Bug 120046 – Crash when calling getCueAsHTML() on a TextTrackCue with empty text

• Status: RESOLVED
• Resolution: WORKSFORME
• Component: Media

[Ryosuke Niwa]

Consider merging https://chromium.googlesource.com/chromium/blink/+/cb63c74ab8b20aebb6373246f936674f5407d610

Even if the TextTrackCue text is empty, a document fragment should still be returned as a result value when calling getCueAsHTML(). Currently, the call crashes the browser, when the cue text is "".

[Ryosuke Niwa]

I couldn't reproduce the crash using the test case they added but the code change seems good so we might want to merge this. If not, please close this bug.

[Brendan Long]

We seem to already do this correctly:

PassRefPtr<DocumentFragment> WebVTTTreeBuilder::buildFromString(const String& cueText)
{
    // Cue text processing based on
    // 5.4 WebVTT cue text parsing rules, and
    // 5.5 WebVTT cue text DOM construction rules.
    RefPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);

    if (cueText.isEmpty()) {
        fragment->parserAppendChild(Text::create(m_document, emptyString()));
        return fragment.release();
    }

    m_currentNode = fragment;

    WebVTTTokenizer tokenizer(cueText);
    m_languageStack.clear();

    while (tokenizer.nextToken(m_token))
        constructTreeFromToken(m_document);
    
    return fragment.release();
}