Fix panic in embedded-opener-remove-frame

[Taym95]

---

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• These changes fix #___ (GitHub issue number if applicable)

• There are tests for these changes OR
• These changes do not require tests because ___

[github-actions]

🔨 Triggering try run (#10455282017) for Linux WPT

[github-actions]

Test results for linux-wpt-layout-2020 from try job (#10455282017):

Flaky unexpected result (12)

• CRASH [expected FAIL] /_mozilla/mozilla/webgl/tex_image_2d_canvas.html
• TIMEOUT [expected PASS] /css/compositing/mix-blend-mode/mix-blend-mode-video.html (#32763)
• OK /css/cssom-view/MediaQueryList-extends-EventTarget-interop.html (#25285)
  • FAIL [expected PASS] subtest: removeEventListener (capture) doesn't remove listener added with addListener

    assert_equals: triggerMQLEvent expected 1 but got 0
    

• TIMEOUT /fetch/metadata/generated/element-img-environment-change.sub.html (#30111)
  • PASS [expected FAIL] subtest: sec-fetch-site - Not sent to non-trustworthy same-origin destination, no attributes
• OK /html/browsers/browsing-the-web/navigating-across-documents/javascript-url-return-value-handling-dynamic.html (#28066)
  • FAIL [expected PASS] subtest: 0041 set in href="" targeting a frame and clicked

    assert_equals: expected "A" but got ""
    

  • FAIL [expected PASS] subtest: 0080 00FF set in href="" targeting a frame and clicked

    assert_equals: expected "�ÿ" but got ""
    

  • FAIL [expected PASS] subtest: 0080 00FF 0100 set in href="" targeting a frame and clicked

    assert_equals: expected "�ÿĀ" but got ""
    

  • FAIL [expected PASS] subtest: D83D DE0D set in href="" targeting a frame and clicked

    assert_equals: expected "😍" but got ""
    

  • FAIL [expected PASS] subtest: DE0D 0041 set in href="" targeting a frame and clicked

    assert_equals: expected "\ufffdA" but got ""
    

• TIMEOUT /html/canvas/element/manual/imagebitmap/createImageBitmap-drawImage.html (#32745)
  • TIMEOUT [expected FAIL] subtest: createImageBitmap from an HTMLVideoElement from a data URL, and drawImage on the created ImageBitmap

    Test timed out
    

  • NOTRUN [expected FAIL] subtest: createImageBitmap from an HTMLVideoElement from a data URL scaled down, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from an HTMLVideoElement from a data URL scaled up, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from an HTMLVideoElement from a data URL resized, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from an HTMLVideoElement from a data URL with negative sw/sh, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from a bitmap HTMLImageElement, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from a bitmap HTMLImageElement scaled down, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from a bitmap HTMLImageElement scaled up, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from a bitmap HTMLImageElement resized, and drawImage on the created ImageBitmap
  • NOTRUN [expected FAIL] subtest: createImageBitmap from a bitmap HTMLImageElement with negative sw/sh, and drawImage on the created ImageBitmap
  • And 6 more unexpected results...
• OK [expected TIMEOUT] /html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html (#24057)
  • FAIL [expected TIMEOUT] subtest: Check that popups from a sandboxed iframe escape the sandbox if allow-popups-to-escape-sandbox is used

    assert_equals: It came from a sandboxed iframe expected "null" but got "http://web-platform.test:8000"
    

• OK [expected CRASH] /html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html (#22154)
• OK [expected TIMEOUT] /html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html (#24066)
  • FAIL [expected NOTRUN] subtest: Check that popups from a sandboxed iframe do not escape the sandbox

    assert_equals: It came from a sandboxed iframe expected "null" but got "http://web-platform.test:8000"
    

• OK [expected TIMEOUT] /html/semantics/embedded-content/the-iframe-element/sandbox-top-navigation-cross-site.tentative.sub.window.html (#31754)
  • FAIL [expected TIMEOUT] subtest: A cross-site unsandboxed iframe navigation consumes user activation and disallows top-level navigation.

    promise_test: Unhandled rejection with value: object "TypeError: element.scrollIntoView is not a function"
    

• OK /html/webappapis/dynamic-markup-insertion/document-write/module-delayed.html (#27659)
  • FAIL [expected PASS] subtest: async document.write in a module

    assert_true: onload must be called expected true got false
    

• OK [expected ERROR] /webxr/render_state_update.https.html (#27535)

Stable unexpected results that are known to be intermittent (10)

• FAIL [expected PASS] /_mozilla/css/dirty_viewport.html (#13731)
• FAIL [expected PASS] /_mozilla/css/iframe/hide_and_show.html (#15265)
• OK /css/css-fonts/variations/at-font-face-font-matching.html (#20684)
  • FAIL [expected PASS] subtest: Matching font-style: 'italic' should prefer 'oblique 5deg 10deg' over 'oblique 5deg'

    assert_equals: Unexpected font on test element expected 487 but got 532
    

• OK /css/cssom-view/MediaQueryList-addListener-removeListener.html (#24569)
  • FAIL [expected PASS] subtest: listener that was added twice is called only once

    assert_equals: expected 1 but got 0
    

  • FAIL [expected PASS] subtest: removing listener from one MQL doesn't remove it from all MQLs

    assert_equals: expected 1 but got 0
    

• OK /html/browsers/browsing-the-web/navigating-across-documents/initial-empty-document/iframe-src-aboutblank-navigate-immediately.html (#29048)
  • PASS [expected FAIL] subtest: Navigating to a different document with form submission
• OK /html/browsers/windows/embedded-opener-remove-frame.html (#23867)
  • PASS [expected FAIL] subtest: opener of discarded auxiliary browsing context
• OK /html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy-reload-location-reload.html (#32595)
  • PASS [expected FAIL] subtest: Reloading iframe loading='lazy' before it is loaded: location.reload
• ERROR /resource-timing/content-type-parsing.html (#29131)
  • TIMEOUT [expected FAIL] subtest: mime-type 16 : text/html;charset=�gbk

    Test timed out
    

  • NOTRUN [expected TIMEOUT] subtest: mime-type 17 : text/html;charset=gbk
• TIMEOUT [expected OK] /resource-timing/nested-context-navigations-iframe.html (#24311)
  • TIMEOUT [expected PASS] subtest: Test that cross-site iframe navigations are not observable by the parent, even after history navigations by the parent

    Test timed out
    

  • NOTRUN [expected PASS] subtest: Test that iframe navigations are not observable by the parent
  • NOTRUN [expected PASS] subtest: Test that crossorigin iframe navigations are not observable by the parent
  • NOTRUN [expected PASS] subtest: Test that cross-site iframe navigations are not observable by the parent
  • NOTRUN [expected PASS] subtest: Test that iframe refreshes are not observable by the parent
  • NOTRUN [expected PASS] subtest: Test that crossorigin iframe refreshes are not observable by the parent
  • NOTRUN [expected PASS] subtest: Test that cross-site iframe refreshes are not observable by the parent
• TIMEOUT /resource-timing/test_resource_timing.https.html (#25216)
  • FAIL [expected PASS] subtest: PerformanceEntry has correct name, initiatorType, startTime, and duration (img)

    assert_equals: expected 14323712 but got 14323456
    

[github-actions]

✨ Try run (#10455282017) succeeded.