Handle clipped overflow correctly in table fragmentation.

When we reach the end of a fragmentable node that clips its overflow,
children do not contribute to additional fragmentainers past that point.
See kDisableFragmentation in NGBreakStatus and
RelayoutWithoutFragmentation() in NGLayoutAlgorithm for details.

The table code didn't handle this correctly. Use
InvolvedInBlockFragmentation() instead of checking if block
fragmentation is active, so that we also handle cases where there's an
incoming break token, but no more fragmentation is to take place.

Table captions need to be re-laid out when we're re-laying out without
fragmentation, so that we resume at the break tokens, instead of
starting from scratch.

Bug: 1459623
Change-Id: I90281cc5dcc1225865daa6ac755534631753df41
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4793490
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1185457}

third_party/blink/renderer/core/layout/ng/table/ng_table_layout_algorithm.cc

@@ -75,7 +75,13 @@ NGConstraintSpace CreateCaptionConstraintSpace(
   builder.SetPercentageResolutionSize(available_size);
   builder.SetInlineAutoBehavior(NGAutoBehavior::kStretchImplicit);
 
-  if (block_offset) {
+  // If a block-offset is specified, it means that table captions are laid out
+  // as part of normal table child layout (rather than in initial table
+  // block-size calculation). That is normally only necessary if block
+  // fragmentation is enabled, but may also occur if block fragmentation *was*
+  // enabled for previous fragments, but is disabled for this fragment, because
+  // of overflow clipping.
+  if (block_offset && table_constraint_space.HasBlockFragmentation()) {
     SetupSpaceBuilderForFragmentation(table_constraint_space, caption,
                                       *block_offset, &builder,
                                       /* is_new_fc */ true, false);
@@ -128,12 +134,14 @@ NGBoxStrut ComputeCaptionMargins(
 }
 
 void ComputeCaptionFragments(
-    const NGConstraintSpace& table_constraint_space,
+    const NGBoxFragmentBuilder& table_builder,
     const ComputedStyle& table_style,
     const NGTableGroupedChildren& grouped_children,
-    const LayoutUnit table_inline_size,
     HeapVector<NGTableLayoutAlgorithm::CaptionResult>* captions,
     LayoutUnit& captions_block_size) {
+  const NGConstraintSpace& table_constraint_space =
+      table_builder.ConstraintSpace();
+  const LayoutUnit table_inline_size = table_builder.InlineSize();
   const LogicalSize available_size = {table_inline_size, kIndefiniteSize};
   for (NGBlockNode caption : grouped_children.captions) {
     NGBoxStrut margins = ComputeCaptionMargins(table_constraint_space, caption,
@@ -151,8 +159,9 @@ void ComputeCaptionFragments(
     // per table node (and e.g. store the table data in the break tokens).
     absl::optional<NGDisableSideEffectsScope> disable_side_effects;
     if ((!captions && !caption.GetLayoutBox()->NeedsLayout()) ||
-        table_constraint_space.HasBlockFragmentation())
+        InvolvedInBlockFragmentation(table_builder)) {
       disable_side_effects.emplace();
+    }
 
     NGTableLayoutAlgorithm::CaptionResult caption_result =
         LayoutCaption(table_constraint_space, table_style, table_inline_size,
@@ -567,8 +576,7 @@ LayoutUnit NGTableLayoutAlgorithm::ComputeTableInlineSize(
 LayoutUnit NGTableLayoutAlgorithm::ComputeCaptionBlockSize() {
   NGTableGroupedChildren grouped_children(Node());
   LayoutUnit captions_block_size;
-  ComputeCaptionFragments(ConstraintSpace(), Node().Style(), grouped_children,
-                          container_builder_.InlineSize(),
+  ComputeCaptionFragments(container_builder_, Node().Style(), grouped_children,
                           /* captions */ nullptr, captions_block_size);
   return captions_block_size;
 }
@@ -633,9 +641,8 @@ const NGLayoutResult* NGTableLayoutAlgorithm::Layout() {
   // block-size given to the table-grid.
   HeapVector<CaptionResult> captions;
   LayoutUnit captions_block_size;
-  ComputeCaptionFragments(ConstraintSpace(), Style(), grouped_children,
-                          container_builder_.InlineSize(), &captions,
-                          captions_block_size);
+  ComputeCaptionFragments(container_builder_, Style(), grouped_children,
+                          &captions, captions_block_size);
 
   NGTableTypes::Rows rows;
   NGTableTypes::CellBlockConstraints cell_block_constraints;
@@ -995,7 +1002,8 @@ const NGLayoutResult* NGTableLayoutAlgorithm::GenerateFragment(
   // size. We can re-use these results now, unless we're in block fragmentation.
   // In that case we need to lay them out again now, so that they fragment and
   // resume properly.
-  const bool relayout_captions = ConstraintSpace().HasBlockFragmentation();
+  const bool relayout_captions =
+      InvolvedInBlockFragmentation(container_builder_);
 
   // Add all the top captions.
   if (!relayout_captions) {

third_party/blink/web_tests/external/wpt/css/css-multicol/crashtests/table-caption-in-clipped-overflow.html

@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=1459623">
+<div style="columns:3; column-fill:auto; height:100px;">
+  <div style="overflow:clip;">
+    <div style="display:table-caption; max-height:190px;">
+      <div style="height:230px;"></div>
+    </div>
+  </div>
+</div>