[flex] Mitigate performance drop during dynamic flex change.

I haven't got a good reproducible test yet, but the issue experienced
in 1479477 is related to a dynamic size change.

There are two layouts which can occur during flexbox column wrap
intrinsic sizing.
1) During base size calculation. For this we simply return the
   border/padding if the child is layout clean.
2) During cross-axis flex-line calculation (primarily for determining
   the baseline, and the cross-axis size). Use the max-content
   contribution for the cross-axis size, and ignore baseline alignment.

(cherry picked from commit b458db7)

Bug: 1272533, 1479477
Change-Id: Ic926616e88b7fb90eb5937897b00db62badae045
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4854071
Reviewed-by: Alison Maher <almaher@microsoft.com>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1194378}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4857171
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Ian Kilpatrick <ikilpatrick@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/5993@{#186}
Cr-Branched-From: 5113507-refs/heads/main@{#1192594}

third_party/blink/renderer/core/layout/flexible_box_algorithm.cc

@@ -546,8 +546,12 @@ void FlexLine::ComputeLineItemsPosition(LayoutUnit main_axis_start_offset,
 
     LayoutUnit child_cross_axis_margin_box_extent;
     const auto alignment = flex_item.Alignment();
-    if (alignment == ItemPosition::kBaseline ||
-        alignment == ItemPosition::kLastBaseline) {
+    // TODO(crbug.com/1272533): We may not have a layout-result during min/max
+    // calculations. This is incorrect, and should be re-enabled once we have
+    // more cache slots.
+    if (flex_item.layout_result_ &&
+        (alignment == ItemPosition::kBaseline ||
+         alignment == ItemPosition::kLastBaseline)) {
       LayoutUnit ascent = flex_item.MarginBoxAscent(
           alignment == ItemPosition::kLastBaseline, is_wrap_reverse);
       LayoutUnit descent =

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

@@ -832,9 +832,12 @@ void NGFlexLayoutAlgorithm::ConstructAndAppendFlexItems(
       if (!layout_result) {
         NGConstraintSpace child_space =
             BuildSpaceForIntrinsicBlockSize(child, max_content_contribution);
-        absl::optional<NGDisableSideEffectsScope> disable_side_effects;
+        // TODO(crbug.com/1272533): This shouldn't return border/padding for
+        // children which are layout-clean. More cache slots are needed to
+        // handle the performance degradation to allow a layout within the
+        // min/max sizing pass.
         if (phase != Phase::kLayout && !Node().GetLayoutBox()->NeedsLayout()) {
-          disable_side_effects.emplace();
+          return border_padding_in_child_writing_mode.BlockSum();
         }
         layout_result = child.Layout(child_space, /* break_token */ nullptr);
         DCHECK(layout_result);
@@ -1318,16 +1321,11 @@ void NGFlexLayoutAlgorithm::PlaceFlexItems(
           flex_item.cross_axis_size_ = ComputeInlineSizeForFragment(
               child_space, flex_item.ng_input_node_, border + padding);
         }
+      } else if (is_computing_multiline_column_intrinsic_size) {
+        flex_item.cross_axis_size_ = *flex_item.max_content_contribution_;
       } else {
         DCHECK((child_space.CacheSlot() == NGCacheSlot::kLayout) ||
-               !flex_item.layout_result_)
-            << "If we already have a 'measure' result from "
-               "ConstructAndAppendFlexItems, we don't want to evict it.";
-        absl::optional<NGDisableSideEffectsScope> disable_side_effects;
-        if (is_computing_multiline_column_intrinsic_size &&
-            !flex_item.ng_input_node_.GetLayoutBox()->NeedsLayout()) {
-          disable_side_effects.emplace();
-        }
+               !flex_item.layout_result_);
         flex_item.layout_result_ = flex_item.ng_input_node_.Layout(
             child_space, nullptr /*break token*/);
         // TODO(layout-dev): Handle abortions caused by block fragmentation.