layout: Switch `IndependentLayout` to use `Au` instead of `Length` (#31083)

* use au in layout

* fmt

* review fix

8 files changed, 52 insertions, 21 deletions

diff --git a/components/layout_2020/flexbox/layout.rs b/components/layout_2020/flexbox/layout.rs
index 05c8b95ad97..55f792e3b07 100644
--- a/components/layout_2020/flexbox/layout.rs
+++ b/components/layout_2020/flexbox/layout.rs
@@ -410,7 +410,7 @@ impl FlexContainer {
 
         IndependentLayout {
             fragments,
-            content_block_size,
+            content_block_size: content_block_size.into(),
             last_inflow_baseline_offset: None,
         }
     }
@@ -1111,7 +1111,7 @@ impl<'a> FlexItem<'a> {
                         let hypothetical_cross_size = self
                             .content_box_size
                             .cross
-                            .auto_is(|| content_block_size)
+                            .auto_is(|| content_block_size.into())
                             .clamp_between_extremums(
                                 self.content_min_size.cross,
                                 self.content_max_size.cross,
diff --git a/components/layout_2020/flow/float.rs b/components/layout_2020/flow/float.rs
index a6f8f06ddf3..1de87a59eb2 100644
--- a/components/layout_2020/flow/float.rs
+++ b/components/layout_2020/flow/float.rs
@@ -930,7 +930,7 @@ impl FloatBox {
                             inline: inline_size,
                             block: box_size
                                 .block
-                                .auto_is(|| independent_layout.content_block_size),
+                                .auto_is(|| independent_layout.content_block_size.into()),
                         };
                         children = independent_layout.fragments;
                     },
diff --git a/components/layout_2020/flow/inline.rs b/components/layout_2020/flow/inline.rs
index e980983552a..c5b9bbd6c5c 100644
--- a/components/layout_2020/flow/inline.rs
+++ b/components/layout_2020/flow/inline.rs
@@ -1949,7 +1949,7 @@ impl IndependentFormattingContext {
                 // https://drafts.csswg.org/css2/visudet.html#block-root-margin
                 let tentative_block_size = box_size
                     .block
-                    .auto_is(|| independent_layout.content_block_size);
+                    .auto_is(|| independent_layout.content_block_size.into());
 
                 // https://drafts.csswg.org/css2/visudet.html#min-max-heights
                 // In this case “applying the rules above again” with a non-auto block-size
@@ -1974,7 +1974,9 @@ impl IndependentFormattingContext {
                     pbm.border,
                     margin,
                     None,
-                    independent_layout.last_inflow_baseline_offset,
+                    independent_layout
+                        .last_inflow_baseline_offset
+                        .map(|t| t.into()),
                     CollapsedBlockMargins::zero(),
                 )
             },
diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs
index 95c03655980..acdfa59ab26 100644
--- a/components/layout_2020/flow/mod.rs
+++ b/components/layout_2020/flow/mod.rs
@@ -30,7 +30,7 @@ use crate::geom::{LogicalRect, LogicalSides, LogicalVec2};
 use crate::positioned::{AbsolutelyPositionedBox, PositioningContext, PositioningContextLength};
 use crate::replaced::ReplacedContent;
 use crate::sizing::{self, ContentSizes};
-use crate::style_ext::{ComputedValuesExt, PaddingBorderMargin};
+use crate::style_ext::{Clamp, ComputedValuesExt, PaddingBorderMargin};
 use crate::ContainingBlock;
 
 mod construct;
@@ -240,10 +240,11 @@ impl BlockFormattingContext {
 
         IndependentLayout {
             fragments: flow_layout.fragments,
-            content_block_size: flow_layout.content_block_size +
+            content_block_size: (flow_layout.content_block_size +
                 flow_layout.collapsible_margins_in_children.end.solve() +
-                clearance.unwrap_or_else(Length::zero),
-            last_inflow_baseline_offset: flow_layout.last_inflow_baseline_offset,
+                clearance.unwrap_or_else(Length::zero))
+            .into(),
+            last_inflow_baseline_offset: flow_layout.last_inflow_baseline_offset.map(|t| t.into()),
         }
     }
 }
@@ -858,7 +859,11 @@ impl NonReplacedFormattingContext {
         let block_size = containing_block_for_children.block_size.auto_is(|| {
             layout
                 .content_block_size
-                .clamp_between_extremums(min_box_size.block, max_box_size.block)
+                .clamp_between_extremums(
+                    min_box_size.block.into(),
+                    max_box_size.block.map(|t| t.into()),
+                )
+                .into()
         });
 
         let content_rect = LogicalRect {
@@ -882,7 +887,7 @@ impl NonReplacedFormattingContext {
             pbm.border,
             margin,
             None, /* clearance */
-            layout.last_inflow_baseline_offset,
+            layout.last_inflow_baseline_offset.map(|t| t.into()),
             block_margins_collapsed_with_children,
         )
     }
@@ -939,12 +944,17 @@ impl NonReplacedFormattingContext {
                     style: &self.style,
                 },
             );
+
             content_size = LogicalVec2 {
                 inline: inline_size,
                 block: block_size.auto_is(|| {
                     layout
                         .content_block_size
-                        .clamp_between_extremums(min_box_size.block, max_box_size.block)
+                        .clamp_between_extremums(
+                            min_box_size.block.into(),
+                            max_box_size.block.map(|t| t.into()),
+                        )
+                        .into()
                 }),
             };
 
@@ -1002,13 +1012,16 @@ impl NonReplacedFormattingContext {
                         style: &self.style,
                     },
                 );
-
                 content_size = LogicalVec2 {
                     inline: proposed_inline_size,
                     block: block_size.auto_is(|| {
                         layout
                             .content_block_size
-                            .clamp_between_extremums(min_box_size.block, max_box_size.block)
+                            .clamp_between_extremums(
+                                min_box_size.block.into(),
+                                max_box_size.block.map(|t| t.into()),
+                            )
+                            .into()
                     }),
                 };
 
@@ -1092,7 +1105,7 @@ impl NonReplacedFormattingContext {
             pbm.border,
             margin,
             clearance,
-            layout.last_inflow_baseline_offset,
+            layout.last_inflow_baseline_offset.map(|t| t.into()),
             block_margins_collapsed_with_children,
         )
     }
diff --git a/components/layout_2020/formatting_contexts.rs b/components/layout_2020/formatting_contexts.rs
index 812ab22fbbc..8c441c98ea7 100644
--- a/components/layout_2020/formatting_contexts.rs
+++ b/components/layout_2020/formatting_contexts.rs
@@ -4,11 +4,11 @@
 
 use std::convert::TryInto;
 
+use app_units::Au;
 use serde::Serialize;
 use servo_arc::Arc;
 use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
-use style::values::computed::Length;
 use style::values::specified::text::TextDecorationLine;
 
 use crate::context::LayoutContext;
@@ -63,12 +63,12 @@ pub(crate) struct IndependentLayout {
     pub fragments: Vec<Fragment>,
 
     /// https://drafts.csswg.org/css2/visudet.html#root-height
-    pub content_block_size: Length,
+    pub content_block_size: Au,
 
     /// The offset of the last inflow baseline of this layout in the content area, if
     /// there was one. This is used to propagate baselines to the ancestors of `display:
     /// inline-block`.
-    pub last_inflow_baseline_offset: Option<Length>,
+    pub last_inflow_baseline_offset: Option<Au>,
 }
 
 impl IndependentFormattingContext {
diff --git a/components/layout_2020/positioned.rs b/components/layout_2020/positioned.rs
index ce1621927b6..9b109a4fbb1 100644
--- a/components/layout_2020/positioned.rs
+++ b/components/layout_2020/positioned.rs
@@ -622,7 +622,8 @@ impl HoistedAbsolutelyPositionedBox {
                             &mut positioning_context,
                             &containing_block_for_children,
                         );
-                        let block_size = size.auto_is(|| independent_layout.content_block_size);
+                        let block_size =
+                            size.auto_is(|| independent_layout.content_block_size.into());
                         Result {
                             content_size: LogicalVec2 {
                                 inline: inline_size,
diff --git a/components/layout_2020/style_ext.rs b/components/layout_2020/style_ext.rs
index a2017e5d0d5..50c19b7d8b6 100644
--- a/components/layout_2020/style_ext.rs
+++ b/components/layout_2020/style_ext.rs
@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use app_units::Au;
 use servo_config::pref;
 use style::computed_values::mix_blend_mode::T as ComputedMixBlendMode;
 use style::computed_values::position::T as ComputedPosition;
@@ -626,3 +627,16 @@ fn size_to_length(size: &Size) -> LengthPercentageOrAuto {
         Size::Auto => LengthPercentageOrAuto::Auto,
     }
 }
+
+pub(crate) trait Clamp: Sized {
+    fn clamp_between_extremums(self, min: Self, max: Option<Self>) -> Self;
+}
+
+impl Clamp for Au {
+    fn clamp_between_extremums(self, min: Self, max: Option<Self>) -> Self {
+        match max {
+            Some(max_value) => self.min(max_value).max(min),
+            None => self.max(min),
+        }
+    }
+}
diff --git a/components/layout_2020/table/mod.rs b/components/layout_2020/table/mod.rs
index 918fa88ac5d..901943ad8e3 100644
--- a/components/layout_2020/table/mod.rs
+++ b/components/layout_2020/table/mod.rs
@@ -7,11 +7,12 @@
 
 mod construct;
 
+use app_units::Au;
 pub(crate) use construct::AnonymousTableContent;
 pub use construct::TableBuilder;
+use euclid::num::Zero;
 use euclid::{Point2D, UnknownUnit, Vector2D};
 use serde::Serialize;
-use style::values::computed::Length;
 
 use super::flow::BlockFormattingContext;
 use crate::context::LayoutContext;
@@ -39,7 +40,7 @@ impl Table {
     ) -> IndependentLayout {
         IndependentLayout {
             fragments: Vec::new(),
-            content_block_size: Length::new(0.),
+            content_block_size: Au::zero(),
             last_inflow_baseline_offset: None,
         }
     }