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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 17:32:43 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 17:32:43 +0000
commit6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch)
treea68f146d7fa01f0134297619fbe7e33db084e0aa /testing/web-platform/tests/paint-timing/fcp-only
parentInitial commit. (diff)
downloadthunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.tar.xz
thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.zip
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/buffered-flag.window.js24
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-background-size.html38
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-set.html36
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-two-steps.html44
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-canvas-context.html24
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-image.html49
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-text.html39
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-ensure-update-the-rendering-step.html55
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-gradient.html27
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-iframe.html27
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-ignore-from-subframe.html27
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate-descendant.html39
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate.html29
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale-transition.html30
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale.html40
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-text.html30
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity-descendant.html46
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity.html40
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds-translate.html30
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds.html39
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-display.html32
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-image.html38
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-opacity.html32
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-text.html28
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-visibility.html32
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-svg.html40
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-text-input.html24
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-typographic-pseudo.html32
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-video-frame.html27
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-video-poster.html28
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-whitespace.html45
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/fcp-with-rtl.html31
-rw-r--r--testing/web-platform/tests/paint-timing/fcp-only/svg-in-iframe.html14
33 files changed, 1116 insertions, 0 deletions
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/buffered-flag.window.js b/testing/web-platform/tests/paint-timing/fcp-only/buffered-flag.window.js
new file mode 100644
index 0000000000..5910b6881f
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/buffered-flag.window.js
@@ -0,0 +1,24 @@
+setup({"hide_test_state": true});
+async_test(t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ // First observer creates a second one in the callback to ensure the entry has been dispatched
+ // by the time the second observer begins observing.
+ new PerformanceObserver(entries => {
+ const entry_seen = entries.getEntriesByName('first-contentful-paint').length > 0;
+ // Abort if we have not yet received the entry.
+ if (!entry_seen)
+ return;
+
+ // Second observer requires 'buffered: true' to see the entry.
+ new PerformanceObserver(t.step_func_done(list => {
+ const fcp = list.getEntriesByName('first-contentful-paint');
+ assert_equals(fcp.length, 1, 'Should have an fcp entry');
+ const entry = fcp[0];
+ assert_equals(entry.entryType, 'paint');
+ })).observe({'type': 'paint', buffered: true});
+ }).observe({'entryTypes': ['paint']});
+ // Trigger the first contentful paint entry.
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+ document.body.appendChild(img);
+}, "PerformanceObserver with buffered flag sees previous FCP entry.");
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-background-size.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-background-size.html
new file mode 100644
index 0000000000..25fe986bde
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-background-size.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to background size</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ background-image: url(../resources/circles.png);
+ background-size: 0 0;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ background-size: 100% 100%;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires due to background size.", load_image);
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-set.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-set.html
new file mode 100644
index 0000000000..443cef630b
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-set.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to background image in image-set</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ background-image: -webkit-image-set(url(../resources/circles.png) 1x);
+ background-image: image-set(url(../resources/circles.png) 1x);
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires due to background image in image-set.", load_image);
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-two-steps.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-two-steps.html
new file mode 100644
index 0000000000..89b161f859
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-bg-image-two-steps.html
@@ -0,0 +1,44 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP should fire for background image only when visible</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ }
+
+ /* contentful and preFCP classes are defined in test_fcp script. */
+ #main.preFCP {
+ visibility: hidden;
+ }
+
+ #main.contentful, #main.preFCP {
+ background-image: url(../resources/circles.png);
+ }
+
+ #main.contentful {
+ visibility: visible;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires for background image only when visible.", load_image);
+</script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-canvas-context.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-canvas-context.html
new file mode 100644
index 0000000000..726e4516ee
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-canvas-context.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP when canvas context is created</title>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<canvas id="canvas" width="50" height="50"></canvas>
+<script>
+ setup({"hide_test_state": true});
+ promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await new Promise(r => window.addEventListener('load', r));
+ await assertNoFirstContentfulPaint(t);
+ const canvas = document.getElementById('canvas');
+ const context = canvas.getContext('2d');
+ context.fillRect(0, 0, 100, 100);
+ await assertFirstContentfulPaint(t);
+ }, 'Canvas should count as contentful when context is created');
+</script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-image.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-image.html
new file mode 100644
index 0000000000..e407f68708
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-image.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html class="hide">
+<head>
+<title>Performance Paint Timing Test: Image FCP due to the documentElement's opacity</title>
+<style>
+ html {
+ will-change: opacity;
+ }
+ .hide {
+ opacity: 0;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+// Load the image, add it to the DOM and make sure it's decoded.
+const load_image = () => {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+ document.body.appendChild(img);
+ return img.decode();
+};
+
+const change_opacity = () => {
+ document.documentElement.className = "";
+}
+
+promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await load_image();
+ await assertNoFirstContentfulPaint(t);
+ change_opacity();
+ await waitForAnimationFrames(3);
+ const fcp_entries = performance.getEntriesByName('first-contentful-paint');
+ assert_equals(fcp_entries.length, 1, "Got an FCP entry");
+ const lcp_entries = await new Promise(resolve => {new PerformanceObserver((list) => resolve(list.getEntries())).observe({type: 'largest-contentful-paint', buffered: true})});
+ assert_equals(lcp_entries.length, 1, "Got an LCP entry");
+ // TODO: Rewrite this assertion after the FCP and LCP precision alignment CL is landed. Currently FCP start time has a higher precision than that of LCP. That means, even if the two are intrinsically the same, FCP.startTime will be larger as it has more fractional digits.
+ isLess = fcp_entries[0].startTime < lcp_entries[0].startTime;
+ isEqualToMicrosecond = Math.abs(fcp_entries[0].startTime - lcp_entries[0].startTime) < 0.001;
+ assert_true(isLess || isEqualToMicrosecond, "FCP should be smaller than FCP.");
+}, "Test that FCP after opacity change is not a larger value than LCP");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-text.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-text.html
new file mode 100644
index 0000000000..12384d5585
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-document-opacity-text.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<html class="hide">
+<head>
+<title>Performance Paint Timing Test: Text FCP due to the documentElement's opacity</title>
+<style>
+ html {
+ will-change: opacity;
+ }
+ .hide {
+ opacity: 0;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">This is content that is extremely contentful.</div>
+<script>
+const change_opacity = () => {
+ document.documentElement.className = "";
+}
+
+promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await assertNoFirstContentfulPaint(t);
+ change_opacity();
+ await waitForAnimationFrames(3);
+ const fcp_entries = performance.getEntriesByName('first-contentful-paint');
+ assert_equals(fcp_entries.length, 1, "Got an FCP entry");
+ const lcp_entries = await new Promise(resolve => {new PerformanceObserver((list) => resolve(list.getEntries())).observe({type: 'largest-contentful-paint', buffered: true})});
+ assert_equals(lcp_entries.length, 1, "Got an LCP entry");
+ assert_less_than_equal(fcp_entries[0].startTime, lcp_entries[0].startTime, "LCP is not smaller than FCP");
+}, "Test that FCP after opacity change is not a larger value than LCP");
+</script>
+</body>
+</html>
+
+
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-ensure-update-the-rendering-step.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-ensure-update-the-rendering-step.html
new file mode 100644
index 0000000000..700707de33
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-ensure-update-the-rendering-step.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<head>
+ <title>
+ Ensure the timing is marked during the `update the rendering` step.
+ </title>
+</head>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ position: relative;
+ top: 0;
+ background-image: url(../resources/circles.png);
+ opacity: 0;
+ }
+
+ #main.contentful {
+ opacity: 0.1;
+ }
+</style>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="main"></div>
+<script>
+setup({"hide_test_state": true});
+async_test(function (t) {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ let fired = false;
+ const main = document.getElementById('main');
+ let animationFrameStamps = [];
+ requestAnimationFrame(function frame(stamp) {
+ animationFrameStamps.unshift(stamp);
+ main.className = "contentful";
+ while (performance.now() - stamp <= 5) {
+ /* Busy-wait */
+ }
+ if(!fired)
+ requestAnimationFrame(frame);
+ });
+ new PerformanceObserver(t.step_func(list=>{
+ for (let entry of list.getEntries()) {
+ if (entry.name == "first-contentful-paint") {
+ fired = true;
+ assert_any(assert_approx_equals, entry.startTime, animationFrameStamps, 1, "One of the past requestAnimationFrame should have the same timestamp as paint entry");
+ t.done();
+ }
+ }
+ })).observe({type: "paint"});
+}, 'The first-contentful-paint timestamp should be same as the last RAF');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-gradient.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-gradient.html
new file mode 100644
index 0000000000..c1e147472f
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-gradient.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP should not fire with gradient-only backgrounds</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ background-image: linear-gradient(to bottom, orange, blue);
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ setup({"hide_test_state": true});
+ promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await new Promise(r => window.addEventListener('load', r));
+ await assertNoFirstContentfulPaint(t);
+ }, 'Gradients should not count as contentful');
+</script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-iframe.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-iframe.html
new file mode 100644
index 0000000000..674bcd9121
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-iframe.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<head>
+ <title>
+ Performance Paint Timing Test: Not only the top level document, paints
+ in the iframe should also generate the entry
+ </title>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+setup({"hide_test_state": true});
+async_test(function (t) {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ window.addEventListener('message', t.step_func(e => {
+ if (e.data.entryType == "paint" && e.data.name == "first-contentful-paint") {
+ t.done();
+ }
+ }));
+ const iframe = document.createElement('iframe');
+ iframe.src = '../resources/subframe-painting.html';
+ document.body.appendChild(iframe);
+}, 'Parent frame ignores paint-timing events fired from child image rendering.');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-ignore-from-subframe.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-ignore-from-subframe.html
new file mode 100644
index 0000000000..7083a93db7
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-ignore-from-subframe.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<head>
+ <title>
+ Performance Paint Timing Test: Paints in the iframe should be reported in the iframe
+ and not in the top document
+ </title>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+setup({"hide_test_state": true});
+promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ const iframe = document.createElement('iframe');
+ iframe.src = '../resources/subframe-painting.html';
+ document.body.appendChild(iframe);
+ await new Promise(resolve => window.addEventListener('message', e => {
+ if (e.data.entryType == "paint" && e.data.name == "first-contentful-paint")
+ resolve()
+ }));
+ await assertNoFirstContentfulPaint(t);
+}, 'Parent frame should not fire own paint-timing events for subframes.');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate-descendant.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate-descendant.html
new file mode 100644
index 0000000000..76d459d0f4
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate-descendant.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to 3d revealing of descendants</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ position: relative;
+ top: 0;
+ transform: rotateX(45deg);
+ transform-style: preserve-3d;
+ }
+
+ /*
+ This tests that given multiplication effect of 3d transforms on bounding rect,
+ An element counts as contentful/paintable only when its bounding rect is truly non-empty */
+ #child {
+ transform: rotateX(45deg);
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ transform: none;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+ <div id="child">Text</div>
+</div>
+<script>
+ test_fcp("First contentful paint fires due to its ancestor getting rotating into view.");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate.html
new file mode 100644
index 0000000000..0b7fc325c5
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-3d-rotate.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to 3d rotation into view</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ transform: rotateY(90deg);
+ position: relative;
+ top: 0;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ transform: none;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">Text</div>
+<script>
+ test_fcp("First contentful paint fires due to 3d rotation into view.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale-transition.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale-transition.html
new file mode 100644
index 0000000000..c0c0af0cdb
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale-transition.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP in transition</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ transform: scale(0);
+ transition: transform 1s;
+ position: relative;
+ top: 0;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ transform: scale(1);
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">TEXT</div>
+<script>
+ test_fcp("First contentful paint fires when revealed during transition.");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale.html
new file mode 100644
index 0000000000..4d3a060e85
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-scale.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to scale change</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ transform: scale(0);
+ position: relative;
+ top: 0;
+ background-image: url(../resources/circles.png);
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ transform: none;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires due to scale becoming positive.", load_image)
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-text.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-text.html
new file mode 100644
index 0000000000..e1b38712a6
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-invisible-text.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP should still fire for invisible text</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ visibility: hidden;
+ color: rgba(0, 0, 0, 0);
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ visibility: visible;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+ INVISIBLE
+</div>
+<script>
+ test_fcp("First contentful paint fires due to pseudo-element becoming visible.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity-descendant.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity-descendant.html
new file mode 100644
index 0000000000..8ada49b767
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity-descendant.html
@@ -0,0 +1,46 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to ancestor opacity</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ position: relative;
+ top: 0;
+ }
+
+ #child {
+ opacity: 0;
+ }
+
+ /* contentful and intermediate classes are defined in test_fcp script. */
+ #main.contentful #child {
+ opacity: 1;
+ }
+
+ #main.intermediate #child {
+ opacity: 1;
+ }
+
+ #main.intermediate {
+ opacity: 0;
+ }
+
+ #main.contentful {
+ opacity: 0.5;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+ <div id="child">Text</div>
+</div>
+<script>
+ test_fcp("First contentful paint fires due to its ancestor getting positive opacity.");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity.html
new file mode 100644
index 0000000000..3c6912c4e6
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-opacity.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to opacity</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ position: relative;
+ top: 0;
+ background-image: url(../resources/circles.png);
+ opacity: 0;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ opacity: 0.1;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires due to opacity-revealed element.", load_image);
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds-translate.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds-translate.html
new file mode 100644
index 0000000000..ee7975eec4
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds-translate.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to transform-based intersection with document</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ transform: translate(-1000px);
+ position: relative;
+ top: 0;
+ background-image: url(../resources/circles.png);
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ transform: none;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ test_fcp("First contentful paint fires due to transform-based intersection with document.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds.html
new file mode 100644
index 0000000000..91556e50e0
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-out-of-bounds.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to intersection with document</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: -1000px;
+ position: relative;
+ top: 0;
+ background-image: url(../resources/circles.png);
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful {
+ left: 0px;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main"></div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires due to intersection with document.", load_image)
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-display.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-display.html
new file mode 100644
index 0000000000..50fd626e89
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-display.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to pseudo-element text</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ }
+
+ #main:after {
+ content: "TEXT";
+ display: none;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful:after {
+ display: block;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+</div>
+<script>
+ test_fcp("First contentful paint fires due to pseudo-element text.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-image.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-image.html
new file mode 100644
index 0000000000..d67ae21cd9
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-image.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to pseudo-element image</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful:after {
+ content: url(../resources/circles.png);
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+</div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("First contentful paint fires due to pseudo-element image.", load_image)
+</script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-opacity.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-opacity.html
new file mode 100644
index 0000000000..b209864d5d
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-opacity.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to pseudo-element getting positive opacity</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ }
+
+ #main:after {
+ content: "TEXT";
+ opacity: 0;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful:after {
+ opacity: 0.5;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+</div>
+<script>
+ test_fcp("First contentful paint fires due to pseudo-element getting positive opacity.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-text.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-text.html
new file mode 100644
index 0000000000..ea2105e453
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-text.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to pseudo-element text</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful:after {
+ content: "TEXT"
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+</div>
+<script>
+ test_fcp("First contentful paint fires due to pseudo-element text.")
+</script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-visibility.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-visibility.html
new file mode 100644
index 0000000000..c903c47218
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-pseudo-element-visibility.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to pseudo-element becoming visible</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ }
+
+ #main:after {
+ content: "TEXT";
+ visibility: hidden;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful:after {
+ visibility: visible;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+</div>
+<script>
+ test_fcp("First contentful paint fires due to pseudo-element becoming visible.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-svg.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-svg.html
new file mode 100644
index 0000000000..bcd2372cfc
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-svg.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP with SVG</title>
+<style>
+ #main {
+ width: 100px;
+ height: 100px;
+ left: 0px;
+ position: relative;
+ }
+
+ #circle {
+ display: none;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful #circle {
+ display: block;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+ <svg viewBox="0 0 10 10" xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink">
+ <defs>
+ <circle id="myCircle" cx="5" cy="5" r="4" stroke="blue"/>
+ </defs>
+ <use id="circle" href="#myCircle" fill="green" />
+ </svg>
+</div>
+<script>
+ test_fcp("First contentful paint fires when SVG becomes contentful.")
+</script>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-text-input.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-text-input.html
new file mode 100644
index 0000000000..e50449abbe
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-text-input.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due for non-empty text input</title>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<input id="input" type="text" />
+<script>
+ setup({"hide_test_state": true});
+ promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await new Promise(r => window.addEventListener('load', r));
+ await assertNoFirstContentfulPaint(t);
+ const input = document.getElementById('input');
+ input.setAttribute('value', ' ');
+ await assertNoFirstContentfulPaint(t);
+ input.setAttribute('value', 'value');
+ await assertFirstContentfulPaint(t);
+ }, 'Text input should become contentful when its value is non-empty');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-typographic-pseudo.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-typographic-pseudo.html
new file mode 100644
index 0000000000..5ec62b7d59
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-typographic-pseudo.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP should not fire when all text is hidden due to typographic pseudo-elements</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ }
+
+ #main *::first-letter {
+ opacity: 0;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful *::first-letter {
+ opacity: 1;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+ <div>A</div>
+</div>
+<script>
+ test_fcp("First contentful paint fires only when some of the text is visible, considering ::first-letter.")
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-video-frame.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-video-frame.html
new file mode 100644
index 0000000000..c54648f001
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-video-frame.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to loaded video frame</title>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/common/media.js"></script>
+<video id="video" autoplay></video>
+<script>
+ setup({"hide_test_state": true});
+ promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await new Promise(r => window.addEventListener('load', r));
+ await assertNoFirstContentfulPaint(t);
+ // Set actual video content to trigger FCP.
+ const video = document.getElementById('video');
+ video.src = getVideoURI('/media/test');
+ await new Promise(resolve => {
+ video.oncanplay = resolve;
+ });
+ await assertFirstContentfulPaint(t);
+ }, 'Video should become contentful when first frame is loaded');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-video-poster.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-video-poster.html
new file mode 100644
index 0000000000..e7eeee3f12
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-video-poster.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to loaded video poster</title>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<video id="video" width="50" height="50"></video>
+<script>
+ setup({"hide_test_state": true});
+ promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await new Promise(r => window.addEventListener('load', r));
+ await assertNoFirstContentfulPaint(t);
+ const video = document.getElementById('video');
+ const src = '../resources/circles.png';
+ const image = new Image();
+ image.src = src;
+ video.setAttribute('poster', src);
+ await new Promise(resolve => {
+ image.onload = async () => resolve();
+ })
+ await assertFirstContentfulPaint(t);
+ }, 'Video should become contentful when poster is loaded');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-whitespace.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-whitespace.html
new file mode 100644
index 0000000000..71c72b018a
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-whitespace.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: Whitespace should not count as contentful</title>
+<style>
+ #main {
+ position: relative;
+ width: 100px;
+ height: 100px;
+ background-image: url(../resources/circles.png);
+ background-size: 0 0;
+ }
+
+ #text {
+ display: none;
+ }
+
+ /* contentful class is defined in test_fcp script. */
+ #main.contentful #text{
+ display: block;
+ }
+</style>
+</head>
+<body>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<div id="main">
+ <div id="whitespace"> </div>
+ <div id="text">TEXT</div>
+</div>
+<script>
+ // Load the image into memory first to make sure it's decoded.
+ function load_image() {
+ const img = document.createElement("img");
+ img.src = "../resources/circles.png";
+
+ return new Promise(resolve => {
+ img.onload = async () => resolve();
+ });
+ }
+
+ test_fcp("Whitespace should not count as contentful.", load_image)
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/fcp-with-rtl.html b/testing/web-platform/tests/paint-timing/fcp-only/fcp-with-rtl.html
new file mode 100644
index 0000000000..5541fcbc72
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/fcp-with-rtl.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<head>
+<title>Performance Paint Timing Test: FCP due to direction change</title>
+<style>
+ #text {
+ right: -100px;
+ position: absolute;
+ }
+
+ body {
+ direction: rtl;
+ }
+</style>
+</head>
+<body>
+<script src="../resources/utils.js"></script>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="text">TEXT</div>
+<script>
+ setup({"hide_test_state": true});
+ promise_test(async t => {
+ assert_implements(window.PerformancePaintTiming, "Paint Timing isn't supported.");
+ await new Promise(r => window.addEventListener('load', r));
+ await assertNoFirstContentfulPaint(t);
+ document.body.style.direction = 'ltr'
+ await assertFirstContentfulPaint(t);
+ }, 'FCP should fire when coordinates are negative, if within document scrollable area');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/paint-timing/fcp-only/svg-in-iframe.html b/testing/web-platform/tests/paint-timing/fcp-only/svg-in-iframe.html
new file mode 100644
index 0000000000..230c166cb0
--- /dev/null
+++ b/testing/web-platform/tests/paint-timing/fcp-only/svg-in-iframe.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<title>Performance Paint Timing Test: SVG in iframe does not trigger FCP</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/utils.js"></script>
+<iframe src="../resources/svg.html"></iframe>
+<script>
+ promise_test(async (t) => {
+ await new Promise(resolve => {
+ window.addEventListener("message", resolve);
+ });
+ return assertNoFirstContentfulPaint(t);
+ }, "SVG in an iframe does not trigger FCP in the main frame");
+</script>