Containing blocks contains styles rather than just a writing mode

components/layout_2020/flow/inline.rs

@@ -69,7 +69,7 @@ struct PartialInlineBoxFragment<'box_tree> {
 
 struct InlineFormattingContextState<'box_tree, 'a> {
     absolutely_positioned_fragments: &'a mut Vec<AbsolutelyPositionedFragment<'box_tree>>,
-    containing_block: &'a ContainingBlock,
+    containing_block: &'a ContainingBlock<'a>,
     line_boxes: LinesBoxes,
     inline_position: Length,
     partial_inline_boxes_stack: Vec<PartialInlineBoxFragment<'box_tree>>,
@@ -292,7 +292,7 @@ impl LinesBoxes {
         self.boxes.push(Fragment::Anonymous(AnonymousFragment {
             children: std::mem::take(&mut top_nesting_level.fragments_so_far),
             rect: Rect { start_corner, size },
-            mode: containing_block.mode,
+            mode: containing_block.style.writing_mode,
         }))
     }
 }
@@ -446,10 +446,11 @@ fn layout_atomic<'box_tree>(
             let containing_block_for_children = ContainingBlock {
                 inline_size,
                 block_size,
-                mode: atomic.style.writing_mode,
+                style: &atomic.style,
             };
             assert_eq!(
-                ifc.containing_block.mode, containing_block_for_children.mode,
+                ifc.containing_block.style.writing_mode,
+                containing_block_for_children.style.writing_mode,
                 "Mixed writing modes are not supported yet"
             );
             // FIXME is this correct?

components/layout_2020/flow/mod.rs

@@ -324,11 +324,15 @@ impl BlockLevelBox {
             },
             BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(box_) => {
                 absolutely_positioned_fragments.push(box_.layout(Vec2::zero(), tree_rank));
-                Fragment::Anonymous(AnonymousFragment::no_op(containing_block.mode))
+                Fragment::Anonymous(AnonymousFragment::no_op(
+                    containing_block.style.writing_mode,
+                ))
             },
             BlockLevelBox::OutOfFlowFloatBox(_box_) => {
                 // TODO
-                Fragment::Anonymous(AnonymousFragment::no_op(containing_block.mode))
+                Fragment::Anonymous(AnonymousFragment::no_op(
+                    containing_block.style.writing_mode,
+                ))
             },
         }
     }
@@ -413,11 +417,11 @@ fn layout_in_flow_non_replaced_block_level<'a>(
     let containing_block_for_children = ContainingBlock {
         inline_size,
         block_size,
-        mode: style.writing_mode,
+        style,
     };
     // https://drafts.csswg.org/css-writing-modes/#orthogonal-flows
     assert_eq!(
-        containing_block.mode, containing_block_for_children.mode,
+        containing_block.style.writing_mode, containing_block_for_children.style.writing_mode,
         "Mixed writing modes are not supported yet"
     );
 
@@ -494,7 +498,7 @@ fn layout_in_flow_non_replaced_block_level<'a>(
             &mut flow_layout.fragments,
             &content_rect.size,
             &padding,
-            containing_block_for_children.mode,
+            style,
         )
     }
     BoxFragment {

components/layout_2020/flow/root.rs

@@ -20,7 +20,7 @@ use crate::{ContainingBlock, DefiniteContainingBlock};
 use rayon::iter::{IntoParallelRefIterator, ParallelExtend, ParallelIterator};
 use script_layout_interface::wrapper_traits::LayoutNode;
 use servo_arc::Arc;
-use style::logical_geometry::WritingMode;
+use style::properties::ComputedValues;
 use style::values::computed::{Length, LengthOrAuto};
 use style::Zero;
 use style_traits::CSSPixel;
@@ -98,6 +98,7 @@ impl BoxTreeRoot {
         layout_context: &LayoutContext,
         viewport: geom::Size<CSSPixel>,
     ) -> FragmentTreeRoot {
+        let style = ComputedValues::initial_values();
         let initial_containing_block_size = Vec2 {
             inline: Length::new(viewport.width),
             block: Length::new(viewport.height),
@@ -108,7 +109,7 @@ impl BoxTreeRoot {
             block_size: LengthOrAuto::LengthPercentage(initial_containing_block_size.block),
             // FIXME: use the document’s mode:
             // https://drafts.csswg.org/css-writing-modes/#principal-flow
-            mode: WritingMode::empty(),
+            style,
         };
         let dummy_tree_rank = 0;
         let mut absolutely_positioned_fragments = vec![];
@@ -121,7 +122,7 @@ impl BoxTreeRoot {
 
         let initial_containing_block = DefiniteContainingBlock {
             size: initial_containing_block_size,
-            mode: initial_containing_block.mode,
+            style,
         };
         independent_layout.fragments.par_extend(
             absolutely_positioned_fragments