Update audioTracks/videoTracks/textTracks versions for Safari

[sideshowbarker]

This change corrects the Safari version data for the audioTracks, videoTracks, and textTracks members of the SourceBuffer interface to reflect, per https://trac.webkit.org/changeset/178172/webkit, the actual version of Safari which first shipped support for them.

Relates to #6102

[foolip]

https://trac.webkit.org/changeset/178172/webkit does not seems related to shipping audioTracks/videoTracks/textTracks, it only moves them around in the IDL file and they're still behind [Conditional=VIDEO_TRACK].

[foolip]

Understanding when this really shipped is made more complicated by [NoInterfaceObject] used on the interface in WebKit until https://trac.webkit.org/changeset/206146/webkit, where it was removed as a drive-by in another change. @vinyldarkscratch FYI you may run into this in the next part of #6642.

[foolip]

I'm unable to confirm the suggested versions, so more evidence would be great.

[foolip]

I've tested http://software.hixie.ch/utilities/js/live-dom-viewer/saved/8420 on iPhones in BrowserStack to try to confirm when MSE was added, but it's not there even on Safari 13. https://caniuse.com/mediasource suggests that it's only for iPad. If that's correct, we should have notes in the BCD data as well.

[foolip]

I've tested https://software.hixie.ch/utilities/js/live-dom-viewer/?saved=8419 on Safari (macOS) in BrowserStack and see support at least back to 10.1. Before that point I'm not sure because the interface object was not exposed at one point. But at any case the methodology here seems unreliable, so another look would be good.

[sideshowbarker]

Paging in @eric-carlson and @jernoble, who I think will be able to give us some guidance here.

Eric, Jer, we’re trying to figure out two things:

1. What were the first versions of Safari and iOS Safari that shipped with audioTracks/videoTracks/textTracks support?
2. What were the first versions of Safari and iOS Safari that shipped with SourceBuffer support?

[jernoble]

1. What were the first versions of Safari and iOS Safari that shipped with audioTracks/videoTracks/textTracks support?

This first landed in Safari 8 on MacOS X Yosemite, and in Mobile Safari on iOS 8.

2. What were the first versions of Safari and iOS Safari that shipped with SourceBuffer support?

This also landed in Safari 8 on MacOS X Yosemite, and later in Mobile Safari on iPad in iOS 13.

[sideshowbarker]

@jernoble Thanks much

One thing I realize now I should have been more clear about: given that both HTMLMediaElement and SourceBuffer have audioTracks/videoTracks/textTracks properties, we need to confirm the data for those properties for both the HTMLMediaElement and SourceBuffer cases.

So can you please either confirm the following, or let me know any further corrections needed —

• audioTracks/videoTracks/textTracks for HTMLMediaElement shipped in macOS Safari 8, and in Mobile Safari on iOS 8
• SourceBuffer — with audioTracks/videoTracks/textTracks properties implemented/exposed — shipped in macOS Safari 8, and later in Mobile Safari in iOS 13

Specifically, the particular details I’m not completely sure about are:

• When SourceBuffer shipped initially, did it implement/expose audioTracks/videoTracks/textTracks properties, or instead was support for those was added later?
• Did Mobile Safari on iPhone in iOS 13 ship with SourceBuffer support implemented/exposed? (I ask because in your previous comment, you specifically mention only Mobile Safari on iPad)

[jernoble]

• When SourceBuffer shipped initially, did it implement/expose audioTracks/videoTracks/textTracks properties, or instead was support for those was added later?

Yes, those properties were exposed from the start. https://bugs.webkit.org/show_bug.cgi?id=123374

• Did Mobile Safari on iPhone in iOS 13 ship with SourceBuffer support implemented/exposed? (I ask because in your previous comment, you specifically mention only Mobile Safari on iPad)

No, Mobile Safari on iPhone does not expose any MSE APIs.

[sideshowbarker]

@foolip I amended the commit to reflect the details from Jer.

To document what Jer indicated about SourceBuffer being exposed in Safari on iPad but not on iPhone, I marked safari_ios for it with partial_implementation:true and an “Exposed in Mobile Safari on iPad but not on iPhone” note. But I’m not sure if that’s actually the best way to indicate it — I don’t know if we have a precedent — so I guess it would be good if @ddbeck could also weigh in with some guidance.

[queengooborg]

We've discussed separating iPadOS into its own column in #6326 a bit. For now, I think you've got the right idea to add a note!

[ddbeck]

Yep putting this in a note is the way to go right now.

[foolip]

Thanks @jernoble for confirming the releases for these bits, and thanks @sideshowbarker! I'll go ahead and land this now.

[foolip]

@vinyldarkscratch there ought to be a whole bunch of MSE APIs that can be updated in a similar way to this PR, in case you want to collect results from iPad.