessextension.js
new file mode 100644
index 0000000000..dc02c075b3
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/webperftestharnessextension.js
@@ -0,0 +1,188 @@
+//
+// Helper functions for Resource Timing tests
+//
+
+var mark_names = [
+    '',
+    '1',
+    'abc',
+];
+
+var measures = [
+    [''],
+    ['2', 1],
+    ['aaa', 'navigationStart', ''],
+];
+
+function test_method_exists(method, method_name, properties)
+{
+    var msg;
+    if (typeof method === 'function')
+        msg = 'performance.' + method.name + ' is supported!';
+    else
+        msg = 'performance.' + method_name + ' is supported!';
+    wp_test(function() { assert_equals(typeof method, 'function', msg); }, msg, properties);
+}
+
+function test_noless_than(value, greater_than, msg, properties)
+{
+    wp_test(function () { assert_true(value >= greater_than, msg); }, msg, properties);
+}
+
+function test_fail(msg, properties)
+{
+    wp_test(function() { assert_unreached(); }, msg, properties);
+}
+
+function test_resource_entries(entries, expected_entries)
+{
+    test(function() {
+        // This is slightly convoluted so that we can sort the output.
+        var actual_entries = {};
+        var origin = window.location.protocol + "//" + window.location.host;
+
+        for (var i = 0; i < entries.length; ++i) {
+            var entry = entries[i];
+            var found = false;
+            for (var expected_entry in expected_entries) {
+                if (entry.name == origin + expected_entry) {
+                    found = true;
+                    if (expected_entry in actual_entries) {
+                        assert_unreached(expected_entry + ' is not expected to have duplicate entries');
+                    }
+                    actual_entries[expected_entry] = entry;
+                    break;
+                }
+            }
+            if (!found) {
+                assert_unreached(entries[i].name + ' is not expected to be in the Resource Timing buffer');
+            }
+        }
+
+        sorted_urls = [];
+        for (var i in actual_entries) {
+            sorted_urls.push(i);
+        }
+        sorted_urls.sort();
+        for (var i in sorted_urls) {
+            var url = sorted_urls[i];
+            assert_equals(actual_entries[url].initiatorType,
+                        expected_entries[url],
+                        origin + url + ' is expected to have initiatorType ' + expected_entries[url]);
+        }
+        for (var j in expected_entries) {
+            if (!(j in actual_entries)) {
+                assert_unreached(origin + j + ' is expected to be in the Resource Timing buffer');
+            }
+        }
+    }, "Testing resource entries");
+}
+
+function performance_entrylist_checker(type)
+{
+    var entryType = type;
+
+    function entry_check(entry, expectedNames)
+    {
+        var msg = 'Entry \"' + entry.name + '\" should be one that we have set.';
+        wp_test(function() { assert_in_array(entry.name, expectedNames, msg); }, msg);
+        test_equals(entry.entryType, entryType, 'entryType should be \"' + entryType + '\".');
+        if (type === "measure") {
+            test_true(isFinite(entry.startTime), 'startTime should be a number.');
+            test_true(isFinite(entry.duration), 'duration should be a number.');
+        } else if (type === "mark") {
+            test_greater_than(entry.startTime, 0, 'startTime should greater than 0.');
+            test_equals(entry.duration, 0, 'duration of mark should be 0.');
+        }
+    }
+
+    function entrylist_order_check(entryList)
+    {
+        var inOrder = true;
+        for (var i = 0; i < entryList.length - 1; ++i)
+        {
+            if (entryList[i + 1].startTime < entryList[i].startTime) {
+                inOrder = false;
+                break;
+            }
+        }
+        return inOrder;
+    }
+
+    function entrylist_check(entryList, expectedLength, expectedNames)
+    {
+        test_equals(entryList.length, expectedLength, 'There should be ' + expectedLength + ' entries.');
+        test_true(entrylist_order_check(entryList), 'Entries in entrylist should be in order.');
+        for (var i = 0; i < entryList.length; ++i)
+        {
+            entry_check(entryList[i], expectedNames);
+        }
+    }
+
+    return{"entrylist_check":entrylist_check};
+}
+
+function PerformanceContext(context)
+{
+    this.performanceContext = context;
+}
+
+PerformanceContext.prototype = {
+    initialMeasures: function(item, index, array)
+    {
+        this.performanceContext.measure.apply(this.performanceContext, item);
+    },
+
+    mark: function()
+    {
+        this.performanceContext.mark.apply(this.performanceContext, arguments);
+    },
+
+    measure: function()
+    {
+        this.performanceContext.measure.apply(this.performanceContext, arguments);
+    },
+
+    clearMarks: function()
+    {
+        this.performanceContext.clearMarks.apply(this.performanceContext, arguments);
+
+    },
+
+    clearMeasures: function()
+    {
+        this.performanceContext.clearMeasures.apply(this.performanceContext, arguments);
+
+    },
+
+    getEntries: function()
+    {
+        return this.performanceContext.getEntries.apply(this.performanceContext, arguments);
+    },
+
+    getEntriesByType: function()
+    {
+        return this.performanceContext.getEntriesByType.apply(this.performanceContext, arguments);
+    },
+
+    getEntriesByName: function()
+    {
+        return this.performanceContext.getEntriesByName.apply(this.performanceContext, arguments);
+    },
+
+    setResourceTimingBufferSize: function()
+    {
+        return this.performanceContext.setResourceTimingBufferSize.apply(this.performanceContext, arguments);
+    },
+
+    registerResourceTimingBufferFullCallback: function(func)
+    {
+        this.performanceContext.onresourcetimingbufferfull = func;
+    },
+
+    clearResourceTimings: function()
+    {
+        this.performanceContext.clearResourceTimings.apply(this.performanceContext, arguments);
+    }
+
+};
diff --git a/testing/web-platform/tests/resource-timing/resources/worker_with_images.js b/testing/web-platform/tests/resource-timing/resources/worker_with_images.js
new file mode 100644
index 0000000000..1fa4893201
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/worker_with_images.js
@@ -0,0 +1,22 @@
+let numComplete = 0;
+
+function checkDone() {
+  ++numComplete;
+  if (numComplete == 2) {
+    const numEntries = performance.getEntries().length;
+    postMessage(numEntries);
+  }
+}
+
+function makeRequest(request) {
+  var xhr = new XMLHttpRequest;
+  xhr.open('get', request, true);
+  xhr.onreadystatechange = function() {
+    if (xhr.readyState == 4) {
+      checkDone();
+    }
+  }
+  xhr.send();
+}
+makeRequest('blue.png');
+makeRequest('resource_timing_test0.png');
diff --git a/testing/web-platform/tests/resource-timing/response-status-code.html b/testing/web-platform/tests/resource-timing/response-status-code.html
new file mode 100644
index 0000000000..3a184c6f01
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/response-status-code.html
@@ -0,0 +1,165 @@
+<!DOCTYPE html>
+<head>
+<meta charset="utf-8" />
+<meta name="timeout" content="long">
+<title>This test validates the response status of resources.</title>
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+</head>
+<body>
+<script>
+const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
+const SAME_ORIGIN = location.origin;
+const status_codes = [
+  200, 203,
+  400, 401, 403, 404,
+  500, 501, 502, 503,
+];
+
+const load_image_object = async path => {
+  return load.object(path, "image/png");
+}
+
+const load_frame_object = async path => {
+  return load.object(path, "text/html");
+}
+
+const load_null_object = async path => {
+  return load.object(path, null);
+}
+
+// Response status for same origin resources is exposed.
+for(const loader of [
+  load.font,
+  load.image,
+  load.script,
+  load.stylesheet,
+  load.xhr_sync,
+  load.xhr_async,
+  load.iframe,
+  load_image_object,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const status of status_codes) {
+    let path = (loader == load.font) ? '/fonts/pass.woff' :
+                                       '/resource-timing/resources/empty.js';
+    path += `?pipe=status(${status})`;
+    attribute_test(
+      loader, new URL(path, ORIGIN),
+      entry => {
+        assert_equals(entry.responseStatus, status,
+          `response status for ${entry.name} should be ${status}`);
+      }
+    );
+  }
+}
+
+// Response status is exposed for CORS requests for cross-origin resources.
+for(const loader of [
+  load.image_with_attrs,
+  load.script_with_attrs,
+  load.stylesheet_with_attrs
+]) {
+  for(const status of status_codes) {
+    const path = `/resource-timing/resources/empty.js?pipe=status(${status})`
+      + `|header(access-control-allow-origin, ${ORIGIN})`;
+    loader_with_crossOrigin_attr = async url => {
+      return loader(url, {"crossOrigin": "anonymous"});
+    }
+    attribute_test(
+      loader_with_crossOrigin_attr, new URL(path, REMOTE_ORIGIN),
+      entry => {
+        assert_equals(entry.responseStatus, status,
+          `response status for ${entry.name} should be ${status}`);
+      }
+    );
+  }
+}
+
+// Response status is 0 when a no-cors request is made for cross origin
+// fonts, images, scripts, stylesheets.
+// Response status is 0 when request's mode is "navigate" and response's
+// URL's origin is not same origin with request's origin. So response
+// status is not exposed for cross origin iframes.
+for(const loader of [
+  load.font,
+  load.image,
+  load.script,
+  load.stylesheet,
+  load.iframe,
+  load_image_object,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const tao of [false, true]) {
+    for(const status of status_codes) {
+      let path = (loader == load.font) ? '/fonts/pass.woff' :
+                                         '/resource-timing/resources/empty.js';
+      path += `?pipe=status(${status})`;
+      if (tao) {
+        path += `|header(timing-allow-origin, *)`;
+      }
+      attribute_test(
+        loader, new URL(path, REMOTE_ORIGIN),
+        entry => {
+          assert_equals(entry.responseStatus, 0,
+            `response status for ${entry.name} should be 0`);
+        }
+      );
+    }
+  }
+}
+
+// Response status for iframes is 0 when cross origin redirects are present
+// Same-Origin => Cross-Origin => Same-Origin => Same-Origin redirect chain
+for(const loader of [
+  load.iframe,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const status of status_codes) {
+    const destUrl =
+      `${SAME_ORIGIN}/resource-timing/resources/multi_redirect.py` +
+        `?page_origin=${SAME_ORIGIN}` +
+        `&cross_origin=${REMOTE_ORIGIN}` +
+        `&final_resource=` +
+        `/resource-timing/resources/empty.js?pipe=status(${status})`;
+    attribute_test(
+      loader, new URL(destUrl),
+      entry => {
+        assert_equals(entry.responseStatus, 0,
+          `response status should be 0 for iframes having cross origin`
+          + ` redirects`);
+      }
+    );
+  }
+}
+
+// Response status for iframes is exposed for same origin redirects
+for(const loader of [
+  load.iframe,
+  load_frame_object,
+  load_null_object
+]) {
+  for(const status of status_codes) {
+    const destUrl = `${SAME_ORIGIN}/resource-timing/resources/redirect-cors.py`
+      + `?location=${SAME_ORIGIN}/resource-timing/resources/empty.js`
+      + `?pipe=status(${status})`;
+    attribute_test(
+      loader, new URL(destUrl),
+      entry => {
+        assert_equals(entry.responseStatus, status,
+          `response status should be exposed for iframes having only same`
+          + ` origin redirects`);
+      }
+    );
+  }
+};
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/same-origin-from-cross-origin-redirect.html b/testing/web-platform/tests/resource-timing/same-origin-from-cross-origin-redirect.html
new file mode 100644
index 0000000000..8740b81b13
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/same-origin-from-cross-origin-redirect.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates resource timing information for a same-origin
+resource fetched through a cross-origin redirect chain.</title>
+<link rel="author" title="Google" href="https://google.com/" />
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+</head>
+<body>
+<script>
+const {HTTP_REMOTE_ORIGIN} = get_host_info();
+let destUrl = `${HTTP_REMOTE_ORIGIN}/resource-timing/resources/multi_redirect.py?`;
+destUrl += `page_origin=http://${document.location.host}`;
+destUrl += `&cross_origin=${HTTP_REMOTE_ORIGIN}`;
+destUrl += `&final_resource=/resource-timing/resources/blank-with-tao.html`;
+
+attribute_test(
+  load.iframe, destUrl,
+  invariants.assert_same_origin_redirected_from_cross_origin_resource,
+  "Verify that cross origin resources' timings are exposed when the final " +
+  "resource at the end of an HTTP redirect chain is same-origin.");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/script-rt-entries.html b/testing/web-platform/tests/resource-timing/script-rt-entries.html
new file mode 100644
index 0000000000..cdd72bd1e2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/script-rt-entries.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing Entry Sequence of Events for Scripts</title>
+<link rel="help" href="https://w3c.github.io/resource-timing/"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+    async_test(t => {
+        const script = document.createElement("script");
+        const url = new URL('resources/empty.js', location.href).toString();
+        script.addEventListener('load', t.step_func(() => {
+            assert_equals(performance.getEntriesByName(url).length, 1);
+            t.done();
+        }));
+        script.src = url;
+        document.body.appendChild(script);
+        t.add_cleanup(() => script.remove());
+    }, "The RT entry for script should be available when the script 'load' event fires");
+
+    async_test(t => {
+        const script = document.createElement("script");
+        const url = new URL('resources/non-existent.js', location.href).toString();
+        script.addEventListener('error', t.step_func(() => {
+            assert_equals(performance.getEntriesByName(url).length, 1);
+            t.done();
+        }));
+        script.src = url;
+        document.body.appendChild(script);
+        t.add_cleanup(() => script.remove());
+    }, "The RT entry for a non-existent script should be available when the script 'error' event fires");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/secure-iframe-in-insecure-context.html b/testing/web-platform/tests/resource-timing/secure-iframe-in-insecure-context.html
new file mode 100644
index 0000000000..87f4711146
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/secure-iframe-in-insecure-context.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/observe-entry.js"></script>
+
+<body>
+</body>
+<script>
+  const { HTTPS_ORIGIN } = get_host_info();
+
+  promise_test(async t => {
+    const iframe = document.createElement('iframe');
+    iframe.src = `${HTTPS_ORIGIN}/resource-timing/resources/200.https.asis?1`;
+    document.body.appendChild(iframe);
+    t.add_cleanup(() => iframe.remove());
+    const entry = await observe_entry(iframe.src);
+    assert_not_equals(entry.secureConnectionStart, 0);
+  }, 'secureConnectionStart is reported for iframes loaded over https in http context');
+
+  promise_test(async t => {
+    const object = document.createElement('object');
+    object.data = `${HTTPS_ORIGIN}/resource-timing/resources/200.https.asis?2`;
+    document.body.appendChild(object);
+    t.add_cleanup(() => object.remove());
+    const entry = await observe_entry(object.data);
+    assert_not_equals(entry.secureConnectionStart, 0);
+  }, 'secureConnectionStart is reported for object documents loaded over https in http context');
+</script>
+
+</html>
diff --git a/testing/web-platform/tests/resource-timing/shared-worker-rt-entry.html b/testing/web-platform/tests/resource-timing/shared-worker-rt-entry.html
new file mode 100644
index 0000000000..194500a095
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/shared-worker-rt-entry.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing Entry for Shared Workers</title>
+<link rel="help" href="https://w3c.github.io/resource-timing/"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/utils.js"></script>
+</head>
+<body>
+<script>
+    promise_test(async () => {
+        const url = new URL(`resources/shared-worker.js?${token()}`, location.href).toString();
+        const worker = new SharedWorker(url, 'name');
+        const {data} = await new Promise(resolve => {
+            worker.port.onmessage = resolve;
+        });
+
+        const timeOrigin = data;
+        const entries = performance.getEntriesByName(url);
+        assert_equals(entries.length, 0, "SharedWorker should not create a ResourceTiming entry");
+    }, "Shared workers should not generate Resource Timing Entries");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/sizes-cache.any.js b/testing/web-platform/tests/resource-timing/sizes-cache.any.js
new file mode 100644
index 0000000000..af70e5a6de
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/sizes-cache.any.js
@@ -0,0 +1,55 @@
+// META: global=window,worker
+// META: script=/resource-timing/resources/sizes-helper.js
+// META: script=/resource-timing/resources/resource-loaders.js
+
+let url = new URL(
+  '/resource-timing/resources/cacheable-and-validated.py' +
+  '?content=loremipsumblablabla',
+  location.href).href;
+const bodySize = 19;
+
+const accumulateEntries = () => {
+  return new Promise(resolve => {
+    const po = new PerformanceObserver(list => {
+      resolve(list);
+    });
+    po.observe({type: "resource", buffered: true});
+  });
+};
+
+const checkResourceSizes = list => {
+  const entries = list.getEntriesByName(url);
+  assert_equals(entries.length, 3, 'Wrong number of entries');
+  let seenCount = 0;
+  for (let entry of entries) {
+    if (seenCount === 0) {
+      // 200 response
+      checkSizeFields(entry, bodySize, bodySize + headerSize);
+    } else if (seenCount === 1) {
+      // from cache
+      checkSizeFields(entry, bodySize, 0);
+    } else if (seenCount === 2) {
+      // 304 response
+      checkSizeFields(entry, bodySize, headerSize);
+    } else {
+      assert_unreached('Too many matching entries');
+    }
+    ++seenCount;
+  }
+};
+
+promise_test(() => {
+  // Use a different URL every time so that the cache behaviour does not
+  // depend on execution order.
+  url = load.cache_bust(url);
+  const eatBody = response => response.arrayBuffer();
+  const mustRevalidate = {headers: {'Cache-Control': 'max-age=0'}};
+  return fetch(url)
+    .then(eatBody)
+    .then(() => fetch(url))
+    .then(eatBody)
+    .then(() => fetch(url, mustRevalidate))
+    .then(eatBody)
+    .then(accumulateEntries)
+    .then(checkResourceSizes);
+}, 'PerformanceResourceTiming sizes caching test');
diff --git a/testing/web-platform/tests/resource-timing/sizes-redirect-img.html b/testing/web-platform/tests/resource-timing/sizes-redirect-img.html
new file mode 100644
index 0000000000..e440029782
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/sizes-redirect-img.html
@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/sizes-helper.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script>
+// Redirects for fetch() always apply CORS rules, whereas normal resources
+// don't, so this test covers extra code paths beyond those covered by
+// resource-timing-sizes-redirect.html.
+
+const baseUrl = new URL('/resource-timing/resources/TAOResponse.py?tao=wildcard&img=true', location.href).href;
+
+const expectedSize = 1010;
+
+const hostInfo = get_host_info();
+
+const redirectUrl = (redirectSourceOrigin, targetUrl) => {
+  return redirectSourceOrigin +
+    '/resource-timing/resources/redirect-cors.py?allow_origin=*&timing_allow_origin=*' +
+    '&location=' + encodeURIComponent(targetUrl);
+};
+
+const verify_entry = entry => {
+  checkSizeFields(entry, expectedSize, expectedSize + headerSize);
+};
+
+attribute_test(load.image, baseUrl,
+  verify_entry,
+  "PerformanceResourceTiming sizes redirect image - direct URL");
+
+attribute_test(load.image,
+  redirectUrl(hostInfo.HTTP_ORIGIN, baseUrl),
+  verify_entry,
+  "PerformanceResourceTiming sizes redirect image - same origin redirect");
+
+attribute_test(load.image_cors,
+  redirectUrl(hostInfo.HTTP_REMOTE_ORIGIN, baseUrl),
+  verify_entry,
+  "PerformanceResourceTiming sizes redirect image - cross origin redirect");
+
+attribute_test(load.image_cors,
+  redirectUrl(hostInfo.HTTP_REMOTE_ORIGIN,
+    redirectUrl(hostInfo.HTTP_ORIGIN, baseUrl)),
+  verify_entry,
+  "PerformanceResourceTiming sizes redirect image - cross origin to same origin redirect");
+
+attribute_test(load.image_cors,
+  redirectUrl(hostInfo.HTTP_ORIGIN,
+    redirectUrl(hostInfo.HTTP_REMOTE_ORIGIN,
+      redirectUrl(hostInfo.HTTP_ORIGIN,
+        baseUrl))),
+  verify_entry,
+  "PerformanceResourceTiming sizes redirect image - same origin to remote " +
+  "origin to same origin redirect");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/sizes-redirect.any.js b/testing/web-platform/tests/resource-timing/sizes-redirect.any.js
new file mode 100644
index 0000000000..e483a4d409
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/sizes-redirect.any.js
@@ -0,0 +1,62 @@
+// META: global=window,worker
+// META: script=/common/get-host-info.sub.js
+// META: script=/resource-timing/resources/sizes-helper.js
+
+const baseUrl =
+  new URL('/resource-timing/resources/TAOResponse.py?tao=wildcard', location.href).href;
+const expectedSize = 4;
+
+const hostInfo = get_host_info();
+performance.clearResourceTimings();
+
+const accumulateEntry = () => {
+  return new Promise(resolve => {
+    const po = new PerformanceObserver(list => {
+      resolve(list);
+    });
+    po.observe({type: "resource", buffered: true});
+  });
+};
+
+const checkResourceSizes = () => {
+  const entries = performance.getEntriesByType('resource');
+  for (let entry of entries) {
+    checkSizeFields(entry, expectedSize, expectedSize + headerSize);
+  }
+}
+
+const redirectUrl = (redirectSourceOrigin, allowOrigin, targetUrl) => {
+  return redirectSourceOrigin +
+    '/resource-timing/resources/redirect-cors.py?allow_origin=' +
+    encodeURIComponent(allowOrigin) +
+    '&timing_allow_origin=*' +
+    '&location=' + encodeURIComponent(targetUrl);
+}
+
+promise_test(() => {
+  // Use a different URL every time so that the cache behaviour does not
+  // depend on execution order.
+  const directUrl = cacheBustUrl(baseUrl);
+  const sameOriginRedirect = redirectUrl(hostInfo.ORIGIN, '*', directUrl);
+  const crossOriginRedirect = redirectUrl(hostInfo.REMOTE_ORIGIN,
+    hostInfo.ORIGIN, directUrl);
+  const mixedRedirect = redirectUrl(hostInfo.REMOTE_ORIGIN,
+    hostInfo.ORIGIN, sameOriginRedirect);
+  const complexRedirect = redirectUrl(hostInfo.ORIGIN,
+    hostInfo.REMOTE_ORIGIN, mixedRedirect);
+  let eatBody = response => response.arrayBuffer();
+  return fetch(directUrl)
+    .then(eatBody)
+    .then(() => fetch(sameOriginRedirect))
+    .then(eatBody)
+    .then(() => fetch(crossOriginRedirect))
+    .then(eatBody)
+    .then(() => fetch(mixedRedirect))
+    .then(eatBody)
+    .then(() => fetch(complexRedirect))
+    .then(eatBody)
+    .then(accumulateEntry)
+    .then(checkResourceSizes);
+}, 'PerformanceResourceTiming sizes Fetch with redirect test');
+
+done();
diff --git a/testing/web-platform/tests/resource-timing/sleep.py b/testing/web-platform/tests/resource-timing/sleep.py
new file mode 100644
index 0000000000..2e803b1b26
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/sleep.py
@@ -0,0 +1,13 @@
+import time
+import timeit
+
+# sleep can be lower than requested value in some platforms: https://bugs.python.org/issue31539
+# We add padding here to compensate for that.
+sleep_padding = 15.0
+
+def sleep_at_least(sleep_in_ms):
+    sleep_until = timeit.default_timer() + (sleep_in_ms / 1E3)
+    time.sleep((sleep_in_ms + sleep_padding) / 1E3)
+    # Check if the padding was sufficient; if not, sleep again.
+    while timeit.default_timer() < sleep_until:
+        time.sleep(sleep_padding / 1E3)
diff --git a/testing/web-platform/tests/resource-timing/status-codes-create-entry.html b/testing/web-platform/tests/resource-timing/status-codes-create-entry.html
new file mode 100644
index 0000000000..cc0cd8ccb8
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/status-codes-create-entry.html
@@ -0,0 +1,40 @@
+<!doctype html>
+<html>
+<head>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<img src="resources/status-code.py?status=200">
+<img src="resources/status-code.py?status=307">
+<img src="resources/status-code.py?status=404">
+<img src="resources/status-code.py?status=502">
+<script src="resources/status-code.py?status=200&script=1"></script>
+<script src="resources/status-code.py?status=307&script=1"></script>
+<script src="resources/status-code.py?status=404&script=1"></script>
+<script src="resources/status-code.py?status=502&script=1"></script>
+<script>
+async_test(t => {
+  window.addEventListener("load", t.step_func_done(() => {
+    const images = document.getElementsByTagName("img");
+    for (let img of images) {
+      const entries = performance.getEntriesByName(img.src);
+      assert_greater_than(entries.length, 0, img.src);
+      assert_greater_than(entries[0].duration, 0, img.src);
+    }
+    const scripts = document.getElementsByTagName("script");
+    let noSrcScriptFound = false;
+    for (let script of scripts) {
+      if (script.src) {
+        const entries = performance.getEntriesByName(script.src);
+        assert_greater_than(entries.length, 0, script.src);
+        assert_greater_than(entries[0].duration, 0, script.src);
+      } else {
+        // Ignore this script, which has no src value. There should only be one such script.
+        assert_false(noSrcScriptFound);
+        noSrcScriptFound = true;
+      }
+    }
+  }));
+}, "Make sure all status codes are reported");
+</script>
diff --git a/testing/web-platform/tests/resource-timing/supported_resource_type.any.js b/testing/web-platform/tests/resource-timing/supported_resource_type.any.js
new file mode 100644
index 0000000000..31e40096dd
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/supported_resource_type.any.js
@@ -0,0 +1,24 @@
+test(() => {
+  if (typeof PerformanceObserver.supportedEntryTypes === "undefined")
+    assert_unreached("supportedEntryTypes is not supported.");
+  assert_true(PerformanceObserver.supportedEntryTypes.includes("resource"),
+    "There should be an entry 'resource' in PerformanceObserver.supportedEntryTypes");
+}, "supportedEntryTypes contains 'resource'.");
+
+if (typeof PerformanceObserver.supportedEntryTypes !== "undefined") {
+  const entryType = "resource";
+  if (PerformanceObserver.supportedEntryTypes.includes(entryType)) {
+    promise_test(async() => {
+      await new Promise((resolve) => {
+        new PerformanceObserver(function (list, observer) {
+          observer.disconnect();
+          resolve();
+        }).observe({entryTypes: [entryType]});
+
+        // Force the PerformanceEntry.
+        // Use `self` for Workers.
+        fetch(self.location.href + "?" + Math.random());
+      })
+    }, `'${entryType}' entries should be observable.`)
+  }
+}
diff --git a/testing/web-platform/tests/resource-timing/test_resource_timing.html b/testing/web-platform/tests/resource-timing/test_resource_timing.html
new file mode 100644
index 0000000000..f4e851abb2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/test_resource_timing.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="UTF-8" />
+        <title>window.performance Resource Timing Entries exist</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="https://w3c.github.io/web-performance/specs/ResourceTiming/Overview.html"/>
+        <script src="/resources/testharness.js"></script>
+        <script src="/resources/testharnessreport.js"></script>
+        <script src="test_resource_timing.js"></script>
+    </head>
+    <body>
+        <h1>Description</h1>
+        <p>
+           NOTE: Due to caching behavior in the browser, it is possible that when revisiting this page, some resources
+           may not have to be fetched from the network.  As a result, the performance timeline will not contain entries
+           for these resources. This test will fail if any entries are missing to ensure that all resources are fetched
+           from the network and entries for these resources exist in the Performance Timeline.  If revisiting this page,
+           please either perform a full reload of the page or clear the cache between visits.
+        </p>
+
+        <div id="log"></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/test_resource_timing.https.html b/testing/web-platform/tests/resource-timing/test_resource_timing.https.html
new file mode 100644
index 0000000000..f4e851abb2
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/test_resource_timing.https.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="UTF-8" />
+        <title>window.performance Resource Timing Entries exist</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="https://w3c.github.io/web-performance/specs/ResourceTiming/Overview.html"/>
+        <script src="/resources/testharness.js"></script>
+        <script src="/resources/testharnessreport.js"></script>
+        <script src="test_resource_timing.js"></script>
+    </head>
+    <body>
+        <h1>Description</h1>
+        <p>
+           NOTE: Due to caching behavior in the browser, it is possible that when revisiting this page, some resources
+           may not have to be fetched from the network.  As a result, the performance timeline will not contain entries
+           for these resources. This test will fail if any entries are missing to ensure that all resources are fetched
+           from the network and entries for these resources exist in the Performance Timeline.  If revisiting this page,
+           please either perform a full reload of the page or clear the cache between visits.
+        </p>
+
+        <div id="log"></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/test_resource_timing.js b/testing/web-platform/tests/resource-timing/test_resource_timing.js
new file mode 100644
index 0000000000..598a727bf8
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/test_resource_timing.js
@@ -0,0 +1,228 @@
+var TEST_ALLOWED_TIMING_DELTA = 20;
+
+var waitTimer;
+var expectedEntries = {};
+
+var initiatorTypes = ["iframe", "img", "link", "script", "xmlhttprequest"];
+
+var tests = {};
+setup(function() {
+    for (var i in initiatorTypes) {
+        var type = initiatorTypes[i];
+        tests[type] = {
+            "entry": async_test("window.performance.getEntriesByName() and window.performance.getEntriesByNameType() return same data (" + type + ")"),
+            "simple_attrs": async_test("PerformanceEntry has correct name, initiatorType, startTime, and duration (" + type + ")"),
+            "timing_attrs": async_test("PerformanceEntry has correct order of timing attributes (" + type + ")"),
+            "network_attrs": async_test("PerformanceEntry has correct network transfer attributes (" + type + ")"),
+            "protocol": async_test("PerformanceEntry has correct protocol attribute (" + type + ")")
+        };
+    }
+});
+
+function resolve(path) {
+    var a = document.createElement("a");
+    a.href = path;
+    return a.href;
+}
+
+onload = function()
+{
+    // check that the Performance Timeline API exists
+    test(function() {
+        assert_idl_attribute(window.performance, "getEntriesByName",
+                             "window.performance.getEntriesByName() is defined");
+    });
+    test(function() {
+        assert_idl_attribute(window.performance, "getEntriesByType",
+                             "window.performance.getEntriesByType() is defined");
+    });
+    test(function() {
+        assert_idl_attribute(window.performance, "getEntries",
+                             "window.performance.getEntries() is defined");
+    });
+
+    var expected_entry;
+    var url;
+    var type;
+    var startTime;
+    var element;
+    var encodedBodySize;
+    var decodedBodySize;
+    for (var i in initiatorTypes) {
+        startTime = window.performance.now();
+        type = initiatorTypes[i];
+        if (type != "xmlhttprequest") {
+            element = document.createElement(type);
+        } else {
+            element = null;
+        }
+        switch (type) {
+        case "iframe":
+            url = resolve("resources/resource_timing_test0.html");
+            element.src = url;
+            encodedBodySize = 215;
+            decodedBodySize = 215;
+            break;
+        case "img":
+            url = resolve("resources/resource_timing_test0.png");
+            element.src = url;
+            encodedBodySize = 249;
+            decodedBodySize = 249;
+            break;
+        case "link":
+            element.rel = "stylesheet";
+            url = resolve("resources/resource_timing_test0.css");
+            element.href = url;
+            encodedBodySize = 44;
+            decodedBodySize = 44;
+            break;
+        case "script":
+            element.type = "text/javascript";
+            url = resolve("resources/resource_timing_test0.js");
+            element.src = url;
+            encodedBodySize = 133;
+            decodedBodySize = 133;
+            break;
+        case "xmlhttprequest":
+            var xmlhttp = new XMLHttpRequest();
+            url = resolve("resources/gzip_xml.py");
+            xmlhttp.open('GET', url, true);
+            xmlhttp.send();
+            encodedBodySize = 112;
+            decodedBodySize = 125;
+            break;
+        }
+
+        expected_entry = {name:url,
+                          startTime: startTime,
+                          initiatorType: type,
+                          encodedBodySize: encodedBodySize,
+                          decodedBodySize: decodedBodySize
+                         };
+
+        switch (type) {
+        case "link":
+            poll_for_stylesheet_load(expected_entry);
+            document.body.appendChild(element);
+            break;
+        case "xmlhttprequest":
+            xmlhttp.onload = (function(entry) {
+                return function (event) {
+                    resource_load(entry);
+                };
+            })(expected_entry);
+            break;
+        default:
+            element.onload = (function(entry) {
+                return function (event) {
+                    resource_load(entry);
+                };
+            })(expected_entry);
+            document.body.appendChild(element);
+        }
+
+    }
+};
+
+function poll_for_stylesheet_load(expected_entry) {
+    var t = tests[expected_entry.initiatorType];
+
+    function inner() {
+        for(var i=0; i<document.styleSheets.length; i++) {
+            var sheet = document.styleSheets[i];
+            if (sheet.href === expected_entry.name) {
+                try {
+                    // try/catch avoids throwing if sheet object exists before it is loaded,
+                    // which is a bug, but not what we are trying to test here.
+                    var hasRules = sheet.cssRules.length > 0;
+                } catch(e) {
+                    hasRules = false;
+                }
+                if (hasRules) {
+                    t["entry"].step_timeout(function() {
+                        resource_load(expected_entry);
+                    }, 200);
+                    return;
+                }
+            }
+        }
+        t["entry"].step_timeout(inner, 100);
+    }
+    inner();
+}
+
+function resource_load(expected)
+{
+    var t = tests[expected.initiatorType];
+
+    t["entry"].step(function() {
+        var entries_by_name = window.performance.getEntriesByName(expected.name);
+        assert_equals(entries_by_name.length, 1, "should have a single entry for each resource (without type)");
+        var entries_by_name_type = window.performance.getEntriesByName(expected.name, "resource");
+        assert_equals(entries_by_name_type.length, 1, "should have a single entry for each resource (with type)");
+        assert_not_equals(entries_by_name, entries_by_name_type, "values should be copies");
+        for (p in entries_by_name[0]) {
+            var assertMethod = assert_equals
+            if (Array.isArray(entries_by_name[0][p]) && Array.isArray(entries_by_name_type[0][p])) {
+              assertMethod = assert_array_equals
+            }
+            assertMethod(entries_by_name[0][p], entries_by_name_type[0][p], "Property " + p + " should match");
+        }
+        this.done();
+    });
+
+    t["simple_attrs"].step(function() {
+        var actual = window.performance.getEntriesByName(expected.name)[0];
+        var expected_type = expected.initiatorType;
+        assert_equals(actual.name, expected.name);
+        assert_equals(actual.initiatorType, expected_type);
+        assert_equals(actual.entryType, "resource");
+        assert_greater_than_equal(actual.startTime, expected.startTime, "startTime is after the script to initiate the load ran");
+        assert_equals(actual.duration, (actual.responseEnd - actual.startTime));
+        this.done();
+    });
+
+    t["timing_attrs"].step(function test() {
+        const entries = window.performance.getEntriesByName(expected.name);
+        assert_equals(entries.length, 1, 'There should be a single matching entry');
+        const actual = entries[0];
+        if (window.location.protocol == "http:") {
+            assert_equals(actual.secureConnectionStart, 0, 'secureConnectionStart should be 0 in http');
+        } else {
+            assert_greater_than(actual.secureConnectionStart, 0, 'secureConnectionStart should not be 0 in https');
+        }
+
+        assert_equals(actual.redirectStart, 0, 'redirectStart should be 0');
+        assert_equals(actual.redirectEnd, 0, 'redirectEnd should be 0');
+        assert_equals(actual.fetchStart, actual.startTime, 'fetchStart is equal to startTime');
+        assert_greater_than_equal(actual.domainLookupStart, actual.fetchStart, 'domainLookupStart after fetchStart');
+        assert_greater_than_equal(actual.domainLookupEnd, actual.domainLookupStart, 'domainLookupEnd after domainLookupStart');
+        assert_greater_than_equal(actual.connectStart, actual.domainLookupEnd, 'connectStart after domainLookupEnd');
+        assert_greater_than_equal(actual.connectEnd, actual.connectStart, 'connectEnd after connectStart');
+        assert_true(actual.secureConnectionStart == 0 || actual.secureConnectionStart <= actual.requestStart,
+            "secureConnectionStart should be either 0 or smaller than/equals to requestStart")
+        assert_greater_than_equal(actual.requestStart, actual.connectEnd, 'requestStart after connectEnd');
+        assert_greater_than_equal(actual.responseStart, actual.requestStart, 'responseStart after requestStart');
+        assert_greater_than_equal(actual.responseEnd, actual.responseStart, 'responseEnd after responseStart');
+        this.done();
+    });
+
+    t["network_attrs"].step(function test() {
+        var actual = window.performance.getEntriesByName(expected.name)[0];
+        assert_equals(actual.encodedBodySize, expected.encodedBodySize, "encodedBodySize size");
+        assert_equals(actual.decodedBodySize, expected.decodedBodySize, "decodedBodySize size");
+
+        // Transfer size will vary from browser to browser based on default headers, etc. This
+        // test verifies that transferSize for uncached resources is greater than on-the-wire
+        // body size.
+        assert_greater_than(actual.transferSize, actual.encodedBodySize, "transferSize size");
+        this.done();
+    });
+
+    t["protocol"].step(function() {
+        var actual = window.performance.getEntriesByName(expected.name)[0];
+        assert_equals(actual.nextHopProtocol, "http/1.1", "expected protocol");
+        this.done();
+    });
+
+}
diff --git a/testing/web-platform/tests/resource-timing/tojson.html b/testing/web-platform/tests/resource-timing/tojson.html
new file mode 100644
index 0000000000..2564b855df
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/tojson.html
@@ -0,0 +1,71 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>This test validates that PerformanceResourceTiming's toJSON method
+       contains all of the entry's attributes.</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help"
+      href="https://www.w3.org/TR/resource-timing-2/#dom-performanceresourcetiming-tojson">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+promise_test(() => {
+  return new Promise((resolve, reject) => {
+    const po = new PerformanceObserver(list => {
+      const entries = list.getEntries();
+      if (entries.length < 1) {
+        throw new Error(`No entries to run the test with.`);
+      }
+      assert_greater_than_equal(entries.length, 1);
+      const entry = entries[0];
+      assert_equals(typeof(entry.toJSON), 'function');
+      const json = entry.toJSON();
+      assert_equals(typeof(json), 'object');
+
+      const performanceResourceTimingKeys = [
+        'name',
+        'entryType',
+        'startTime',
+        'duration',
+        'initiatorType',
+        'nextHopProtocol',
+        'workerStart',
+        'redirectStart',
+        'redirectEnd',
+        'fetchStart',
+        'domainLookupStart',
+        'domainLookupEnd',
+        'connectStart',
+        'connectEnd',
+        'secureConnectionStart',
+        'requestStart',
+        'responseStart',
+        'responseEnd',
+        'transferSize',
+        'encodedBodySize',
+        'decodedBodySize',
+        'renderBlockingStatus',
+        'responseStatus',
+        'contentType',
+      ];
+      for (const key of performanceResourceTimingKeys) {
+        try {
+          assert_false(json[key] === undefined,
+            `entry.toJSON().${key} is undefined`);
+          assert_equals(json[key], entry[key],
+            `entry.toJSON().${key} should match entry.${key}`);
+        } catch(e) {
+          reject(e);
+        }
+      }
+      resolve();
+    });
+    po.observe({type: "resource", buffered: true});
+  });
+}, 'Test toJSON() in PerformanceResourceTiming');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/workerStart-tao-protected.https.html b/testing/web-platform/tests/resource-timing/workerStart-tao-protected.https.html
new file mode 100644
index 0000000000..f54c0f2756
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/workerStart-tao-protected.https.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing - Check that workerStart is TAO protected</title>
+<link rel="author" title="Google" href="http://www.google.com/" />
+<link rel="help"
+  href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="resources/resource-loaders.js"></script>
+</head>
+<body>
+<script>
+
+const {HTTPS_REMOTE_ORIGIN} = get_host_info();
+
+const worker_has_unregistered = new Promise(resolve => {
+  addEventListener("message", e => {
+    if (e.data === "unregistered") {
+      resolve();
+    }
+  });
+});
+
+// Open window to remote origin with a SW install.
+let openee;
+const service_worker_has_installed = new Promise(resolve => {
+  addEventListener("message", e => {
+    if (e.data === 'installed') {
+      resolve();
+    }
+  });
+  openee = window.open(HTTPS_REMOTE_ORIGIN +
+    "/resource-timing/resources/sw-install.html");
+});
+
+const load_after_sw_install = async path => {
+  await service_worker_has_installed;
+  return load.iframe(path);
+}
+
+attribute_test(load_after_sw_install,
+  `${HTTPS_REMOTE_ORIGIN}/resource-timing/resources/green.html`,
+  entry => {
+    assert_equals(entry.workerStart, 0, "workerStart must be zero");
+    invariants.assert_tao_failure_resource(entry);
+  },
+  "A resource from a cross-origin service worker must not expose workerStart " +
+  "when there is a TAO failure");
+
+attribute_test(load_after_sw_install,
+  `${HTTPS_REMOTE_ORIGIN}/resource-timing/resources/blank-with-tao.html`,
+  entry => {
+    assert_greater_than(entry.workerStart, 0,
+      "workerStart must be greater than zero");
+    // TODO(crbug.com/925239): need to add coverage for transferSize,
+    // encoded/decodedBodySize but that's broken right now.
+    // TODO(crbug.com/1171767): need to add coverage for SW-handled resources
+    // that redirect. Should workerStart be non-zero if any piece of the
+    // redirect chain is handled by a SW?
+  },
+  "A resource from a cross-origin service worker must expose workerStart " +
+  "when there is a TAO match");
+
+promise_test(async () => {
+  openee.postMessage("unregister", "*");
+  await worker_has_unregistered;
+  openee.close();
+}, "Not a test - needed to unregister the SW and close its embedder");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/worklet-rt-entries.https.html b/testing/web-platform/tests/resource-timing/worklet-rt-entries.https.html
new file mode 100644
index 0000000000..8ed280be17
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/worklet-rt-entries.https.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>Resource Timing Entry Sequence of Events for Worklets</title>
+<link rel="help" href="https://w3c.github.io/resource-timing/"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+    promise_test(async() => {
+        const url = new URL("/worklets/resources/empty-worklet-script.js", location.href).toString();
+        await CSS.paintWorklet.addModule(url);
+        assert_equals(performance.getEntriesByName(url).length, 1);
+    }, "Worklets should generate Resource Timing Entries");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/resource-timing/xhr-resource-timing.html b/testing/web-platform/tests/resource-timing/xhr-resource-timing.html
new file mode 100644
index 0000000000..6f8f333186
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/xhr-resource-timing.html
@@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset="utf-8" />
+<title>This test validates that a failed cross-origin fetch creates an opaque network timing entry.
+</title>
+<link rel="author" title="Noam Rosenthal" href="noam@webkit.org">
+<link rel="help" href="https://www.w3.org/TR/resource-timing-2/#sec-performanceresourcetiming"/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/resource-loaders.js"></script>
+<script src="resources/entry-invariants.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+</head>
+<body>
+<script>
+const {REMOTE_ORIGIN} = get_host_info();
+
+attribute_test(
+  load.xhr_async, "/common/dummy.xml",
+  invariants.assert_tao_pass_no_redirect_http,
+  "Verify resource timing entry creation for successful XHR");
+
+attribute_test(
+  load.xhr_async, `${REMOTE_ORIGIN}/common/dummy.xml`,
+  invariants.assert_tao_failure_resource,
+    "Verify resource timing entry creation for XHR failing with CORS");
+</script>
+</body>
+\ No newline at end of file
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-07 19:33:14 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-07 19:33:14 +0000
commit	36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree	105e8c98ddea1c1e4784a60a5a6410fa416be2de /testing/web-platform/tests/resource-timing
parent	Initial commit. (diff)
download	firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip