Do not cache media time until media engine returns a non-zero value

[Eric Carlson]

It can sometimes take a media engine a non-insignificant amount of time to begin playing after receiving a play command, so do not cache current time until the media engine returns a non-zero value.

[Eric Carlson]

Created attachment 224518 [details]
Proposed patch.

[Jer Noble]

Comment on attachment 224518 [details]
Proposed patch.

View in context: https://bugs.webkit.org/attachment.cgi?id=224518&action=review

r=me, with nits.

> Source/WebCore/ChangeLog:4
> +        Do not cache media time until media engine returns a non-zero value
> +        https://bugs.webkit.org/show_bug.cgi?id=128976

This doesn't say _why_ we shouldn't cache the media time in this case.

> Source/WebCore/html/HTMLMediaElement.cpp:2446
> +    if (m_cachedTime) {
> +        LOG(Media, "HTMLMediaElement::refreshCachedTime - caching time %f", m_cachedTime);
> +        m_clockTimeAtLastCachedTimeUpdate = monotonicallyIncreasingTime();
> +    } else
> +        invalidateCachedTime();

I would structure this a little differently, to be a bit more clear about what's going on:

if (!m_cachedTime) {
    // Short comment about why not caching a 0-currentTime is the right thing to do.
    invalidateCachedTime();
    return;
}

LOG(Media, "HTMLMediaElement::refreshCachedTime - caching time %f", m_cachedTime);
m_clockTimeAtLastCachedTimeUpdate = monotonicallyIncreasingTime();

[Eric Carlson]

Committed r164296: https://trac.webkit.org/r164296

[WebKit Commit Bot]

Re-opened since this is blocked by bug 128989

[Eric Carlson]

Resubmitted as https://trac.webkit.org/r164318.