[webkit-dev] Animations feature flag

[Dean Jackson]

Hi floks,

I’m about to add a flag WEB_ANIMATIONS, behind which I’ll start:

- Implementing an animation engine that matches the model in W3C’s Web Animation spec
- Allowing CSS and SVG animations to use the new engine
- Exposing enough internal JS API to allow improved testing (currently a very weak point for us)
- Possibly looking at implementing parts of the public API

The last point was controversial when it was raised here a while ago. We should
discuss it again when we have something to implement upon.

There will also be a runtime flag to enable the new engine. With the flag disabled,
nothing should break. Eventually we’ll be able to toggle the flag and have a better
animation engine.

Dean