From 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Fri, 19 Apr 2024 03:47:29 +0200
Subject: Adding upstream version 115.8.0esr.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../ancestor-throttle-iframe-csp.https.html        |  18 +
 ...ancestor-throttle-iframe-csp.https.html.headers |   2 +
 .../ancestor-throttle-iframe-xfo.https.html        |  18 +
 ...ancestor-throttle-iframe-xfo.https.html.headers |   2 +
 .../resources/ancestor-throttle-inner.https.html   |  33 ++
 .../ancestor-throttle-inner.https.html.headers     |   1 +
 .../resources/ancestor-throttle-nested.https.html  |  22 +
 .../ancestor-throttle-nested.https.html.headers    |   1 +
 .../resources/automatic-beacon-store.py            |  25 +
 .../resources/background-fetch-inner.https.html    |  47 ++
 .../background-fetch-inner.https.html.headers      |   1 +
 .../resources/background-fetch-sw-inner.https.html |  38 ++
 .../background-fetch-sw-inner.https.html.headers   |   1 +
 .../fenced-frame/resources/background-fetch-sw.js  |  36 ++
 .../resources/background-sync-helper.js            |  23 +
 .../resources/background-sync-inner.https.html     |  32 ++
 .../background-sync-inner.https.html.headers       |   1 +
 .../resources/background-sync-sw-inner.https.html  |  41 ++
 .../background-sync-sw-inner.https.html.headers    |   1 +
 .../fenced-frame/resources/background-sync-sw.js   |  21 +
 .../tests/fenced-frame/resources/badging-sw.js     |  23 +
 .../resources/before-unload-inner.html             |  27 ++
 .../resources/before-unload-inner.html.headers     |   1 +
 .../resources/check-header-referrer.py             |  16 +
 .../resources/check-header-sec-fetch-dest.py       |  14 +
 .../client-hints-iframe-inner.sub.https.html       |  11 +
 ...lient-hints-iframe-inner.sub.https.html.headers |   4 +
 .../resources/client-hints-inner.sub.https.html    |  27 ++
 .../client-hints-inner.sub.https.html.headers      |   5 +
 .../client-hints-meta-iframe-inner.sub.https.html  |  15 +
 ...-hints-meta-iframe-inner.sub.https.html.headers |   2 +
 .../client-hints-meta-inner.sub.https.html         |  31 ++
 .../client-hints-meta-inner.sub.https.html.headers |   2 +
 .../fenced-frame/resources/content-index-sw.js     |  28 ++
 .../resources/cookie-access.https.html             |  11 +
 .../resources/cookie-access.https.html.headers     |   1 +
 .../resources/create-credential-inner.https.html   |  38 ++
 .../create-credential-inner.https.html.headers     |   1 +
 .../tests/fenced-frame/resources/create-popup.html |  18 +
 .../resources/create-popup.html.headers            |   1 +
 .../csp-fenced-frame-src-allowed-inner.html        |   7 +
 ...csp-fenced-frame-src-allowed-inner.html.headers |   1 +
 .../csp-fenced-frame-src-blocked-inner.html        |  10 +
 ...csp-fenced-frame-src-blocked-inner.html.headers |   1 +
 .../resources/csp-frame-src-allowed-inner.html     |   7 +
 .../csp-frame-src-allowed-inner.html.headers       |   1 +
 .../resources/csp-frame-src-blocked-inner.html     |   9 +
 .../csp-frame-src-blocked-inner.html.headers       |   1 +
 .../tests/fenced-frame/resources/csp-inner.html    |  37 ++
 .../fenced-frame/resources/csp-inner.html.headers  |   2 +
 .../tests/fenced-frame/resources/csp.png           | Bin 0 -> 4476 bytes
 .../resources/dangling-markup-helper.js            |  15 +
 .../resources/default-enabled-features-helper.js   |  45 ++
 .../default-enabled-features-redirect.https.html   |  32 ++
 ...lt-enabled-features-redirect.https.html.headers |   1 +
 ...nabled-features-subframe-fencedframe.https.html |  21 +
 ...eatures-subframe-fencedframe.https.html.headers |   2 +
 ...ult-enabled-features-subframe-iframe.https.html |  19 +
 ...led-features-subframe-iframe.https.html.headers |   1 +
 .../fenced-frame/resources/download-helper.js      |  29 ++
 .../fenced-frame/resources/download-inner.html     |  34 ++
 .../resources/download-inner.html.headers          |   1 +
 .../tests/fenced-frame/resources/download-stash.py |  28 ++
 .../tests/fenced-frame/resources/dummy.html        |   2 +
 .../tests/fenced-frame/resources/embeddee.html     |   7 +
 .../fenced-frame/resources/embeddee.html.headers   |   1 +
 .../fenced-frame/resources/embedder-policy.js      |  39 ++
 .../tests/fenced-frame/resources/empty-worker.js   |   1 +
 .../fedcm-get-credential-inner.https.html          |  45 ++
 .../fedcm-get-credential-inner.https.html.headers  |   1 +
 .../resources/fence-api-inner.https.html           |  22 +
 .../resources/fence-api-inner.https.html.headers   |   1 +
 .../resources/fenced-frame-loaded.html             |  13 +
 .../resources/fenced-frame-loaded.html.headers     |   1 +
 ...t-ready-for-outermost-document-to-navigate.html |  16 +
 ...for-outermost-document-to-navigate.html.headers |   1 +
 .../resources/fledge-bidding-logic-with-size.js    |  37 ++
 .../fledge-bidding-logic-with-size.js.headers      |   2 +
 .../fenced-frame/resources/fledge-bidding-logic.js |  34 ++
 .../resources/fledge-bidding-logic.js.headers      |   2 +
 .../resources/fledge-decision-logic.js             |  15 +
 .../resources/fledge-decision-logic.js.headers     |   2 +
 ...frame-navigation-inner-create-nested.https.html |  48 ++
 ...vigation-inner-create-nested.https.html.headers |   1 +
 .../frame-navigation-inner-simple.https.html       |  13 +
 ...rame-navigation-inner-simple.https.html.headers |   1 +
 .../frame-with-intersection-observer.html          |  29 ++
 .../frame-with-intersection-observer.html.headers  |   1 +
 .../fenced-frame/resources/gamepad-inner.html      |  13 +
 .../resources/gamepad-inner.html.headers           |   1 +
 .../resources/get-nested-configs-inner.html        |  10 +
 .../get-nested-configs-inner.html.headers          |   1 +
 .../get-nested-configs-nested-iframe.html          |  10 +
 .../get-nested-configs-nested-iframe.html.headers  |   1 +
 .../tests/fenced-frame/resources/get_battery.html  |  17 +
 .../resources/get_battery.html.headers             |   1 +
 .../resources/header-referrer-inner.html           |  40 ++
 .../resources/header-referrer-inner.html.headers   |   1 +
 .../resources/header-secFetchDest-inner.html       |  26 ++
 .../header-secFetchDest-inner.html.headers         |   1 +
 ...rward-should-not-work-in-fenced-tree-inner.html |  45 ++
 ...ould-not-work-in-fenced-tree-inner.html.headers |   1 +
 ...s-replace-do-not-contribute-to-joint-inner.html | 115 +++++
 ...e-do-not-contribute-to-joint-inner.html.headers |   1 +
 ...e-navigation-not-reflected-in-fenced-inner.html |  72 +++
 ...tion-not-reflected-in-fenced-inner.html.headers |   1 +
 ...nore-child-fenced-frame-onload-event-inner.html |  41 ++
 ...ld-fenced-frame-onload-event-inner.html.headers |   1 +
 .../fenced-frame/resources/key-value-store.py      |  46 ++
 .../location-ancestorOrigins-inner.https.html      |  53 +++
 ...cation-ancestorOrigins-inner.https.html.headers |   1 +
 .../navigate-ancestor-destination.https.html       |  17 +
 ...avigate-ancestor-destination.https.html.headers |   1 +
 ...te-ancestor-from-nested-fenced-frame.https.html |  39 ++
 ...tor-from-nested-fenced-frame.https.html.headers |   1 +
 ...navigate-ancestor-from-nested-iframe.https.html |  38 ++
 ...-ancestor-from-nested-iframe.https.html.headers |   1 +
 .../resources/navigate-ancestor-helper.https.html  |  33 ++
 .../navigate-ancestor-helper.https.html.headers    |   1 +
 .../resources/navigate-ancestor-helper.js          |  28 ++
 .../navigate-ancestor-test-runner.https.html       |  76 ++++
 .../resources/navigate-by-name-inner.html          |  45 ++
 .../resources/navigate-by-name-inner.html.headers  |   1 +
 .../navigate-by-name-reporting-helper.html         |  34 ++
 .../navigate-by-name-reporting-helper.html.headers |   1 +
 .../resources/navigate-nested-config.html          |  14 +
 .../resources/navigate-nested-config.html.headers  |   1 +
 .../navigator-keyboard-layout-map-inner.html       |  21 +
 ...avigator-keyboard-layout-map-inner.html.headers |   1 +
 .../resources/navigator-keyboard-lock-inner.html   |  21 +
 .../navigator-keyboard-lock-inner.html.headers     |   1 +
 .../fenced-frame/resources/notification-sw.js      |  20 +
 .../resources/opaque-ad-sizes-utils.js             |  47 ++
 .../fenced-frame/resources/payment-handler-sw.js   |  10 +
 .../resources/permission-api-denied-inner.html     |  15 +
 .../permission-api-denied-inner.html.headers       |   1 +
 .../resources/permission-geolocation-inner.html    |  16 +
 .../permission-geolocation-inner.html.headers      |   1 +
 .../permission-geolocation-test-runner.html        |  24 +
 .../resources/permission-notification-inner.html   |  13 +
 .../permission-notification-inner.html.headers     |   1 +
 .../resources/popup-noopener-destination.html      |  20 +
 .../resources/popup-noopener-inner.html            |  48 ++
 .../resources/popup-noopener-inner.html.headers    |   1 +
 .../fenced-frame/resources/prerender-inner.html    |  20 +
 .../resources/prerender-inner.html.headers         |   1 +
 .../resources/presentation-receiver-inner.html     |  17 +
 .../presentation-receiver-inner.html.headers       |   1 +
 .../resources/remote-context-executor.https.html   |  29 ++
 .../tests/fenced-frame/resources/report-url.html   |   7 +
 .../fenced-frame/resources/report-url.html.headers |   1 +
 .../resources/resize-lock-inner-input.html         |  43 ++
 .../resources/resize-lock-inner-input.html.headers |   1 +
 .../fenced-frame/resources/resize-lock-inner.html  |  23 +
 .../resources/resize-lock-inner.html.headers       |   1 +
 .../tests/fenced-frame/resources/response-204.py   |   4 +
 .../sandbox-mandatory-flags-iframe.sub.html        |  13 +
 .../sandbox-mandatory-flags-inner.sub.html         |   6 +
 .../sandbox-mandatory-flags-inner.sub.html.headers |   1 +
 ...box-mandatory-flags-looser-restriction.sub.html |  14 +
 .../resources/sandboxed-features-inner.sub.html    |  20 +
 .../sandboxed-features-inner.sub.html.headers      |   1 +
 .../sandboxed-features-looser-restriction.sub.html |  19 +
 ...ed-features-looser-restriction.sub.html.headers |   1 +
 .../fenced-frame/resources/sandboxed-features.js   | 126 ++++++
 .../serviceWorker-dedicated-worker-inner.html      |  28 ++
 ...rviceWorker-dedicated-worker-inner.html.headers |   1 +
 .../resources/serviceWorker-dedicated-worker-sw.js |  18 +
 .../serviceWorker-dedicated-worker-sw.js.headers   |   1 +
 .../resources/serviceWorker-dedicated-worker.js    |   8 +
 .../resources/serviceWorker-frameType-inner.html   |  37 ++
 .../serviceWorker-frameType-inner.html.headers     |   1 +
 .../resources/serviceWorker-frameType-nested.html  |  25 +
 .../serviceWorker-frameType-nested.html.headers    |   1 +
 .../resources/serviceWorker-frameType.js           |  19 +
 .../serviceWorker-navigate-inner-success.html      |  11 +
 ...rviceWorker-navigate-inner-success.html.headers |   1 +
 .../resources/serviceWorker-navigate-inner.html    |  16 +
 .../serviceWorker-navigate-inner.html.headers      |   1 +
 .../resources/serviceWorker-navigate.js            |  18 +
 .../resources/serviceWorker-push-sw.js             |  19 +
 .../unique-cookie-partition-inner.https.html       |  42 ++
 ...nique-cookie-partition-inner.https.html.headers |   2 +
 .../tests/fenced-frame/resources/utils.js          | 501 +++++++++++++++++++++
 .../resources/web-bluetooth-inner.html             |  33 ++
 .../resources/web-bluetooth-inner.html.headers     |   1 +
 .../resources/web-nfc-inner.https.html             |  23 +
 .../resources/web-nfc-inner.https.html.headers     |   1 +
 .../fenced-frame/resources/web-share-inner.html    |  21 +
 .../resources/web-share-inner.html.headers         |   1 +
 .../resources/window-frameElement-inner.html       |  14 +
 .../window-frameElement-inner.html.headers         |   1 +
 .../resources/window-navigation-204-inner.html     |  23 +
 .../window-navigation-204-inner.html.headers       |   1 +
 .../resources/window-outer-dimensions-inner.html   |  36 ++
 .../window-outer-dimensions-inner.html.headers     |   1 +
 .../resources/window-parent-inner.html             |  64 +++
 .../resources/window-parent-inner.html.headers     |   1 +
 .../fenced-frame/resources/window-top-inner.html   |  63 +++
 .../resources/window-top-inner.html.headers        |   1 +
 200 files changed, 3754 insertions(+)
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/automatic-beacon-store.py
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-fetch-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-sync-helper.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/background-sync-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/badging-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/check-header-referrer.py
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/check-header-sec-fetch-dest.py
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/content-index-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/create-popup.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/create-popup.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/csp.png
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/dangling-markup-helper.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-helper.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/download-helper.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/download-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/download-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/download-stash.py
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/dummy.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/embeddee.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/embeddee.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/embedder-policy.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/empty-worker.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/get_battery.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/get_battery.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/key-value-store.py
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-test-runner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/notification-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/opaque-ad-sizes-utils.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/payment-handler-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-geolocation-test-runner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/popup-noopener-destination.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/prerender-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/prerender-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/remote-context-executor.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/report-url.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/report-url.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/response-204.py
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-iframe.sub.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-looser-restriction.sub.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/sandboxed-features.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/serviceWorker-push-sw.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/utils.js
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/web-share-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/web-share-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html.headers
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-top-inner.html
 create mode 100644 testing/web-platform/tests/fenced-frame/resources/window-top-inner.html.headers

(limited to 'testing/web-platform/tests/fenced-frame/resources')

diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html
new file mode 100644
index 0000000000..28fadb296c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<script src="utils.js"></script>
+<title>Header Inheritance CSP Reporting Page</title>
+<body>
+<script>
+// This file is embedded in an iframe by ancestor-throttle-inner.https.html
+// which in turn has been embedded in a fenced frame by
+// ancestor-throttle.https.html
+async function init() {
+  const [ancestor_key] = parseKeylist();
+  writeValueToServer(ancestor_key, "loaded");
+}
+
+init();
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html.headers
new file mode 100644
index 0000000000..bb76329b1d
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-csp.https.html.headers
@@ -0,0 +1,2 @@
+Supports-Loading-Mode: fenced-frame
+Content-Security-Policy: frame-ancestors 'self'
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html
new file mode 100644
index 0000000000..267aa076c0
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<script src="utils.js"></script>
+<title>Header Inheritance XFO Reporting Page</title>
+<body>
+<script>
+// This file is embedded in an iframe by ancestor-throttle-inner.https.html
+// which in turn has been embedded in a fenced frame by
+// ancestor-throttle.https.html
+async function init() {
+  const [ancestor_key] = parseKeylist();
+  writeValueToServer(ancestor_key, "loaded");
+}
+
+init();
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html.headers
new file mode 100644
index 0000000000..63d5019c35
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-iframe-xfo.https.html.headers
@@ -0,0 +1,2 @@
+Supports-Loading-Mode: fenced-frame
+X-Frame-Options: SAMEORIGIN
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html
new file mode 100644
index 0000000000..e0977c73f0
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<html>
+<script src="utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<title>Header Inheritance Inner Page</title>
+<body>
+<script>
+// This file is embedded in a fenced frame by ancestor-throttle.https.html.
+// This is an intermediate step that embeds another page in an iframe to check
+// that the child page only checks up to this page's origin when deciding
+// if it should load.
+async function init() {
+  const [ancestor_key, embed_url, cross_origin_iframe] =
+      parseKeylist();
+  // The URL will be ancestor-throttle-iframe-*.https.html
+  let iframe_url;
+  if (cross_origin_iframe == "true") {
+    iframe_url = generateURL(new URL(embed_url,
+        get_host_info().HTTPS_REMOTE_ORIGIN), parseKeylist());
+  } else {
+    iframe_url = generateURL(new URL(embed_url,
+        get_host_info().HTTPS_ORIGIN), parseKeylist());
+  }
+
+  const iframe = document.createElement('iframe');
+  iframe.src = iframe_url;
+  document.body.append(iframe);
+}
+
+init();
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html
new file mode 100644
index 0000000000..a26b7bfdc2
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<script src="utils.js"></script>
+<title>Header Inheritance CSP Reporting Page</title>
+<body>
+<script>
+// This file is embedded in an iframe by ancestor-throttle-inner.https.html
+// which in turn has been embedded in a fenced frame by
+// ancestor-throttle.https.html. This in turn will load a same-origin iframe.
+async function init() {
+  const url = new URL(location.href);
+  const embed_url = generateURL(url.searchParams.get("nested_url"),
+      parseKeylist());
+  const iframe = document.createElement('iframe');
+  iframe.src = embed_url;
+  document.body.append(iframe);
+}
+
+init();
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ancestor-throttle-nested.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/automatic-beacon-store.py b/testing/web-platform/tests/fenced-frame/resources/automatic-beacon-store.py
new file mode 100644
index 0000000000..f783c8530c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/automatic-beacon-store.py
@@ -0,0 +1,25 @@
+"""Automatic beacon store server.
+
+- When a request body is not specified, serves a 200 response whose body
+  contains the stored value from the last automatic beacon. If the stored value
+  doesn't exist, serves a 200 response with an empty body.
+- When a request body is specified, stores the data in the body and serves a 200
+  response without body.
+"""
+# Use an arbitrary key since `request.server.stash.put` expects a valid UUID.
+BEACON_KEY = "0c02dba4-f01e-11ed-a05b-0242ac120003"
+
+def main(request, response):
+    # Requests with a body imply they were sent as an automatic beacon for
+    # reserved.top_navigation. Note that this only stores the most recent beacon
+    # that was sent.
+    if request.body:
+        request.server.stash.put(BEACON_KEY, request.body)
+        return (200, [], b"")
+
+    # Requests without a body imply they were sent as the request from
+    # nextAutomaticBeacon().
+    data = request.server.stash.take(BEACON_KEY)
+    if not data and data != "":
+        return (200, [], b"<Not set>")
+    return (200, [], data)
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html
new file mode 100644
index 0000000000..1bca25a957
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of background fetch</title>
+
+<body>
+  <script>
+    (async function () {
+      const [background_fetch_register_key, method] = parseKeylist();
+      const file = 'background-fetch-inner.https.html.headers';
+
+      navigator.serviceWorker.register("empty-worker.js", { scope: location.href });
+      const registration = await navigator.serviceWorker.ready;
+
+      const url = new URL(location.href);
+
+      let promise;
+      switch (method) {
+        case 'fetch':
+          promise = registration.backgroundFetch.fetch('test-fetch', file);
+          break;
+        case 'get':
+          promise = registration.backgroundFetch.get('test-fetch');
+          break;
+        case 'getIds':
+          promise = registration.backgroundFetch.getIds();
+          break
+        default:
+          promise = Promise.resolve();
+      }
+
+      promise
+        .then(() => {
+          writeValueToServer(background_fetch_register_key,
+            `[backgroundFetch.${method}] Unexpectedly started`);
+        })
+        .catch(() => {
+          writeValueToServer(background_fetch_register_key,
+            `[backgroundFetch.${method}] Failed inside fencedframe as expected`);
+        })
+        .finally(() => {
+          registration.unregister();
+        });
+    })();
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-fetch-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html
new file mode 100644
index 0000000000..78e58e5bbf
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of background fetch in SW</title>
+
+<body>
+  <script type="module">
+      const [background_fetch_register_key, method] = parseKeylist();
+
+      const getController = () => {
+        if (navigator.serviceWorker.controller) {
+          return navigator.serviceWorker.controller;
+        }
+        return new Promise(resolve => {
+          navigator.serviceWorker.addEventListener('controllerchange', () => {
+            resolve(navigator.serviceWorker.controller);
+          });
+        });
+      };
+
+      const sendMessageToServiceWorker = async () => {
+        const ctrl = await getController();
+        return new Promise(resolve => {
+          ctrl.postMessage(method);
+          navigator.serviceWorker.onmessage = e => {
+            resolve(e.data);
+          }
+        });
+      };
+
+      await navigator.serviceWorker.register(
+        "background-fetch-sw.js", { scope: location.href });
+      const data = await sendMessageToServiceWorker();
+
+      writeValueToServer(background_fetch_register_key, data);
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw.js b/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw.js
new file mode 100644
index 0000000000..44b7d087b5
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-fetch-sw.js
@@ -0,0 +1,36 @@
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', async e => {
+  const method = e.data;
+
+  let promise;
+  switch (method) {
+    case 'fetch':
+      promise = self.registration.backgroundFetch.fetch(
+          'test-fetch', ['background-fetch-inner.https.html.headers'],
+          {title: 'Background Fetch'});
+      break;
+    case 'get':
+      promise = self.registration.backgroundFetch.get('test-fetch')
+      break;
+    case 'getIds':
+      promise = registration.backgroundFetch.getIds();
+      break;
+    default:
+      promise = Promise.resolve();
+      break;
+  }
+
+  const message =
+      await promise
+          .then(() => {
+            return `[backgroundFetch.${method}] Unexpectedly started`;
+          })
+          .catch((e) => {
+            return `[backgroundFetch.${
+                method}] Failed inside fencedframe as expected`;
+          });
+
+  e.source.postMessage(message);
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-sync-helper.js b/testing/web-platform/tests/fenced-frame/resources/background-sync-helper.js
new file mode 100644
index 0000000000..78b69f15de
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-sync-helper.js
@@ -0,0 +1,23 @@
+const getOneShotSyncPromise = (registration, method) => {
+  if (method === 'register') {
+    return registration.sync.register('fencedframe-oneshot');
+  } else if (method === 'getTags') {
+    return registration.sync.getTags();
+  }
+  return Promise.resolve();
+};
+
+const getPeriodicSyncPromise = (registration, method) => {
+  if (method === 'register') {
+    return registration.periodicSync.register(
+        'fencedframe-periodic', {minInterval: 1000});
+  } else if (method === 'getTags') {
+    return registration.periodicSync.getTags();
+  } else if (method === 'unregister') {
+    return registration.periodicSync.unregister('fencedframe-periodic');
+  } else {
+    return Promise.resolve();
+  }
+};
+
+export {getOneShotSyncPromise, getPeriodicSyncPromise}
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html
new file mode 100644
index 0000000000..81974c803a
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of background sync's register</title>
+
+<body>
+<script type="module">
+  import {getOneShotSyncPromise, getPeriodicSyncPromise} from './background-sync-helper.js';
+
+  const [background_sync_register_key] = parseKeylist();
+  const searchParams = new URL(location.href).searchParams;
+  const method = searchParams.get('method');
+  const periodic = searchParams.get('periodic');
+
+  navigator.serviceWorker.register("empty-worker.js", { scope: location.href });
+  const registration = await navigator.serviceWorker.ready;
+
+  try {
+    if (periodic) {
+      await getPeriodicSyncPromise(registration, method);
+    } else {
+      await getOneShotSyncPromise(registration, method);
+    }
+    writeValueToServer(background_sync_register_key, "unexpectedly registered");
+  } catch (e) {
+    writeValueToServer(background_sync_register_key, e.message);
+  } finally {
+    registration.unregister();
+  }
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-sync-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html
new file mode 100644
index 0000000000..b9521a4e20
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of background sync's register in SW</title>
+
+<body>
+<script type="module">
+  const [background_sync_register_key] = parseKeylist();
+  const searchParams = new URL(location.href).searchParams;
+  const method = searchParams.get('method');
+  const isPeriodic = searchParams.get('periodic');
+
+  const getController = () => {
+    if (navigator.serviceWorker.controller) {
+      return navigator.serviceWorker.controller;
+    }
+    return new Promise(resolve => {
+      navigator.serviceWorker.addEventListener('controllerchange', () => {
+        resolve(navigator.serviceWorker.controller);
+      });
+    });
+  };
+
+  const sendMessageToServiceWorker = async () => {
+    const ctrl = await getController();
+    return new Promise(resolve => {
+      ctrl.postMessage({method, isPeriodic});
+      navigator.serviceWorker.onmessage = e => {
+        resolve(e.data);
+      }
+    });
+  };
+
+  await navigator.serviceWorker.register(
+    "background-sync-sw.js", { scope: location.href, type: "module" });
+  const data = await sendMessageToServiceWorker();
+
+  writeValueToServer(background_sync_register_key, data);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-sync-sw-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/background-sync-sw.js b/testing/web-platform/tests/fenced-frame/resources/background-sync-sw.js
new file mode 100644
index 0000000000..5b0c791f0d
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/background-sync-sw.js
@@ -0,0 +1,21 @@
+import {getOneShotSyncPromise, getPeriodicSyncPromise} from './background-sync-helper.js';
+
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', async e => {
+  const {method, isPeriodic} = e.data;
+  const promise = isPeriodic ?
+      getPeriodicSyncPromise(self.registration, method) :
+      getOneShotSyncPromise(self.registration, method);
+  const message =
+      await promise
+          .then(() => {
+            return `[background synnc ${method}] Unexpectedly started`;
+          })
+          .catch((e) => {
+            return e.message;
+          });
+
+  e.source.postMessage(message);
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/badging-sw.js b/testing/web-platform/tests/fenced-frame/resources/badging-sw.js
new file mode 100644
index 0000000000..5bc3c9a190
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/badging-sw.js
@@ -0,0 +1,23 @@
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', async e => {
+  const method = e.data;
+
+  let promise;
+  if (method === 'setAppBadge') {
+    promise = self.navigator.setAppBadge(1);
+  } else if (method === 'clearAppBadge') {
+    promise = self.navigator.clearAppBadge();
+  } else {
+    promise = Promise.resolve();
+  }
+
+  const error = await promise
+                      .then(() => {
+                        return `[Badging API ${method}] Unexpectedly started`;
+                      })
+                      .catch((e) => e);
+
+  e.source.postMessage(error);
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html b/testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html
new file mode 100644
index 0000000000..6d23cf88a3
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the beforeunload event is not fired</title>
+
+<body>
+<script>
+window.onload = () => {
+  const [before_unload_key] = parseKeylist();
+  const url = new URL(location.href);
+  const next_url = url.searchParams.get('next_url');
+
+  if (next_url != null) {
+    writeValueToServer(
+        before_unload_key, 'Loaded the next url in a fenced frame');
+    return;
+  }
+
+  window.onbeforeunload = () => {
+    writeValueToServer(
+        before_unload_key, 'The beforeunload event is unexpectely fired.');
+  };
+
+  location.href =
+      generateURL('before-unload-inner.html?next_url', [before_unload_key]);
+};
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/before-unload-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/check-header-referrer.py b/testing/web-platform/tests/fenced-frame/resources/check-header-referrer.py
new file mode 100644
index 0000000000..b06fbc2704
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/check-header-referrer.py
@@ -0,0 +1,16 @@
+import os
+
+from wptserve.utils import isomorphic_decode
+
+
+def main(request, response):
+    response.headers.set(b"supports-loading-mode", b"fenced-frame")
+
+    script = u"""
+        <script src="utils.js"></script>
+        <script>
+            const [referrer_key, _] = parseKeylist();
+            writeValueToServer(referrer_key, "%s")
+        </script>
+    """ % (isomorphic_decode(request.headers.get(b"referer", b"")))
+    return (200, [], script)
diff --git a/testing/web-platform/tests/fenced-frame/resources/check-header-sec-fetch-dest.py b/testing/web-platform/tests/fenced-frame/resources/check-header-sec-fetch-dest.py
new file mode 100644
index 0000000000..98231079b3
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/check-header-sec-fetch-dest.py
@@ -0,0 +1,14 @@
+import os
+
+
+def main(request, response):
+    response.headers.set(b"supports-loading-mode", b"fenced-frame")
+
+    script = u"""
+        <script src="utils.js"></script>
+        <script>
+            const [secfetch_key] = parseKeylist();
+            writeValueToServer(secfetch_key, "%s")
+        </script>
+    """ % (request.headers.get(b"sec-fetch-dest", b"none"))
+    return (200, [], script)
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html b/testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html
new file mode 100644
index 0000000000..d02abd6957
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<title>Client Hint Echoing Iframe</title>
+<body>
+<script>
+window.parent.postMessage({'headers': {
+    'sec-ch-viewport-width': '{{header_or_default(sec-ch-viewport-width, )}}',
+    'sec-ch-ua-reduced': '{{header_or_default(sec-ch-ua-reduced, )}}',
+    'sec-ch-ua-mobile': '{{header_or_default(sec-ch-ua-mobile, )}}',
+}}, '*');
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html.headers
new file mode 100644
index 0000000000..f500a60ae8
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-iframe-inner.sub.https.html.headers
@@ -0,0 +1,4 @@
+Supports-Loading-Mode: fenced-frame
+Accept-CH: sec-ch-viewport-width, sec-ch-ua-reduced
+Feature-Policy: ch-viewport-width *, ch-ua-reduced *
+Access-Control-Allow-Origin: *
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html b/testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html
new file mode 100644
index 0000000000..0271d0290d
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Client Hints Helper</title>
+<body>
+<script type="module">
+const [key] = parseKeylist();
+let iframe = document.createElement('iframe');
+let p = new Promise((resolve, reject) => {
+  window.addEventListener('message', e => {
+    resolve(e.data);
+  });
+});
+iframe.src = 'client-hints-iframe-inner.sub.https.html';
+document.body.appendChild(iframe);
+const response = await p;
+const result = {
+  'root-fenced-frame-headers': {
+    'sec-ch-viewport-width': '{{header_or_default(sec-ch-viewport-width, )}}',
+    'sec-ch-ua-reduced': '{{header_or_default(sec-ch-ua-reduced, )}}',
+    'sec-ch-ua-mobile': '{{header_or_default(sec-ch-ua-mobile, )}}',
+  },
+  'iframe-headers': response.headers,
+};
+writeValueToServer(key, JSON.stringify(result));
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html.headers
new file mode 100644
index 0000000000..ea4cf59d16
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-inner.sub.https.html.headers
@@ -0,0 +1,5 @@
+Supports-Loading-Mode: fenced-frame
+Accept-CH: sec-ch-viewport-width, sec-ch-ua-reduced
+Feature-Policy: ch-viewport-width *, ch-ua-reduced *
+Access-Control-Allow-Origin: *
+
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html
new file mode 100644
index 0000000000..9afb5c6a85
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<meta http-equiv="Accept-CH"
+      content="sec-ch-viewport-width, sec-ch-ua-reduced"/>
+<meta http-equiv="Feature-Policy"
+      content="ch-viewport-width *, ch-ua-reduced *"/>
+<title>Client Hint Echoing Iframe</title>
+<body>
+<script>
+window.parent.postMessage({'headers': {
+    'sec-ch-viewport-width': '{{header_or_default(sec-ch-viewport-width, )}}',
+    'sec-ch-ua-reduced': '{{header_or_default(sec-ch-ua-reduced, )}}',
+    'sec-ch-ua-mobile': '{{header_or_default(sec-ch-ua-mobile, )}}',
+}}, '*');
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html.headers
new file mode 100644
index 0000000000..b7952e5d05
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-iframe-inner.sub.https.html.headers
@@ -0,0 +1,2 @@
+
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html
new file mode 100644
index 0000000000..b84f16ffd0
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<meta http-equiv="Accept-CH"
+      content="sec-ch-viewport-width, sec-ch-ua-reduced"/>
+<meta http-equiv="Feature-Policy"
+      content="ch-viewport-width *, ch-ua-reduced *"/>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Client Hints Helper</title>
+<body>
+<script type="module">
+const [key] = parseKeylist();
+let iframe = document.createElement('iframe');
+let p = new Promise((resolve, reject) => {
+  window.addEventListener('message', e => {
+    resolve(e.data);
+  });
+});
+iframe.src = 'client-hints-meta-iframe-inner.sub.https.html';
+document.body.appendChild(iframe);
+const response = await p;
+const result = {
+  'root-fenced-frame-headers': {
+    'sec-ch-viewport-width': '{{header_or_default(sec-ch-viewport-width, )}}',
+    'sec-ch-ua-reduced': '{{header_or_default(sec-ch-ua-reduced, )}}',
+    'sec-ch-ua-mobile': '{{header_or_default(sec-ch-ua-mobile, )}}',
+  },
+  'iframe-headers': response.headers,
+};
+writeValueToServer(key, JSON.stringify(result));
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html.headers
new file mode 100644
index 0000000000..afe7b4f317
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/client-hints-meta-inner.sub.https.html.headers
@@ -0,0 +1,2 @@
+Supports-Loading-Mode: fenced-frame
+Access-Control-Allow-Origin: *
diff --git a/testing/web-platform/tests/fenced-frame/resources/content-index-sw.js b/testing/web-platform/tests/fenced-frame/resources/content-index-sw.js
new file mode 100644
index 0000000000..c2759d9630
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/content-index-sw.js
@@ -0,0 +1,28 @@
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', async event => {
+  const method = event.data;
+  const {index} = self.registration;
+  const id = 'fenced-frame-id-sw';
+
+  let promise;
+  if (method === 'add') {
+    promise = index.add({
+      id,
+      title: 'same title',
+      description: 'same description',
+      url: 'resources/'
+    });
+  } else if (method === 'delete') {
+    promise = index.delete(id);
+  } else if (method === 'getAll') {
+    promise = index.getAll();
+  } else {
+    promise = Promise.resolve();
+  }
+
+  const message = await promise.then(() => 'success').catch(e => e.message);
+
+  event.source.postMessage(message);
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html b/testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html
new file mode 100644
index 0000000000..34e5681139
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Page loaded in a frame in a fenced frame tree</title>
+<script>
+  // This page is loaded either in an iframe or a fenced frame
+  // nested inside a root fenced frame.
+  document.cookie = 'G=nested_in_fenced_frame; SameSite=Lax';
+  const [cookie_value_key] = parseKeylist()
+  const cookie_value = document.cookie;
+  writeValueToServer(cookie_value_key, cookie_value);
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/cookie-access.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html
new file mode 100644
index 0000000000..5725177f21
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/webauthn/helpers.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of navigator.credentials.create</title>
+
+<body>
+<script>
+function base_path() {
+  return location.pathname.replace(/\/[^\/]*$/, '/');
+}
+
+standardSetup(function() {
+  'use strict';
+  async function init() {
+    // This file is meant to be navigated to from a <fencedframe> element. It
+    // reports back to the page hosting the <fencedframe> whether or not
+    // `navigator.credentials.create` is allowed.
+    const [key] = parseKeylist();
+
+    // Report whether or not `credentials.create` is allowed.
+    createCredential().then(
+        () => {
+          writeValueToServer(key, 'createCredential passed');
+        },
+        () => {
+          writeValueToServer(key, 'createCredential failed');
+        },
+    );
+  }
+
+  init();
+});
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/create-credential-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/create-popup.html b/testing/web-platform/tests/fenced-frame/resources/create-popup.html
new file mode 100644
index 0000000000..a6cd81ec14
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/create-popup.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Nested frames in a Fenced Frame tree creating popups</title>
+<script>
+  // It is the document that `popup-noopener-inner.html` loads in a nested
+  // iframe/fenced frame.
+  // It's expected that the opener/openee references should be null, and
+  // window.name should be the empty string.
+  const [popup_noopener_key, popup_openee_key, popup_name_key] = parseKeylist();
+  const src_popup = generateURL(`popup-noopener-destination.html`,
+      [popup_noopener_key, popup_name_key]);
+  const popup = window.open(src_popup, "foo");
+  if (popup) {
+    writeValueToServer(popup_openee_key, "FAIL");
+  } else {
+    writeValueToServer(popup_openee_key, "PASS");
+  }
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/create-popup.html.headers b/testing/web-platform/tests/fenced-frame/resources/create-popup.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/create-popup.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html
new file mode 100644
index 0000000000..bdb448c347
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Page embedded as a fenced frame</title>
+<script>
+  const [key] = parseKeylist();
+  writeValueToServer(key, "loaded");
+</script>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-allowed-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html
new file mode 100644
index 0000000000..990f5ee469
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Page embedded as a fenced frame</title>
+<script>
+  // This file is expected to be unreachable from
+  // `csp-fenced-frame-src-blocked.html` in the parent directory because of CSP
+  // violation.
+  const [key] = parseKeylist();
+  writeValueToServer(key, "loaded");
+</script>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-fenced-frame-src-blocked-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html
new file mode 100644
index 0000000000..bdb448c347
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Page embedded as a fenced frame</title>
+<script>
+  const [key] = parseKeylist();
+  writeValueToServer(key, "loaded");
+</script>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-allowed-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html
new file mode 100644
index 0000000000..eb90bb94e9
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Page embedded as a fenced frame</title>
+<script>
+  // This file is expected to be unreachable from `csp-frame-src-blocked.html`
+  // in the parent directory because of CSP violation.
+  const [key] = parseKeylist();
+  writeValueToServer(key, "loaded");
+</script>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-frame-src-blocked-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-inner.html b/testing/web-platform/tests/fenced-frame/resources/csp-inner.html
new file mode 100644
index 0000000000..99df39fdc5
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-inner.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+  <script src="utils.js"></script>
+
+  <style>
+    body {background-color: red;}
+  </style>
+
+  <title>Fenced frame content to test Content Security Policies</title>
+
+  <body>
+    <script>
+      const [csp_key] = parseKeylist();
+
+      function fail() {
+        writeValueToServer(csp_key,
+          "FAIL: img-src policy was not honored in fenced frame");
+      }
+
+      function pass() {
+        // The parent page is going to attempt to pass a
+        // style-src: 'none' CSP to the fenced frame. Make sure that
+        // the header is not honored.
+        const bgcolor = window.getComputedStyle(document.body, null)
+                        .getPropertyValue('background-color');
+
+        if (bgcolor != "rgb(255, 0, 0)") {
+          writeValueToServer(csp_key,
+            "FAIL: style-src policy was passed to fenced frame");
+          return;
+        }
+
+        writeValueToServer(csp_key, "pass");
+      }
+    </script>
+    <img src="csp.png" id="my_img" onload="fail();" onerror="pass();">
+  </body>
+</html>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/csp-inner.html.headers
new file mode 100644
index 0000000000..e89be70a43
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/csp-inner.html.headers
@@ -0,0 +1,2 @@
+Supports-Loading-Mode: fenced-frame
+Content-Security-Policy: img-src 'none'
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/csp.png b/testing/web-platform/tests/fenced-frame/resources/csp.png
new file mode 100644
index 0000000000..53a9748ae0
Binary files /dev/null and b/testing/web-platform/tests/fenced-frame/resources/csp.png differ
diff --git a/testing/web-platform/tests/fenced-frame/resources/dangling-markup-helper.js b/testing/web-platform/tests/fenced-frame/resources/dangling-markup-helper.js
new file mode 100644
index 0000000000..9e0fff2301
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/dangling-markup-helper.js
@@ -0,0 +1,15 @@
+// These are used in tests that rely on URLs containing dangling markup. See
+// https://github.com/whatwg/fetch/pull/519.
+const kDanglingMarkupSubstrings = [
+  "blo\nck<ed",
+  "blo\rck<ed",
+  "blo\tck<ed",
+  "blo<ck\ned",
+  "blo<ck\red",
+  "blo<ck\ted",
+];
+
+function getTimeoutPromise(t) {
+  return new Promise(resolve =>
+      t.step_timeout(() => resolve("NOT LOADED"), 1500));
+}
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-helper.js b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-helper.js
new file mode 100644
index 0000000000..821ebf69e3
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-helper.js
@@ -0,0 +1,45 @@
+// This is a helper file used for the attribution-reporting-*.https.html tests.
+// To use this, make sure you import these scripts:
+// <script src="/resources/testharness.js"></script>
+// <script src="/resources/testharnessreport.js"></script>
+// <script src="/common/utils.js"></script>
+// <script src="/common/dispatcher/dispatcher.js"></script>
+// <script src="resources/utils.js"></script>
+// <script src="/common/get-host-info.sub.js"></script>
+
+async function runDefaultEnabledFeaturesTest(t, should_load, fenced_origin,
+    generator_api="fledge", allow="") {
+  const fencedframe = await attachFencedFrameContext({
+      generator_api: generator_api,
+      attributes: [["allow", allow]],
+      origin: fenced_origin});
+
+  if (!should_load) {
+    const fencedframe_blocked = new Promise(r => t.step_timeout(r, 1000));
+    const fencedframe_loaded = fencedframe.execute(() => {});
+    assert_equals(await Promise.any([
+      fencedframe_blocked.then(() => "blocked"),
+      fencedframe_loaded.then(() => "loaded"),
+    ]), "blocked", "The fenced frame should not be loaded.");
+    return;
+  }
+
+  await fencedframe.execute((generator_api) => {
+    assert_true(
+        document.featurePolicy.allowsFeature('attribution-reporting'),
+        "Attribution reporting should be allowed if the fenced " +
+        "frame loaded using FLEDGE or shared storage.");
+
+    if (generator_api == "fledge") {
+      assert_false(
+            document.featurePolicy.allowsFeature('shared-storage'),
+            "Shared storage should be disallowed if the fenced " +
+            "frame loaded using FLEDGE.");
+    } else {
+      assert_true(
+            document.featurePolicy.allowsFeature('shared-storage'),
+            "Shared storage should be allowed if the fenced " +
+            "frame loaded using shared storage.");
+    }
+  }, [generator_api]);
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html
new file mode 100644
index 0000000000..000b1eb6dd
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<title>Fenced frame attribution reporting redirect test</title>
+
+<body>
+<script>
+// This helper function will redirect a fenced frame to a remote origin page
+// while embedded in a frame that does not allow attribution reporting on
+// remote origins. That redirect should fail to load because of the attribution
+// reporting restriction.
+const [key1, key2] = parseKeylist();
+
+if (location.origin == get_host_info().ORIGIN) {
+  const result_val =
+      document.featurePolicy.allowsFeature('attribution-reporting') &
+      document.featurePolicy.allowsFeature('shared-storage');
+
+  writeValueToServer(key1,
+      document.featurePolicy.allowsFeature('attribution-reporting'));
+
+  const next_url = getRemoteOriginURL(generateURL(
+      "attribution-reporting-redirect.https.html", [key1, key2]));
+  location.href = next_url;
+} else {
+  // The redirect should have been unsuccessful, so we should not reach this
+  // point.
+  writeValueToServer(key2, "FAIL");
+}
+
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-redirect.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html
new file mode 100644
index 0000000000..e098736528
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+
+<body>
+<script>
+// This page is loaded into a fenced frame. The document policies for this page
+// disable shared storage. This then creates a child iframe to determine if
+// document deliviered policies are reflected in the child frame.
+const [key, should_restrict_select_url] = parseKeylist();
+
+const iframe_url = generateURL(
+    'default-enabled-features-subframe-iframe.https.html', [key]);
+const iframe = document.createElement("iframe");
+iframe.src = iframe_url;
+if (should_restrict_select_url == "true") {
+  iframe.allow = "shared-storage-select-url 'none';"
+}
+document.body.appendChild(iframe);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html.headers
new file mode 100644
index 0000000000..e52511f18a
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-fencedframe.https.html.headers
@@ -0,0 +1,2 @@
+Supports-Loading-Mode: fenced-frame
+Permissions-Policy: shared-storage=()
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html
new file mode 100644
index 0000000000..a3ab056944
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+
+<body>
+<script>
+// This page is loaded into an iframe that is nested within a fenced frame tree.
+// This is used to tell the test whether policies that are restricted by a
+// fenced frame's document policies also are restricted in subframes.
+const [key] = parseKeylist();
+
+const allows_shared_storage =
+    document.featurePolicy.allowsFeature('shared-storage');
+const allows_select_url =
+    document.featurePolicy.allowsFeature('shared-storage-select-url');
+
+writeValueToServer(key, allows_shared_storage + "," + allows_select_url);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/default-enabled-features-subframe-iframe.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/download-helper.js b/testing/web-platform/tests/fenced-frame/resources/download-helper.js
new file mode 100644
index 0000000000..011d5c867f
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/download-helper.js
@@ -0,0 +1,29 @@
+function StreamDownloadFinishDelay() {
+  return 1000;
+}
+
+function DownloadVerifyDelay() {
+  return 1000;
+}
+
+async function VerifyDownload(test_obj, token) {
+  const verifyToken = async (token) => {
+    const url = `resources/download-stash.py?verify-token&token=${token}`;
+    const response = await fetch(url);
+    if (!response.ok) {
+      throw new Error('An error happened in the server');
+    }
+    const message = await response.text();
+    return message === 'TOKEN_SET';
+  };
+
+  return new Promise((resolve) => {
+    test_obj.step_wait(
+        async () => {
+          const result = await verifyToken(token);
+          resolve(result);
+        },
+        'Check if the download has finished or not',
+        StreamDownloadFinishDelay() + DownloadVerifyDelay());
+  });
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/download-inner.html b/testing/web-platform/tests/fenced-frame/resources/download-inner.html
new file mode 100644
index 0000000000..9bc816cbf3
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/download-inner.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+  <title>The page triggering download embedded as a Fenced Frame</title>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="download-helper.js"></script>
+  <script src="utils.js"></script>
+  <script>
+    window.addEventListener('DOMContentLoaded', async () => {
+      const [download_key, download_ack_key] = parseKeylist();
+      const type = new URL(location).searchParams.get('type');
+      const href = `download-stash.py?token=${download_key}`;
+
+      if (type == 'anchor') {
+        const anchor = document.querySelector('#download');
+        anchor.href = href;
+        test_driver.click(anchor);
+      } else {
+        const delay = StreamDownloadFinishDelay();
+        location.href = `${href}&finish-delay=${delay}`
+      }
+
+      await writeValueToServer(download_ack_key, 'Triggered the action for download');
+    });
+  </script>
+</head>
+
+<body>
+  <a id="download" download>Download</a>
+</body>
+
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/download-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/download-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/download-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/download-stash.py b/testing/web-platform/tests/fenced-frame/resources/download-stash.py
new file mode 100644
index 0000000000..497f7cb018
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/download-stash.py
@@ -0,0 +1,28 @@
+import time
+
+
+def main(request, response):
+    token = request.GET[b"token"]
+    response.status = 200
+    response.headers.append(b"Content-Type", b"text/html")
+    if b"verify-token" in request.GET:
+        if request.server.stash.take(token):
+            return u'TOKEN_SET'
+        return u'TOKEN_NOT_SET'
+
+    if b"finish-delay" not in request.GET:
+        # <a download>
+        request.server.stash.put(token, True)
+        return
+
+    # navigation to download
+    response.headers.append(b"Content-Disposition", b"attachment")
+    response.write_status_headers()
+    finish_delay = float(request.GET[b"finish-delay"]) / 1E3
+    count = 10
+    single_delay = finish_delay / count
+    for i in range(count):  # pylint: disable=unused-variable
+        time.sleep(single_delay)
+        if not response.writer.write_content(b"\n"):
+            return
+    request.server.stash.put(token, True)
diff --git a/testing/web-platform/tests/fenced-frame/resources/dummy.html b/testing/web-platform/tests/fenced-frame/resources/dummy.html
new file mode 100644
index 0000000000..a0cf50713e
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/dummy.html
@@ -0,0 +1,2 @@
+<!DOCTYPE html>
+<title>Dummy page</title>
diff --git a/testing/web-platform/tests/fenced-frame/resources/embeddee.html b/testing/web-platform/tests/fenced-frame/resources/embeddee.html
new file mode 100644
index 0000000000..3423be9aa4
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/embeddee.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>A page embedded as a Fenced Frame for COEP tests</title>
+<script>
+const [uuid] = parseKeylist();
+writeValueToServer(uuid, "PASS");
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/embeddee.html.headers b/testing/web-platform/tests/fenced-frame/resources/embeddee.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/embeddee.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/embedder-policy.js b/testing/web-platform/tests/fenced-frame/resources/embedder-policy.js
new file mode 100644
index 0000000000..8c96afafce
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/embedder-policy.js
@@ -0,0 +1,39 @@
+// This file should be loaded alongside with utils.js.
+//
+// This file is loaded by:
+// - embedder-no-coep.https.html
+// - embedder-require-corp.https.html
+
+// Make input list to be used as a wptserve pipe
+// (https://web-platform-tests.org/writing-tests/server-pipes.html).
+// e.g.
+// args: ['content-type,text/plain','Age,0']
+// return: 'header(content-type,text/plain)|header(Age,0)'
+function generateHeader(headers) {
+  return headers.map((h) => {
+    return 'header(' + h + ')';
+  }).join('|');
+}
+
+// Setup a fenced frame for embedder-* WPTs.
+async function setupTest(test_type, uuid, hostname='') {
+  let headers = ["Supports-Loading-Mode,fenced-frame"];
+  switch (test_type) {
+    case "coep:require-corp":
+      headers.push("cross-origin-embedder-policy,require-corp");
+      headers.push("cross-origin-resource-policy,same-origin");
+      break;
+    case "no coep":
+      break;
+    default:
+      assert_unreachable("unknown test_type:" + test_type);
+      break;
+  }
+  const tmp_url = new URL('resources/embeddee.html', location.href);
+  if (hostname) {
+    tmp_url.hostname = hostname;
+  }
+  tmp_url.searchParams.append("pipe", generateHeader(headers));
+  const url = generateURL(tmp_url.toString(), [uuid]);
+  return attachFencedFrame(url);
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/empty-worker.js b/testing/web-platform/tests/fenced-frame/resources/empty-worker.js
new file mode 100644
index 0000000000..49ceb2648a
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/empty-worker.js
@@ -0,0 +1 @@
+// Do nothing.
diff --git a/testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html
new file mode 100644
index 0000000000..f30cd77838
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of navigator.credentials.get</title>
+
+<body>
+<script>
+function isExpectedErrorMessage(e) {
+  return e.name === 'NotAllowedError' &&
+      e.message ===
+      'The credential operation is not allowed in a fenced frame tree.';
+}
+
+// This file is meant to be navigated to from a <fencedframe> element. It
+// reports back to the page hosting the <fencedframe> whether or not
+// `navigator.credentials.get` is allowed.
+const [key] = parseKeylist();
+
+const test_options = {
+  federated: {
+    providers: [{
+      configURL: 'https://idp.test/fedcm.json',
+      clientId: '1',
+      nonce: '2',
+    }]
+  }
+};
+navigator.credentials.get(test_options)
+    .then(
+        () => {
+          writeValueToServer(key, 'unexpected passed');
+        },
+        (e) => {
+          if (isExpectedErrorMessage(e)) {
+            writeValueToServer(key, 'navigator.credentials.get failed');
+          } else {
+            writeValueToServer(
+              key, 'navigator.credentials.get failed by unexpected reason');
+          }
+        },
+    );
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fedcm-get-credential-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html
new file mode 100644
index 0000000000..814ea78559
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to test window.fence object</title>
+
+<body>
+<script>
+
+  // Get the token for communication with the parent.
+  const [fence_api_token] = parseKeylist();
+
+  // Check that window.fence is visible inside fenced frames.
+  assert_true(window.fence != null,
+              "window.fence should be visible inside fenced frames");
+  assert_true(fence != null,
+              "fence should be visible inside fenced frames");
+
+  // Tell the parent that the test succeeded.
+  writeValueToServer(fence_api_token, "");
+
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fence-api-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html
new file mode 100644
index 0000000000..0054762783
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+<script src="utils.js"></script>
+<title>Fenced frame loaded</title>
+<body>
+<script>
+(async function() {
+  const [parent_key] = parseKeylist();
+  writeValueToServer(parent_key, "fenced frame loaded");
+})();
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html.headers b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-loaded.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html
new file mode 100644
index 0000000000..9b67be775e
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Nested fenced frame named navigation helper</title>
+<!-- This is a helper file. It is meant to be the document loaded inside a
+     nested fenced frame by `navigate-by-name-inner.html`. Once this document is
+     loaded and changes its `window.name` to `target_frame`, it reports to the
+     server so that the outermost document can attempt to navigate it by name.
+     (The navigation should not succeed - see the test expectations).
+-->
+<body>
+<script>
+  const [ready_for_navigation_key] = parseKeylist();
+  window.name = "target_frame";
+  writeValueToServer(ready_for_navigation_key, "READY");
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html.headers b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fenced-frame-set-name-and-report-ready-for-outermost-document-to-navigate.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js
new file mode 100644
index 0000000000..1a22bcec3d
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js
@@ -0,0 +1,37 @@
+// These functions are used by FLEDGE to determine the logic for the ad buyer.
+// For our testing purposes, we only need the minimal amount of boilerplate
+// code in place to allow them to be invoked properly and move the FLEDGE
+// process along. The tests do not deal with reporting results, so we leave
+// `reportWin` empty. See `generateURNFromFledge` in "utils.js" to see how
+// these files are used.
+
+function generateBid(interestGroup, auctionSignals, perBuyerSignals,
+  trustedBiddingSignals, browserSignals) {
+  const ad = interestGroup.ads[0];
+
+  // `auctionSignals` controls whether or not component auctions are allowed.
+  let allowComponentAuction =
+    typeof auctionSignals === 'string' &&
+    auctionSignals.includes('bidderAllowsComponentAuction');
+
+  let result = {
+    'ad': ad,
+    'bid': 1,
+    'render': { url: ad.renderUrl, width: "100px", height: "50px" },
+    'allowComponentAuction': allowComponentAuction
+  };
+  if (interestGroup.adComponents && interestGroup.adComponents.length > 0)
+    result.adComponents = interestGroup.adComponents.map((component) => {
+      return {
+        url: component.renderUrl,
+        width: "100px",
+        height: "50px"
+      };
+    });
+  return result;
+}
+
+function reportWin(
+  auctionSignals, perBuyerSignals, sellerSignals, browserSignals) {
+  return;
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js.headers b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js.headers
new file mode 100644
index 0000000000..776bf2987b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic-with-size.js.headers
@@ -0,0 +1,2 @@
+Content-Type: Application/Javascript
+X-Allow-FLEDGE: true
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js
new file mode 100644
index 0000000000..ab6685f184
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js
@@ -0,0 +1,34 @@
+// These functions are used by FLEDGE to determine the logic for the ad buyer.
+// For our testing purposes, we only need the minimal amount of boilerplate
+// code in place to allow them to be invoked properly and move the FLEDGE
+// process along. The tests do not deal with reporting results, so we leave
+// `reportWin` empty. See `generateURNFromFledge` in "utils.js" to see how
+// these files are used.
+
+function generateBid(interestGroup, auctionSignals, perBuyerSignals,
+  trustedBiddingSignals, browserSignals) {
+  const ad = interestGroup.ads[0];
+
+  // `auctionSignals` controls whether or not component auctions are allowed.
+  let allowComponentAuction =
+      typeof auctionSignals === 'string' &&
+      auctionSignals.includes('bidderAllowsComponentAuction');
+
+  let result = {'ad': ad, 'bid': 1, 'render': ad.renderUrl,
+      'allowComponentAuction': allowComponentAuction};
+  if (interestGroup.adComponents && interestGroup.adComponents.length > 0)
+    result.adComponents = interestGroup.adComponents.map((component) => {
+      return component.renderUrl;
+    });
+  return result;
+}
+
+function reportWin(
+    auctionSignals, perBuyerSignals, sellerSignals, browserSignals) {
+  registerAdBeacon({
+    'reserved.top_navigation':
+        browserSignals.interestGroupOwner +
+        '/fenced-frame/resources/automatic-beacon-store.py'
+  });
+  return;
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js.headers b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js.headers
new file mode 100644
index 0000000000..776bf2987b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fledge-bidding-logic.js.headers
@@ -0,0 +1,2 @@
+Content-Type: Application/Javascript
+X-Allow-FLEDGE: true
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js b/testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js
new file mode 100644
index 0000000000..dc92f5a5e1
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js
@@ -0,0 +1,15 @@
+// These functions are used by FLEDGE to determine the logic for the ad seller.
+// For our testing purposes, we only need the minimal amount of boilerplate
+// code in place to allow them to be invoked properly and move the FLEDGE
+// process along. The tests do not deal with reporting results, so we leave
+// `reportResult` empty. See `generateURNFromFledge` in "utils.js" to see how
+// these files are used.
+
+function scoreAd(
+  adMetadata, bid, auctionConfig, trustedScoringSignals, browserSignals) {
+  return 2*bid;
+}
+
+function reportResult(auctionConfig, browserSignals) {
+  return;
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js.headers b/testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js.headers
new file mode 100644
index 0000000000..776bf2987b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/fledge-decision-logic.js.headers
@@ -0,0 +1,2 @@
+Content-Type: Application/Javascript
+X-Allow-FLEDGE: true
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html
new file mode 100644
index 0000000000..9a56a3d9fb
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="utils.js"></script>
+<title>Test nested fenced frame navigation (by a parent frame setting its src).</title>
+
+<body>
+  <script>
+    async function init() { // Needed in order to use top-level await.
+      // This file is meant to run in a <fencedframe>. It communicates with
+      // the embedder to confirm that nested fenced frames can be navigated.
+
+      const [navigation_key, navigation_ack_key] = parseKeylist();
+
+      // Create URL prefixes to simulate different origins.
+      // (www1 and www2 are different origins)
+      const simple_url = generateURL("frame-navigation-inner-simple.https.html",
+      [navigation_key, navigation_ack_key]);
+
+      const origin1_simple_url = getRemoteOriginURL(simple_url);
+      const origin2_simple_url = getRemoteOriginURL(simple_url)
+          .toString().replace("www1", "www2");
+
+      const url_prefix = location.href + "/../";
+
+      // Tell the embedder that this frame has loaded.
+      writeValueToServer(navigation_key, "create-nested");
+      await nextValueFromServer(navigation_ack_key);
+
+      // Create an inner frame.
+      inner_frame = attachFencedFrame(origin1_simple_url);
+      // Wait for our parent to tell us they're done communicating.
+      await nextValueFromServer(navigation_ack_key);
+
+      // Navigate (cross-origin) and wait.
+      inner_frame.config = new FencedFrameConfig(
+          generateURL(origin2_simple_url, []));
+      await nextValueFromServer(navigation_ack_key);
+
+      // Navigate (same-origin) and wait.
+      inner_frame.config = new FencedFrameConfig(
+          generateURL(origin2_simple_url, []));
+      await nextValueFromServer(navigation_ack_key);
+    }
+
+    init();
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-create-nested.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html
new file mode 100644
index 0000000000..643ea48a76
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Test that a fenced frame successfully loaded.</title>
+
+<body>
+  <script>
+      // This file is meant to run in a <fencedframe>. It reports back to the
+      // outermost page to confirm that loading succeeded.
+      const [navigation_key, navigation_ack_key] = parseKeylist();
+      writeValueToServer(navigation_key, "pass");
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/frame-navigation-inner-simple.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html b/testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html
new file mode 100644
index 0000000000..dd36b20399
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<div id="target" style="width: 100px; height: 100px; position: fixed; top: 0px; left: 0px"></div>
+<script>
+let next_token = 0;
+function init() {
+  const tokens = parseKeylist();
+  let observer = new IntersectionObserver((entries) => {
+    assert_equals(entries.length, 1);
+    let rect = entries[0].intersectionRect.x + "," +
+               entries[0].intersectionRect.y + "," +
+               entries[0].intersectionRect.width + "," +
+               entries[0].intersectionRect.height + "," +
+               entries[0].isVisible;
+    writeValueToServer(tokens[next_token], rect);
+    next_token = next_token + 1;
+
+    if (next_token == tokens.length) {
+      observer.disconnect();
+    }
+  }, {trackVisibility: true, delay: 100, threshold: [0.6, 0.75]});
+  observer.observe(document.getElementById("target"));
+}
+
+init();
+</script>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html.headers b/testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/frame-with-intersection-observer.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html b/testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html
new file mode 100644
index 0000000000..3e253e4915
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>getGamepads should throw an error in a fenced frame</title>
+<script>
+const [key] = parseKeylist();
+try {
+  navigator.getGamepads();
+  writeValueToServer(key, 'Expected exception but successed');
+} catch (e) {
+  writeValueToServer(key, e.name);
+}
+</script>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/gamepad-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html
new file mode 100644
index 0000000000..a83ba93aa6
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Send the results of getNestedConfigs() to the embedder</title>
+<script>
+const [key] = parseKeylist();
+const configs = window.fence.getNestedConfigs();
+const data_to_send = [configs.length, configs.length > 0 ? configs[0].url : "N/a"];
+writeValueToServer(key, data_to_send.join(","));
+</script>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html
new file mode 100644
index 0000000000..9bd5d9f492
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>getGamepads should throw an error in a fenced frame</title>
+<body>
+  <script>
+  const [key] = parseKeylist();
+  attachIFrame(generateURL("get-nested-configs-inner.html", [key]));
+  </script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html.headers b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/get-nested-configs-nested-iframe.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/get_battery.html b/testing/web-platform/tests/fenced-frame/resources/get_battery.html
new file mode 100644
index 0000000000..0532deca4b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/get_battery.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>getBattery should fail in a fenced frame</title>
+<script>
+async function init() { // Needed in order to use top-level await.
+  const [uuid] = parseKeylist();
+  try {
+    await navigator.getBattery();
+    writeValueToServer(uuid, 'Expected an exception but the call succeeded');
+  } catch (err) {
+    writeValueToServer(uuid, err.name);
+  }
+}
+
+init();
+</script>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/get_battery.html.headers b/testing/web-platform/tests/fenced-frame/resources/get_battery.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/get_battery.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html b/testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html
new file mode 100644
index 0000000000..2940dbac8e
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of header.referrer</title>
+
+<body>
+<script>
+async function init() { // Needed in order to use top-level await.
+  // This file is meant to run in a <fencedframe>. It reports back to the
+  // outermost page the value of `referer` in the request header:
+  //   1.) Nested iframes inside a fenced frame
+  //   2.) Nested fenced frames
+  //   3.) Top-level fenced frames (aka this frame) after initial navigation
+  const [referrer_key, referrer_ack_key] = parseKeylist();
+
+  const referrer_url = generateURL("check-header-referrer.py",
+      [referrer_key, referrer_ack_key]);
+
+  const iframe = document.createElement('iframe');
+  iframe.src = referrer_url;
+  document.body.append(iframe);
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `referrer_key` stash that the iframe above wrote to, and we can write
+  // to it again.
+  await nextValueFromServer(referrer_ack_key);
+
+  attachFencedFrame(referrer_url);
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `referrer_key` stash that the nested fenced frame wrote to, and we can
+  // can write to it again.
+  await nextValueFromServer(referrer_ack_key);
+
+  location.href = referrer_url;
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/header-referrer-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html b/testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html
new file mode 100644
index 0000000000..aa3fe9e34c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of `Sec-Fetch-Dest` header</title>
+
+<body>
+<script>
+(() => {
+  // This file is meant to run in a <fencedframe>. It reports back to the
+  // outermost page the value of `Sec-Fetch-Dest` in the request header for
+  // nested iframes inside a fenced frame.
+  const [sec_fetch_dest_value_key] = parseKeylist();
+  const https_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
+  const https_origin_url =
+      getRemoteOriginURL(
+          generateURL(
+              'check-header-sec-fetch-dest.py',
+              [sec_fetch_dest_value_key]));
+
+  const iframe = document.createElement('iframe');
+  iframe.src = https_origin_url;
+  document.body.append(iframe);
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/header-secFetchDest-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html b/testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html
new file mode 100644
index 0000000000..9620249d76
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>history-back-and-forward-should-not-work-in-fenced-tree-inner</title>
+
+<body>
+  <script>
+    // This is a helper file that will serve as the document loaded inside
+    // a fenced frame by 'history-back-and-forward-should-not-work-in-fenced
+    // -tree' Once loaded, it will sequentially perform the back and forward
+    // history navigations to observe whether these methods were successfuly
+    // restricted for the fenced tree.
+
+    const [history_navigation_performed_key, outer_page_ready_key,
+           embed_scope] = parseKeylist();
+
+    (async function () {
+      const url = new URL(location.href);
+      const test = url.searchParams.get("test");
+
+      writeValueToServer(history_navigation_performed_key, "yes");
+
+      // Execute history.back() within fenced frame and iframe.
+      await nextValueFromServer(outer_page_ready_key);
+      window.history.back();
+      writeValueToServer(history_navigation_performed_key, "yes");
+
+      // Execute history.forward() within fenced frame and iframe.
+      await nextValueFromServer(outer_page_ready_key);
+      window.history.forward();
+      writeValueToServer(history_navigation_performed_key, "yes");
+
+      if (embed_scope === "outerPage::fencedFrame::iframe") return;
+
+      const iframe = document.createElement('iframe');
+      const iframe_embed_scope = "outerPage::fencedFrame::iframe";
+      iframe.src = generateURL(
+          "history-back-and-forward-should-not-work-in-fenced-tree-" +
+          "inner.html",
+          [history_navigation_performed_key, outer_page_ready_key,
+           iframe_embed_scope]);
+      document.body.append(iframe);
+    })();
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/history-back-and-forward-should-not-work-in-fenced-tree-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html b/testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html
new file mode 100644
index 0000000000..726fafd65b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html
@@ -0,0 +1,115 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Nested fenced frame named navigation helper</title>
+
+<body>
+<script>
+(async () => {
+  // We need to wait for the window's `load` event to fire, because client-side
+  // redirect navigations that take place before a document is "completely
+  // loaded" [1] are carried out with replacement, as specified in [2]. Just
+  // waiting for `load` is not enough though! After the `load` event is fired
+  // (but before a document is marked "completely loaded"), a microtask
+  // checkpoint is performed, which is where the below `Promise`'s `then`
+  // handler is invoked (i.e., the rest of the script). So if we just resolve
+  // the promise and continue, the whole script continues in the next immediate
+  // microtask before the document is completely loaded. So we have to queue
+  // another task so that we only continue executing once the document is
+  // considered completely loaded, and then `location.href` assignments will not
+  // be made with replacement history handling.
+  //
+  // [1]: https://html.spec.whatwg.org/C#the-end:completely-finish-loading
+  // [2]: https://html.spec.whatwg.org/#the-location-interface:completely-loaded
+  await new Promise(resolve => {
+    window.onload = e => {
+      setTimeout(resolve, 0);
+    };
+  });
+
+  const kNavigationLimit = 5;
+  // This is a helper file meant to be loaded inside a fenced frame. It performs
+  // various navigations inside of the "fence" defined by this document, and
+  // ensures that they are all done in a replace-only fashion [1].
+  // Once we ensure that they are all done with replacement, we report back to
+  // the outermost page via the server stash, and it ensures that there was no
+  // impact on the joint session history as observed from beyond the fence.
+  //
+  // [1]: https://html.spec.whatwg.org/C/#hh-replace
+
+  // See documentation in the outer page.
+  const [fenced_navigation_complete_key,
+         outer_page_ready_for_next_fenced_navigation_key,
+         level] = parseKeylist();
+
+  const url = new URL(location.href);
+  const is_top_level_fenced_frame = (level == "top-level-fenced-frame");
+
+  ////////////// Navigation code that may impact `history.length` should go here
+  // The code in this block performs navigations that will run inside:
+  //   - The top-level fenced frame
+  //   - The nested fenced frame
+  //   - The nested iframe
+
+  // First, perform some real navigations to this same page. Normally this would
+  // increase `history.length`.
+  if (url.searchParams.get("navigationNumber") == null)
+    url.searchParams.append("navigationNumber", 0);
+
+  let navigationNumber = parseInt(url.searchParams.get("navigationNumber"));
+
+  if (navigationNumber <= kNavigationLimit) {
+    url.searchParams.set('navigationNumber', navigationNumber + 1);
+    location.href = url;
+    return;
+  }
+
+  // At this point we're done performing 5 subsequent navigations...
+
+  // Next, perform `history.pushState()`s.
+  history.pushState({} , "");
+  history.pushState({} , "");
+  history.pushState({} , "");
+  ////////////// END
+
+  // Finally observe `history.length` from within the fenced frame, and report
+  // the results back to the outermost page.
+  if (history.length == 1) {
+    writeValueToServer(fenced_navigation_complete_key, "PASS > " +
+        level);
+  } else {
+    writeValueToServer(fenced_navigation_complete_key,
+        "FAIL > " + level + " history.length: " +
+        history.length);
+  }
+
+  // We're only testing fenced frames, nested fenced frames, and iframes nested
+  // within fenced frames. The below code adds a nested fenced frame and a
+  // nested iframe, so it should only be reached by the top-level fenced frame.
+  if (level != "top-level-fenced-frame")
+    return;
+
+  // Only top-level fenced frames will attach a nested fenced frame and run the
+  // same tests there.
+  await nextValueFromServer(outer_page_ready_for_next_fenced_navigation_key);
+  const nested_fenced_frame_level = "nested-fenced-frame";
+  attachFencedFrame(generateURL(
+      "history-length-fenced-navigations-replace-do-not-" +
+      "contribute-to-joint-inner.html",
+      [fenced_navigation_complete_key,
+      outer_page_ready_for_next_fenced_navigation_key,
+      nested_fenced_frame_level]));
+
+  await nextValueFromServer(outer_page_ready_for_next_fenced_navigation_key);
+  const iframe = document.createElement('iframe');
+  const nested_iframe_level = "nested-iframe";
+  iframe.src = generateURL(
+      "history-length-fenced-navigations-replace-do-not-contribute-to-joint-" +
+      "inner.html",
+      [fenced_navigation_complete_key,
+      outer_page_ready_for_next_fenced_navigation_key,
+      nested_iframe_level]);
+  document.body.append(iframe);
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/history-length-fenced-navigations-replace-do-not-contribute-to-joint-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html b/testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html
new file mode 100644
index 0000000000..2bdb90ab64
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html
@@ -0,0 +1,72 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>history-length-outer-page-navigation-not-reflected-in-fenced-inner</title>
+
+<body>
+<script>
+(async () => {
+  // This is a helper file that will servec as the document loaded inside
+  // a fenced frame b 'history-length-outer-page-navigation-not-reflected-in-
+  // fenced' Once loaded, it reports to the observed value of history.length to
+  // the server so that the outer document can assert the value is 1.
+
+  const [fenced_history_length_key, outer_page_ready_for_next_navigation_key,
+         embed_scope, embed_scope_reporting] =
+      parseKeylist();
+
+  const url = new URL(location.href);
+
+  if (embed_scope == "outer_page::iframe"){
+    ////////////// BEGIN NAVIGATIONS
+    // This block performs a sequence of 'kNavigationLimit' navigations in:
+    // -- the iframe
+    const kNavigationLimit = 5
+
+    const url = new URL(location.href);
+
+    // First, perform some real navigations as well as history.pushState to
+    // this same page. Normally this would increase `history.length`.
+    if (url.searchParams.get("navigationCount") == null)
+      url.searchParams.append("navigationCount", 1);
+
+    let navigationCount = parseInt(url.searchParams.get("navigationCount"));
+
+    if (navigationCount <= kNavigationLimit) {
+      url.searchParams.set('navigationCount', ++navigationCount);
+      location.href = url;
+      history.pushState({} , "");
+      return;
+    }
+    ////////////// END
+    writeValueToServer(outer_page_ready_for_next_navigation_key, "READY");
+    return
+  }
+
+  if (embed_scope == embed_scope_reporting) {
+    // Observe 'history.length' from within the 'embed_scope_reporting',
+    // and report the results back to the outer page.
+    if (history.length == 1) {
+      writeValueToServer(fenced_history_length_key,
+        "PASS > " + " history.length: " + history.length);
+    } else {
+      writeValueToServer(fenced_history_length_key,
+        "FAIL > " + " history.length: " + history.length);
+    }
+    return
+  }
+
+  if (embed_scope_reporting == "outer_page::fenced_frame::iframe") {
+    // Append an iframe to the 'outer_page::fenced_frame' to report
+    // history.length to the outer_page from within the iframe
+    const iframe = document.createElement('iframe');
+    const embed_scope = "outer_page::fenced_frame::iframe";
+    iframe.src = generateURL(
+      "history-length-outer-page-navigation-not-reflected-in-fenced-inner.html",
+      [fenced_history_length_key, outer_page_ready_for_next_navigation_key,
+      embed_scope, embed_scope_reporting]);
+    document.body.append(iframe);
+    return
+  }
+})();
+</script>
+</body>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/history-length-outer-page-navigation-not-reflected-in-fenced-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html b/testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html
new file mode 100644
index 0000000000..4fe496f29c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<title>child frame with delayed onload event</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+
+<body>
+</body>
+<script>
+  (function () {
+    const [element_type, toplevel_loaded_key, result_key] = parseKeylist();
+
+    // Delays the onload event of the iframe for 2 sec.
+    if (element_type == "iframe") {
+      const img = document.createElement("img");
+      img.src = "/common/square.png?pipe=trickle(d2)";
+      document.body.appendChild(img);
+      return;
+    }
+
+    const iframe = document.createElement('iframe');
+    iframe.src = generateURL("ignore-child-fenced-frame-onload-event-inner." +
+      "html", ["iframe"]);
+    document.body.append(iframe);
+
+    let iframe_loaded = false;
+    let result = "passed";
+    window.onload = async function () {
+      const toplevel_loaded = await readValueFromServer(toplevel_loaded_key);
+      if (!toplevel_loaded.status || !iframe_loaded)
+        result = "failed";
+      writeValueToServer(result_key, result);
+    }
+
+    iframe.onload = function () {
+      iframe_loaded = true;
+    }
+  })();
+</script>
+
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/key-value-store.py b/testing/web-platform/tests/fenced-frame/resources/key-value-store.py
new file mode 100644
index 0000000000..c9fd81b2a3
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/key-value-store.py
@@ -0,0 +1,46 @@
+"""Key-Value store server.
+
+The request takes "key=" and "value=" URL parameters. The key must be UUID
+generated by token().
+
+- When only the "key=" is specified, serves a 200 response whose body contains
+  the stored value specified by the key. If the stored value doesn't exist,
+  serves a 200 response with an empty body.
+- When both the "key=" and "value=" are specified, stores the pair and serves
+  a 200 response without body.
+"""
+
+
+def main(request, response):
+    key = request.GET.get(b"key")
+    value = request.GET.get(b"value")
+
+    # Store the value.
+    # We have two ways to check the truthiness of `value`:
+    #   1. `if value`
+    #   2. `if value != None`
+    # While (1) is the most intuitive, we actually need (2), which is a looser
+    # check. We need the looser check so that if the URL contains `&value=` to
+    # set the value equal to the empty string (a case we need to support), this
+    # condition still evaluates to true and we enter this branch.
+    if value != None:
+        # We opted for (2) above which is the looser of the truthiness tests
+        # that lets empty strings into this branch. So you might think that when
+        # the URL contains `&value=`, then the `value` variable here would be
+        # equal `""`, but instead it equals the empty byte string. If you just
+        # store that empty byte string into the stash and retrieve it later, you
+        # actually get <Not set> because it doesn't recognize the empty byte
+        # string as a real value, so we instead have to override it to the empty
+        # normal string, and then we can store it for later use. This is
+        # because we have to support storage and retrieval of empty strings.
+        if type(value) is bytes and value == b'':
+            value = ""
+
+        request.server.stash.put(key, value)
+        return (200, [], b"")
+
+    # Get the value.
+    data = request.server.stash.take(key)
+    if not data and data != "":
+        return (200, [], b"<Not set>")
+    return (200, [], data)
diff --git a/testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html
new file mode 100644
index 0000000000..3c9411c520
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of location.ancestorOrigins</title>
+
+<body>
+<script>
+async function init() { // Needed in order to use top-level await.
+  // This file is meant to run in a <fencedframe>. It reports back to the
+  // outermost page the value of `location.ancestorOrigins` correct for:
+  //   1.) Top-level fenced frames
+  //   2.) Nested iframes inside a fenced frame
+  //   3.) Nested fenced frames
+  const url = new URL(location.href);
+
+  const [location_ao_key, location_ao_ack_key, nested] = parseKeylist();
+
+  const is_nested_fenced_frame = nested == "nested";
+
+  // Report `location.ancestorOrigins`.
+  writeValueToServer(location_ao_key, Array.from(location.ancestorOrigins).join());
+
+  // If this page is a nested fenced frame, all we need to do is report the
+  // top-level value.
+  if (is_nested_fenced_frame)
+    return;
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `location_ao_key` stash and we can write to it again.
+  await nextValueFromServer(location_ao_ack_key);
+
+  const nested_url = generateURL("location-ancestorOrigins-inner.https.html",
+      [location_ao_key, location_ao_ack_key, "nested"]);
+
+  // Send `location.ancestorOrigins` from an iframe.
+  const iframe = document.createElement('iframe');
+  iframe.src = nested_url;
+  const load_promise = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+  document.body.append(iframe);
+
+  // Wait for ACK, so we know that the outer page has read the ancestorOrigins
+  // from the iframe.
+  await nextValueFromServer(location_ao_ack_key);
+
+  attachFencedFrame(nested_url);
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/location-ancestorOrigins-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html
new file mode 100644
index 0000000000..f12849c8ec
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Nested fenced frame named navigation helper</title>
+<!-- See `navigate-ancestor-from-nested-{fencedframe,iframe}.https.html` for
+     more documentation -->
+<script>
+  // This is a helper file. It is the document that
+  // `navigate-ancestor-from-nested{fencedframe,iframe}-helper.https.html`
+  // explicitly navigates the "correct" ancestor frame to, for any test run by
+  // `navigate-ancestor-test-runner.https.html`. The test itself is responsible
+  // for verifying that this document loaded in the correct frame. We just
+  // simply report that we successfully wound up in this document, to indicate
+  // that we're finished.
+  const [navigate_ancestor_key] = parseKeylist();
+  writeValueToServer(navigate_ancestor_key,
+      "navigate-ancestor-destination.https.html");
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-destination.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html
new file mode 100644
index 0000000000..74800b969f
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<title>Navigate ancestor helper</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+
+<body>
+<script>
+(async () => {
+  // This document is loaded into a fenced frame by
+  // `navigate-ancestor-test-runner.https.html`. It creates a nested fenced
+  // frame and navigates it to `navigate-ancestor-helper.https.html`.
+
+  // - navigate_ancestor_key:
+  // Sent by `navigate-ancestor-destination.https.html`. We listen to it, and
+  // report back to our embedder that it loaded correctly and did not navigate
+  // *this* frame.
+  // - navigate_ancestor_from_nested_key:
+  // Sent by us to our embedder to indicate (depending on the message) either:
+  //   - PASS: The nested fenced frame was navigated correctly when it tried to
+  //           navigate its ancestor (parent or top) frame
+  //   - FAIL: When the nested fenced frame tried to navigate its ancestor
+  //           frame, it actually navigated *this frame*, which is wrong
+  const [navigate_ancestor_key, navigate_ancestor_from_nested_key,
+      ancestor_type] = parseKeylist();
+
+  window.onbeforeunload = e => {
+    writeValueToServer(navigate_ancestor_from_nested_key,
+                       `FAIL nested fenced frame ${ancestor_type}`);
+  }
+
+  attachFencedFrame(generateURL(`navigate-ancestor-helper.https.html`,
+      [navigate_ancestor_key, ancestor_type]));
+  await nextValueFromServer(navigate_ancestor_key);
+  window.onbeforeunload = null;
+  writeValueToServer(navigate_ancestor_from_nested_key, "PASS");
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-fenced-frame.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html
new file mode 100644
index 0000000000..63a0cca8b4
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<title>Navigate ancestor helper from nested fenced frame</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+
+<body>
+<script>
+(async () => {
+  // This document is loaded into a fenced frame by
+  // `navigate-ancestor-test-runner.https.html`. It creates a nested iframe and
+  // navigates it to `navigate-ancestor-helper.https.html`.
+
+  // navigate_ancestor_from_nested_key sent by us to our embedder to
+  // indicate that an message was sent from the nested iframe when it failed to
+  // navigate the ancestor (this) frame.
+  const [navigate_ancestor_key, navigate_ancestor_from_nested_key,
+      ancestor_type] = parseKeylist();
+
+  // An message should be sent from the iframe.
+  window.addEventListener('message', (e) => {
+    window.onbeforeunload = null;
+    writeValueToServer(
+        navigate_ancestor_from_nested_key,
+        `PASS: [${ancestor_type}] ${e.data}`);
+  });
+
+  // When the iframe tries to navigate its ancestor frame, it should not
+  // navigate *this* frame, because the sandboxed navigation browsing context
+  // flag [1] must be set in fenced frame trees.
+  // [1] https://html.spec.whatwg.org/multipage/origin.html#sandboxed-navigation-browsing-context-flag
+  const iframe = document.createElement('iframe');
+  iframe.src = generateURL(`navigate-ancestor-helper.https.html`,
+      [navigate_ancestor_key, ancestor_type]);
+  document.body.append(iframe);
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-from-nested-iframe.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html
new file mode 100644
index 0000000000..2cd8fcf786
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<title>Navigate ancestor helper</title>
+
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="utils.js"></script>
+<body>
+<script>
+(async () => {
+  // This document is loaded into either a top-level fenced frame, a nested
+  // fenced frame, or an iframe in a top-level fenced frame. In any case, this
+  // document is always the inner-most document in any test. It navigates an
+  // ancestor frame by clicking the anchor above via script. When this document
+  // is loaded in a fenced frame, the frame that should actually navigate is
+  // this one, since fenced frames are top-level browsing contexts.
+  // When this document is loaded into a top-level fenced frame or a nested
+  // fenced frame, we test that the right frame is navigated in
+  // `navigate-ancestor-test-runner.https.html`. When this document is loaded
+  // into an iframe in a top-level fenced frame, we test that the navigation is
+  // blocked due to the sandbox behavior of fenced frame trees.
+  const [navigate_ancestor_key, ancestor_type] = parseKeylist();
+  const url = generateURL(`navigate-ancestor-destination.https.html`,
+      [navigate_ancestor_key]);
+  await simulateGesture();
+  try {
+    window[ancestor_type].location = url;
+  } catch (e) {
+    window[ancestor_type].postMessage('location change failed.');
+  }
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.js b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.js
new file mode 100644
index 0000000000..6178ea78da
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-helper.js
@@ -0,0 +1,28 @@
+
+async function runNavigateAncestorTest(test_type, ancestor_type) {
+  // See documentation in `resources/navigate-ancestor-test-runner.https.html`.
+  // For each test type here, this document opens a new auxiliary window that
+  // runs the actual test. The tests in some way or another, direct a frame
+  // *inside* a fenced frame to navigate an ancestor frame via an
+  // <a target="_parent|_top"></a>. We need to run the real test in a new window
+  // so that if that window ends up navigating unexpectedly (because the fenced
+  // frame can accidentally navigated its embedder, for example) we can detect
+  // it from ths page, which never navigates away.
+  const navigate_ancestor_key = token();
+  const navigate_ancestor_from_nested_key = token();
+
+  const win = window.open(generateURL(
+      "resources/navigate-ancestor-test-runner.https.html",
+      [navigate_ancestor_key, navigate_ancestor_from_nested_key]));
+  await new Promise(resolve => {
+    win.onload = resolve;
+  });
+
+  const unloadPromise = new Promise(resolve => {
+    win.onunload = resolve;
+  });
+
+  await win.runTest(test_type, ancestor_type);
+  win.close();
+  await unloadPromise;
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-test-runner.https.html b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-test-runner.https.html
new file mode 100644
index 0000000000..d0f2e8d694
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-ancestor-test-runner.https.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<title>Test navigating an ancestor frame from within a fenced frame</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+
+<body>
+<script>
+// This function is called by `window.opener`, which is a same-origin window.
+window.runTest = function(test_type, ancestor_type) {
+  // Messages by this key are sent from
+  // `navigate-ancestor-destination.https.html` to let us know if the "_parent"
+  // navigations performed inside fenced frames landed on the right page.
+  // If somehow *this document* gets navigated unexpectedly, the test will fail
+  // given `beforeunloadPromise` below.
+  // For "nested" tests, this document hosts a top-level fenced frame navigated
+  // to `navigate-ancestor-from-nested-{fenced-frame,iframe}.https.html`,
+  // which itself hosts a nested fenced frame or iframe. The top-level fenced
+  // frame will wait for the right confirmation that the nested document has
+  // operated correctly, and report back to *us* that everything is OK via this
+  // key below.
+  const [navigate_ancestor_key, navigate_ancestor_from_nested_key] =
+      parseKeylist();
+
+  const beforeunloadPromise = new Promise((resolve, reject) => {
+    window.onbeforeunload = e => {
+      reject(`The top-level test runner document does not navigate when a ` +
+             `${test_type} navigates ${ancestor_type}`);
+    }
+  });
+
+  let test_promise = null;
+  switch (test_type) {
+    case 'top-level fenced frame':
+      // This fenced frame will attempt to navigate its parent to
+      // `navigate-ancestor-destination.https.html`. It should end up navigating
+      // *itself* since it is a top-level browsing context. Just in case it
+      // accidentally navigates *this* frame, we have an `onbeforeunload`
+      // handler that will automatically fail the test before.
+      attachFencedFrame(generateURL(
+          `navigate-ancestor-helper.https.html`,
+          [navigate_ancestor_key, ancestor_type]));
+      test_promise = nextValueFromServer(navigate_ancestor_key);
+      break;
+    case 'nested fenced frame':
+      attachFencedFrame(generateURL(
+        `navigate-ancestor-from-nested-fenced-frame.https.html`,
+        [navigate_ancestor_key, navigate_ancestor_from_nested_key,
+         ancestor_type]));
+      test_promise = nextValueFromServer(navigate_ancestor_from_nested_key)
+        .then(message => {
+          if (message != "PASS") {
+            throw message;
+          }
+        });
+      break;
+    case 'nested iframe':
+      attachFencedFrame(generateURL(
+        `navigate-ancestor-from-nested-iframe.https.html`,
+        [navigate_ancestor_key, navigate_ancestor_from_nested_key,
+         ancestor_type]));
+      test_promise = nextValueFromServer(navigate_ancestor_from_nested_key)
+        .then(message => {
+          if (message != `PASS: [${ancestor_type}] location change failed.`) {
+            throw message;
+          }
+        });
+
+      break;
+  }
+
+  return Promise.race([test_promise, beforeunloadPromise]);
+}
+</script>
+
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html
new file mode 100644
index 0000000000..c7d7d6f278
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame hosting named frames</title>
+
+<body>
+<script>
+async function init() {
+  // This file is meant to run in a <fencedframe>. It sets up multiple frames
+  // all with the name `target_frame` in the following arrangements:
+  //   1.) A top-level fenced frame
+  //   2.) An iframe within a fenced frame
+  //   3.) A nested fenced frame
+  // Navigations to all of the above should fail, and thus should open a new
+  // top-level popup window instead of navigating these frames.
+
+  const [ready_for_navigation_key, test_type] = parseKeylist();
+
+  switch (test_type) {
+    case "top-level fenced frame":
+      // Set up the named frame and report to the outer document that we're ready
+      // for it to try and navigate the named frame.
+      window.name = "target_frame";
+      writeValueToServer(ready_for_navigation_key, "READY");
+      break;
+    case "nested iframe":
+      const iframe = document.createElement('iframe');
+      iframe.name = "target_frame";
+      document.body.append(iframe);
+      writeValueToServer(ready_for_navigation_key, "READY");
+      break;
+    case "nested fenced frame":
+      // This fenced frame will report to the outermost document when it is ready.
+      const ff =
+          attachFencedFrame(generateURL(
+              "fenced-frame-set-name-and-report-ready-for-" +
+              "outermost-document-to-navigate.html",
+              [ready_for_navigation_key]));
+      break;
+  }
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html
new file mode 100644
index 0000000000..d3bd955697
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Navigate reporting helper</title>
+<!-- This document is used as a helper by `../navigate-by-name.html`. That test
+     attempts to navigate various frames all named `target_frame`, to this
+     document. All of these navigations should fail, due to the frames being
+     unreachable to the initiator (because of the "fence" of the fenced frame).
+     As a result, this document should always load in a new top-level
+     "outermost" pop-up window.
+-->
+
+<script>
+const [navigation_success_key] = parseKeylist();
+
+// We're currently using `window.opener` as a proxy for "did this load in a new
+// outermost popup window?". Note that if we try and test navigations initiated
+// from inside a fenced frame and they open up in a new outermost popup, there
+// will be no opener by default (crbug.com/1250694) so using `window.opener` as
+// a signal will be insufficient. In order to test anchor navigations to this
+// document from within a fenced frame, we'll need a better signal for
+// outermost-ness. We should consider adding a value to `document.loadingMode`
+// for fenced frames:
+// https://wicg.github.io/nav-speculation/prerendering.htmlprerendering.html#browsing-context-loading-mode.
+//
+// Alternatively if we really want to detect if this loaded inside a fenced
+// frame, we could just remove the opt-in headers and then implementations that
+// support fenced frame opt-ins would timeout if they somehow don't honor the
+// fence on named frame navigations, but that's not a very good outcome.
+if (window.opener) {
+  writeValueToServer(navigation_success_key, "PASS");
+} else {
+  writeValueToServer(navigation_success_key, "FAIL");
+}
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-by-name-reporting-helper.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html b/testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html
new file mode 100644
index 0000000000..85c5194c6c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Navigate a fenced frame to a nested config</title>
+<body>
+<script>
+  const [key] = parseKeylist();
+  const configs = window.fence.getNestedConfigs();
+  const ff = document.createElement("fencedframe");
+  ff.config = configs[0]
+  document.body.appendChild(ff);
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigate-nested-config.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html
new file mode 100644
index 0000000000..59170c7512
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of navigator.keyboard.getLayoutMap</title>
+
+<body>
+<script>
+async function init() { // Needed in order to use top-level await.
+  // This file is meant to be navigated to from a <fencedframe> element. It
+  // reports back to the page hosting the <fencedframe> whether or not
+  // `keyboard.getLayoutMap` is allowed.
+  const keyboard_layout_key = parseKeylist();
+  // Report whether or not `navigator.keyboard.getLayoutMap()` is allowed.
+  navigator.keyboard.getLayoutMap().then(
+    () => { writeValueToServer(keyboard_layout_key, "resolved"); },
+    () => { writeValueToServer(keyboard_layout_key, "rejected");},
+  );
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-layout-map-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html
new file mode 100644
index 0000000000..105166c7ad
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of navigator.keyboard.lock</title>
+
+<body>
+<script>
+async function init() { // Needed in order to use top-level await.
+  // This file is meant to be navigated to from a <fencedframe> element. It
+  // reports back to the page hosting the <fencedframe> whether or not
+  // `keyboard.lock` is allowed.
+  const [keyboard_lock_key] = parseKeylist();
+  // Report whether or not `navigator.keyboard.lock()` is allowed.
+  navigator.keyboard.lock().then(
+    () => { writeValueToServer(keyboard_lock_key, "resolved"); },
+    () => { writeValueToServer(keyboard_lock_key, "rejected");},
+  );
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/navigator-keyboard-lock-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/notification-sw.js b/testing/web-platform/tests/fenced-frame/resources/notification-sw.js
new file mode 100644
index 0000000000..e9b1e2b9dd
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/notification-sw.js
@@ -0,0 +1,20 @@
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', async event => {
+  const method = event.data;
+
+  if (method === 'constructor') {
+    try {
+      new Notification('test');
+    } catch (e) {
+      event.source.postMessage(e.message);
+    }
+  } else if (method === 'showNotification') {
+    try {
+      await self.registration.showNotification('test', {body: 'test'});
+    } catch (e) {
+      event.source.postMessage(e.message);
+    }
+  }
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/opaque-ad-sizes-utils.js b/testing/web-platform/tests/fenced-frame/resources/opaque-ad-sizes-utils.js
new file mode 100644
index 0000000000..edf8640f20
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/opaque-ad-sizes-utils.js
@@ -0,0 +1,47 @@
+async function runOpaqueAdSizesTest(input_width, input_height, output_width, output_height) {
+  // Attach a FLEDGE fenced frame whose outer container has dimensions
+  // `input_width` by `input_height`.
+  const frame = await attachFencedFrameContext({
+      generator_api: "fledge", resolve_to_config: true, attributes: [
+      ["width", input_width], ["height", input_height]]});
+
+  const assert_dimensions =
+      (label, input_width, input_height, output_width, output_height) => {
+    assert_equals(getComputedStyle(document.documentElement).width,
+        output_width+"px",
+        label + " the computed width coerces to " + output_width);
+    assert_equals(window.innerWidth, output_width,
+        label + " the innerWidth " + input_width + " coerces to " + output_width);
+    assert_equals(window.innerHeight, output_height,
+        label + " the innerHeight " + input_height + " coerces to " + output_height);
+  }
+
+  // Assert that the fenced frame sees its dimensions rounded to the nearest
+  // ad size.
+  await frame.execute(assert_dimensions,
+      ["After navigation", input_width, input_height, output_width, output_height]);
+
+  // Assert that the embedder sees the fenced frame's original dimensions.
+  assert_equals(frame.width, input_width.toString(),
+      "The outer container width is the requested width.");
+  assert_equals(frame.height, input_height.toString(),
+      "The outer container height is the requested height.");
+
+  // Resize the fenced frame's outer container.
+  const new_size_x = 320;
+  const new_size_y = 50;
+  frame.width = new_size_x;
+  frame.height = new_size_y;
+
+  // Refresh the fenced frame.
+  await frame.execute(() => {
+    window.executor.suspend(() => {
+      location.href = location.href;
+    });
+  });
+
+  // Observe that navigations after the first don't change the fenced frame's
+  // inner dimensions.
+  await frame.execute(assert_dimensions,
+      ["After resizing", input_width, input_height, output_width, output_height]);
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/payment-handler-sw.js b/testing/web-platform/tests/fenced-frame/resources/payment-handler-sw.js
new file mode 100644
index 0000000000..8b5e83cddf
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/payment-handler-sw.js
@@ -0,0 +1,10 @@
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', event => {
+  try {
+    self.registration.paymentManager;
+  } catch (e) {
+    event.source.postMessage(e);
+  }
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html b/testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html
new file mode 100644
index 0000000000..06724ac061
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of navigator.permissions.query</title>
+
+<body>
+  <script>
+    (async () => {
+      const [permission_key, permission_name] = parseKeylist();
+      // Push permission without userVisibleOnly:true is not supported.
+      let user_visible_only = permission_name === 'push' ? true : false;
+      const result = await navigator.permissions.query({ name: permission_name, userVisibleOnly: user_visible_only });
+      writeValueToServer(permission_key, `result: ${result.state}`);
+    })();
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-api-denied-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html b/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html
new file mode 100644
index 0000000000..07c3e662bf
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of navigator.geolocation.getCurrentPosition()</title>
+
+<body>
+<script>
+(async () => {
+  const [permission_geolocation_key] = parseKeylist();
+  const result = await new Promise(resolve => {
+    navigator.geolocation.getCurrentPosition(
+        () => resolve('granted'), () => resolve('denied'));
+  });
+  writeValueToServer(permission_geolocation_key, `result: ${result}`);
+})();
+</script>
+</body>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-test-runner.html b/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-test-runner.html
new file mode 100644
index 0000000000..724a35ce9a
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-geolocation-test-runner.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<title>Fenced frame content to report the result of navigator.geolocation.getCurrentPosition()</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="utils.js"></script>
+
+<body>
+<script>
+
+window.runTest = async (fenced_frame_url) => {
+  const [permission_geolocation_key] = parseKeylist();
+  await test_driver.set_permission({name: 'geolocation'}, 'granted', true);
+
+  attachFencedFrame(generateURL(fenced_frame_url, [permission_geolocation_key]));
+  const actual_result = await nextValueFromServer(permission_geolocation_key);
+
+  assert_equals(
+      actual_result, 'result: denied',
+      'geolocation permission is not permitted for fenced frames.');
+};
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html b/testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html
new file mode 100644
index 0000000000..d01d10034c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of Notification.requestPermission</title>
+
+<body>
+<script>
+(async () => {
+  const [permission_notification_key] = parseKeylist();
+  const result = await Notification.requestPermission();
+  writeValueToServer(permission_notification_key, `result: ${result}`);
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/permission-notification-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/popup-noopener-destination.html b/testing/web-platform/tests/fenced-frame/resources/popup-noopener-destination.html
new file mode 100644
index 0000000000..30cc21f22c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/popup-noopener-destination.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Destination page opened by a frame in a Fenced Frame tree</title>
+<script>
+  // It is the document that `popup-noopener-inner.html` loads in a new
+  // window/tab from a root fenced frame, an iframe in a fenced frame and from
+  // a nested fenced frame. It's expected that any popup opened from a Fenced
+  // Frame tree cannot reach the opener.
+  const [popup_noopener_key, popup_name_key] = parseKeylist();
+  if (window.opener) {
+    writeValueToServer(popup_noopener_key, "FAIL: window.opener is not null");
+  } else {
+    writeValueToServer(popup_noopener_key, "PASS");
+  }
+  if (window.name) {
+    writeValueToServer(popup_name_key, "FAIL: window.name is not empty");
+  } else {
+    writeValueToServer(popup_name_key, "PASS");
+  }
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html b/testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html
new file mode 100644
index 0000000000..6a79fd21b2
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame creating popups</title>
+
+<body>
+<script>
+async function init() {
+  // This file is meant to run in a <fencedframe>. It sets up multiple frames
+  // in the following arrangements:
+  //   1.) A top-level fenced frame
+  //   2.) An iframe within a fenced frame
+  //   3.) A nested fenced frame
+  // All of the above frames create a popup which should not return a reference
+  // to the new window.
+
+  const [popup_noopener_key, popup_openee_key, popup_name_key, test_type] =
+      parseKeylist();
+
+  switch (test_type) {
+    case "top-level fenced frame":
+      src_popup = generateURL(`popup-noopener-destination.html`,
+          [popup_noopener_key, popup_name_key]);
+      const popup = window.open(src_popup, "foo");
+      if (popup) {
+        writeValueToServer(popup_openee_key, "FAIL");
+      } else {
+        writeValueToServer(popup_openee_key, "PASS");
+      }
+      break;
+    case "nested iframe":
+      const iframe = document.createElement('iframe');
+      document.body.append(iframe);
+      iframe.src = generateURL(`create-popup.html`,
+          [popup_noopener_key, popup_openee_key, popup_name_key]);
+      break;
+    case "nested fenced frame":
+      const ff =
+          attachFencedFrame(generateURL(`create-popup.html`,
+              [popup_noopener_key, popup_openee_key, popup_name_key]));
+      break;
+  }
+
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/popup-noopener-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/prerender-inner.html b/testing/web-platform/tests/fenced-frame/resources/prerender-inner.html
new file mode 100644
index 0000000000..a523ef31c1
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/prerender-inner.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of prerendering</title>
+
+<body>
+<script>
+(() => {
+  [prerender_ready_key, prerender_loaded_key, prerender_activated_key] =
+      parseKeylist();
+  document.addEventListener('prerenderingchange', () => {
+    writeValueToServer(prerender_activated_key, 'activated');
+  });
+  if (document.prerendering) {
+    writeValueToServer(prerender_ready_key, 'ready');
+  } else {
+    writeValueToServer(prerender_loaded_key, 'loaded');
+  }
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/prerender-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/prerender-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/prerender-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html b/testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html
new file mode 100644
index 0000000000..2e170dd91b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of navigator.presentation.receiver</title>
+
+<body>
+<script>
+(async () => {
+  const [presentation_receiver_key] = parseKeylist();
+  const result = await navigator.presentation.receiver;
+  if (result == null) {
+    writeValueToServer(presentation_receiver_key, "denied");
+  } else {
+    writeValueToServer(presentation_receiver_key, "allowed");
+  }
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/presentation-receiver-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/remote-context-executor.https.html b/testing/web-platform/tests/fenced-frame/resources/remote-context-executor.https.html
new file mode 100644
index 0000000000..6b2f5ccc00
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/remote-context-executor.https.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/common/get-host-info.sub.js"></script>
+<script src="/common/utils.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<title>Script to wait for instructions from RemoteContext.</title>
+
+<body>
+<script>
+window.addEventListener("load", async () => {
+  // Find the uuid to communicate with the parent.
+  const uuid = new URLSearchParams(window.location.search).get('uuid');
+
+  // Wait for the window to have its size computed and become visible,
+  // so that simulated user gestures will be handled properly.
+  while (window.innerWidth == 0) {
+    await new Promise(resolve => requestAnimationFrame(resolve));
+  }
+
+  // Create a RemoteContext Executor, which will wait in the background
+  // for scripts to execute.
+  window.executor = new Executor(uuid);
+});
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/report-url.html b/testing/web-platform/tests/fenced-frame/resources/report-url.html
new file mode 100644
index 0000000000..e0b7d0982a
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/report-url.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>A page embedded as a fenced frame that reports the document URL</title>
+<script>
+const [uuid] = parseKeylist();
+writeValueToServer(uuid, location.href);
+</script>
diff --git a/testing/web-platform/tests/fenced-frame/resources/report-url.html.headers b/testing/web-platform/tests/fenced-frame/resources/report-url.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/report-url.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html
new file mode 100644
index 0000000000..cb17789b45
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+  <script src="utils.js"></script>
+  <title>Fenced frame content to report any changes in inner dimensions</title>
+
+  <style>
+    body {
+      width: 500px;
+      height: 500px;
+      background: grey;
+    }
+  </style>
+  <body>
+    <script>
+      let eventCount = 0;
+      async function init() {
+        const [resize_lock_inner_page_is_ready_key,
+               resize_lock_resize_is_done_key,
+               resize_lock_report_click_location_key,
+               resize_lock_report_click_location_key_after_resize,
+               resize_lock_report_click_location_key_after_resize_2] = parseKeylist();
+
+        window.addEventListener('mousedown', async (event) => {
+          eventCount++;
+          let point = event.clientX + "," + event.clientY;
+          if (eventCount == 1) {
+            writeValueToServer(resize_lock_report_click_location_key, point);
+            await nextValueFromServer(resize_lock_resize_is_done_key)
+          } else if (eventCount == 2) {
+            writeValueToServer(
+              resize_lock_report_click_location_key_after_resize, point);
+          } else {
+            writeValueToServer(
+              resize_lock_report_click_location_key_after_resize_2, point);
+          }
+        });
+
+        writeValueToServer(resize_lock_inner_page_is_ready_key, "ready");
+      }
+
+      init();
+    </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html.headers b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner-input.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html
new file mode 100644
index 0000000000..fbaf436330
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+  <script src="utils.js"></script>
+  <title>Fenced frame content to report any changes in inner dimensions</title>
+
+  <body>
+    <script>
+      async function init() {
+        const [resize_lock_inner_page_is_ready_key,
+               resize_lock_resize_is_done_key,
+               resize_lock_report_inner_dimensions_key] = parseKeylist();
+
+        writeValueToServer(resize_lock_inner_page_is_ready_key, "ready");
+
+        await nextValueFromServer(resize_lock_resize_is_done_key);
+
+        const response = window.innerWidth + "x" + window.innerHeight;
+        writeValueToServer(resize_lock_report_inner_dimensions_key, response);
+      }
+
+      init();
+    </script>
+  </body>
+</html>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/resize-lock-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/response-204.py b/testing/web-platform/tests/fenced-frame/resources/response-204.py
new file mode 100644
index 0000000000..e6cf8d4ac9
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/response-204.py
@@ -0,0 +1,4 @@
+def main(request, response):
+    response_headers = []
+    body = "No content"
+    return (204, response_headers, body)
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-iframe.sub.html b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-iframe.sub.html
new file mode 100644
index 0000000000..7ee8b7d98f
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-iframe.sub.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<title>Iframe content to load a fenced frame and report a value to the server</title>
+<script src="utils.js"></script>
+
+<body>
+<script>
+  const fencedframe = document.createElement("fencedframe");
+  fencedframe.config = new FencedFrameConfig(
+      generateURL("sandbox-mandatory-flags-inner.sub.html?key={{GET[key]}}" +
+          "&value={{GET[value]}}", []));
+  document.body.appendChild(fencedframe);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html
new file mode 100644
index 0000000000..5f400b5bde
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<title>Fenced frame content to report a value to the server</title>
+
+<body>
+<img src="key-value-store.py?key={{GET[key]}}&value={{GET[value]}}">
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html.headers b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-inner.sub.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-looser-restriction.sub.html b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-looser-restriction.sub.html
new file mode 100644
index 0000000000..0ad64c1a5c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandbox-mandatory-flags-looser-restriction.sub.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<title>Iframe content to load a nested sandboxed iframe with all mandatory allow-* flags</title>
+
+<body>
+<iframe
+  src="sandbox-mandatory-flags-iframe.sub.html?key={{GET[key]}}&value={{GET[value]}}"
+  sandbox="allow-same-origin
+           allow-forms
+           allow-scripts
+           allow-popups
+           allow-popups-to-escape-sandbox
+           allow-top-navigation-by-user-activation">
+</iframe>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html
new file mode 100644
index 0000000000..f3bcbc8ba1
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="utils.js"></script>
+<script src="sandboxed-features.js"></script>
+<body>
+<script>
+(async () => {
+  try {
+    await {{GET[test_func]}}();
+  } catch (e) {
+    writeValueToServer('{{GET[key]}}', e.message);
+    return;
+  }
+  writeValueToServer('{{GET[key]}}', 'done');
+})()
+</script>
+</body>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html.headers b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-inner.sub.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html
new file mode 100644
index 0000000000..44584440e1
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<body>
+<iframe
+  src="sandboxed-features-inner.sub.html?key={{GET[key]}}&test_func={{GET[test_func]}}"
+  sandbox="allow-forms
+           allow-modals
+           allow-orientation-lock
+           allow-pointer-lock
+           allow-popups
+           allow-popups-to-escape-sandbox
+           allow-presentation
+           allow-same-origin
+           allow-scripts
+           allow-top-navigation
+           allow-top-navigation-by-user-activation
+           allow-downloads">
+</iframe>
+
+</body>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html.headers b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features-looser-restriction.sub.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/sandboxed-features.js b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features.js
new file mode 100644
index 0000000000..1cbd4a48f3
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/sandboxed-features.js
@@ -0,0 +1,126 @@
+const run_in_fenced_frame = (func_name, description, is_nested) => {
+  promise_test(async test => {
+    const key = token();
+    const url = is_nested ?
+                'resources/sandboxed-features-looser-restriction.sub.html?' :
+                'resources/sandboxed-features-inner.sub.html?';
+    let params = new URLSearchParams();
+    params.set('key', key);
+    params.set('test_func', func_name);
+    const frame = document.createElement('fencedframe');
+    const frame_url = 'resources/sandboxed-features-inner.sub.html?' +
+    params.toString();
+    const config = new FencedFrameConfig(generateURL(frame_url, []));
+    frame.config = config;
+    test.add_cleanup(() => {
+      frame.remove();
+    });
+    document.body.appendChild(frame);
+    assert_equals(await nextValueFromServer(key), 'done');
+  }, description);
+};
+
+const run_sanboxed_feature_test = (func_name, description) => {
+  run_in_fenced_frame(func_name, description, false);
+  run_in_fenced_frame(func_name, description + '[looser sandboxed]', true);
+};
+
+async function test_prompt() {
+  assert_equals(
+    window.prompt('Test prompt'),
+    null,
+    'window.prompt() must synchronously return null in a fenced frame without' +
+    ' blocking on user input.');
+}
+
+async function test_alert() {
+  assert_equals(
+    window.alert('Test alert'),
+    undefined,
+    'window.alert() must synchronously return undefined in a fenced frame' +
+    '  without blocking on user input.');
+}
+
+async function test_confirm() {
+  assert_equals(
+    window.confirm('Test confirm'),
+    false,
+    'window.confirm() must synchronously return false in a fenced frame' +
+    ' without blocking on user input.');
+}
+
+async function test_print() {
+  assert_equals(
+    window.print(),
+    undefined,
+    'window.print() must synchronously return undefined in a fenced frame' +
+    ' without blocking on user input.');
+
+  assert_equals(
+    document.execCommand('print', false, null),
+    false,
+    'execCommand(\'print\') must synchronously return false in a fenced frame' +
+    ' without blocking on user input.');
+}
+
+async function test_document_domain() {
+  assert_throws_dom('SecurityError', () => {
+    document.domain = 'example.test';
+  });
+  assert_throws_dom('SecurityError', () => {
+    document.domain = document.domain;
+  });
+  assert_throws_dom('SecurityError', () => {
+    (new Document).domain = document.domain;
+  });
+  assert_throws_dom('SecurityError', () => {
+    document.implementation.createHTMLDocument().domain = document.domain;
+  });
+  assert_throws_dom('SecurityError', () => {
+    document.implementation.createDocument(null, '').domain = document.domain;
+  });
+  assert_throws_dom('SecurityError', () => {
+    document.createElement('template').content.ownerDocument.domain =
+        document.domain;
+  });
+}
+
+async function test_presentation_request() {
+  assert_throws_dom('SecurityError', () => {
+    new PresentationRequest([location.href]);
+  });
+}
+
+async function test_screen_orientation_lock() {
+  try {
+    await screen.orientation.lock('portrait');
+  } catch (e) {
+    assert_equals(
+      e.name,
+      'SecurityError',
+      'orientation.lock() must throw a SecurityError in a fenced frame.');
+    return;
+  }
+  assert_unreached('orientation.lock() must throw an error');
+}
+
+async function test_pointer_lock() {
+  await simulateGesture();
+
+  const canvas = document.createElement('canvas');
+  document.body.appendChild(canvas);
+  const pointerlockerror_promise = new Promise(resolve => {
+    document.addEventListener('pointerlockerror', resolve);
+  });
+  try {
+    await canvas.requestPointerLock();
+  } catch (e) {
+    assert_equals(
+      e.name,
+      'SecurityError',
+      'orientation.lock() must throws a SecurityError in a fenced frame.');
+    await pointerlockerror_promise;
+    return;
+  }
+  assert_unreached('requestPointerLock() must fail in a fenced frame');
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html
new file mode 100644
index 0000000000..02f28bd82e
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+
+<body>
+  <script type="module">
+    // Ask the worker to do a fetch request that will be handled by the service
+    // worker via postMessage.
+    const checkIfServiceWorkerCanControlWebWorker = async () => {
+      const dedicated_worker = new Worker('serviceWorker-dedicated-worker.js');
+      return new Promise((resolve, reject) => {
+        dedicated_worker.addEventListener('message', e => {
+          resolve(e.data)
+        });
+        dedicated_worker.postMessage('fetch');
+      })
+    }
+
+    const [key] = parseKeylist();
+    const url = new URL(location.href);
+    if (url.searchParams.get('useServiceWorkerInFencedFrame')) {
+      await navigator.serviceWorker.register('serviceWorker-dedicated-worker-sw.js');
+      await navigator.serviceWorker.ready;
+    }
+
+    const result = await checkIfServiceWorkerCanControlWebWorker();
+    writeValueToServer(key, result);
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js
new file mode 100644
index 0000000000..027995a218
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js
@@ -0,0 +1,18 @@
+self.addEventListener('fetch', async (e) => {
+  if (e.request.url.includes('fenced_frame_dedicated_worker_test')) {
+    e.respondWith(new Response('OK'));
+    return;
+  }
+
+  e.respondWith(fetch(e.request).catch(() => {
+    return new Response('not found');
+  }));
+})
+
+self.addEventListener('install', () => {
+  return self.skipWaiting();
+});
+
+self.addEventListener('activate', () => {
+  return self.clients.claim();
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js.headers b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js.headers
new file mode 100644
index 0000000000..d0b9633bb0
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker-sw.js.headers
@@ -0,0 +1 @@
+Service-Worker-Allowed: /
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker.js b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker.js
new file mode 100644
index 0000000000..8a9fa5ef36
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-dedicated-worker.js
@@ -0,0 +1,8 @@
+self.addEventListener('message', async (e) => {
+  if (e.data === 'fetch') {
+    // Send a request to non-existing URL but handled by SW.
+    const res = await fetch('./fenced_frame_dedicated_worker_test');
+    const data = res.ok ? await res.text() : res.statusText;
+    self.postMessage(data);
+  }
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html
new file mode 100644
index 0000000000..103236e52a
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<body>
+<script>
+
+function getFrameType(service_worker, url) {
+  return new Promise((resolve, reject) => {
+    const channel = new MessageChannel();
+    channel.port1.onmessage = e => {
+      resolve(e.data);
+    };
+    service_worker.postMessage({port:channel.port2, url:url},
+                               [channel.port2]);
+  });
+}
+
+(async function() {
+  await navigator.serviceWorker.register('serviceWorker-frameType.js');
+  const registration = await navigator.serviceWorker.ready;
+  const service_worker = registration.active;
+
+  const [frame_type_key, frame_type_ack_key] = parseKeylist();
+
+  const frame_type = await getFrameType(service_worker, location.href);
+  writeValueToServer(frame_type_key, frame_type);
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `serviceWorker.frameType` stash and we can write to it again.
+  await nextValueFromServer(frame_type_ack_key);
+
+  const iframe = document.createElement('iframe');
+  iframe.src = generateURL("serviceWorker-frameType-nested.html",
+      [frame_type_key]);
+  document.body.append(iframe);
+})();
+</script>
+</body>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html
new file mode 100644
index 0000000000..10bb7ff8bd
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<body>
+<script>
+
+function getFrameType(service_worker, url) {
+  return new Promise((resolve, reject) => {
+    const channel = new MessageChannel();
+    channel.port1.onmessage = e => {
+      resolve(e.data);
+    };
+    service_worker.postMessage({port:channel.port2, url:url},
+                               [channel.port2]);
+  });
+}
+
+(async function() {
+  const service_worker = navigator.serviceWorker.controller;
+  const frame_type = await getFrameType(service_worker, location.href);
+
+  const [frame_type_key] = parseKeylist();
+  writeValueToServer(frame_type_key, frame_type);
+})();
+</script>
+</body>
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html.headers b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType-nested.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType.js b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType.js
new file mode 100644
index 0000000000..91003fc131
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-frameType.js
@@ -0,0 +1,19 @@
+self.onmessage = function(e) {
+  var port = e.data.port;
+  var url = e.data.url;
+
+  e.waitUntil(self.clients.matchAll({includeUncontrolled: true})
+    .then(function(clients) {
+        var frame_type = "none";
+        for (client of clients) {
+          if (client.url === url) {
+            frame_type = client.frameType;
+            break;
+          }
+        }
+        port.postMessage(frame_type);
+      })
+    .catch(e => {
+        port.postMessage('clients.matchAll() rejected: ' + e);
+      }));
+};
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html
new file mode 100644
index 0000000000..4d77d9e9a6
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<body>
+<script>
+
+(async function() {
+  const [navigate_key] = parseKeylist();
+  writeValueToServer(navigate_key, 'success');
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html.headers b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner-success.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html
new file mode 100644
index 0000000000..aaf330f4f6
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<body>
+<script>
+
+(async function() {
+  await navigator.serviceWorker.register('serviceWorker-navigate.js');
+  const registration = await navigator.serviceWorker.ready;
+  const service_worker = registration.active;
+
+  const [navigate_key] = parseKeylist();
+
+  service_worker.postMessage({key:navigate_key, url:location.href});
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate.js b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate.js
new file mode 100644
index 0000000000..a7a4db52ee
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-navigate.js
@@ -0,0 +1,18 @@
+self.importScripts('utils.js');
+
+self.onmessage = function(e) {
+  var key = e.data.key;
+  var url = e.data.url;
+
+  e.waitUntil(self.clients.claim().then(() => {
+      return self.clients.matchAll({type: 'window'});
+    }).then(clients => {
+      return clients.map(client => {
+        // Check to make sure WindowClient.navigate() is supported.
+        if (client.url === url) {
+          return client.navigate(generateURL('serviceWorker-navigate-inner-success.html',
+                                        [key]));
+        }
+      });
+    }));
+};
diff --git a/testing/web-platform/tests/fenced-frame/resources/serviceWorker-push-sw.js b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-push-sw.js
new file mode 100644
index 0000000000..e344b45fd8
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/serviceWorker-push-sw.js
@@ -0,0 +1,19 @@
+self.addEventListener('install', e => e.waitUntil(skipWaiting()));
+self.addEventListener('activate', e => e.waitUntil(clients.claim()));
+
+self.addEventListener('message', async e => {
+  const method = e.data;
+
+  const promise = method === 'subscribe' ?
+      self.registration.pushManager.subscribe({userVisibleOnly: true}) :
+      Promise.resolve();
+  const message = await promise
+                      .then(() => {
+                        return `${method}: Unexpectedly started`;
+                      })
+                      .catch((e) => {
+                        return e.message;
+                      });
+
+  e.source.postMessage(message);
+});
diff --git a/testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html
new file mode 100644
index 0000000000..1cf3fc8680
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame accessing cookies</title>
+
+<body>
+<script>
+async function init() {
+  // This file is meant to run in a <fencedframe>. It sets up multiple frames
+  // in the following arrangements:
+  //   1.) A top-level fenced frame
+  //   2.) An iframe within a fenced frame
+  //   3.) A nested fenced frame
+
+  // Set cookies in the root fenced frame via document and cookieStore APIs.
+  const [cookie_value_key, test_type] = parseKeylist();
+  document.cookie = 'C=fenced; SameSite=Lax';
+  document.cookie = 'D=fenced; SameSite=None; Secure';
+  await cookieStore.set('E', 'fenced');
+
+  const cookie_access_url = generateURL("cookie-access.https.html",
+      [cookie_value_key]);
+
+  switch (test_type) {
+    case "top-level fenced frame":
+      const cookie_value = document.cookie;
+      writeValueToServer(cookie_value_key, cookie_value);
+      break;
+    case "nested iframe":
+      const iframe = document.createElement('iframe');
+      document.body.append(iframe);
+      iframe.src = cookie_access_url;
+      break;
+    case "nested fenced frame":
+      const ff = attachFencedFrame(cookie_access_url);
+      break;
+  }
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html.headers
new file mode 100644
index 0000000000..e2b453f463
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/unique-cookie-partition-inner.https.html.headers
@@ -0,0 +1,2 @@
+Supports-Loading-Mode: fenced-frame
+Set-Cookie: F=fenced; SameSite=Lax
diff --git a/testing/web-platform/tests/fenced-frame/resources/utils.js b/testing/web-platform/tests/fenced-frame/resources/utils.js
new file mode 100644
index 0000000000..4638f37cbb
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/utils.js
@@ -0,0 +1,501 @@
+const STORE_URL = '/fenced-frame/resources/key-value-store.py';
+const BEACON_URL = '/fenced-frame/resources/automatic-beacon-store.py';
+const REMOTE_EXECUTOR_URL = '/fenced-frame/resources/remote-context-executor.https.html';
+const FLEDGE_BIDDING_URL = '/fenced-frame/resources/fledge-bidding-logic.js';
+const FLEDGE_BIDDING_WITH_SIZE_URL = '/fenced-frame/resources/fledge-bidding-logic-with-size.js';
+const FLEDGE_DECISION_URL = '/fenced-frame/resources/fledge-decision-logic.js';
+
+// Creates a URL that includes a list of stash key UUIDs that are being used
+// in the test. This allows us to generate UUIDs on the fly and let anything
+// (iframes, fenced frames, pop-ups, etc...) that wouldn't have access to the
+// original UUID variable know what the UUIDs are.
+// @param {string} href - The base url of the page being navigated to
+// @param {string list} keylist - The list of key UUIDs to be used. Note that
+//                                order matters when extracting the keys
+function generateURL(href, keylist) {
+  const ret_url = new URL(href, location.href);
+  ret_url.searchParams.append("keylist", keylist.join(','));
+  return ret_url;
+}
+
+function getRemoteContextURL(origin) {
+  return new URL(REMOTE_EXECUTOR_URL, origin);
+}
+
+async function runSelectRawURL(href, resolve_to_config = false) {
+  try {
+    await sharedStorage.worklet.addModule(
+      "/shared-storage/resources/simple-module.js");
+  } catch (e) {
+    // Shared Storage needs to have a module added before we can operate on it.
+    // It is generated on the fly with this call, and since there's no way to
+    // tell through the API if a module already exists, wrap the addModule call
+    // in a try/catch so that if it runs a second time in a test, it will
+    // gracefully fail rather than bring the whole test down.
+  }
+  return await sharedStorage.selectURL(
+      'test-url-selection-operation', [{url: href}], {
+        data: {'mockResult': 0},
+        resolveToConfig: resolve_to_config,
+        keepAlive: true
+      });
+}
+
+// Similar to generateURL, but creates
+// 1. An urn:uuid if `resolve_to_config` is false.
+// 2. A fenced frame config object if `resolve_to_config` is true.
+// This relies on a mock Shared Storage auction, since it is the simplest
+// WP-exposed way to turn a url into an urn:uuid or a fenced frame config.
+// Note: this function, unlike generateURL, is asynchronous and needs to be
+// called with an await operator.
+// @param {string} href - The base url of the page being navigated to
+// @param {string list} keylist - The list of key UUIDs to be used. Note that
+//                                order matters when extracting the keys
+// @param {boolean} [resolve_to_config = false] - Determines whether the result
+//                                                of `sharedStorage.selectURL()`
+//                                                is an urn:uuid or a fenced
+//                                                frame config.
+// Note:
+// 1. There is a limit of 3 calls per origin per pageload for
+// `sharedStorage.selectURL()`, so `runSelectURL()` must also respect this
+// limit.
+// 2. If `resolve_to_config` is true, blink feature `FencedFramesAPIChanges`
+// needs to be enabled for `selectURL()` to return a fenced frame config.
+// Otherwise `selectURL()` will fall back to the old behavior that returns an
+// urn:uuid.
+async function runSelectURL(href, keylist = [], resolve_to_config = false) {
+  const full_url = generateURL(href, keylist);
+  return await runSelectRawURL(full_url, resolve_to_config);
+}
+
+async function generateURNFromFledgeRawURL(href,
+  nested_urls,
+  resolve_to_config = false,
+  ad_with_size = false,
+  requested_size = null) {
+  const bidding_token = token();
+  const seller_token = token();
+
+  const ad_components_list = nested_urls.map((url) => {
+    return ad_with_size ?
+      { renderUrl: url, sizeGroup: "group1" } :
+      { renderUrl: url }
+  });
+
+  const interestGroup = ad_with_size ?
+    {
+      name: 'testAd1',
+      owner: location.origin,
+      biddingLogicUrl: new URL(FLEDGE_BIDDING_WITH_SIZE_URL, location.origin),
+      ads: [{ renderUrl: href, sizeGroup: "group1", bid: 1 }],
+      userBiddingSignals: { biddingToken: bidding_token },
+      trustedBiddingSignalsKeys: ['key1'],
+      adComponents: ad_components_list,
+      adSizes: { "size1": { width: "100px", height: "50px" } },
+      sizeGroups: { "group1": ["size1"] }
+    } :
+    {
+      name: 'testAd1',
+      owner: location.origin,
+      biddingLogicUrl: new URL(FLEDGE_BIDDING_URL, location.origin),
+      ads: [{ renderUrl: href, bid: 1 }],
+      userBiddingSignals: { biddingToken: bidding_token },
+      trustedBiddingSignalsKeys: ['key1'],
+      adComponents: ad_components_list,
+    };
+
+  // Pick an arbitrarily high duration to guarantee that we never leave the
+  // ad interest group while the test runs.
+  navigator.joinAdInterestGroup(interestGroup, /*durationSeconds=*/3000000);
+
+  let auctionConfig = {
+    seller: location.origin,
+    interestGroupBuyers: [location.origin],
+    decisionLogicUrl: new URL(FLEDGE_DECISION_URL, location.origin),
+    auctionSignals: {biddingToken: bidding_token, sellerToken: seller_token},
+    resolveToConfig: resolve_to_config
+  };
+  if (requested_size) {
+    auctionConfig['requestedSize'] = {width: requested_size[0], height: requested_size[1]};
+  }
+  return navigator.runAdAuction(auctionConfig);
+}
+
+// Similar to runSelectURL, but uses FLEDGE instead of Shared Storage as the
+// auctioning tool.
+// Note: this function, unlike generateURL, is asynchronous and needs to be
+// called with an await operator. @param {string} href - The base url of the
+// page being navigated to @param {string list} keylist - The list of key UUIDs
+// to be used. Note that order matters when extracting the keys
+// @param {string} href - The base url of the page being navigated to
+// @param {string list} keylist - The list of key UUIDs to be used. Note that
+//                                order matters when extracting the keys
+// @param {string list} nested_urls - A list of urls that will eventually become
+//                                    the nested configs/ad components
+// @param {boolean} [resolve_to_config = false] - Determines whether the result
+//                                                of `navigator.runAdAuction()`
+//                                                is an urn:uuid or a fenced
+//                                                frame config.
+// @param {boolean} [ad_with_size = false] - Determines whether the auction is
+//                                           run with ad sizes specified.
+async function generateURNFromFledge(href, keylist, nested_urls=[], resolve_to_config = false, ad_with_size = false, requested_size = null) {
+  const full_url = generateURL(href, keylist);
+  return generateURNFromFledgeRawURL(full_url, nested_urls, resolve_to_config, ad_with_size, requested_size);
+}
+
+// Extracts a list of UUIDs from the from the current page's URL.
+// @returns {string list} - The list of UUIDs extracted from the page. This can
+//                          be read into multiple variables using the
+//                          [key1, key2, etc...] = parseKeyList(); pattern.
+function parseKeylist() {
+  const url = new URL(location.href);
+  const keylist = url.searchParams.get("keylist");
+  return keylist.split(',');
+}
+
+// Converts a same-origin URL to a cross-origin URL
+// @param {URL} url - The URL object whose origin is being converted
+// @param {boolean} [https=true] - Whether or not to use the HTTPS origin
+//
+// @returns {URL} The new cross-origin URL
+function getRemoteOriginURL(url, https=true) {
+  const same_origin = location.origin;
+  const cross_origin = https ? get_host_info().HTTPS_REMOTE_ORIGIN
+      : get_host_info().HTTP_REMOTE_ORIGIN;
+  return new URL(url.toString().replace(same_origin, cross_origin));
+}
+
+// Builds a URL to be used as a remote context executor.
+function generateRemoteContextURL(headers, origin) {
+  // Generate the unique id for the parent/child channel.
+  const uuid = token();
+
+  // Use the absolute path of the remote context executor source file, so that
+  // nested contexts will work.
+  const url = getRemoteContextURL(origin ? origin : location.origin);
+  url.searchParams.append('uuid', uuid);
+
+  // Add the header to allow loading in a fenced frame.
+  headers.push(["Supports-Loading-Mode", "fenced-frame"]);
+
+  // Transform the headers into the expected format.
+  // https://web-platform-tests.org/writing-tests/server-pipes.html#headers
+  function escape(s) {
+    return s.replace('(', '\\(').replace(')', '\\)');
+  }
+  const formatted_headers = headers.map((header) => {
+    return `header(${escape(header[0])}, ${escape(header[1])})`;
+  });
+  url.searchParams.append('pipe', formatted_headers.join('|'));
+
+  return [uuid, url];
+}
+
+function buildRemoteContextForObject(object, uuid, html) {
+  // https://github.com/web-platform-tests/wpt/blob/master/common/dispatcher/README.md
+  const context = new RemoteContext(uuid);
+  if (html) {
+    context.execute_script(
+      (html_source) => {
+        document.body.insertAdjacentHTML('beforebegin', html_source);
+      },
+    [html]);
+  }
+
+  // We need a little bit of boilerplate in the handlers because Proxy doesn't
+  // work so nicely with HTML elements.
+  const handler = {
+    get: (target, key) => {
+      if (key == "execute") {
+        return context.execute_script;
+      }
+      if (key == "element") {
+        return object;
+      }
+      if (key in target) {
+        return target[key];
+      }
+      return context[key];
+    },
+    set: (target, key, value) => {
+      target[key] = value;
+      return value;
+    }
+  };
+
+  const proxy = new Proxy(object, handler);
+  return proxy;
+}
+
+// Attaches an object that waits for scripts to execute from RemoteContext.
+// (In practice, this is either a frame or a window.)
+// Returns a proxy for the object that first resolves to the object itself,
+// then resolves to the RemoteContext if the property isn't found.
+// The proxy also has an extra attribute `execute`, which is an alias for the
+// remote context's `execute_script(fn, args=[])`.
+function attachContext(object_constructor, html, headers, origin) {
+  const [uuid, url] = generateRemoteContextURL(headers, origin);
+  const object = object_constructor(url);
+  return buildRemoteContextForObject(object, uuid, html);
+}
+
+// TODO(crbug.com/1347953): Update this function to also test
+// `sharedStorage.selectURL()` that returns a fenced frame config object.
+// This should be done after fixing the following flaky tests that use this
+// function.
+// 1. crbug.com/1372536: resize-lock-input.https.html
+// 2. crbug.com/1394559: unfenced-top.https.html
+async function attachOpaqueContext(generator_api, resolve_to_config, ad_with_size, requested_size, object_constructor, html, headers, origin) {
+  const [uuid, url] = generateRemoteContextURL(headers, origin);
+  const id = await (generator_api == 'fledge' ? generateURNFromFledge(url, [], [], resolve_to_config, ad_with_size, requested_size) : runSelectURL(url, [], resolve_to_config));
+  const object = object_constructor(id);
+  return buildRemoteContextForObject(object, uuid, html);
+}
+
+function attachPotentiallyOpaqueContext(generator_api, resolve_to_config, ad_with_size, requested_size, frame_constructor, html, headers, origin) {
+  generator_api = generator_api.toLowerCase();
+  if (generator_api == 'fledge' || generator_api == 'sharedstorage') {
+    return attachOpaqueContext(generator_api, resolve_to_config, ad_with_size, requested_size, frame_constructor, html, headers, origin);
+  } else {
+    return attachContext(frame_constructor, html, headers, origin);
+  }
+}
+
+function attachFrameContext(element_name, generator_api, resolve_to_config, ad_with_size, requested_size, html, headers, attributes, origin) {
+  frame_constructor = (id) => {
+    frame = document.createElement(element_name);
+    attributes.forEach(attribute => {
+      frame.setAttribute(attribute[0], attribute[1]);
+    });
+    if (element_name == "iframe") {
+      frame.src = id;
+    } else if (id instanceof FencedFrameConfig) {
+      frame.config = id;
+    } else {
+      const config = new FencedFrameConfig(id);
+      frame.config = config;
+    }
+    document.body.append(frame);
+    return frame;
+  };
+  return attachPotentiallyOpaqueContext(generator_api, resolve_to_config, ad_with_size, requested_size, frame_constructor, html, headers, origin);
+}
+
+function replaceFrameContext(frame_proxy, {generator_api="", resolve_to_config=false, ad_with_size=false, requested_size=null, html="", headers=[], origin=""}={}) {
+  frame_constructor = (id) => {
+    if (frame_proxy.element.nodeName == "IFRAME") {
+      frame_proxy.element.src = id;
+    } else if (id instanceof FencedFrameConfig) {
+      frame_proxy.element.config = id;
+    } else {
+      const config = new FencedFrameConfig(id);
+      frame_proxy.element.config = config;
+    }
+    return frame_proxy.element;
+  };
+  return attachPotentiallyOpaqueContext(generator_api, resolve_to_config, ad_with_size, requested_size, frame_constructor, html, headers, origin);
+}
+
+// Attach a fenced frame that waits for scripts to execute.
+// Takes as input a(n optional) dictionary of configs:
+// - generator_api: the name of the API that should generate the urn/config.
+//    Supports (case-insensitive) "fledge" and "sharedstorage", or any other
+//    value as a default.
+//    If you generate a urn, then you need to await the result of this function.
+// - resolve_to_config: whether a config should be used. (currently only works
+//    for FLEDGE and sharedStorage generator_api)
+// - ad_with_size: whether an ad auction is run with size specified for the ads
+//    and ad components. (currently only works for FLEDGE)
+// - requested_size: A 2-element list with the width and height for
+//    requestedSize in the FLEDGE auction config.
+// - html: extra HTML source code to inject into the loaded frame
+// - headers: an array of header pairs [[key, value], ...]
+// - attributes: an array of attribute pairs to set on the frame [[key, value], ...]
+// - origin: origin of the url, default to location.origin if not set
+// Returns a proxy that acts like the frame HTML element, but with an extra
+// function `execute`. See `attachFrameContext` or the README for more details.
+function attachFencedFrameContext({generator_api="", resolve_to_config=false, ad_with_size=false, requested_size=null, html = "", headers=[], attributes=[], origin=""}={}) {
+  return attachFrameContext('fencedframe', generator_api, resolve_to_config, ad_with_size, requested_size, html, headers, attributes, origin);
+}
+
+// Attach an iframe that waits for scripts to execute.
+// See `attachFencedFrameContext` for more details.
+function attachIFrameContext({generator_api="", html="", headers=[], attributes=[], origin=""}={}) {
+  return attachFrameContext('iframe', generator_api, resolve_to_config=false, ad_with_size=false, requested_size=null, html, headers, attributes, origin);
+}
+
+// Open a window that waits for scripts to execute.
+// Returns a proxy that acts like the window object, but with an extra
+// function `execute`. See `attachContext` for more details.
+function attachWindowContext({target="_blank", html="", headers=[], origin=""}={}) {
+  window_constructor = (url) => {
+    return window.open(url, target);
+  }
+
+  return attachContext(window_constructor, html, headers, origin);
+}
+
+// Converts a key string into a key uuid using a cryptographic hash function.
+// This function only works in secure contexts (HTTPS).
+async function stringToStashKey(string) {
+  // Compute a SHA-256 hash of the input string, and convert it to hex.
+  const data = new TextEncoder().encode(string);
+  const digest = await crypto.subtle.digest('SHA-256', data);
+  const digest_array = Array.from(new Uint8Array(digest));
+  const digest_as_hex = digest_array.map(b => b.toString(16).padStart(2, '0')).join('');
+
+  // UUIDs are structured as 8X-4X-4X-4X-12X.
+  // Use the first 32 hex digits and ignore the rest.
+  const digest_slices = [digest_as_hex.slice(0,8),
+                         digest_as_hex.slice(8,12),
+                         digest_as_hex.slice(12,16),
+                         digest_as_hex.slice(16,20),
+                         digest_as_hex.slice(20,32)];
+  return digest_slices.join('-');
+}
+
+// Create a fenced frame. Then navigate it using the given `target`, which can
+// be either an urn:uuid or a fenced frame config object.
+function attachFencedFrame(target) {
+  assert_implements(
+      window.HTMLFencedFrameElement,
+      'The HTMLFencedFrameElement should be exposed on the window object');
+
+  const fenced_frame = document.createElement('fencedframe');
+
+  if (target instanceof FencedFrameConfig) {
+    fenced_frame.config = target;
+  } else {
+    const config = new FencedFrameConfig(target);
+    fenced_frame.config = config;
+  }
+
+  document.body.append(fenced_frame);
+  return fenced_frame;
+}
+
+function attachIFrame(url) {
+  const iframe = document.createElement('iframe');
+  iframe.src = url;
+  document.body.append(iframe);
+  return iframe;
+}
+
+// Reads the value specified by `key` from the key-value store on the server.
+async function readValueFromServer(key) {
+  // Resolve the key if it is a Promise.
+  key = await key;
+
+  const serverUrl = `${STORE_URL}?key=${key}`;
+  const response = await fetch(serverUrl);
+  if (!response.ok)
+    throw new Error('An error happened in the server');
+  const value = await response.text();
+
+  // The value is not stored in the server.
+  if (value === "<Not set>")
+    return { status: false };
+
+  return { status: true, value: value };
+}
+
+// Convenience wrapper around the above getter that will wait until a value is
+// available on the server.
+async function nextValueFromServer(key) {
+  // Resolve the key if it is a Promise.
+  key = await key;
+
+  while (true) {
+    // Fetches the test result from the server.
+    const { status, value } = await readValueFromServer(key);
+    if (!status) {
+      // The test result has not been stored yet. Retry after a while.
+      await new Promise(resolve => setTimeout(resolve, 20));
+      continue;
+    }
+
+    return value;
+  }
+}
+
+// Reads the data from the latest automatic beacon sent to the server.
+async function readAutomaticBeaconDataFromServer() {
+  const serverUrl = `${BEACON_URL}`;
+  const response = await fetch(serverUrl);
+  if (!response.ok)
+    throw new Error('An error happened in the server');
+  const value = await response.text();
+
+  // The value is not stored in the server.
+  if (value === "<Not set>")
+    return { status: false };
+
+  return { status: true, value: value };
+}
+
+// Convenience wrapper around the above getter that will wait until a value is
+// available on the server.
+async function nextAutomaticBeacon() {
+  while (true) {
+    // Fetches the test result from the server.
+    const { status, value } = await readAutomaticBeaconDataFromServer();
+    if (!status) {
+      // The test result has not been stored yet. Retry after a while.
+      await new Promise(resolve => setTimeout(resolve, 20));
+      continue;
+    }
+
+    return value;
+  }
+}
+
+// Writes `value` for `key` in the key-value store on the server.
+async function writeValueToServer(key, value, origin = '') {
+  // Resolve the key if it is a Promise.
+  key = await key;
+
+  const serverUrl = `${origin}${STORE_URL}?key=${key}&value=${value}`;
+  await fetch(serverUrl, {"mode": "no-cors"});
+}
+
+// Simulates a user gesture.
+async function simulateGesture() {
+  // Wait until the window size is initialized.
+  while (window.innerWidth == 0) {
+    await new Promise(resolve => requestAnimationFrame(resolve));
+  }
+  await test_driver.bless('simulate gesture');
+}
+
+// Fenced frames are always put in the public IP address space which is the
+// least privileged. In case a navigation to a local data: URL or blob: URL
+// resource is allowed, they would only be able to fetch things that are *also*
+// in the public IP address space. So for the document described by these local
+// URLs, we'll set them up to only communicate back to the outer page via
+// resources obtained in the public address space.
+function createLocalSource(key, url) {
+  return `
+    <head>
+      <script src="${url}"><\/script>
+    </head>
+    <body>
+      <script>
+        writeValueToServer("${key}", "LOADED", /*origin=*/"${url.origin}");
+      <\/script>
+    </body>
+  `;
+}
+
+function setupCSP(csp, second_csp=null) {
+  let meta = document.createElement('meta');
+  meta.httpEquiv = "Content-Security-Policy";
+  meta.content = "fenced-frame-src " + csp;
+  document.head.appendChild(meta);
+
+  if (second_csp != null) {
+    let second_meta = document.createElement('meta');
+    second_meta.httpEquiv = "Content-Security-Policy";
+    second_meta.content = "frame-src " + second_csp;
+    document.head.appendChild(second_meta);
+  }
+}
diff --git a/testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html b/testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html
new file mode 100644
index 0000000000..3236886b97
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to test Web Bluetooth</title>
+
+<body>
+<button id="button">Button</button>
+<script>
+(async () => {
+  await simulateGesture();
+  const [bluetooth_request_device_key] = parseKeylist();
+  try {
+    await navigator.bluetooth.requestDevice({filters: [{name: 'device'}]});
+    writeValueToServer(bluetooth_request_device_key,
+                      'Web Bluetooth requestDevice() succeeded');
+  } catch(e) {
+    if (e.name == 'NotAllowedError' &&
+        e.message.includes(
+          'Web Bluetooth is not allowed in a fenced frame tree.')) {
+      writeValueToServer(bluetooth_request_device_key,
+                        'Web Bluetooth requestDevice() failed');
+    } else {
+      writeValueToServer(
+          bluetooth_request_device_key,
+          'Web Bluetooth requestDevice() failed with unknown error - ' +
+          `${e.name}: ${e.message}`);
+    }
+  }
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/web-bluetooth-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html b/testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html
new file mode 100644
index 0000000000..682805d5d2
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of Web NFC API</title>
+
+<body>
+<script>
+async function init() {
+  const [ndef_write_key, ndef_scan_key] = parseKeylist();
+
+  const ndef = new NDEFReader();
+  ndef.write("Hello").then(
+    () => { writeValueToServer(ndef_write_key, "resolved"); },
+    () => { writeValueToServer(ndef_write_key, "rejected"); }
+  );
+  ndef.scan().then(
+    () => { writeValueToServer(ndef_scan_key, "resolved"); },
+    () => { writeValueToServer(ndef_scan_key, "rejected"); }
+  );
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html.headers b/testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/web-nfc-inner.https.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/web-share-inner.html b/testing/web-platform/tests/fenced-frame/resources/web-share-inner.html
new file mode 100644
index 0000000000..aada6f04e1
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/web-share-inner.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<script src="/resources/testdriver.js"></script>
+<script src="/resources/testdriver-actions.js"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to test Web Share</title>
+
+<body>
+<script>
+(async () => {
+  await simulateGesture();
+  const [navigator_share_key] = parseKeylist();
+  try {
+    await navigator.share({text: 'hello world'});
+    writeValueToServer(navigator_share_key, 'Web Share succeeded');
+  } catch(error) {
+    writeValueToServer(navigator_share_key, 'Web Share failed');
+  }
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/web-share-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/web-share-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/web-share-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html b/testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html
new file mode 100644
index 0000000000..897d9a0d59
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of window.frameElement</title>
+
+<body>
+<script>
+(async () => {
+  // Report whether or not `window.frameElement` is null
+  const [frame_element_key] = parseKeylist();
+  let result = (window.frameElement == null) ? "PASS" : "FAIL";
+  writeValueToServer(frame_element_key, result);
+})();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-frameElement-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html b/testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html
new file mode 100644
index 0000000000..e5e5adef1d
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of window.navigation</title>
+
+<body>
+<script>
+function init() {
+  // This file is meant to be navigated to from a <fencedframe> element. It
+  // reports back to the page hosting the <fencedframe> after manual timeout
+  // indicating that the 204 navigation succeeds without navigating away.
+  location.href = "response-204.py";
+
+  step_timeout(function() {
+    const [window_data_key] = parseKeylist();
+    writeValueToServer(window_data_key, "still in page");
+  }, 1000);
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html.headers
new file mode 100644
index 0000000000..1b63235b7c
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-navigation-204-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html b/testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html
new file mode 100644
index 0000000000..81dee800fc
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the result of prerendering</title>
+
+<body>
+  <script>
+    async function report() { // Needed in order to use top-level await.
+      // This file is meant to run in a <fencedframe>. It reports its dimensions
+      // back to the outermost page, which in turn checks for correctness.
+      const [window_outer_size_key, window_inner_size_key, dimension,
+             extra_children] = parseKeylist();
+
+      const url = new URL(location.href);
+
+      if (extra_children == "0") {
+        let outer_result = (dimension == "width") ?
+          window.outerWidth : window.outerHeight;
+
+        let inner_result = (dimension == "width") ?
+          window.innerWidth : window.innerHeight;
+
+        writeValueToServer(window_outer_size_key, outer_result);
+        writeValueToServer(window_inner_size_key, inner_result);
+      } else {
+          const iframe = document.createElement('iframe');
+          const frame_url = generateURL('window-outer-dimensions-inner.html',
+            [window_outer_size_key, window_inner_size_key, dimension,
+            (parseInt(extra_children) - 1)]);
+          iframe.src = frame_url;
+          document.body.append(iframe);
+      }
+
+    }
+    report();
+  </script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-outer-dimensions-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html b/testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html
new file mode 100644
index 0000000000..9008d7d923
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html
@@ -0,0 +1,64 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of window.parent</title>
+
+<body>
+<script>
+async function init() { // Needed in order to use top-level await.
+  // This file is meant to run in a <fencedframe>. It reports back to the
+  // outermost page whether or not the value of `window.parent` was correct for:
+  //   1.) Top-level fenced frames
+  //   2.) Nested iframes inside a fenced frame
+  //   3.) Nested fenced frames
+  const url = new URL(location.href);
+
+  const [window_parent_key, window_parent_ack_key, nested] = parseKeylist();
+  const is_nested_fenced_frame = (nested == "nested");
+
+  // Report whether or not `window.parent` was correct.
+  let pass_string = "";
+  if (is_nested_fenced_frame)
+    pass_string = "pass: fenced frame > fenced frame";
+  else
+    pass_string = "pass: fenced frame";
+
+  let result = (window.parent == window) ? pass_string : "fail";
+  writeValueToServer(window_parent_key, result);
+
+  // If this page is a nested fenced frame, all we need to do is report the
+  // top-level value.
+  if (is_nested_fenced_frame)
+    return;
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `window_parent_key` stash and we can write to it again.
+  await nextValueFromServer(window_parent_ack_key);
+
+  // Now test `window.parent` inside an iframe.
+  const iframe = document.createElement('iframe');
+  iframe.src = "dummy.html";
+  const load_promise = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+  document.body.append(iframe);
+
+  await load_promise;
+
+  // Report whether or not the subframe's `window.parent` was correct.
+  result = (iframe.contentWindow.parent == window) ?
+      "pass: fenced frame > iframe" : "fail";
+  writeValueToServer(window_parent_key, result);
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `window_parent_key` stash and we can write to it again.
+  await nextValueFromServer(window_parent_ack_key);
+
+  attachFencedFrame(generateURL("window-parent-inner.html",
+      [window_parent_key, window_parent_ack_key, "nested"]));
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-parent-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-top-inner.html b/testing/web-platform/tests/fenced-frame/resources/window-top-inner.html
new file mode 100644
index 0000000000..ddc30bf71b
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-top-inner.html
@@ -0,0 +1,63 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="utils.js"></script>
+<title>Fenced frame content to report the value of window.top</title>
+
+<body>
+<script>
+async function init() { // Needed in order to use top-level await.
+  // This file is meant to run in a <fencedframe>. It reports back to the
+  // outermost page whether or not the value of `window.top` was correct for:
+  //   1.) Top-level fenced frames
+  //   2.) Nested iframes inside a fenced frame
+  //   3.) Nested fenced frames
+  const url = new URL(location.href);
+
+  const [window_top_key, window_top_ack_key, nested] = parseKeylist();
+
+  // Report whether or not `window.top` was correct.
+  let pass_string = "";
+  if (nested == "nested")
+    pass_string = "pass: fenced frame > fenced frame";
+  else
+    pass_string = "pass: fenced frame";
+
+  let result = (window.top == window) ? pass_string : "fail";
+  writeValueToServer(window_top_key, result);
+
+  // If this page is a nested fenced frame, all we need to do is report the
+  // top-level value.
+  if (nested == "nested")
+    return;
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `window_top_key` stash and we can write to it again.
+  await nextValueFromServer(window_top_ack_key);
+
+  // Now test `window.top` inside an iframe.
+  const iframe = document.createElement('iframe');
+  iframe.src = "dummy.html";
+  const load_promise = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+  document.body.append(iframe);
+
+  await load_promise;
+
+  // Report whether or not the subframe's `window.top` was correct.
+  result = (iframe.contentWindow.top == window) ?
+      "pass: fenced frame > iframe" : "fail";
+  writeValueToServer(window_top_key, result);
+
+  // Wait for ACK, so we know that the outer page has read the last value from
+  // the `window_top_key` stash and we can write to it again.
+  await nextValueFromServer(window_top_ack_key);
+
+  attachFencedFrame(generateURL("window-top-inner.html",
+      [window_top_key, window_top_ack_key, "nested"]));
+}
+
+init();
+</script>
+</body>
diff --git a/testing/web-platform/tests/fenced-frame/resources/window-top-inner.html.headers b/testing/web-platform/tests/fenced-frame/resources/window-top-inner.html.headers
new file mode 100644
index 0000000000..6247f6d632
--- /dev/null
+++ b/testing/web-platform/tests/fenced-frame/resources/window-top-inner.html.headers
@@ -0,0 +1 @@
+Supports-Loading-Mode: fenced-frame
\ No newline at end of file
-- 
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