[css-flexbox] Apply min-height: auto to nested flexboxes again

To avoid the previous regression (see analysis in bug), we force
layout in the case where we otherwise would get an outdated result.

This relands https://chromium-review.googlesource.com/c/chromium/src/+/1246730
with an additional fix for the Chrome UI CSS. I also split out the
test change into its own patch.

IF THIS BREAKS ANY FURTHER CHROME UI:
Please don't revert this patch; instead, add min-height: 0 to any
inner nested flexboxes that may be affected by this patch. This is
an important change for web interop with the other browsers.

Bug: 596743,890100
Change-Id: Ice629c2a7823ef07d075fa23b99022b4012c6200
Reviewed-on: https://chromium-review.googlesource.com/1252682Reviewed-by: Wenzhao (Colin) Zang <wzang@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595225}

chrome/browser/resources/chromeos/wallpaper_manager/css/wallpaper_manager.css

@@ -409,6 +409,7 @@ body.v2 {
 .v2 .dialog-body {
   display: flex;
   height: 100%;
+  min-height: 0;
 }
 
 .v2 .dialog-topbar {

third_party/WebKit/LayoutTests/TestExpectations

@@ -2470,8 +2470,6 @@ crbug.com/467127 external/wpt/css/css-flexbox/getcomputedstyle/flexbox_computeds
 crbug.com/467127 [ Mac Win ] external/wpt/css/css-flexbox/ttwf-reftest-flex-wrap-reverse.html [ Failure ]
 crbug.com/467127 [ Mac Win ] external/wpt/css/css-flexbox/ttwf-reftest-flex-wrap.html [ Failure ]
 
-crbug.com/596743 external/wpt/css/css-flexbox/flex-minimum-height-flex-items-009.html [ Failure ]
-
 crbug.com/467127 external/wpt/css/css-flexbox/negative-margins-001.html [ Failure ]
 crbug.com/467127 external/wpt/css/css-flexbox/percentage-heights-003.html [ Failure ]
 crbug.com/467127 external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/flexbox/flexbox-align-content-horiz-001a.xhtml [ Failure ]

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

@@ -437,6 +437,14 @@ bool LayoutFlexibleBox::IsMultiline() const {
   return StyleRef().FlexWrap() != EFlexWrap::kNowrap;
 }
 
+bool LayoutFlexibleBox::ShouldApplyMinSizeAutoForChild(
+    const LayoutBox& child) const {
+  Length min = IsHorizontalFlow() ? child.StyleRef().MinWidth()
+                                  : child.StyleRef().MinHeight();
+  return min.IsAuto() && !child.ShouldApplySizeContainment() &&
+         MainAxisOverflowForChild(child) == EOverflow::kVisible;
+}
+
 Length LayoutFlexibleBox::FlexBasisForChild(const LayoutBox& child) const {
   Length flex_length = child.StyleRef().FlexBasis();
   if (flex_length.IsAuto()) {
@@ -997,14 +1005,7 @@ MinMaxSize LayoutFlexibleBox::ComputeMinAndMaxSizesForChild(
     // computeMainAxisExtentForChild can return -1 when the child has a
     // percentage min size, but we have an indefinite size in that axis.
     sizes.min_size = std::max(LayoutUnit(), sizes.min_size);
-  } else if (min.IsAuto() && !child.ShouldApplySizeContainment() &&
-             MainAxisOverflowForChild(child) == EOverflow::kVisible &&
-             !(IsColumnFlow() && child.IsFlexibleBox())) {
-    // TODO(cbiesinger): For now, we do not handle min-height: auto for nested
-    // column flexboxes. We need to implement
-    // https://drafts.csswg.org/css-flexbox/#intrinsic-sizes before that
-    // produces reasonable results. Tracking bug: https://crbug.com/581553
-    // css-flexbox section 4.5
+  } else if (ShouldApplyMinSizeAutoForChild(child)) {
     LayoutUnit content_size =
         ComputeMainAxisExtentForChild(child, kMinSize, Length(kMinContent));
     DCHECK_GE(content_size, LayoutUnit());
@@ -1124,6 +1125,14 @@ LayoutUnit LayoutFlexibleBox::AdjustChildSizeForAspectRatioCrossAxisMinAndMax(
 DISABLE_CFI_PERF
 FlexItem LayoutFlexibleBox::ConstructFlexItem(LayoutBox& child,
                                               ChildLayoutType layout_type) {
+  if (layout_type == kLayoutIfNeeded && IsColumnFlow() &&
+      child.IsFlexibleBox() && ShouldApplyMinSizeAutoForChild(child)) {
+    // In this case, we have to force-layout to update the intrinsic height of
+    // our child; otherwise, it may be too big because it is based on previous
+    // flexing of a descendant, which would be a problem for applying
+    // min-size: auto.
+    layout_type = kForceLayout;
+  }
   if (layout_type != kNeverLayout && ChildHasIntrinsicMainAxisSize(child)) {
     // If this condition is true, then ComputeMainAxisExtentForChild will call
     // child.IntrinsicContentLogicalHeight() and

third_party/blink/renderer/core/layout/layout_flexible_box.h

@@ -111,6 +111,7 @@ class CORE_EXPORT LayoutFlexibleBox : public LayoutBlock {
   bool IsColumnFlow() const;
   bool IsLeftToRightFlow() const;
   bool IsMultiline() const;
+  bool ShouldApplyMinSizeAutoForChild(const LayoutBox& child) const;
   Length FlexBasisForChild(const LayoutBox& child) const;
   LayoutUnit CrossAxisExtentForChild(const LayoutBox& child) const;
   LayoutUnit CrossAxisIntrinsicExtentForChild(const LayoutBox& child) const;