1506300 - WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file /builds/worker/workspace/build/src/obj-firefox/dist/include/mozilla/DOMEventTargetHelper.h, line 145 when adding event listener on video.textTracks

Status: NEW

(Core :: Audio/Video: Playback, enhancement, P3)

Description

[Tim Guan-tin Chien [:timdream] (please needinfo)]

Please see the fuzzing text case in bug 1505957 and specifically bug 1505957 comment 5. During the construction of the video controls UA Widget calling

> video.textTracks.addEventListener("addtrack", this, { mozSystemGroup: true, capture: true });

results in an NS_ERROR_UNEXPECTED exception.

When I tried to see if the same exception can be produced in the web content, DevTools console prints |Restricted {}| when I type |video.textTracks|.

I guess when <video> is being appendChild() to another document without adoptNode() or importNode(), the TextTrackList object would lose track of the window it should be associated with (no pun intended)

Comment 1

[Tim Guan-tin Chien [:timdream] (please needinfo)]

Attachment: reduced test case

This is the reduced test case from bug 1505957. You would need to reference a video file in the same dir, and refresh a few times because the test case might hit

JavaScript error: http://127.0.0.1:8080/bug1505957test.html, line 9: TypeError: o is undefined; can't access its "parentNode" property

sometimes.

Comment 2

[Tim Guan-tin Chien [:timdream] (please needinfo)]

(In reply to Tim Guan-tin Chien [:timdream] (please needinfo) from comment #0)
> I guess when <video> is being appendChild() to another document without
> adoptNode() or importNode(), the TextTrackList object would lose track of
> the window it should be associated with (no pun intended)

appendChild()

Comment 3

[Tim Guan-tin Chien [:timdream] (please needinfo)]

(In reply to Tim Guan-tin Chien [:timdream] (please needinfo) from comment #0)
> I guess when <video> is being appendChild() to another document without
> adoptNode() or importNode(), the TextTrackList object would lose track of
> the window it should be associated with (no pun intended)

appendChild() does adopt the node when appending from a different document. There shouldn't be a need to call adoptNode() explicitly.

https://dom.spec.whatwg.org/#dom-node-appendchild
https://dom.spec.whatwg.org/#concept-node-append
https://dom.spec.whatwg.org/#concept-node-pre-insert
https://dom.spec.whatwg.org/#concept-node-adopt