style: Use Rust sizes for flex-basis, width, height, and their min/max properties.

Really sorry for the size of the patch :(

Only intentional behavior change is in the uses of HasLengthAndPercentage(),
where it's easier to do the right thing. The checks that used to check for
(IsCalcUnit() && CalcHasPercentage()) are wrong since bug 957915.

Differential Revision: https://phabricator.services.mozilla.com/D19553

components/style/values/generics/grid.rs

@@ -192,10 +192,7 @@ impl<L> TrackBreadth<L> {
     /// <https://drafts.csswg.org/css-grid/#typedef-fixed-breadth>
     #[inline]
     pub fn is_fixed(&self) -> bool {
-        match *self {
-            TrackBreadth::Breadth(ref _lp) => true,
-            _ => false,
-        }
+        matches!(*self, TrackBreadth::Breadth(..))
     }
 }