[FlexNG] Fix perf regression for stretched overflow:auto items

Old code wasn't taking advantage of both cache slots.

This was not just a regression relative to a previous FlexNG
version, but was also significantly worse than legacy flex.

Bug: 845235, 1064411
Change-Id: I03955e4dffd4fae6829f60b8d5e105b1a058da7d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2121738Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: David Grogan <dgrogan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756070}

third_party/blink/renderer/core/layout/ng/ng_flex_layout_algorithm.cc

@@ -331,8 +331,9 @@ LayoutUnit CalculateFixedCrossSize(LayoutUnit available_size,
 
 NGConstraintSpace NGFlexLayoutAlgorithm::BuildSpaceForIntrinsicBlockSize(
     const NGBlockNode& flex_item,
-    const NGPhysicalBoxStrut& physical_margins,
-    const MinMaxSizes& cross_axis_min_max) const {
+    const NGPhysicalBoxStrut& physical_margins = NGPhysicalBoxStrut(),
+    const MinMaxSizes& cross_axis_min_max = MinMaxSizes{
+        kIndefiniteSize, kIndefiniteSize}) const {
   const ComputedStyle& child_style = flex_item.Style();
   NGConstraintSpaceBuilder space_builder(ConstraintSpace(),
                                          child_style.GetWritingMode(),
@@ -346,7 +347,8 @@ NGConstraintSpace NGFlexLayoutAlgorithm::BuildSpaceForIntrinsicBlockSize(
   LogicalSize child_available_size = content_box_size_;
   if (ShouldItemShrinkToFit(flex_item)) {
     space_builder.SetIsShrinkToFit(true);
-  } else if (WillChildCrossSizeBeContainerCrossSize(flex_item)) {
+  } else if (cross_axis_min_max.min_size != kIndefiniteSize &&
+             WillChildCrossSizeBeContainerCrossSize(flex_item)) {
     if (is_column_) {
       space_builder.SetIsFixedInlineSize(true);
       child_available_size.inline_size =
@@ -429,16 +431,18 @@ void NGFlexLayoutAlgorithm::ConstructAndAppendFlexItems() {
     base::Optional<MinMaxSizes> min_max_size;
     auto MinMaxSizesFunc = [&]() -> MinMaxSizes {
       if (!min_max_size) {
-        if (child.Style().OverflowBlockDirection() == EOverflow::kAuto) {
+        NGConstraintSpace child_space = BuildSpaceForIntrinsicBlockSize(child);
+        if (child_style.OverflowBlockDirection() == EOverflow::kAuto) {
           // Ensure this child has been laid out so its auto scrollbars are
           // included in its intrinsic sizes.
-          child.Layout(flex_basis_space);
+          child.Layout(child_space);
         }
-        // We want the child's min/max size in its writing mode, not ours.
-        // We'll only ever use it if the child's inline axis is our main axis.
+        // We want the child's intrinsic inline sizes in its writing mode, so
+        // pass child's writing mode as the first parameter, which is nominally
+        // |container_writing_mode|.
         min_max_size = child.ComputeMinMaxSizes(
             child_style.GetWritingMode(),
-            MinMaxSizesInput(content_box_size_.block_size), &flex_basis_space);
+            MinMaxSizesInput(content_box_size_.block_size), &child_space);
       }
       return *min_max_size;
     };