Unprefixing CSS properties

Web authors have complained a lot about excessive need for vendor
prefixing. Henri Sivonen has recently blogged about the damage prefixing
can do to the Web --- see http://hsivonen.iki.fi/vendor-prefixes/.

One observation is that when browser vendors already agree closely on the
syntax and semantics of a property, and when Web authors routinely use the
same property value for multiple engines' prefixed properties and the
unprefixed property, in public Web content, vendor prefixes are providing
negligible benefit and incur considerable costs --- or outright harm. I
think we can improve the situation in the short term with relatively low
risk by identifying properties whose specs are not yet in CR, but where the
spec is considered stable (but for whatever reason not ready to enter CR,
perhaps because it contains other properties that aren't stable), and
agreeing to encourage unprefixed implementations of those properties.
Naturally we still want implementations to be reasonably conformant before
shipping unprefixed.

We had a meeting about this with some Mozilla developers today and came up
with a proposed list of properties/features which we think are eligible for
unprefixing:

2D Transforms: all properties
3D Transforms: all properties
Transitions: all properties
Animations: all properties (responses to feedback urgently need to be added
to the spec, and that should probably happen first)
Conditional: nested @-rules (probably no-one would have prefixed this
anyway)
Images: image() value, 'object-*', 'image-*'
Text: 'tab-size', 'hyphens', 'text-align-last', 'text-decoration-*'
Values: a subset of calc() (the intersection of what IE9 and Gecko
implement), the new units
Selectors 4: :matches, :any-link, :nth-match, :nth-last-match, :column,
:nth-column, :nth-last-column

Any objections? :-)

Rob
-- 
"If we claim to be without sin, we deceive ourselves and the truth is not
in us. If we confess our sins, he is faithful and just and will forgive us
our sins and purify us from all unrighteousness. If we claim we have not
sinned, we make him out to be a liar and his word is not in us." [1 John
1:8-10]