Refine logic for laying out flex item in column layout after #34346 (#34372)

- Clamp the stretch size to not be negative when the sum of padding,
  borders and margins exceed the available space. This avoids a 2nd
  layout.
- Avoid computing the inline content sizes if the result isn't needed.
- Instead of clamping both the min-content and max-content sizes to be
  between the min and max constraints, just compute the fit-content size
  first, and then clamp. Then `ContentSizes::map()` can be removed.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>

components/layout_2020/flexbox/layout.rs

@@ -1882,12 +1882,20 @@ impl FlexItem<'_> {
         } else {
             (
                 cross_size.auto_is(|| {
+                    let style = self.box_.style();
+                    let stretch_size =
+                        Au::zero().max(containing_block.inline_size - self.pbm_auto_is_zero.cross);
+                    if flex_context
+                        .config
+                        .item_with_auto_cross_size_stretches_to_container_size(style, &self.margin)
+                    {
+                        return stretch_size;
+                    }
                     let constraint_space = ConstraintSpace::new(
                         SizeConstraint::Definite(used_main_size),
                         item_writing_mode,
                     );
-                    let content_contributions = self
+                    self.box_
-                        .box_
                         .independent_formatting_context
                         .inline_content_sizes(
                             flex_context.layout_context,
@@ -1895,22 +1903,11 @@ impl FlexItem<'_> {
                             &containing_block.into(),
                         )
                         .sizes
-                        .map(|size| {
+                        .shrink_to_fit(stretch_size)
-                            size.clamp_between_extremums(
+                        .clamp_between_extremums(
-                                self.content_min_size.cross,
+                            self.content_min_size.cross,
-                                self.content_max_size.cross,
+                            self.content_max_size.cross,
-                            )
+                        )
-                        });
-                    let stretch_size = containing_block.inline_size - self.pbm_auto_is_zero.cross;
-                    let style = self.box_.style();
-                    if flex_context
-                        .config
-                        .item_with_auto_cross_size_stretches_to_container_size(style, &self.margin)
-                    {
-                        stretch_size
-                    } else {
-                        content_contributions.shrink_to_fit(stretch_size)
-                    }
                 }),
                 // The main size of a flex item is considered to be definite if its flex basis is definite
                 // or the flex container has a definite main size.

components/layout_2020/sizing.rs

@@ -40,13 +40,6 @@ pub(crate) struct ContentSizes {
 
 /// <https://drafts.csswg.org/css-sizing/#intrinsic-sizes>
 impl ContentSizes {
-    pub fn map(&self, f: impl Fn(Au) -> Au) -> Self {
-        Self {
-            min_content: f(self.min_content),
-            max_content: f(self.max_content),
-        }
-    }
-
     pub fn max(&self, other: Self) -> Self {
         Self {
             min_content: self.min_content.max(other.min_content),