Avoid recomputing inline_content_sizes() when not needed (#33806)

The result of `inline_content_sizes()` may depend on the block size of
the containing block, so we were always recomputing in case we got
a different block size.

However, if no content has a vertical percentage or stretches vertically,
then we don't need to recompute: the result will be the same anyways.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>

components/layout_2020/flexbox/construct.rs

@@ -171,7 +171,7 @@ where
                     let non_replaced = NonReplacedFormattingContext {
                         base_fragment_info: info.into(),
                         style: info.style.clone(),
-                        content_sizes: None,
+                        content_sizes_result: None,
                         contents: NonReplacedFormattingContextContents::Flow(
                             block_formatting_context,
                         ),

components/layout_2020/flexbox/layout.rs

@@ -31,7 +31,7 @@ use crate::geom::{AuOrAuto, LogicalRect, LogicalSides, LogicalVec2};
 use crate::positioned::{
     relative_adjustement, AbsolutelyPositionedBox, PositioningContext, PositioningContextLength,
 };
-use crate::sizing::{ContentSizes, IntrinsicSizingMode};
+use crate::sizing::{ContentSizes, InlineContentSizesResult, IntrinsicSizingMode};
 use crate::style_ext::{Clamp, ComputedValuesExt, PaddingBorderMargin};
 use crate::{ContainingBlock, IndefiniteContainingBlock};
 
@@ -336,6 +336,7 @@ struct FlexItemBoxInlineContentSizesInfo {
     min_flex_factors: DesiredFlexFractionAndGrowOrShrinkFactor,
     max_flex_factors: DesiredFlexFractionAndGrowOrShrinkFactor,
     min_content_main_size_for_multiline_container: Au,
+    depends_on_block_constraints: bool,
 }
 
 impl FlexContainer {
@@ -348,7 +349,7 @@ impl FlexContainer {
         &mut self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         match self.config.flex_axis {
             FlexAxis::Row => {
                 self.main_content_sizes(layout_context, containing_block_for_children, || {
@@ -367,14 +368,15 @@ impl FlexContainer {
         &mut self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         // <https://drafts.csswg.org/css-flexbox/#intrinsic-cross-sizes>
         assert_eq!(
             self.config.flex_axis,
             FlexAxis::Column,
             "The cross axis should be the inline one"
         );
-        let mut content_sizes = ContentSizes::zero();
+        let mut sizes = ContentSizes::zero();
+        let mut depends_on_block_constraints = false;
         for kid in self.children.iter() {
             let kid = &mut *kid.borrow_mut();
             match kid {
@@ -383,17 +385,22 @@ impl FlexContainer {
                     // columns, and sum the column sizes and gaps.
                     // TODO: Use the proper automatic minimum size.
                     let ifc = &mut item.independent_formatting_context;
-                    content_sizes.max_assign(ifc.outer_inline_content_sizes(
+                    let result = ifc.outer_inline_content_sizes(
                         layout_context,
                         containing_block_for_children,
                         &LogicalVec2::zero(),
                         false, /* auto_block_size_stretches_to_containing_block */
-                    ));
+                    );
+                    sizes.max_assign(result.sizes);
+                    depends_on_block_constraints |= result.depends_on_block_constraints;
                 },
                 FlexLevelBox::OutOfFlowAbsolutelyPositionedBox(_) => {},
             }
         }
-        content_sizes
+        InlineContentSizesResult {
+            sizes,
+            depends_on_block_constraints,
+        }
     }
 
     fn main_content_sizes<'a>(
@@ -401,7 +408,7 @@ impl FlexContainer {
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
         flex_context_getter: impl Fn() -> &'a FlexContext<'a>,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         // - TODO: calculate intrinsic cross sizes when container is a column
         // (and check for ‘writing-mode’?)
         // - TODO: Collapsed flex items need to be skipped for intrinsic size calculation.
@@ -483,6 +490,7 @@ impl FlexContainer {
         } else {
             Au::zero()
         };
+        let mut container_depends_on_block_constraints = false;
 
         for FlexItemBoxInlineContentSizesInfo {
             outer_flex_base_size,
@@ -492,6 +500,7 @@ impl FlexContainer {
             min_flex_factors,
             max_flex_factors,
             min_content_main_size_for_multiline_container,
+            depends_on_block_constraints,
         } in item_infos.iter()
         {
             // > 4. Add each item’s flex base size to the product of its flex grow factor (scaled flex shrink
@@ -528,11 +537,16 @@ impl FlexContainer {
                 container_min_content_size
                     .max_assign(*min_content_main_size_for_multiline_container);
             }
+
+            container_depends_on_block_constraints |= depends_on_block_constraints;
         }
 
-        ContentSizes {
+        InlineContentSizesResult {
+            sizes: ContentSizes {
                 min_content: container_min_content_size,
                 max_content: container_max_content_size,
+            },
+            depends_on_block_constraints: container_depends_on_block_constraints,
         }
     }
 
@@ -573,6 +587,7 @@ impl FlexContainer {
             FlexAxis::Row => containing_block.inline_size,
             FlexAxis::Column => containing_block.block_size.auto_is(|| {
                 self.main_content_sizes(layout_context, &containing_block.into(), || &flex_context)
+                    .sizes
                     .max_content
             }),
         };
@@ -1023,7 +1038,7 @@ impl<'a> FlexItem<'a> {
             flex_context.config.flex_axis,
         );
 
-        let (content_box_size, min_size, max_size, pbm) = box_
+        let (content_box_size, min_size, max_size, pbm, _) = box_
             .style()
             .content_box_sizes_and_padding_border_margin_deprecated(&containing_block.into());
 
@@ -1735,6 +1750,7 @@ impl FlexItem<'_> {
                             &containing_block_for_children,
                             &containing_block.into(),
                         )
+                        .sizes
                         .map(|size| {
                             size.clamp_between_extremums(
                                 self.content_min_size.cross,
@@ -2008,7 +2024,7 @@ impl FlexItemBox {
         let cross_axis_is_item_block_axis =
             cross_axis_is_item_block_axis(container_is_horizontal, item_is_horizontal, flex_axis);
 
-        let (content_box_size, content_min_size, content_max_size, pbm) =
+        let (content_box_size, content_min_size, content_max_size, pbm, _) =
             style.content_box_sizes_and_padding_border_margin_deprecated(containing_block);
         let padding = main_start_cross_start.sides_to_flex_relative(pbm.padding);
         let border = main_start_cross_start.sides_to_flex_relative(pbm.border);
@@ -2069,17 +2085,23 @@ impl FlexItemBox {
 
         // Compute the min-content and max-content contributions of the item.
         // <https://drafts.csswg.org/css-flexbox/#intrinsic-item-contributions>
-        let content_contribution_sizes = match flex_axis {
+        let (content_contribution_sizes, depends_on_block_constraints) = match flex_axis {
-            FlexAxis::Row => self
+            FlexAxis::Row => {
+                let InlineContentSizesResult {
+                    sizes,
+                    depends_on_block_constraints,
+                } = self
                     .independent_formatting_context
                     .outer_inline_content_sizes(
                         layout_context,
                         containing_block,
                         &content_min_size_no_auto,
                         item_with_auto_cross_size_stretches_to_container_size,
-                ),
+                    );
-            FlexAxis::Column => self
+                (sizes, depends_on_block_constraints)
-                .layout_for_block_content_size(
+            },
+            FlexAxis::Column => {
+                let size = self.layout_for_block_content_size(
                     flex_context_getter(),
                     &pbm,
                     content_box_size,
@@ -2087,8 +2109,9 @@ impl FlexItemBox {
                     content_max_size,
                     item_with_auto_cross_size_stretches_to_container_size,
                     IntrinsicSizingMode::Contribution,
-                )
+                );
-                .into(),
+                (size.into(), true)
+            },
         };
 
         let content_box_size = flex_axis.vec2_to_flex_relative(content_box_size);
@@ -2155,6 +2178,7 @@ impl FlexItemBox {
             min_flex_factors,
             max_flex_factors,
             min_content_main_size_for_multiline_container,
+            depends_on_block_constraints,
         }
     }
 
@@ -2282,6 +2306,7 @@ impl FlexItemBox {
                     &containing_block_for_children,
                     containing_block,
                 )
+                .sizes
                 .min_content
         } else {
             block_content_size_callback(self)
@@ -2444,6 +2469,7 @@ impl FlexItemBox {
                             &containing_block_for_children,
                             containing_block,
                         )
+                        .sizes
                         .max_content;
                     if let Some(ratio) = ratio {
                         max_content.clamp_between_extremums(
@@ -2522,11 +2548,12 @@ impl FlexItemBox {
                             let style = non_replaced.style.clone();
                             let containing_block_for_children =
                                 IndefiniteContainingBlock::new_for_style(&style);
-                            let inline_content_sizes = non_replaced.inline_content_sizes(
+                            non_replaced
+                                .inline_content_sizes(
                                     flex_context.layout_context,
                                     &containing_block_for_children,
-                            );
+                                )
-                            inline_content_sizes
+                                .sizes
                                 .shrink_to_fit(containing_block_inline_size_minus_pbm)
                         }
                     })

components/layout_2020/flow/inline/mod.rs

@@ -126,7 +126,7 @@ use crate::fragment_tree::{
 };
 use crate::geom::{LogicalRect, LogicalVec2, ToLogical};
 use crate::positioned::{AbsolutelyPositionedBox, PositioningContext};
-use crate::sizing::ContentSizes;
+use crate::sizing::{ContentSizes, InlineContentSizesResult};
 use crate::style_ext::{ComputedValuesExt, PaddingBorderMargin};
 use crate::{ContainingBlock, IndefiniteContainingBlock};
 
@@ -1565,7 +1565,7 @@ impl InlineFormattingContext {
         &self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         ContentSizesComputation::compute(self, layout_context, containing_block_for_children)
     }
 
@@ -2184,16 +2184,23 @@ struct ContentSizesComputation<'layout_data> {
     /// Stack of ending padding, margin, and border to add to the length
     /// when an inline box finishes.
     ending_inline_pbm_stack: Vec<Au>,
+    depends_on_block_constraints: bool,
 }
 
 impl<'layout_data> ContentSizesComputation<'layout_data> {
-    fn traverse(mut self, inline_formatting_context: &InlineFormattingContext) -> ContentSizes {
+    fn traverse(
+        mut self,
+        inline_formatting_context: &InlineFormattingContext,
+    ) -> InlineContentSizesResult {
         for inline_item in inline_formatting_context.inline_items.iter() {
             self.process_item(&mut inline_item.borrow_mut(), inline_formatting_context);
         }
 
         self.forced_line_break();
-        self.paragraph
+        InlineContentSizesResult {
+            sizes: self.paragraph,
+            depends_on_block_constraints: self.depends_on_block_constraints,
+        }
     }
 
     fn process_item(
@@ -2299,12 +2306,16 @@ impl<'layout_data> ContentSizesComputation<'layout_data> {
                     self.line_break_opportunity();
                 }
 
-                let outer = atomic.outer_inline_content_sizes(
+                let InlineContentSizesResult {
+                    sizes: outer,
+                    depends_on_block_constraints,
+                } = atomic.outer_inline_content_sizes(
                     self.layout_context,
                     self.containing_block,
                     &LogicalVec2::zero(),
                     false, /* auto_block_size_stretches_to_containing_block */
                 );
+                self.depends_on_block_constraints |= depends_on_block_constraints;
 
                 if !inline_formatting_context
                     .next_character_prevents_soft_wrap_opportunity(*offset_in_text)
@@ -2356,7 +2367,7 @@ impl<'layout_data> ContentSizesComputation<'layout_data> {
         inline_formatting_context: &InlineFormattingContext,
         layout_context: &'layout_data LayoutContext,
         containing_block: &'layout_data IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         Self {
             layout_context,
             containing_block,
@@ -2366,6 +2377,7 @@ impl<'layout_data> ContentSizesComputation<'layout_data> {
             had_content_yet_for_min_content: false,
             had_content_yet_for_max_content: false,
             ending_inline_pbm_stack: Vec::new(),
+            depends_on_block_constraints: false,
         }
         .traverse(inline_formatting_context)
     }

components/layout_2020/flow/mod.rs

@@ -37,7 +37,7 @@ use crate::geom::{
 };
 use crate::positioned::{AbsolutelyPositionedBox, PositioningContext, PositioningContextLength};
 use crate::replaced::ReplacedContent;
-use crate::sizing::{self, ContentSizes};
+use crate::sizing::{self, ContentSizes, InlineContentSizesResult};
 use crate::style_ext::{Clamp, ComputedValuesExt, PaddingBorderMargin};
 use crate::{ContainingBlock, IndefiniteContainingBlock};
 
@@ -234,7 +234,7 @@ impl OutsideMarker {
             &IndefiniteContainingBlock::new_for_style(&self.marker_style),
         );
         let containing_block_for_children = ContainingBlock {
-            inline_size: content_sizes.max_content,
+            inline_size: content_sizes.sizes.max_content,
             block_size: AuOrAuto::auto(),
             style: &self.marker_style,
         };
@@ -361,28 +361,29 @@ fn calculate_inline_content_size_for_block_level_boxes(
     boxes: &[ArcRefCell<BlockLevelBox>],
     layout_context: &LayoutContext,
     containing_block: &IndefiniteContainingBlock,
-) -> ContentSizes {
+) -> InlineContentSizesResult {
     let get_box_info = |box_: &ArcRefCell<BlockLevelBox>| {
         match &mut *box_.borrow_mut() {
             BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(_) |
             BlockLevelBox::OutsideMarker { .. } => None,
             BlockLevelBox::OutOfFlowFloatBox(ref mut float_box) => {
-                let size = float_box
+                let inline_content_sizes_result = float_box.contents.outer_inline_content_sizes(
-                    .contents
-                    .outer_inline_content_sizes(
                     layout_context,
                     containing_block,
                     &LogicalVec2::zero(),
                     false, /* auto_block_size_stretches_to_containing_block */
-                    )
+                );
-                    .max(ContentSizes::zero());
                 let style_box = &float_box.contents.style().get_box();
-                Some((size, style_box.float, style_box.clear))
+                Some((
+                    inline_content_sizes_result,
+                    style_box.float,
+                    style_box.clear,
+                ))
             },
             BlockLevelBox::SameFormattingContextBlock {
                 style, contents, ..
             } => {
-                let size = sizing::outer_inline(
+                let inline_content_sizes_result = sizing::outer_inline(
                     style,
                     containing_block,
                     &LogicalVec2::zero(),
@@ -390,30 +391,34 @@ fn calculate_inline_content_size_for_block_level_boxes(
                     |containing_block_for_children| {
                         contents.inline_content_sizes(layout_context, containing_block_for_children)
                     },
-                )
+                );
-                .max(ContentSizes::zero());
                 // A block in the same BFC can overlap floats, it's not moved next to them,
                 // so we shouldn't add its size to the size of the floats.
                 // Instead, we treat it like an independent block with 'clear: both'.
-                Some((size, Float::None, Clear::Both))
+                Some((inline_content_sizes_result, Float::None, Clear::Both))
             },
             BlockLevelBox::Independent(ref mut independent) => {
-                let size = independent
+                let inline_content_sizes_result = independent.outer_inline_content_sizes(
-                    .outer_inline_content_sizes(
                     layout_context,
                     containing_block,
                     &LogicalVec2::zero(),
                     false, /* auto_block_size_stretches_to_containing_block */
-                    )
+                );
-                    .max(ContentSizes::zero());
+                Some((
-                Some((size, Float::None, independent.style().get_box().clear))
+                    inline_content_sizes_result,
+                    Float::None,
+                    independent.style().get_box().clear,
+                ))
             },
         }
     };
 
     /// When iterating the block-level boxes to compute the inline content sizes,
     /// this struct contains the data accumulated up to the current box.
+    #[derive(Default)]
     struct AccumulatedData {
+        /// Whether the inline size depends on the block one.
+        depends_on_block_constraints: bool,
         /// The maximum size seen so far, not including trailing uncleared floats.
         max_size: ContentSizes,
         /// The size of the trailing uncleared floats with 'float: left'.
@@ -447,7 +452,13 @@ fn calculate_inline_content_size_for_block_level_boxes(
         }
     }
 
-    let accumulate = |mut data: AccumulatedData, (size, float, clear)| {
+    let accumulate =
+        |mut data: AccumulatedData,
+         (inline_content_sizes_result, float, clear): (InlineContentSizesResult, _, _)| {
+            let size = inline_content_sizes_result.sizes.max(ContentSizes::zero());
+            let depends_on_block_constraints =
+                inline_content_sizes_result.depends_on_block_constraints;
+            data.depends_on_block_constraints |= depends_on_block_constraints;
             data.clear_floats(clear);
             match float {
                 Float::Left => data.left_floats = data.left_floats.union(&size),
@@ -462,22 +473,23 @@ fn calculate_inline_content_size_for_block_level_boxes(
             }
             data
         };
-    let zero = AccumulatedData {
-        max_size: ContentSizes::zero(),
-        left_floats: ContentSizes::zero(),
-        right_floats: ContentSizes::zero(),
-    };
     let data = if layout_context.use_rayon {
         boxes
             .par_iter()
             .filter_map(get_box_info)
             .collect::<Vec<_>>()
             .into_iter()
-            .fold(zero, accumulate)
+            .fold(AccumulatedData::default(), accumulate)
     } else {
-        boxes.iter().filter_map(get_box_info).fold(zero, accumulate)
+        boxes
+            .iter()
+            .filter_map(get_box_info)
+            .fold(AccumulatedData::default(), accumulate)
     };
-    data.max_size_including_uncleared_floats()
+    InlineContentSizesResult {
+        depends_on_block_constraints: data.depends_on_block_constraints,
+        sizes: data.max_size_including_uncleared_floats(),
+    }
 }
 
 impl BlockContainer {
@@ -512,7 +524,7 @@ impl BlockContainer {
         &self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         match &self {
             Self::BlockLevelBoxes(boxes) => calculate_inline_content_size_for_block_level_boxes(
                 boxes,
@@ -1984,6 +1996,7 @@ impl IndependentFormattingContext {
                         );
                     non_replaced
                         .inline_content_sizes(layout_context, &containing_block_for_children)
+                        .sizes
                 };
 
                 // https://drafts.csswg.org/css2/visudet.html#float-width

components/layout_2020/formatting_contexts.rs

@@ -18,7 +18,7 @@ use crate::fragment_tree::{BaseFragmentInfo, BoxFragment, Fragment, FragmentFlag
 use crate::geom::LogicalSides;
 use crate::positioned::PositioningContext;
 use crate::replaced::ReplacedContent;
-use crate::sizing::{self, ContentSizes};
+use crate::sizing::{self, InlineContentSizesResult};
 use crate::style_ext::{AspectRatio, DisplayInside};
 use crate::table::Table;
 use crate::{AuOrAuto, ContainingBlock, IndefiniteContainingBlock, LogicalVec2};
@@ -36,7 +36,7 @@ pub(crate) struct NonReplacedFormattingContext {
     #[serde(skip_serializing)]
     pub style: Arc<ComputedValues>,
     /// If it was requested during construction
-    pub content_sizes: Option<(AuOrAuto, ContentSizes)>,
+    pub content_sizes_result: Option<(AuOrAuto, InlineContentSizesResult)>,
     pub contents: NonReplacedFormattingContextContents,
 }
 
@@ -152,7 +152,7 @@ impl IndependentFormattingContext {
                 Self::NonReplaced(NonReplacedFormattingContext {
                     style: Arc::clone(&node_and_style_info.style),
                     base_fragment_info,
-                    content_sizes: None,
+                    content_sizes_result: None,
                     contents,
                 })
             },
@@ -187,7 +187,7 @@ impl IndependentFormattingContext {
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
         containing_block: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         match self {
             Self::NonReplaced(inner) => {
                 inner.inline_content_sizes(layout_context, containing_block_for_children)
@@ -206,7 +206,7 @@ impl IndependentFormattingContext {
         containing_block: &IndefiniteContainingBlock,
         auto_minimum: &LogicalVec2<Au>,
         auto_block_size_stretches_to_containing_block: bool,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         match self {
             Self::NonReplaced(non_replaced) => non_replaced.outer_inline_content_sizes(
                 layout_context,
@@ -274,20 +274,22 @@ impl NonReplacedFormattingContext {
         &mut self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         assert_eq!(
             containing_block_for_children.size.inline,
             AuOrAuto::Auto,
             "inline_content_sizes() got non-auto containing block inline-size",
         );
-        if let Some((previous_cb_block_size, result)) = self.content_sizes {
+        if let Some((previous_cb_block_size, result)) = self.content_sizes_result {
-            if previous_cb_block_size == containing_block_for_children.size.block {
+            if !result.depends_on_block_constraints ||
+                previous_cb_block_size == containing_block_for_children.size.block
+            {
                 return result;
             }
             // TODO: Should we keep multiple caches for various block sizes?
         }
 
-        self.content_sizes
+        self.content_sizes_result
             .insert((
                 containing_block_for_children.size.block,
                 self.contents
@@ -302,7 +304,7 @@ impl NonReplacedFormattingContext {
         containing_block: &IndefiniteContainingBlock,
         auto_minimum: &LogicalVec2<Au>,
         auto_block_size_stretches_to_containing_block: bool,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         sizing::outer_inline(
             &self.style.clone(),
             containing_block,
@@ -320,7 +322,7 @@ impl NonReplacedFormattingContextContents {
         &mut self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         match self {
             Self::Flow(inner) => inner
                 .contents

components/layout_2020/lib.rs

@@ -65,7 +65,7 @@ impl<'a> IndefiniteContainingBlock<'a> {
         style: &'a ComputedValues,
         auto_minimum: &LogicalVec2<Au>,
     ) -> Self {
-        let (content_box_size, content_min_size, content_max_size, _) =
+        let (content_box_size, content_min_size, content_max_size, _, _) =
             style.content_box_sizes_and_padding_border_margin_deprecated(self);
         let block_size = content_box_size.block.map(|v| {
             v.clamp_between_extremums(

components/layout_2020/positioned.rs

@@ -587,6 +587,7 @@ impl HoistedAbsolutelyPositionedBox {
                                 );
                         non_replaced
                             .inline_content_sizes(layout_context, &containing_block_for_children)
+                            .sizes
                             .shrink_to_fit(available_size)
                     });
 

components/layout_2020/replaced.rs

@@ -29,7 +29,7 @@ use crate::context::LayoutContext;
 use crate::dom::NodeExt;
 use crate::fragment_tree::{BaseFragmentInfo, Fragment, IFrameFragment, ImageFragment};
 use crate::geom::{LogicalVec2, PhysicalPoint, PhysicalRect, PhysicalSize};
-use crate::sizing::ContentSizes;
+use crate::sizing::InlineContentSizesResult;
 use crate::style_ext::{AspectRatio, Clamp, ComputedValuesExt, PaddingBorderMargin};
 use crate::{AuOrAuto, ContainingBlock, IndefiniteContainingBlock};
 
@@ -263,21 +263,27 @@ impl ReplacedContent {
         _: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
         preferred_aspect_ratio: Option<AspectRatio>,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         // FIXME: min/max-content of replaced elements is not defined in
         // https://dbaron.org/css/intrinsic/
         // This seems sensible?
         let block_size = containing_block_for_children.size.block;
-        let inline_size = match (block_size, preferred_aspect_ratio) {
+        match (block_size, preferred_aspect_ratio) {
-            (AuOrAuto::LengthPercentage(block_size), Some(ratio)) => {
+            (AuOrAuto::LengthPercentage(block_size), Some(ratio)) => InlineContentSizesResult {
-                ratio.compute_dependent_size(Direction::Inline, block_size)
+                sizes: ratio
+                    .compute_dependent_size(Direction::Inline, block_size)
+                    .into(),
+                depends_on_block_constraints: true,
             },
-            _ => self
+            _ => InlineContentSizesResult {
+                sizes: self
                     .flow_relative_intrinsic_size(containing_block_for_children.style)
                     .inline
-                .unwrap_or_else(Au::zero),
+                    .unwrap_or_else(Au::zero)
-        };
+                    .into(),
-        inline_size.into()
+                depends_on_block_constraints: false,
+            },
+        }
     }
 
     pub fn make_fragments(

components/layout_2020/sizing.rs

@@ -118,10 +118,15 @@ pub(crate) fn outer_inline(
     containing_block: &IndefiniteContainingBlock,
     auto_minimum: &LogicalVec2<Au>,
     auto_block_size_stretches_to_containing_block: bool,
-    get_content_size: impl FnOnce(&IndefiniteContainingBlock) -> ContentSizes,
+    get_content_size: impl FnOnce(&IndefiniteContainingBlock) -> InlineContentSizesResult,
-) -> ContentSizes {
+) -> InlineContentSizesResult {
-    let (content_box_size, content_min_size, content_max_size, pbm) =
+    let (
-        style.content_box_sizes_and_padding_border_margin_deprecated(containing_block);
+        content_box_size,
+        content_min_size,
+        content_max_size,
+        pbm,
+        mut depends_on_block_constraints,
+    ) = style.content_box_sizes_and_padding_border_margin_deprecated(containing_block);
     let content_min_size = LogicalVec2 {
         inline: content_min_size.inline.auto_is(|| auto_minimum.inline),
         block: content_min_size.block.auto_is(|| auto_minimum.block),
@@ -132,11 +137,15 @@ pub(crate) fn outer_inline(
         v.clamp_between_extremums(content_min_size.inline, content_max_size.inline) + pbm_inline_sum
     };
     match content_box_size.inline {
-        AuOrAuto::LengthPercentage(inline_size) => adjust(inline_size).into(),
+        AuOrAuto::LengthPercentage(inline_size) => InlineContentSizesResult {
+            sizes: adjust(inline_size).into(),
+            depends_on_block_constraints: false,
+        },
         AuOrAuto::Auto => {
             let block_size = if content_box_size.block.is_auto() &&
                 auto_block_size_stretches_to_containing_block
             {
+                depends_on_block_constraints = true;
                 let outer_block_size = containing_block.size.block;
                 outer_block_size.map(|v| v - pbm.padding_border_sums.block - margin.block_sum())
             } else {
@@ -145,7 +154,18 @@ pub(crate) fn outer_inline(
             .map(|v| v.clamp_between_extremums(content_min_size.block, content_max_size.block));
             let containing_block_for_children =
                 IndefiniteContainingBlock::new_for_style_and_block_size(style, block_size);
-            get_content_size(&containing_block_for_children).map(adjust)
+            let content_result = get_content_size(&containing_block_for_children);
+            InlineContentSizesResult {
+                sizes: content_result.sizes.map(adjust),
+                depends_on_block_constraints: content_result.depends_on_block_constraints &&
+                    depends_on_block_constraints,
+            }
         },
     }
 }
+
+#[derive(Clone, Copy, Debug, Serialize)]
+pub(crate) struct InlineContentSizesResult {
+    pub sizes: ContentSizes,
+    pub depends_on_block_constraints: bool,
+}

components/layout_2020/style_ext.rs

@@ -29,7 +29,7 @@ use crate::dom_traversal::Contents;
 use crate::fragment_tree::FragmentFlags;
 use crate::geom::{
     AuOrAuto, LengthPercentageOrAuto, LogicalSides, LogicalVec2, PhysicalSides, PhysicalSize,
-    PhysicalVec, Size,
+    PhysicalVec, Size, SizeKeyword,
 };
 use crate::{ContainingBlock, IndefiniteContainingBlock};
 
@@ -249,6 +249,7 @@ pub(crate) trait ComputedValuesExt {
         LogicalVec2<Size<Au>>,
         LogicalVec2<Size<Au>>,
         PaddingBorderMargin,
+        bool, /* depends_on_block_constraints */
     );
     fn content_box_sizes_and_padding_border_margin_deprecated(
         &self,
@@ -258,6 +259,7 @@ pub(crate) trait ComputedValuesExt {
         LogicalVec2<AuOrAuto>,
         LogicalVec2<Option<Au>>,
         PaddingBorderMargin,
+        bool, /* depends_on_block_constraints */
     );
     fn padding_border_margin(&self, containing_block: &ContainingBlock) -> PaddingBorderMargin;
     fn padding_border_margin_for_intrinsic_size(
@@ -499,6 +501,7 @@ impl ComputedValuesExt for ComputedValues {
         LogicalVec2<Size<Au>>,
         LogicalVec2<Size<Au>>,
         PaddingBorderMargin,
+        bool, /* depends_on_block_constraints */
     ) {
         // <https://drafts.csswg.org/css-sizing-3/#cyclic-percentage-contribution>
         // If max size properties or preferred size properties are set to a value containing
@@ -513,25 +516,45 @@ impl ComputedValuesExt for ComputedValues {
             writing_mode,
             containing_block.size.inline.auto_is(Au::zero),
         );
-        let box_size = self
+        let box_size = self.box_size(writing_mode);
-            .box_size(writing_mode)
+        let min_size = self.min_box_size(writing_mode);
-            .maybe_percentages_relative_to_basis(&containing_block_size);
+        let max_size = self.max_box_size(writing_mode);
+        let depends_on_block_constraints = |size: &Size<LengthPercentage>| {
+            match size {
+                // fit-content is like clamp(min-content, stretch, max-content), but currently
+                // min-content and max-content have the same behavior in the block axis,
+                // so there is no dependency on block constraints.
+                // TODO: for flex and grid layout, min-content and max-content should be different.
+                // TODO: We are assuming that Size::Initial doesn't stretch. However, it may actually
+                // stretch flex and grid items depending on the CSS Align properties, in that case
+                // the caller needs to take care of it.
+                Size::Keyword(SizeKeyword::Stretch) => true,
+                Size::Numeric(length_percentage) => length_percentage.has_percentage(),
+                _ => false,
+            }
+        };
+        let depends_on_block_constraints = depends_on_block_constraints(&box_size.block) ||
+            depends_on_block_constraints(&min_size.block) ||
+            depends_on_block_constraints(&max_size.block);
+        let box_size = box_size.maybe_percentages_relative_to_basis(&containing_block_size);
         let content_box_size = self
             .content_box_size_for_box_size(box_size, &pbm)
             .map(|v| v.map(Au::from));
-        let min_size = self
+        let min_size = min_size.percentages_relative_to_basis(&containing_block_size_auto_is_zero);
-            .min_box_size(writing_mode)
-            .percentages_relative_to_basis(&containing_block_size_auto_is_zero);
         let content_min_size = self
             .content_min_box_size_for_min_size(min_size, &pbm)
             .map(|v| v.map(Au::from));
-        let max_size = self
+        let max_size = max_size.maybe_percentages_relative_to_basis(&containing_block_size);
-            .max_box_size(writing_mode)
-            .maybe_percentages_relative_to_basis(&containing_block_size);
         let content_max_size = self
             .content_max_box_size_for_max_size(max_size, &pbm)
             .map(|v| v.map(Au::from));
-        (content_box_size, content_min_size, content_max_size, pbm)
+        (
+            content_box_size,
+            content_min_size,
+            content_max_size,
+            pbm,
+            depends_on_block_constraints,
+        )
     }
 
     fn content_box_sizes_and_padding_border_margin_deprecated(
@@ -542,14 +565,21 @@ impl ComputedValuesExt for ComputedValues {
         LogicalVec2<AuOrAuto>,
         LogicalVec2<Option<Au>>,
         PaddingBorderMargin,
+        bool, /* depends_on_block_constraints */
     ) {
-        let (content_box_size, content_min_size, content_max_size, pbm) =
+        let (
-            self.content_box_sizes_and_padding_border_margin(containing_block);
+            content_box_size,
+            content_min_size,
+            content_max_size,
+            pbm,
+            depends_on_block_constraints,
+        ) = self.content_box_sizes_and_padding_border_margin(containing_block);
         (
             content_box_size.map(Size::to_auto_or),
             content_min_size.map(Size::to_auto_or),
             content_max_size.map(Size::to_numeric),
             pbm,
+            depends_on_block_constraints,
         )
     }
 

components/layout_2020/table/construct.rs

@@ -137,7 +137,7 @@ impl Table {
         IndependentFormattingContext::NonReplaced(NonReplacedFormattingContext {
             base_fragment_info: (&anonymous_info).into(),
             style: grid_and_wrapper_style,
-            content_sizes: None,
+            content_sizes_result: None,
             contents: NonReplacedFormattingContextContents::Table(table),
         })
     }
@@ -858,7 +858,7 @@ where
                         context: ArcRefCell::new(NonReplacedFormattingContext {
                             style: info.style.clone(),
                             base_fragment_info: info.into(),
-                            content_sizes: None,
+                            content_sizes_result: None,
                             contents,
                         }),
                     };

components/layout_2020/table/layout.rs

@@ -38,7 +38,7 @@ use crate::geom::{
     Size, SizeKeyword, ToLogical, ToLogicalWithContainingBlock,
 };
 use crate::positioned::{relative_adjustement, PositioningContext, PositioningContextLength};
-use crate::sizing::ContentSizes;
+use crate::sizing::{ContentSizes, InlineContentSizesResult};
 use crate::style_ext::{Clamp, ComputedValuesExt, PaddingBorderMargin};
 use crate::table::TableSlotCoordinates;
 use crate::{ContainingBlock, IndefiniteContainingBlock};
@@ -298,10 +298,13 @@ impl<'a> TableLayout<'a> {
                     let mut inline_content_sizes = if is_in_fixed_mode {
                         ContentSizes::zero()
                     } else {
-                        cell.contents.contents.inline_content_sizes(
+                        cell.contents
+                            .contents
+                            .inline_content_sizes(
                                 layout_context,
                                 &IndefiniteContainingBlock::new_for_style(&cell.style),
                             )
+                            .sizes
                     };
                     inline_content_sizes.min_content += padding_border_sums.inline;
                     inline_content_sizes.max_content += padding_border_sums.inline;
@@ -784,6 +787,7 @@ impl<'a> TableLayout<'a> {
                         &LogicalVec2::zero(),
                         false, /* auto_block_size_stretches_to_containing_block */
                     )
+                    .sizes
                     .min_content
             })
             .max()
@@ -2611,7 +2615,7 @@ impl Table {
         &mut self,
         layout_context: &LayoutContext,
         containing_block_for_children: &IndefiniteContainingBlock,
-    ) -> ContentSizes {
+    ) -> InlineContentSizesResult {
         let writing_mode = containing_block_for_children.style.writing_mode;
         let mut layout = TableLayout::new(self);
         let mut table_content_sizes = layout.compute_grid_min_max(layout_context, writing_mode);
@@ -2638,7 +2642,10 @@ impl Table {
                 .max_assign(caption_minimum_inline_size);
         }
 
-        table_content_sizes
+        InlineContentSizesResult {
+            sizes: table_content_sizes,
+            depends_on_block_constraints: false,
+        }
     }
 
     fn get_column_measure_for_column_at_index(