[css-nav-1] Define properties with animation type

[cdoublev]

Adds Animation Type: not animatable to all property definitions. According to Web Animations 1, they would be otherwise considered as animatable:

Unless otherwise specified, all CSS properties are animatable.

[tabatkins]

I presume these should be discretely animatable.

[cdoublev]

Would they accept mix()?

A mix() notation is invalid if either of its <declaration-value>s are invalid when interpreted as a whole value for the property the function is used in, or if the property using it is not animatable.

[tabatkins]

I'm not sure I understand the purpose of the question. mix() just relies on the animation concept; if you can animate, you can mix().

[cdoublev]

Forget it, I was trying to give an argument for not animatable, based on wrong thinking, indeed.

I am not sure exactly when a property should be not animatable, looking at the current list of not animatable properties.

Do you want me to set Animation type to discrete or close this PR and discuss the matter in a dedicated issue?

[tabatkins]

Properties are only "not animatable" if they actually cause problems to animate. The animation-* properties are the obvious example, due to circularity, but a handful of other properties have been special-cased due to impl reasons. But absent any special reason, every property is animatable, just discretely if there's nothing else reasonable to do; that's why the Animations spec has that default in the first place.

Go ahead and just change these to discrete.