layout: Combine layout_2020 and layout_thread_2020 into a crate called layout (#36613)

Now that legacy layout has been removed, the name `layout_2020` doesn't
make much sense any longer, also it's 2025 now for better or worse. The
split between the "layout thread" and "layout" also doesn't make as much
sense since layout doesn't run on it's own thread. There's a possibility
that it will in the future, but that should be something that the user
of the crate controls rather than layout iself.

This is part of the larger layout interface cleanup and optimization
that
@Looriool and I are doing.

Testing: Covered by existing tests as this is just code movement.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/layout/taffy/stylo_taffy/wrapper.rs

@@ -0,0 +1,226 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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 std::ops::Deref;
+
+use style::properties::ComputedValues;
+
+use super::convert;
+
+/// A wrapper struct for anything that Deref's to a [`ComputedValues`], which
+/// implements Taffy's layout traits and can used with Taffy's layout algorithms.
+pub struct TaffyStyloStyle<T: Deref<Target = ComputedValues>>(pub T);
+
+impl<T: Deref<Target = ComputedValues>> From<T> for TaffyStyloStyle<T> {
+    fn from(value: T) -> Self {
+        Self(value)
+    }
+}
+
+impl<T: Deref<Target = ComputedValues>> taffy::CoreStyle for TaffyStyloStyle<T> {
+    #[inline]
+    fn box_generation_mode(&self) -> taffy::BoxGenerationMode {
+        convert::box_generation_mode(self.0.get_box().display)
+    }
+
+    #[inline]
+    fn is_block(&self) -> bool {
+        convert::is_block(self.0.get_box().display)
+    }
+
+    #[inline]
+    fn box_sizing(&self) -> taffy::BoxSizing {
+        convert::box_sizing(self.0.get_position().box_sizing)
+    }
+
+    #[inline]
+    fn overflow(&self) -> taffy::Point<taffy::Overflow> {
+        let box_styles = self.0.get_box();
+        taffy::Point {
+            x: convert::overflow(box_styles.overflow_x),
+            y: convert::overflow(box_styles.overflow_y),
+        }
+    }
+
+    #[inline]
+    fn scrollbar_width(&self) -> f32 {
+        0.0
+    }
+
+    #[inline]
+    fn position(&self) -> taffy::Position {
+        convert::position(self.0.get_box().position)
+    }
+
+    #[inline]
+    fn inset(&self) -> taffy::Rect<taffy::LengthPercentageAuto> {
+        let position_styles = self.0.get_position();
+        taffy::Rect {
+            left: convert::inset(&position_styles.left),
+            right: convert::inset(&position_styles.right),
+            top: convert::inset(&position_styles.top),
+            bottom: convert::inset(&position_styles.bottom),
+        }
+    }
+
+    #[inline]
+    fn size(&self) -> taffy::Size<taffy::Dimension> {
+        let position_styles = self.0.get_position();
+        taffy::Size {
+            width: convert::dimension(&position_styles.width),
+            height: convert::dimension(&position_styles.height),
+        }
+    }
+
+    #[inline]
+    fn min_size(&self) -> taffy::Size<taffy::Dimension> {
+        let position_styles = self.0.get_position();
+        taffy::Size {
+            width: convert::dimension(&position_styles.min_width),
+            height: convert::dimension(&position_styles.min_height),
+        }
+    }
+
+    #[inline]
+    fn max_size(&self) -> taffy::Size<taffy::Dimension> {
+        let position_styles = self.0.get_position();
+        taffy::Size {
+            width: convert::max_size_dimension(&position_styles.max_width),
+            height: convert::max_size_dimension(&position_styles.max_height),
+        }
+    }
+
+    #[inline]
+    fn aspect_ratio(&self) -> Option<f32> {
+        convert::aspect_ratio(self.0.get_position().aspect_ratio)
+    }
+
+    #[inline]
+    fn margin(&self) -> taffy::Rect<taffy::LengthPercentageAuto> {
+        let margin_styles = self.0.get_margin();
+        taffy::Rect {
+            left: convert::margin(&margin_styles.margin_left),
+            right: convert::margin(&margin_styles.margin_right),
+            top: convert::margin(&margin_styles.margin_top),
+            bottom: convert::margin(&margin_styles.margin_bottom),
+        }
+    }
+
+    #[inline]
+    fn padding(&self) -> taffy::Rect<taffy::LengthPercentage> {
+        let padding_styles = self.0.get_padding();
+        taffy::Rect {
+            left: convert::length_percentage(&padding_styles.padding_left.0),
+            right: convert::length_percentage(&padding_styles.padding_right.0),
+            top: convert::length_percentage(&padding_styles.padding_top.0),
+            bottom: convert::length_percentage(&padding_styles.padding_bottom.0),
+        }
+    }
+
+    #[inline]
+    fn border(&self) -> taffy::Rect<taffy::LengthPercentage> {
+        let border_styles = self.0.get_border();
+        taffy::Rect {
+            left: taffy::LengthPercentage::Length(border_styles.border_left_width.to_f32_px()),
+            right: taffy::LengthPercentage::Length(border_styles.border_right_width.to_f32_px()),
+            top: taffy::LengthPercentage::Length(border_styles.border_top_width.to_f32_px()),
+            bottom: taffy::LengthPercentage::Length(border_styles.border_bottom_width.to_f32_px()),
+        }
+    }
+}
+
+impl<T: Deref<Target = ComputedValues>> taffy::GridContainerStyle for TaffyStyloStyle<T> {
+    type TemplateTrackList<'a>
+        = Vec<taffy::TrackSizingFunction>
+    where
+        Self: 'a;
+    type AutoTrackList<'a>
+        = Vec<taffy::NonRepeatedTrackSizingFunction>
+    where
+        Self: 'a;
+
+    #[inline]
+    fn grid_template_rows(&self) -> Self::TemplateTrackList<'_> {
+        convert::grid_template_tracks(&self.0.get_position().grid_template_rows)
+    }
+
+    #[inline]
+    fn grid_template_columns(&self) -> Self::TemplateTrackList<'_> {
+        convert::grid_template_tracks(&self.0.get_position().grid_template_columns)
+    }
+
+    #[inline]
+    fn grid_auto_rows(&self) -> Self::AutoTrackList<'_> {
+        convert::grid_auto_tracks(&self.0.get_position().grid_auto_rows)
+    }
+
+    #[inline]
+    fn grid_auto_columns(&self) -> Self::AutoTrackList<'_> {
+        convert::grid_auto_tracks(&self.0.get_position().grid_auto_columns)
+    }
+
+    #[inline]
+    fn grid_auto_flow(&self) -> taffy::GridAutoFlow {
+        convert::grid_auto_flow(self.0.get_position().grid_auto_flow)
+    }
+
+    #[inline]
+    fn gap(&self) -> taffy::Size<taffy::LengthPercentage> {
+        let position_styles = self.0.get_position();
+        taffy::Size {
+            width: convert::gap(&position_styles.column_gap),
+            height: convert::gap(&position_styles.row_gap),
+        }
+    }
+
+    #[inline]
+    fn align_content(&self) -> Option<taffy::AlignContent> {
+        convert::content_alignment(self.0.get_position().align_content.0)
+    }
+
+    #[inline]
+    fn justify_content(&self) -> Option<taffy::JustifyContent> {
+        convert::content_alignment(self.0.get_position().justify_content.0)
+    }
+
+    #[inline]
+    fn align_items(&self) -> Option<taffy::AlignItems> {
+        convert::item_alignment(self.0.get_position().align_items.0)
+    }
+
+    #[inline]
+    fn justify_items(&self) -> Option<taffy::AlignItems> {
+        convert::item_alignment(self.0.get_position().justify_items.computed.0)
+    }
+}
+
+impl<T: Deref<Target = ComputedValues>> taffy::GridItemStyle for TaffyStyloStyle<T> {
+    #[inline]
+    fn grid_row(&self) -> taffy::Line<taffy::GridPlacement> {
+        let position_styles = self.0.get_position();
+        taffy::Line {
+            start: convert::grid_line(&position_styles.grid_row_start),
+            end: convert::grid_line(&position_styles.grid_row_end),
+        }
+    }
+
+    #[inline]
+    fn grid_column(&self) -> taffy::Line<taffy::GridPlacement> {
+        let position_styles = self.0.get_position();
+        taffy::Line {
+            start: convert::grid_line(&position_styles.grid_column_start),
+            end: convert::grid_line(&position_styles.grid_column_end),
+        }
+    }
+
+    #[inline]
+    fn align_self(&self) -> Option<taffy::AlignSelf> {
+        convert::item_alignment(self.0.get_position().align_self.0.0)
+    }
+
+    #[inline]
+    fn justify_self(&self) -> Option<taffy::AlignSelf> {
+        convert::item_alignment(self.0.get_position().justify_self.0.0)
+    }
+}