Bug 157834

There have been some changes on the spec so we need to update the implementation. This bug is about 2 changes that are interrelated. 1) First change [1] is from January 2015 [2]: "When appearing outside a minmax() notation, implies an automatic minimum (i.e. ''minmax(auto, <flex>)'')." Right now, we're considering that "1fr" is equivalent to "minmax(1fr, 1fr)". But it should be "minmax(auto, 1fr)". 2) Another change [3] from the spec that we should implement. "fr" should be invalid if it's used in the min slot of minmax(). The new syntax on the spec is [4]: <track-size> = <track-breadth> | minmax( <inflexible-breadth> , <track-breadth> ) <inflexible-breadth> = <length> | <percentage> | min-content | max-content | auto This means that a declaration like "grid-column: minmax(1fr, 100px);" should be considered invalid. As you can see both changes are very related. It would be strange that we're rejecting "fr" explicitly on the min slot (e.g. "minmax(1fr, 100px)"), but accepting it implicitly as "1fr" would behave like "minmax(1fr, 1fr)" instead of "minmax(auto, 1fr)". BTW, this has been already fixed in Blink: https://codereview.chromium.org/1979603002/ [1] https://drafts.csswg.org/css-grid/#valdef-grid-template-columns-flex [2] https://github.com/w3c/csswg-drafts/commit/129f2c1ad684e47ef85900f8e156efe07a3f13d6 [3] https://github.com/w3c/csswg-drafts/commit/4040ba7fa068905f7fe1c1bf35d665a2062acafa [4] https://drafts.csswg.org/css-grid/#typedef-track-size