diff --git a/components/layout_2020/flow/construct.rs b/components/layout_2020/flow/construct.rs
index f72bbf1ad13c..666a39d29321 100644
--- a/components/layout_2020/flow/construct.rs
+++ b/components/layout_2020/flow/construct.rs
@@ -14,7 +14,7 @@ use crate::flow::{BlockContainer, BlockFormattingContext, BlockLevelBox};
 use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragments::Tag;
 use crate::positioned::AbsolutelyPositionedBox;
-use crate::sizing::{BoxContentSizes, ContentSizes, ContentSizesRequest};
+use crate::sizing::{self, BoxContentSizes, ContentSizes, ContentSizesRequest};
 use crate::style_ext::{ComputedValuesExt, DisplayGeneratingBox, DisplayInside, DisplayOutside};
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use rayon_croissant::ParallelIteratorExt;
@@ -701,10 +701,11 @@ where
                     ),
                 );
                 if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
-                    to.max_assign(
-                        &box_content_sizes
-                            .outer_inline(&info.style, not_actually_containing_block_writing_mode),
-                    )
+                    to.max_assign(&sizing::outer_inline(
+                        &info.style,
+                        not_actually_containing_block_writing_mode,
+                        || box_content_sizes.expect_inline().clone(),
+                    ))
                 }
                 let block_level_box = ArcRefCell::new(BlockLevelBox::SameFormattingContextBlock {
                     tag: Tag::from_node_and_style_info(info),
@@ -731,12 +732,11 @@ where
                     propagated_text_decoration_line,
                 );
                 if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
-                    to.max_assign(
-                        &contents.content_sizes.outer_inline(
-                            &contents.style,
-                            not_actually_containing_block_writing_mode,
-                        ),
-                    )
+                    to.max_assign(&sizing::outer_inline(
+                        &contents.style,
+                        not_actually_containing_block_writing_mode,
+                        || contents.content_sizes.expect_inline().clone(),
+                    ))
                 }
                 (
                     ArcRefCell::new(BlockLevelBox::Independent(contents)),
diff --git a/components/layout_2020/flow/inline.rs b/components/layout_2020/flow/inline.rs
index 4736cb272038..7872dd8110e2 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::ContentSizes;
+use crate::sizing::{self, ContentSizes};
 use crate::style_ext::{ComputedValuesExt, Display, DisplayGeneratingBox, DisplayOutside};
 use crate::ContainingBlock;
 use app_units::Au;
@@ -200,9 +200,10 @@ impl InlineFormattingContext {
                             }
                         },
                         InlineLevelBox::Atomic(atomic) => {
-                            let (outer, pc) = atomic.content_sizes.outer_inline_and_percentages(
+                            let (outer, pc) = sizing::outer_inline_and_percentages(
                                 &atomic.style,
                                 self.containing_block_writing_mode,
+                                || atomic.content_sizes.expect_inline().clone(),
                             );
                             self.current_line.min_content += outer.min_content;
                             self.current_line.max_content += outer.max_content;
diff --git a/components/layout_2020/sizing.rs b/components/layout_2020/sizing.rs
index af8c6ac0ecb8..dd9574d4f854 100644
--- a/components/layout_2020/sizing.rs
+++ b/components/layout_2020/sizing.rs
@@ -64,7 +64,7 @@ impl ContentSizes {
         }
     }
 
-    fn map(&self, f: impl Fn(Length) -> Length) -> Self {
+    pub fn map(&self, f: impl Fn(Length) -> Length) -> Self {
         Self {
             min_content: f(self.min_content),
             max_content: f(self.max_content),
@@ -98,95 +98,13 @@ pub(crate) enum BoxContentSizes {
 }
 
 impl BoxContentSizes {
-    fn expect_inline(&self) -> &ContentSizes {
+    pub fn expect_inline(&self) -> &ContentSizes {
         match self {
             Self::NoneWereRequested => panic!("Accessing content size that was not requested"),
             Self::Inline(s) => s,
         }
     }
 
-    /// https://dbaron.org/css/intrinsic/#outer-intrinsic
-    pub fn outer_inline(
-        &self,
-        style: &ComputedValues,
-        containing_block_writing_mode: WritingMode,
-    ) -> ContentSizes {
-        let (mut outer, percentages) =
-            self.outer_inline_and_percentages(style, containing_block_writing_mode);
-        outer.adjust_for_pbm_percentages(percentages);
-        outer
-    }
-
-    pub(crate) fn outer_inline_and_percentages(
-        &self,
-        style: &ComputedValues,
-        containing_block_writing_mode: WritingMode,
-    ) -> (ContentSizes, Percentage) {
-        let padding = style.padding(containing_block_writing_mode);
-        let border = style.border_width(containing_block_writing_mode);
-        let margin = style.margin(containing_block_writing_mode);
-
-        let mut pbm_percentages = Percentage::zero();
-        let mut decompose = |x: &LengthPercentage| {
-            pbm_percentages += x.to_percentage().unwrap_or_else(Zero::zero);
-            x.to_length().unwrap_or_else(Zero::zero)
-        };
-        let pb_lengths =
-            border.inline_sum() + decompose(padding.inline_start) + decompose(padding.inline_end);
-        let mut m_lengths = Length::zero();
-        if let Some(m) = margin.inline_start.non_auto() {
-            m_lengths += decompose(m)
-        }
-        if let Some(m) = margin.inline_end.non_auto() {
-            m_lengths += decompose(m)
-        }
-
-        let box_sizing = style.get_position().box_sizing;
-        let inline_size = style
-            .box_size(containing_block_writing_mode)
-            .inline
-            .non_auto()
-            // Percentages for 'width' are treated as 'auto'
-            .and_then(|lp| lp.to_length());
-        let min_inline_size = style
-            .min_box_size(containing_block_writing_mode)
-            .inline
-            // Percentages for 'min-width' are treated as zero
-            .percentage_relative_to(Length::zero())
-            // FIXME: 'auto' is not zero in Flexbox
-            .auto_is(Length::zero);
-        let max_inline_size = style
-            .max_box_size(containing_block_writing_mode)
-            .inline
-            // Percentages for 'max-width' are treated as 'none'
-            .and_then(|lp| lp.to_length());
-        let clamp = |l: Length| l.clamp_between_extremums(min_inline_size, max_inline_size);
-
-        let border_box_sizes = match inline_size {
-            Some(non_auto) => {
-                let clamped = clamp(non_auto);
-                let border_box_size = match box_sizing {
-                    BoxSizing::ContentBox => clamped + pb_lengths,
-                    BoxSizing::BorderBox => clamped,
-                };
-                ContentSizes {
-                    min_content: border_box_size,
-                    max_content: border_box_size,
-                }
-            },
-            None => self.expect_inline().map(|content_box_size| {
-                match box_sizing {
-                    // Clamp to 'min-width' and 'max-width', which are sizing the…
-                    BoxSizing::ContentBox => clamp(content_box_size) + pb_lengths,
-                    BoxSizing::BorderBox => clamp(content_box_size + pb_lengths),
-                }
-            }),
-        };
-
-        let outer = border_box_sizes.map(|s| s + m_lengths);
-        (outer, pbm_percentages)
-    }
-
     /// 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();
@@ -195,3 +113,84 @@ impl BoxContentSizes {
             .min(inline.max_content)
     }
 }
+
+pub(crate) fn outer_inline(
+    style: &ComputedValues,
+    containing_block_writing_mode: WritingMode,
+    get_content_size: impl FnOnce() -> ContentSizes,
+) -> ContentSizes {
+    let (mut outer, percentages) =
+        outer_inline_and_percentages(style, containing_block_writing_mode, get_content_size);
+    outer.adjust_for_pbm_percentages(percentages);
+    outer
+}
+
+pub(crate) fn outer_inline_and_percentages(
+    style: &ComputedValues,
+    containing_block_writing_mode: WritingMode,
+    get_content_size: impl FnOnce() -> ContentSizes,
+) -> (ContentSizes, Percentage) {
+    let padding = style.padding(containing_block_writing_mode);
+    let border = style.border_width(containing_block_writing_mode);
+    let margin = style.margin(containing_block_writing_mode);
+
+    let mut pbm_percentages = Percentage::zero();
+    let mut decompose = |x: &LengthPercentage| {
+        pbm_percentages += x.to_percentage().unwrap_or_else(Zero::zero);
+        x.to_length().unwrap_or_else(Zero::zero)
+    };
+    let pb_lengths =
+        border.inline_sum() + decompose(padding.inline_start) + decompose(padding.inline_end);
+    let mut m_lengths = Length::zero();
+    if let Some(m) = margin.inline_start.non_auto() {
+        m_lengths += decompose(m)
+    }
+    if let Some(m) = margin.inline_end.non_auto() {
+        m_lengths += decompose(m)
+    }
+
+    let box_sizing = style.get_position().box_sizing;
+    let inline_size = style
+        .box_size(containing_block_writing_mode)
+        .inline
+        .non_auto()
+        // Percentages for 'width' are treated as 'auto'
+        .and_then(|lp| lp.to_length());
+    let min_inline_size = style
+        .min_box_size(containing_block_writing_mode)
+        .inline
+        // Percentages for 'min-width' are treated as zero
+        .percentage_relative_to(Length::zero())
+        // FIXME: 'auto' is not zero in Flexbox
+        .auto_is(Length::zero);
+    let max_inline_size = style
+        .max_box_size(containing_block_writing_mode)
+        .inline
+        // Percentages for 'max-width' are treated as 'none'
+        .and_then(|lp| lp.to_length());
+    let clamp = |l: Length| l.clamp_between_extremums(min_inline_size, max_inline_size);
+
+    let border_box_sizes = match inline_size {
+        Some(non_auto) => {
+            let clamped = clamp(non_auto);
+            let border_box_size = match box_sizing {
+                BoxSizing::ContentBox => clamped + pb_lengths,
+                BoxSizing::BorderBox => clamped,
+            };
+            ContentSizes {
+                min_content: border_box_size,
+                max_content: border_box_size,
+            }
+        },
+        None => get_content_size().map(|content_box_size| {
+            match box_sizing {
+                // Clamp to 'min-width' and 'max-width', which are sizing the…
+                BoxSizing::ContentBox => clamp(content_box_size) + pb_lengths,
+                BoxSizing::BorderBox => clamp(content_box_size + pb_lengths),
+            }
+        }),
+    };
+
+    let outer = border_box_sizes.map(|s| s + m_lengths);
+    (outer, pbm_percentages)
+}