[FlexNG] Fix percentage-heights-010.html

This fixes the above testcase, marked as failing in:
https://chromium-review.googlesource.com/c/chromium/src/+/2015101

Essentially a flex-item, if it has any %-block-size children, needs to
mark itself as depending on %-block-size, as its definiteness can
change.

See note in ng_physical_container_fragment.cc as this is a *little* too
broad, as we should only check if the definiteness changes, not the
percentage block resolution size.

Bug: 845235
Change-Id: I78120f5dd65186ef9ad597f8a5717923cfa49144
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2016634
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: David Grogan <dgrogan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734553}

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

@@ -212,16 +212,23 @@ bool NGPhysicalContainerFragment::DependsOnPercentageBlockSize(
   // element if it has a percentage block-size however, but this will return
   // the correct result from below.
 
+  // There are two conditions where we need to know about an (arbitrary)
+  // descendant which depends on a %-block-size.
+  //  - In quirks mode, the arbitrary descendant may depend the percentage
+  //    resolution block-size given (to this node), and need to relayout if
+  //    this size changes.
+  //  - A flex-item may have its "definiteness" change, (e.g. if itself is a
+  //    flex item which is being stretched). This definiteness change will
+  //    affect any %-block-size children.
+  //
+  // NOTE(ikilpatrick): For the flex-item case this is potentially too general.
+  // We only need to know about if this flex-item has a %-block-size child if
+  // the "definiteness" changes, not if the percentage resolution size changes.
   if ((builder.has_descendant_that_depends_on_percentage_block_size_ ||
        builder.is_legacy_layout_root_) &&
-      node.UseParentPercentageResolutionBlockSizeForChildren()) {
-    // Quirks mode has different %-block-size behaviour, than standards mode.
-    // An arbitrary descendant may depend on the percentage resolution
-    // block-size given.
-    // If this is also an anonymous block we need to mark ourselves dependent
-    // if we have a dependent child.
+      (node.UseParentPercentageResolutionBlockSizeForChildren() ||
+       node.IsFlexItem()))
     return true;
-  }
 
   const ComputedStyle& style = builder.Style();
   if (style.LogicalHeight().IsPercentOrCalc() ||

third_party/blink/web_tests/TestExpectations

@@ -1328,7 +1328,6 @@ crbug.com/845235 virtual/layout_ng_flex_box/css3/flexbox/relpos-with-percentage-
 crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/css-flexbox/flex-aspect-ratio-img-column-004.html [ Failure ]
 crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/css-flexbox/hittest-overlapping-margin.html [ Failure ]
 crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/css-flexbox/hittest-overlapping-order.html [ Failure ]
-crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/css-flexbox/percentage-heights-010.html [ Failure ]
 crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/css-flexbox/quirks-auto-block-size-with-percentage-item.html [ Pass Failure ]
 crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/flexbox/flexbox-intrinsic-ratio-003.html [ Failure ]
 crbug.com/845235 virtual/layout_ng_flex_box/external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/flexbox/flexbox-intrinsic-ratio-004.html [ Failure ]