[webkit-gtk] WebKitGTK+ VS Apple WebKit

[Michael Catanzaro]

On Wed, 2017-01-25 at 15:29 +0000, Andrea Giammarchi wrote:
> If I might ask my last question: who makes the decision of "what
> ships where"?

Whoever is working on the feature. If the people working on the feature
decide to enable it in WebKitGTK+, then we'll get it. If not, we'll
never get it until someone working on WebKitGTK+ decides they want it.
Nobody keeps track of the delta in feature differences between the two
ports. It's certainly something that would be desirable.

> As example, how comes Safari is shipping customElements but latest
> WebKitGTK+ doesn't even have them behind a flag?

Ah, I figured this out: the problem is you are testing the stable
branch. In 2.14 there is a hidden and unsupported
-DENABLE_CUSTOM_ELEMENTS build flag you can try using, but it might not
be enough because it'll probably be disabled at runtime as well, and we
have no way to enumerate or enable runtime experimental features except
for CSS grid. We have a WebKitGTK+ experimental features environment
variable that only covers CSS grid and does not map to the actual
experimental features we have in WebKit. We should probably remove this
 or fix it somehow because it's surely not working properly right now:
it's not OK for it to only work for only one particular experimental
feature.

But if you're testing 2.15.3, custom elements should be enabled and
working by default. At least I see a progress bar on the custom element
demo page, exactly the same as in Chromium, whereas in 2.14 I don't see
anything. So the problem is just different release cycles. We really do
need the full six months to make sure we're releasing a stable product.
2.16 will be released in two months.

Michael