diff --git a/testing/web-platform/tests/event-timing/event-timing-bufferbeforeonload.html b/testing/web-platform/tests/event-timing/event-timing-bufferbeforeonload.html
deleted file mode 100644
index 6e38dc8a0062..000000000000
--- a/testing/web-platform/tests/event-timing/event-timing-bufferbeforeonload.html
+++ /dev/null
@@ -1,80 +0,0 @@
-
-
-
-Event Timing: buffer long-latency events before onload
-
-
-
-
-
-
-
-
-
-
diff --git a/testing/web-platform/tests/event-timing/event-timing-crossiframe.html b/testing/web-platform/tests/event-timing/event-timing-crossiframe.html
deleted file mode 100644
index 877901257b4e..000000000000
--- a/testing/web-platform/tests/event-timing/event-timing-crossiframe.html
+++ /dev/null
@@ -1,90 +0,0 @@
-
-
-
-
-
- Event Timing: entries should be observable by its own frame.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
diff --git a/testing/web-platform/tests/event-timing/event-timing-observer-manual.html b/testing/web-platform/tests/event-timing/event-timing-observer-manual.html
deleted file mode 100644
index 9ef7e32a0200..000000000000
--- a/testing/web-platform/tests/event-timing/event-timing-observer-manual.html
+++ /dev/null
@@ -1,79 +0,0 @@
-
-
-
-
- Event Timing: entries should be observable by its own frame.
-
-
-
-
-
Description:
-
-
- The goal of this manual test is to verify that observers that have
- registered "event" entry type can observe the long-latency input events,
- and verify the same behavior within iframe and in cross-frame scenario.
-
-
-
Manual test steps:
-
-
- Step 1: Click the "make busy" button to make main-thread busy for 2 seconds.
-
-
- Step 2: do several clicks on "click while busy" while busy to generate long-latency inputs.
-
-
- Step 3: observe in the "timeline" section that the long-latency clicks are captured by the observer.
-
-
- Step 4: do step 1 to step 3 for the iframe. Observe that the observers only observe input events within its frame.
-
-
-
-
diff --git a/testing/web-platform/tests/event-timing/resources/event-timing-support.js b/testing/web-platform/tests/event-timing/resources/event-timing-support.js
deleted file mode 100644
index 60f4faaf6ed4..000000000000
--- a/testing/web-platform/tests/event-timing/resources/event-timing-support.js
+++ /dev/null
@@ -1,51 +0,0 @@
-function clickOnElement(id, resolve) {
- const element = document.getElementById(id);
- test_driver.click(element).then(resolve);
-}
-
-function mainThreadBusy(duration) {
- const now = performance.now();
- while (performance.now() < now + duration);
-}
-
-// This method should receive an entry of type 'event'. |is_first| is true only
-// when the event also happens to correspond to the first event. In this case,
-// the timings of the 'firstInput' entry should be equal to those of this entry.
-function verifyClickEvent(entry, is_first=false) {
- assert_true(entry.cancelable);
- assert_equals(entry.name, 'mousedown');
- assert_equals(entry.entryType, 'event');
- assert_greater_than(entry.duration, 50,
- "The entry's duration should be greater than 50ms.");
- assert_greater_than(entry.processingStart, entry.startTime,
- "The entry's processingStart should be greater than startTime.");
- assert_greater_than_equal(entry.processingEnd, entry.processingStart,
- "The entry's processingEnd must be at least as large as processingStart.");
- assert_greater_than_equal(entry.duration, entry.processingEnd - entry.startTime,
- "The entry's duration must be at least as large as processingEnd - startTime.");
- if (is_first) {
- const firstInputs = performance.getEntriesByType('firstInput');
- assert_equals(firstInputs.length, 1, 'There should be a single firstInput entry');
- const firstInput = firstInputs[0];
- assert_equals(firstInput.name, entry.name);
- assert_equals(firstInput.entryType, 'firstInput');
- assert_equals(firstInput.startTime, entry.startTime);
- assert_equals(firstInput.duration, entry.duration);
- assert_equals(firstInput.processingStart, entry.processingStart);
- assert_equals(firstInput.processingEnd, entry.processingEnd);
- assert_equals(firstInput.cancelable, entry.cancelable);
- }
-}
-
-function wait() {
- return new Promise((resolve, reject) => {
- step_timeout(resolve, 0);
- });
-}
-
-function clickAndBlockMain(id) {
- return new Promise((resolve, reject) => {
- clickOnElement(id, resolve);
- mainThreadBusy(300);
- });
-}
diff --git a/testing/web-platform/tests/event-timing/resources/slow-image.py b/testing/web-platform/tests/event-timing/resources/slow-image.py
deleted file mode 100644
index 5c2d1b1fc5d8..000000000000
--- a/testing/web-platform/tests/event-timing/resources/slow-image.py
+++ /dev/null
@@ -1,7 +0,0 @@
-import time
-
-def main(request, response):
- # Sleep for 500ms to delay onload.
- time.sleep(0.5)
- response.headers.set("Cache-Control", "no-cache, must-revalidate");
- response.headers.set("Location", "data:image/gif;base64,R0lGODlhAQABAJAAAMjIyAAAACwAAAAAAQABAAACAgQBADs%3D");