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/computed/flex.rs

@@ -14,6 +14,6 @@ impl FlexBasis {
     /// `auto`
     #[inline]
     pub fn auto() -> Self {
-        GenericFlexBasis::Width(Size::auto())
+        GenericFlexBasis::Size(Size::auto())
     }
 }

components/style/values/generics/flex.rs

@@ -19,9 +19,12 @@
     ToComputedValue,
     ToCss,
 )]
-pub enum FlexBasis<Width> {
+#[repr(C)]
+pub enum GenericFlexBasis<S> {
     /// `content`
     Content,
     /// `<width>`
-    Width(Width),
+    Size(S),
 }
+
+pub use self::GenericFlexBasis as FlexBasis;

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(..))
     }
 }
 

components/style/values/generics/length.rs

@@ -96,14 +96,17 @@ impl<LengthPercentage: Parse> Parse for LengthPercentageOrAuto<LengthPercentage>
     ToComputedValue,
     ToCss,
 )]
-pub enum Size<LengthPercentage> {
-    LengthPercentage(LengthPercentage),
+#[repr(C, u8)]
+pub enum GenericSize<LengthPercent> {
+    LengthPercentage(LengthPercent),
     Auto,
     #[cfg(feature = "gecko")]
     #[animation(error)]
     ExtremumLength(ExtremumLength),
 }
 
+pub use self::GenericSize as Size;
+
 impl<LengthPercentage> Size<LengthPercentage> {
     /// `auto` value.
     #[inline]
@@ -134,14 +137,17 @@ impl<LengthPercentage> Size<LengthPercentage> {
     ToComputedValue,
     ToCss,
 )]
-pub enum MaxSize<LengthPercentage> {
-    LengthPercentage(LengthPercentage),
+#[repr(C, u8)]
+pub enum GenericMaxSize<LengthPercent> {
+    LengthPercentage(LengthPercent),
     None,
     #[cfg(feature = "gecko")]
     #[animation(error)]
     ExtremumLength(ExtremumLength),
 }
 
+pub use self::GenericMaxSize as MaxSize;
+
 impl<LengthPercentage> MaxSize<LengthPercentage> {
     /// `none` value.
     #[inline]

components/style/values/specified/flex.rs

@@ -18,8 +18,8 @@ impl Parse for FlexBasis {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
-        if let Ok(width) = input.try(|i| Size::parse(context, i)) {
-            return Ok(GenericFlexBasis::Width(width));
+        if let Ok(size) = input.try(|i| Size::parse(context, i)) {
+            return Ok(GenericFlexBasis::Size(size));
         }
         try_match_ident_ignore_ascii_case! { input,
             "content" => Ok(GenericFlexBasis::Content),
@@ -31,12 +31,12 @@ impl FlexBasis {
     /// `auto`
     #[inline]
     pub fn auto() -> Self {
-        GenericFlexBasis::Width(Size::auto())
+        GenericFlexBasis::Size(Size::auto())
     }
 
     /// `0%`
     #[inline]
     pub fn zero_percent() -> Self {
-        GenericFlexBasis::Width(Size::zero_percent())
+        GenericFlexBasis::Size(Size::zero_percent())
     }
 }