commit 2a023b35ecade9e3370800b430818c75af1819cb
author Dominic Farolino <dom@chromium.org> Fri Feb 23 03:50:25 2024
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> Fri Feb 23 04:08:33 2024
tree 018d297405348fd8370f7c47a21e1e4e107494e9
parent b4d3a4ecdd4dbbc8ed1fe3993ba1f510075c6247

DOM: Add iframe insertion & removal steps WPTs

To help resolve https://github.com/whatwg/dom/issues/808, we need WPTs
asserting exactly when (DOM-observing) script can and cannot be invoked
during the insertion and removing steps for iframes and script elements.

The tests in this CL assert the current spec behavior of:

Iframe:
 - Insertion:
    - Synchronously fire the `load` event in the iframe document
 - Removal:
    - No script is run in between multiple iframe removals. Script
      cannot observe the state of the DOM in between multiple
      synchronous removals because, i.e., no `unload` events are fired
      in this case per HTML [1].
Script:
 - Insertion:
    - Synchronously execute <script> elements upon insertion, even in
      between the insertions of individual <script> elements that are
      added "atomically" by a single DocumentFragment insertion. Note
      that Chromium and Gecko fail this test. In the DocumentFragment
      case, both of these browsers insert all <scripts> into the DOM
      before executing any of them. This means that once the scripts
      start executing, they can all observe each other's participation
      in the DOM tree.

At the moment, there is ongoing discussion [2] about the possibility of
changing the DOM/HTML Standard's model to more-closely match what Gecko
and Chromium do with "atomic" DOM insertion (i.e., running script as a
side effect very explicitly after all DOM node insertion is done).

[1]: https://html.spec.whatwg.org/C#the-iframe-element:html-element-removing-steps
[2]: https://github.com/whatwg/dom/issues/808#issuecomment-1918711297

R=masonf@chromium.org

Bug: 40150299
Change-Id: Iff959bbb0d32d772ae7162d5d9e54a5817959086
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5251828
Reviewed-by: Mason Freed <masonf@chromium.org>
Commit-Queue: Dominic Farolino <dom@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1264406}