Unprefixed stretch keyword for size-declaring CSS properties

[BenjaminAster]

Description

The stretch value for (min-/max-)width/height/inline-size/block-size is currently implemented as -webkit-fill-available in Chromium and WebKit, and -moz-available in Firefox.

Note that there are some layout edge cases with floats etc. that still need to be fixed in various browsers, and the implementations generally differ significantly from the specification.

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This issue is one of seven issues regarding unprefixing CSS properties/values, originally all in #702 (as per #702 (comment)). The aim is to group the properties together into multiple (but not seven) focus areas.

Specification

https://drafts.csswg.org/css-sizing-4/#sizing-values

Additional Signals

• Chromium bug
• WebKit bug
• Firefox bugs: 1, 2, 3.
• See also:
  o [css-sizing-4] stretch keyword for sizing properties mozilla/standards-positions#1054 (comment)
  o Umbrella Focus Area for unprefixing various CSS properties/values #702 (comment)

[yisibl]

Chrome is ready to improve it:
https://groups.google.com/a/chromium.org/g/blink-dev/c/fxGpXGV0hYc

[davidsgrogan]

The first set of tests for this feature recently landed here.

There are a few more tests scattered around in other directories that we could probably also include if we just substitute stretch in place of the vendor prefixed version of stretch.

I also intend to land more tests for stretch behavior in the same directory during the week of Oct 28 - Nov 1.