Compute content sizes lazily in layout 2020

11 files changed, 176 insertions, 247 deletions

diff --git a/components/layout_2020/flexbox/construct.rs b/components/layout_2020/flexbox/construct.rs
index 385b45985e1..6c7c90635f2 100644
--- a/components/layout_2020/flexbox/construct.rs
+++ b/components/layout_2020/flexbox/construct.rs
@@ -12,7 +12,6 @@ use crate::element_data::LayoutBox;
 use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragments::Tag;
 use crate::positioned::AbsolutelyPositionedBox;
-use crate::sizing::{BoxContentSizes, ContentSizes, ContentSizesRequest};
 use crate::style_ext::DisplayGeneratingBox;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use std::borrow::Cow;
@@ -23,9 +22,8 @@ impl FlexContainer {
         context: &LayoutContext,
         info: &NodeAndStyleInfo<impl NodeExt<'dom>>,
         contents: NonReplacedContents,
-        content_sizes: ContentSizesRequest,
         propagated_text_decoration_line: TextDecorationLine,
-    ) -> (Self, BoxContentSizes) {
+    ) -> Self {
         let text_decoration_line =
             propagated_text_decoration_line | info.style.clone_text_decoration_line();
         let mut builder = FlexContainerBuilder {
@@ -37,11 +35,7 @@ impl FlexContainer {
             has_text_runs: false,
         };
         contents.traverse(context, info, &mut builder);
-        let content_sizes = content_sizes.compute(|| {
-            // FIXME
-            ContentSizes::zero()
-        });
-        (builder.finish(), content_sizes)
+        builder.finish()
     }
 }
 
@@ -152,7 +146,6 @@ where
             .map(|job| match job {
                 FlexLevelJob::TextRuns(runs) => ArcRefCell::new(FlexLevelBox::FlexItem(
                     IndependentFormattingContext::construct_for_text_runs(
-                        self.context,
                         &self
                             .info
                             .new_replacing_style(anonymous_style.clone().unwrap()),
@@ -161,7 +154,6 @@ where
                             text: run.text.into(),
                             parent_style: run.info.style,
                         }),
-                        ContentSizesRequest::None, // FIXME: request sizes when we start using them
                         self.text_decoration_line,
                     ),
                 )),
@@ -191,7 +183,6 @@ where
                                 &info,
                                 display_inside,
                                 contents,
-                                ContentSizesRequest::None, // FIXME: request sizes when we start using them
                                 self.text_decoration_line,
                             ),
                         ))
diff --git a/components/layout_2020/flexbox/mod.rs b/components/layout_2020/flexbox/mod.rs
index c7aed0bd0e9..5dd0c476727 100644
--- a/components/layout_2020/flexbox/mod.rs
+++ b/components/layout_2020/flexbox/mod.rs
@@ -5,6 +5,7 @@
 use crate::cell::ArcRefCell;
 use crate::formatting_contexts::IndependentFormattingContext;
 use crate::positioned::AbsolutelyPositionedBox;
+use crate::sizing::ContentSizes;
 
 mod construct;
 mod layout;
@@ -19,3 +20,9 @@ pub(crate) enum FlexLevelBox {
     FlexItem(IndependentFormattingContext),
     OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
 }
+
+impl FlexContainer {
+    pub fn inline_content_sizes(&self) -> ContentSizes {
+        unimplemented!()
+    }
+}
diff --git a/components/layout_2020/flow/construct.rs b/components/layout_2020/flow/construct.rs
index 7d72209c6e8..0f49fb85422 100644
--- a/components/layout_2020/flow/construct.rs
+++ b/components/layout_2020/flow/construct.rs
@@ -14,14 +14,12 @@ use crate::flow::{BlockContainer, BlockFormattingContext, BlockLevelBox};
 use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragments::Tag;
 use crate::positioned::AbsolutelyPositionedBox;
-use crate::sizing::{self, BoxContentSizes, ContentSizes, ContentSizesRequest};
-use crate::style_ext::{ComputedValuesExt, DisplayGeneratingBox, DisplayInside, DisplayOutside};
+use crate::style_ext::{DisplayGeneratingBox, DisplayInside, DisplayOutside};
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use rayon_croissant::ParallelIteratorExt;
 use servo_arc::Arc;
 use std::borrow::Cow;
 use std::convert::{TryFrom, TryInto};
-use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
 use style::selector_parser::PseudoElement;
 use style::values::specified::text::TextDecorationLine;
@@ -31,34 +29,24 @@ impl BlockFormattingContext {
         context: &LayoutContext,
         info: &NodeAndStyleInfo<Node>,
         contents: NonReplacedContents,
-        content_sizes: ContentSizesRequest,
         propagated_text_decoration_line: TextDecorationLine,
-    ) -> (Self, BoxContentSizes)
+    ) -> Self
     where
         Node: NodeExt<'dom>,
     {
-        let (contents, contains_floats, inline_content_sizes) = BlockContainer::construct(
-            context,
-            info,
-            contents,
-            content_sizes,
-            propagated_text_decoration_line,
-        );
-        // FIXME: add contribution to `inline_content_sizes` of floats in this formatting context
-        // https://dbaron.org/css/intrinsic/#intrinsic
+        let (contents, contains_floats) =
+            BlockContainer::construct(context, info, contents, propagated_text_decoration_line);
         let bfc = Self {
             contents,
             contains_floats: contains_floats == ContainsFloats::Yes,
         };
-        (bfc, inline_content_sizes)
+        bfc
     }
 
     pub fn construct_for_text_runs<'dom>(
-        context: &LayoutContext,
         runs: impl Iterator<Item = TextRun>,
-        content_sizes: ContentSizesRequest,
         text_decoration_line: TextDecorationLine,
-    ) -> (Self, BoxContentSizes) {
+    ) -> Self {
         // FIXME: do white space collapsing
         let inline_level_boxes = runs
             .map(|run| ArcRefCell::new(InlineLevelBox::TextRun(run)))
@@ -68,18 +56,12 @@ impl BlockFormattingContext {
             inline_level_boxes,
             text_decoration_line,
         };
-        // FIXME: this is the wrong writing mode
-        // but we plan to remove eager content size computation.
-        let not_actually_containing_block_writing_mode = WritingMode::empty();
-        let content_sizes = content_sizes.compute(|| {
-            ifc.inline_content_sizes(context, not_actually_containing_block_writing_mode)
-        });
         let contents = BlockContainer::InlineFormattingContext(ifc);
         let bfc = Self {
             contents,
             contains_floats: false,
         };
-        (bfc, content_sizes)
+        bfc
     }
 }
 
@@ -181,9 +163,8 @@ impl BlockContainer {
         context: &LayoutContext,
         info: &NodeAndStyleInfo<Node>,
         contents: NonReplacedContents,
-        content_sizes: ContentSizesRequest,
         propagated_text_decoration_line: TextDecorationLine,
-    ) -> (BlockContainer, ContainsFloats, BoxContentSizes)
+    ) -> (BlockContainer, ContainsFloats)
     where
         Node: NodeExt<'dom>,
     {
@@ -209,35 +190,22 @@ impl BlockContainer {
             .is_empty()
         {
             if builder.block_level_boxes.is_empty() {
-                // FIXME: this is the wrong writing mode
-                // but we plan to remove eager content size computation.
-                let not_actually_containing_block_writing_mode = info.style.writing_mode;
-                let content_sizes = content_sizes.compute(|| {
-                    builder
-                        .ongoing_inline_formatting_context
-                        .inline_content_sizes(context, not_actually_containing_block_writing_mode)
-                });
                 let container = BlockContainer::InlineFormattingContext(
                     builder.ongoing_inline_formatting_context,
                 );
-                return (container, builder.contains_floats, content_sizes);
+                return (container, builder.contains_floats);
             }
             builder.end_ongoing_inline_formatting_context();
         }
 
         struct Accumulator {
             contains_floats: ContainsFloats,
-            outer_content_sizes_of_children: ContentSizes,
         }
         let mut acc = Accumulator {
             contains_floats: builder.contains_floats,
-            outer_content_sizes_of_children: ContentSizes::zero(),
         };
         let mapfold = |acc: &mut Accumulator, creator: BlockLevelJob<'dom, _>| {
-            let (block_level_box, box_contains_floats) = creator.finish(
-                context,
-                content_sizes.if_requests_inline(|| &mut acc.outer_content_sizes_of_children),
-            );
+            let (block_level_box, box_contains_floats) = creator.finish(context);
             acc.contains_floats |= box_contains_floats;
             block_level_box
         };
@@ -250,14 +218,9 @@ impl BlockContainer {
                     mapfold,
                     || Accumulator {
                         contains_floats: ContainsFloats::No,
-                        outer_content_sizes_of_children: ContentSizes::zero(),
                     },
                     |left, right| {
                         left.contains_floats |= right.contains_floats;
-                        if content_sizes.requests_inline() {
-                            left.outer_content_sizes_of_children
-                                .max_assign(&right.outer_content_sizes_of_children)
-                        }
                     },
                 )
                 .collect()
@@ -270,12 +233,8 @@ impl BlockContainer {
         };
         let container = BlockContainer::BlockLevelBoxes(block_level_boxes);
 
-        let Accumulator {
-            contains_floats,
-            outer_content_sizes_of_children,
-        } = acc;
-        let content_sizes = content_sizes.compute(|| outer_content_sizes_of_children);
-        (container, contains_floats, content_sizes)
+        let Accumulator { contains_floats } = acc;
+        (container, contains_floats)
     }
 }
 
@@ -439,7 +398,6 @@ where
         display_inside: DisplayInside,
         contents: Contents,
     ) -> ArcRefCell<InlineLevelBox> {
-        let style = &info.style;
         let box_ = if display_inside == DisplayInside::Flow && !contents.is_replaced() {
             // We found un inline box.
             // Whatever happened before, all we need to do before recurring
@@ -464,14 +422,12 @@ where
             inline_box.last_fragment = true;
             ArcRefCell::new(InlineLevelBox::InlineBox(inline_box))
         } else {
-            let content_sizes = ContentSizesRequest::inline_if(!style.inline_size_is_length());
             ArcRefCell::new(InlineLevelBox::Atomic(
                 IndependentFormattingContext::construct(
                     self.context,
                     info,
                     display_inside,
                     contents,
-                    content_sizes,
                     // Text decorations are not propagated to atomic inline-level descendants.
                     TextDecorationLine::NONE,
                 ),
@@ -681,32 +637,11 @@ impl<'dom, Node> BlockLevelJob<'dom, Node>
 where
     Node: NodeExt<'dom>,
 {
-    fn finish(
-        self,
-        context: &LayoutContext,
-        max_assign_in_flow_outer_content_sizes_to: Option<&mut ContentSizes>,
-    ) -> (ArcRefCell<BlockLevelBox>, ContainsFloats) {
+    fn finish(self, context: &LayoutContext) -> (ArcRefCell<BlockLevelBox>, ContainsFloats) {
         let info = &self.info;
-        // FIXME: this is the wrong writing mode
-        // but we plan to remove eager content size computation.
-        let not_actually_containing_block_writing_mode = info.style.writing_mode;
         let (block_level_box, contains_floats) = match self.kind {
             BlockLevelCreator::SameFormattingContextBlock(contents) => {
-                let (contents, contains_floats, box_content_sizes) = contents.finish(
-                    context,
-                    info,
-                    ContentSizesRequest::inline_if(
-                        max_assign_in_flow_outer_content_sizes_to.is_some() &&
-                            !info.style.inline_size_is_length(),
-                    ),
-                );
-                if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
-                    to.max_assign(&sizing::outer_inline(
-                        &info.style,
-                        not_actually_containing_block_writing_mode,
-                        || box_content_sizes.expect_inline().clone(),
-                    ))
-                }
+                let (contents, contains_floats) = contents.finish(context, info);
                 let block_level_box = ArcRefCell::new(BlockLevelBox::SameFormattingContextBlock {
                     tag: Tag::from_node_and_style_info(info),
                     contents,
@@ -719,25 +654,13 @@ where
                 contents,
                 propagated_text_decoration_line,
             } => {
-                let content_sizes = ContentSizesRequest::inline_if(
-                    max_assign_in_flow_outer_content_sizes_to.is_some() &&
-                        !info.style.inline_size_is_length(),
-                );
                 let context = IndependentFormattingContext::construct(
                     context,
                     info,
                     display_inside,
                     contents,
-                    content_sizes,
                     propagated_text_decoration_line,
                 );
-                if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
-                    to.max_assign(&sizing::outer_inline(
-                        &context.style(),
-                        not_actually_containing_block_writing_mode,
-                        || context.content_sizes(),
-                    ))
-                }
                 (
                     ArcRefCell::new(BlockLevelBox::Independent(context)),
                     ContainsFloats::No,
@@ -775,35 +698,21 @@ impl IntermediateBlockContainer {
         self,
         context: &LayoutContext,
         info: &NodeAndStyleInfo<Node>,
-        content_sizes: ContentSizesRequest,
-    ) -> (BlockContainer, ContainsFloats, BoxContentSizes)
+    ) -> (BlockContainer, ContainsFloats)
     where
         Node: NodeExt<'dom>,
     {
         match self {
             IntermediateBlockContainer::Deferred(contents, propagated_text_decoration_line) => {
-                BlockContainer::construct(
-                    context,
-                    info,
-                    contents,
-                    content_sizes,
-                    propagated_text_decoration_line,
-                )
+                BlockContainer::construct(context, info, contents, propagated_text_decoration_line)
             },
             IntermediateBlockContainer::InlineFormattingContext(ifc) => {
-                // FIXME: this is the wrong writing mode
-                // but we plan to remove eager content size computation.
-                let not_actually_containing_block_writing_mode = info.style.writing_mode;
-                let content_sizes = content_sizes.compute(|| {
-                    ifc.inline_content_sizes(context, not_actually_containing_block_writing_mode)
-                });
                 // If that inline formatting context contained any float, those
                 // were already taken into account during the first phase of
                 // box construction.
                 (
                     BlockContainer::InlineFormattingContext(ifc),
                     ContainsFloats::No,
-                    content_sizes,
                 )
             },
         }
diff --git a/components/layout_2020/flow/float.rs b/components/layout_2020/flow/float.rs
index da70838499f..22b0b1bb66e 100644
--- a/components/layout_2020/flow/float.rs
+++ b/components/layout_2020/flow/float.rs
@@ -5,8 +5,7 @@
 use crate::context::LayoutContext;
 use crate::dom_traversal::{Contents, NodeAndStyleInfo, NodeExt};
 use crate::formatting_contexts::IndependentFormattingContext;
-use crate::sizing::ContentSizesRequest;
-use crate::style_ext::{ComputedValuesExt, DisplayInside};
+use crate::style_ext::DisplayInside;
 use style::values::specified::text::TextDecorationLine;
 
 #[derive(Debug, Serialize)]
@@ -32,14 +31,12 @@ impl FloatBox {
         display_inside: DisplayInside,
         contents: Contents,
     ) -> Self {
-        let content_sizes = ContentSizesRequest::inline_if(!info.style.inline_size_is_length());
         Self {
             contents: IndependentFormattingContext::construct(
                 context,
                 info,
                 display_inside,
                 contents,
-                content_sizes,
                 // Text decorations are not propagated to any out-of-flow descendants
                 TextDecorationLine::NONE,
             ),
diff --git a/components/layout_2020/flow/inline.rs b/components/layout_2020/flow/inline.rs
index f6895258dab..910f9e20cea 100644
--- a/components/layout_2020/flow/inline.rs
+++ b/components/layout_2020/flow/inline.rs
@@ -16,7 +16,7 @@ use crate::positioned::{
     relative_adjustement, AbsolutelyPositionedBox, HoistedAbsolutelyPositionedBox,
     PositioningContext,
 };
-use crate::sizing::{self, ContentSizes};
+use crate::sizing::ContentSizes;
 use crate::style_ext::{ComputedValuesExt, Display, DisplayGeneratingBox, DisplayOutside};
 use crate::ContainingBlock;
 use app_units::Au;
@@ -200,10 +200,9 @@ impl InlineFormattingContext {
                             }
                         },
                         InlineLevelBox::Atomic(atomic) => {
-                            let (outer, pc) = sizing::outer_inline_and_percentages(
-                                &atomic.style(),
+                            let (outer, pc) = atomic.outer_inline_and_percentages(
+                                self.layout_context,
                                 self.containing_block_writing_mode,
-                                || atomic.content_sizes(),
                             );
                             self.current_line.min_content += outer.min_content;
                             self.current_line.max_content += outer.max_content;
@@ -595,7 +594,9 @@ fn layout_atomic(
             // https://drafts.csswg.org/css2/visudet.html#inlineblock-width
             let tentative_inline_size = box_size.inline.auto_is(|| {
                 let available_size = ifc.containing_block.inline_size - pbm_sums.inline_sum();
-                non_replaced.content_sizes.shrink_to_fit(available_size)
+                non_replaced
+                    .inline_content_sizes(layout_context)
+                    .shrink_to_fit(available_size)
             });
 
             // https://drafts.csswg.org/css2/visudet.html#min-max-widths
diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs
index b8c0d7e500d..c256c6c9a23 100644
--- a/components/layout_2020/flow/mod.rs
+++ b/components/layout_2020/flow/mod.rs
@@ -18,11 +18,13 @@ use crate::fragments::{
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::positioned::{AbsolutelyPositionedBox, PositioningContext};
 use crate::replaced::ReplacedContent;
+use crate::sizing::{self, ContentSizes};
 use crate::style_ext::{ComputedValuesExt, PaddingBorderMargin};
 use crate::ContainingBlock;
 use rayon::iter::{IndexedParallelIterator, IntoParallelRefIterator, ParallelIterator};
 use rayon_croissant::ParallelIteratorExt;
 use servo_arc::Arc;
+use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
 use style::values::computed::{Length, LengthOrAuto};
 use style::Zero;
@@ -132,6 +134,29 @@ impl BlockContainer {
             ),
         }
     }
+
+    pub(super) fn inline_content_sizes(
+        &self,
+        layout_context: &LayoutContext,
+        containing_block_writing_mode: WritingMode,
+    ) -> ContentSizes {
+        match &self {
+            Self::BlockLevelBoxes(boxes) => {
+                let mut content_sizes = ContentSizes::zero();
+                for box_ in boxes {
+                    content_sizes.max_assign(
+                        &box_
+                            .borrow_mut()
+                            .inline_content_sizes(layout_context, containing_block_writing_mode),
+                    );
+                }
+                content_sizes
+            },
+            Self::InlineFormattingContext(context) => {
+                context.inline_content_sizes(layout_context, containing_block_writing_mode)
+            },
+        }
+    }
 }
 
 fn layout_block_level_children(
@@ -350,6 +375,28 @@ impl BlockLevelBox {
             },
         }
     }
+
+    fn inline_content_sizes(
+        &mut self,
+        layout_context: &LayoutContext,
+        containing_block_writing_mode: WritingMode,
+    ) -> ContentSizes {
+        match self {
+            Self::SameFormattingContextBlock {
+                style, contents, ..
+            } => sizing::outer_inline(style, containing_block_writing_mode, || {
+                contents.inline_content_sizes(layout_context, style.writing_mode)
+            }),
+            Self::Independent(independent) => {
+                independent.outer_inline(layout_context, containing_block_writing_mode)
+            },
+            BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(_) => ContentSizes::zero(),
+            BlockLevelBox::OutOfFlowFloatBox(_box_) => {
+                // TODO: Actually implement that.
+                ContentSizes::zero()
+            },
+        }
+    }
 }
 
 enum NonReplacedContents<'a> {
diff --git a/components/layout_2020/flow/root.rs b/components/layout_2020/flow/root.rs
index 55c325a3cd0..247d6bde904 100644
--- a/components/layout_2020/flow/root.rs
+++ b/components/layout_2020/flow/root.rs
@@ -22,7 +22,6 @@ use crate::geom::{PhysicalPoint, PhysicalRect, PhysicalSize};
 use crate::positioned::AbsolutelyPositionedBox;
 use crate::positioned::PositioningContext;
 use crate::replaced::ReplacedContent;
-use crate::sizing::ContentSizesRequest;
 use crate::style_ext::ComputedValuesExt;
 use crate::style_ext::{Display, DisplayGeneratingBox, DisplayInside};
 use crate::wrapper::GetStyleAndLayoutData;
@@ -291,7 +290,6 @@ fn construct_for_root_element<'dom>(
                 &info,
                 display_inside,
                 contents,
-                ContentSizesRequest::None,
                 propagated_text_decoration_line,
             )),
         )
diff --git a/components/layout_2020/formatting_contexts.rs b/components/layout_2020/formatting_contexts.rs
index 5f9549238af..9b493f5e168 100644
--- a/components/layout_2020/formatting_contexts.rs
+++ b/components/layout_2020/formatting_contexts.rs
@@ -9,13 +9,14 @@ use crate::flow::BlockFormattingContext;
 use crate::fragments::{Fragment, Tag};
 use crate::positioned::PositioningContext;
 use crate::replaced::ReplacedContent;
-use crate::sizing::{BoxContentSizes, ContentSizes, ContentSizesRequest};
+use crate::sizing::{self, ContentSizes};
 use crate::style_ext::DisplayInside;
 use crate::ContainingBlock;
 use servo_arc::Arc;
 use std::convert::TryInto;
+use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
-use style::values::computed::Length;
+use style::values::computed::{Length, Percentage};
 use style::values::specified::text::TextDecorationLine;
 
 /// https://drafts.csswg.org/css-display/#independent-formatting-context
@@ -31,7 +32,7 @@ pub(crate) struct NonReplacedFormattingContext {
     #[serde(skip_serializing)]
     pub style: Arc<ComputedValues>,
     /// If it was requested during construction
-    pub content_sizes: BoxContentSizes,
+    pub content_sizes: Option<ContentSizes>,
     pub contents: NonReplacedFormattingContextContents,
 }
 
@@ -65,41 +66,36 @@ impl IndependentFormattingContext {
         info: &NodeAndStyleInfo<impl NodeExt<'dom>>,
         display_inside: DisplayInside,
         contents: Contents,
-        content_sizes: ContentSizesRequest,
         propagated_text_decoration_line: TextDecorationLine,
     ) -> Self {
         match contents.try_into() {
-            Ok(non_replaced) => match display_inside {
-                DisplayInside::Flow | DisplayInside::FlowRoot => {
-                    let (bfc, content_sizes) = BlockFormattingContext::construct(
-                        context,
-                        info,
-                        non_replaced,
-                        content_sizes,
-                        propagated_text_decoration_line,
-                    );
-                    Self::NonReplaced(NonReplacedFormattingContext {
-                        tag: Tag::from_node_and_style_info(info),
-                        style: Arc::clone(&info.style),
-                        content_sizes,
-                        contents: NonReplacedFormattingContextContents::Flow(bfc),
-                    })
-                },
-                DisplayInside::Flex => {
-                    let (fc, content_sizes) = FlexContainer::construct(
-                        context,
-                        info,
-                        non_replaced,
-                        content_sizes,
-                        propagated_text_decoration_line,
-                    );
-                    Self::NonReplaced(NonReplacedFormattingContext {
-                        tag: Tag::from_node_and_style_info(info),
-                        style: Arc::clone(&info.style),
-                        content_sizes,
-                        contents: NonReplacedFormattingContextContents::Flex(fc),
-                    })
-                },
+            Ok(non_replaced) => {
+                let contents = match display_inside {
+                    DisplayInside::Flow | DisplayInside::FlowRoot => {
+                        NonReplacedFormattingContextContents::Flow(
+                            BlockFormattingContext::construct(
+                                context,
+                                info,
+                                non_replaced,
+                                propagated_text_decoration_line,
+                            ),
+                        )
+                    },
+                    DisplayInside::Flex => {
+                        NonReplacedFormattingContextContents::Flex(FlexContainer::construct(
+                            context,
+                            info,
+                            non_replaced,
+                            propagated_text_decoration_line,
+                        ))
+                    },
+                };
+                Self::NonReplaced(NonReplacedFormattingContext {
+                    tag: Tag::from_node_and_style_info(info),
+                    style: Arc::clone(&info.style),
+                    content_sizes: None,
+                    contents,
+                })
             },
             Err(contents) => Self::Replaced(ReplacedFormattingContext {
                 tag: Tag::from_node_and_style_info(info),
@@ -110,22 +106,16 @@ impl IndependentFormattingContext {
     }
 
     pub fn construct_for_text_runs<'dom>(
-        context: &LayoutContext,
         info: &NodeAndStyleInfo<impl NodeExt<'dom>>,
         runs: impl Iterator<Item = crate::flow::inline::TextRun>,
-        content_sizes: ContentSizesRequest,
         propagated_text_decoration_line: TextDecorationLine,
     ) -> Self {
-        let (bfc, content_sizes) = BlockFormattingContext::construct_for_text_runs(
-            context,
-            runs,
-            content_sizes,
-            propagated_text_decoration_line,
-        );
+        let bfc =
+            BlockFormattingContext::construct_for_text_runs(runs, propagated_text_decoration_line);
         Self::NonReplaced(NonReplacedFormattingContext {
             tag: Tag::from_node_and_style_info(info),
             style: Arc::clone(&info.style),
-            content_sizes,
+            content_sizes: None,
             contents: NonReplacedFormattingContextContents::Flow(bfc),
         })
     }
@@ -144,10 +134,40 @@ impl IndependentFormattingContext {
         }
     }
 
-    pub fn content_sizes(&self) -> ContentSizes {
+    pub fn outer_inline(
+        &mut self,
+        layout_context: &LayoutContext,
+        containing_block_writing_mode: WritingMode,
+    ) -> ContentSizes {
+        let (mut outer, percentages) =
+            self.outer_inline_and_percentages(layout_context, containing_block_writing_mode);
+        outer.adjust_for_pbm_percentages(percentages);
+        outer
+    }
+
+    pub fn outer_inline_and_percentages(
+        &mut self,
+        layout_context: &LayoutContext,
+        containing_block_writing_mode: WritingMode,
+    ) -> (ContentSizes, Percentage) {
         match self {
-            Self::NonReplaced(inner) => inner.content_sizes.expect_inline().clone(),
-            Self::Replaced(inner) => inner.contents.inline_content_sizes(&inner.style),
+            Self::NonReplaced(non_replaced) => {
+                let style = &non_replaced.style;
+                let content_sizes = &mut non_replaced.content_sizes;
+                let contents = &non_replaced.contents;
+                sizing::outer_inline_and_percentages(&style, containing_block_writing_mode, || {
+                    content_sizes
+                        .get_or_insert_with(|| {
+                            contents.inline_content_sizes(layout_context, style.writing_mode)
+                        })
+                        .clone()
+                })
+            },
+            Self::Replaced(replaced) => sizing::outer_inline_and_percentages(
+                &replaced.style,
+                containing_block_writing_mode,
+                || replaced.contents.inline_content_sizes(&replaced.style),
+            ),
         }
     }
 }
@@ -175,4 +195,27 @@ impl NonReplacedFormattingContext {
             ),
         }
     }
+
+    pub fn inline_content_sizes(&mut self, layout_context: &LayoutContext) -> ContentSizes {
+        let writing_mode = self.style.writing_mode;
+        let contents = &self.contents;
+        self.content_sizes
+            .get_or_insert_with(|| contents.inline_content_sizes(layout_context, writing_mode))
+            .clone()
+    }
+}
+
+impl NonReplacedFormattingContextContents {
+    pub fn inline_content_sizes(
+        &self,
+        layout_context: &LayoutContext,
+        containing_block_writing_mode: WritingMode,
+    ) -> ContentSizes {
+        match self {
+            Self::Flow(inner) => inner
+                .contents
+                .inline_content_sizes(layout_context, containing_block_writing_mode),
+            Self::Flex(inner) => inner.inline_content_sizes(),
+        }
+    }
 }
diff --git a/components/layout_2020/positioned.rs b/components/layout_2020/positioned.rs
index dcb1388b36c..853b22347e9 100644
--- a/components/layout_2020/positioned.rs
+++ b/components/layout_2020/positioned.rs
@@ -9,7 +9,6 @@ use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragments::{BoxFragment, CollapsedBlockMargins, Fragment};
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::geom::{LengthOrAuto, LengthPercentageOrAuto};
-use crate::sizing::ContentSizesRequest;
 use crate::style_ext::{ComputedValuesExt, DisplayInside};
 use crate::{ContainingBlock, DefiniteContainingBlock};
 use rayon::iter::{IntoParallelRefMutIterator, ParallelExtend};
@@ -74,22 +73,12 @@ impl AbsolutelyPositionedBox {
         display_inside: DisplayInside,
         contents: Contents,
     ) -> Self {
-        // "Shrink-to-fit" in https://drafts.csswg.org/css2/visudet.html#abs-non-replaced-width
-        let content_sizes = ContentSizesRequest::inline_if(
-            // If inline-size is non-auto, that value is used without shrink-to-fit
-            !node_info.style.inline_size_is_length() &&
-            // If it is, then the only case where shrink-to-fit is *not* used is
-            // if both offsets are non-auto, leaving inline-size as the only variable
-            // in the constraint equation.
-            !node_info.style.inline_box_offsets_are_both_non_auto(),
-        );
         Self {
             context: IndependentFormattingContext::construct(
                 context,
                 node_info,
                 display_inside,
                 contents,
-                content_sizes,
                 // Text decorations are not propagated to any out-of-flow descendants.
                 TextDecorationLine::NONE,
             ),
@@ -472,7 +461,9 @@ impl HoistedAbsolutelyPositionedBox {
                         };
                         let available_size =
                             cbis - anchor - pbm.padding_border_sums.inline - margin.inline_sum();
-                        non_replaced.content_sizes.shrink_to_fit(available_size)
+                        non_replaced
+                            .inline_content_sizes(layout_context)
+                            .shrink_to_fit(available_size)
                     });
 
                     let containing_block_for_children = ContainingBlock {
diff --git a/components/layout_2020/sizing.rs b/components/layout_2020/sizing.rs
index dd9574d4f85..ec07861c374 100644
--- a/components/layout_2020/sizing.rs
+++ b/components/layout_2020/sizing.rs
@@ -11,44 +11,6 @@ use style::properties::ComputedValues;
 use style::values::computed::{Length, LengthPercentage, Percentage};
 use style::Zero;
 
-/// Which min/max-content values should be computed during box construction
-#[derive(Clone, Copy, Debug)]
-pub(crate) enum ContentSizesRequest {
-    Inline,
-    None,
-}
-
-impl ContentSizesRequest {
-    pub fn inline_if(condition: bool) -> Self {
-        if condition {
-            Self::Inline
-        } else {
-            Self::None
-        }
-    }
-
-    pub fn requests_inline(self) -> bool {
-        match self {
-            Self::Inline => true,
-            Self::None => false,
-        }
-    }
-
-    pub fn if_requests_inline<T>(self, f: impl FnOnce() -> T) -> Option<T> {
-        match self {
-            Self::Inline => Some(f()),
-            Self::None => None,
-        }
-    }
-
-    pub fn compute(self, compute_inline: impl FnOnce() -> ContentSizes) -> BoxContentSizes {
-        match self {
-            Self::Inline => BoxContentSizes::Inline(compute_inline()),
-            Self::None => BoxContentSizes::NoneWereRequested,
-        }
-    }
-}
-
 #[derive(Clone, Debug, Serialize)]
 pub(crate) struct ContentSizes {
     pub min_content: Length,
@@ -90,27 +52,10 @@ impl ContentSizes {
     }
 }
 
-/// Optional min/max-content for storage in the box tree
-#[derive(Debug, Serialize)]
-pub(crate) enum BoxContentSizes {
-    NoneWereRequested, // … during box construction
-    Inline(ContentSizes),
-}
-
-impl BoxContentSizes {
-    pub fn expect_inline(&self) -> &ContentSizes {
-        match self {
-            Self::NoneWereRequested => panic!("Accessing content size that was not requested"),
-            Self::Inline(s) => s,
-        }
-    }
-
+impl ContentSizes {
     /// https://drafts.csswg.org/css2/visudet.html#shrink-to-fit-float
-    pub(crate) fn shrink_to_fit(&self, available_size: Length) -> Length {
-        let inline = self.expect_inline();
-        available_size
-            .max(inline.min_content)
-            .min(inline.max_content)
+    pub fn shrink_to_fit(&self, available_size: Length) -> Length {
+        available_size.max(self.min_content).min(self.max_content)
     }
 }
 
diff --git a/components/style/values/generics/length.rs b/components/style/values/generics/length.rs
index bed574861cb..9ae86c7d991 100644
--- a/components/style/values/generics/length.rs
+++ b/components/style/values/generics/length.rs
@@ -75,7 +75,7 @@ where
 {
     /// Resolves `auto` values by calling `f`.
     #[inline]
-    pub fn auto_is(&self, f: impl Fn() -> LengthPercentage) -> LengthPercentage {
+    pub fn auto_is(&self, f: impl FnOnce() -> LengthPercentage) -> LengthPercentage {
         match self {
             LengthPercentageOrAuto::LengthPercentage(length) => length.clone(),
             LengthPercentageOrAuto::Auto => f(),