[FlexNG] Subtract inline margins from available size

When laying out items in a column container for flex basis calculation,
we have to subtract inline margins from the container width to get the
right available width for the items.

This also fixes the browser test
PrintPreviewPagesSettingsTest.InvalidPageRanges
which used to crash.

Bug: 845235
Change-Id: Ie9382c0e6cfa89333fc92c2bc4eb8e95c592c923
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2106821
Commit-Queue: David Grogan <dgrogan@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751205}

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

@@ -325,7 +325,8 @@ double NGFlexLayoutAlgorithm::GetMainOverCrossAspectRatio(
 }
 
 NGConstraintSpace NGFlexLayoutAlgorithm::BuildSpaceForIntrinsicBlockSize(
-    const NGBlockNode& flex_item) const {
+    const NGBlockNode& flex_item,
+    const NGPhysicalBoxStrut& physical_margins) const {
   const ComputedStyle& child_style = flex_item.Style();
   NGConstraintSpaceBuilder space_builder(ConstraintSpace(),
                                          child_style.GetWritingMode(),
@@ -334,16 +335,25 @@ NGConstraintSpace NGFlexLayoutAlgorithm::BuildSpaceForIntrinsicBlockSize(
   space_builder.SetCacheSlot(NGCacheSlot::kMeasure);
   space_builder.SetIsPaintedAtomically(true);
 
-  if (ShouldItemShrinkToFit(flex_item))
+  NGBoxStrut margins = physical_margins.ConvertToLogical(
+      ConstraintSpace().GetWritingMode(), Style().Direction());
+  LogicalSize child_available_size = content_box_size_;
+  if (ShouldItemShrinkToFit(flex_item)) {
     space_builder.SetIsShrinkToFit(true);
-  // TODO(dgrogan): Do you need to account for item's min and max cross sizes
-  // before SetIsFixed{Inline,Block}Size(true) ?
-  if (WillChildCrossSizeBeContainerCrossSize(flex_item)) {
+  } else if (WillChildCrossSizeBeContainerCrossSize(flex_item)) {
+    // TODO(dgrogan): Do you need to further adjust available size by item's min
+    // and max cross sizes before SetIsFixed{Inline,Block}Size(true) ?
     if (is_column_) {
       space_builder.SetIsFixedInlineSize(true);
+      child_available_size.inline_size =
+          (child_available_size.inline_size - margins.InlineSum())
+              .ClampNegativeToZero();
     } else {
       space_builder.SetIsFixedBlockSize(true);
       DCHECK_NE(content_box_size_.block_size, kIndefiniteSize);
+      child_available_size.block_size =
+          (child_available_size.block_size - margins.BlockSum())
+              .ClampNegativeToZero();
     }
   }
 
@@ -358,10 +368,10 @@ NGConstraintSpace NGFlexLayoutAlgorithm::BuildSpaceForIntrinsicBlockSize(
   if (is_column_)
     child_percentage_size.block_size = kIndefiniteSize;
 
+  space_builder.SetAvailableSize(child_available_size);
+  space_builder.SetPercentageResolutionSize(child_percentage_size);
   // TODO(dgrogan): The SetReplacedPercentageResolutionSize calls in this file
   // may be untested. Write a test or determine why they're unnecessary.
-  space_builder.SetAvailableSize(content_box_size_);
-  space_builder.SetPercentageResolutionSize(child_percentage_size);
   space_builder.SetReplacedPercentageResolutionSize(child_percentage_size);
   space_builder.SetTextDirection(child_style.Direction());
   return space_builder.ToConstraintSpace();
@@ -394,6 +404,9 @@ void NGFlexLayoutAlgorithm::ConstructAndAppendFlexItems() {
     const ComputedStyle& child_style = child.Style();
     NGConstraintSpace flex_basis_space = BuildSpaceForFlexBasis(child);
 
+    NGPhysicalBoxStrut physical_child_margins =
+        ComputePhysicalMargins(flex_basis_space, child_style);
+
     NGBoxStrut border_padding_in_child_writing_mode =
         ComputeBorders(flex_basis_space, child_style) +
         ComputePadding(flex_basis_space, child_style);
@@ -412,7 +425,8 @@ void NGFlexLayoutAlgorithm::ConstructAndAppendFlexItems() {
     base::Optional<LayoutUnit> intrinsic_block_size;
     auto IntrinsicBlockSizeFunc = [&]() -> LayoutUnit {
       if (!intrinsic_block_size) {
-        NGConstraintSpace child_space = BuildSpaceForIntrinsicBlockSize(child);
+        NGConstraintSpace child_space =
+            BuildSpaceForIntrinsicBlockSize(child, physical_child_margins);
         intrinsic_block_size =
             child.Layout(child_space, /* break_token */ nullptr)
                 ->IntrinsicBlockSize();
@@ -423,14 +437,15 @@ void NGFlexLayoutAlgorithm::ConstructAndAppendFlexItems() {
     base::Optional<MinMaxSizes> min_max_size;
     auto MinMaxSizesFunc = [&]() -> MinMaxSizes {
       if (!min_max_size) {
-        // 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.
-        NGConstraintSpace child_space = BuildSpaceForIntrinsicBlockSize(child);
+        NGConstraintSpace child_space =
+            BuildSpaceForIntrinsicBlockSize(child, physical_child_margins);
         if (child.Style().OverflowBlockDirection() == EOverflow::kAuto) {
           // Ensure this child has been laid out so its auto scrollbars are
           // included in its intrinsic sizes.
           IntrinsicBlockSizeFunc();
         }
+        // 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.
         min_max_size = child.ComputeMinMaxSizes(
             child_style.GetWritingMode(),
             MinMaxSizesInput(content_box_size_.block_size), &child_space);
@@ -690,8 +705,6 @@ void NGFlexLayoutAlgorithm::ConstructAndAppendFlexItems() {
 
     // TODO(dgrogan): Should min_max_sizes_in_cross_axis_direction include
     // cross_axis_border_padding?
-    NGPhysicalBoxStrut physical_child_margins =
-        ComputePhysicalMargins(flex_basis_space, child_style);
     algorithm_
         ->emplace_back(nullptr, child.Style(), flex_base_content_size,
                        min_max_sizes_in_main_axis_direction,

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

@@ -52,7 +52,8 @@ class CORE_EXPORT NGFlexLayoutAlgorithm
 
   NGConstraintSpace BuildSpaceForFlexBasis(const NGBlockNode& flex_item) const;
   NGConstraintSpace BuildSpaceForIntrinsicBlockSize(
-      const NGBlockNode& flex_item) const;
+      const NGBlockNode& flex_item,
+      const NGPhysicalBoxStrut& physical_margins) const;
   void ConstructAndAppendFlexItems();
   void ApplyStretchAlignmentToChild(FlexItem& flex_item);
   void GiveLinesAndItemsFinalPositionAndSize();

third_party/blink/web_tests/external/wpt/css/css-flexbox/flex-basis-item-margins-001.html

+<!DOCTYPE html>
+<title>Flexbox: margins and available space</title>
+<link rel="author" title="David Grogan" href="mailto:dgrogan@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#algo-main-item" title="Case E">
+<link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+<meta name="flags" content="" />
+<meta name="assert" content="An item's inline margins are subtracted from available space when laying out to determine flex-basis in a column container." />
+
+<style>
+.inline-block {
+  display: inline-block;
+  width: 40px;
+  height: 50px;
+}
+
+#reference-overlapped-red {
+  position: absolute;
+  background-color: red;
+  width: 100px;
+  height: 100px;
+  z-index: -1;
+}
+</style>
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div id="reference-overlapped-red"></div>
+
+<div style="display: flex; flex-direction: column; width: 100px; background: green;">
+  <!-- 21px makes the inline-blocks wrap -->
+  <div style="margin-right: 21px; flex: 0 0 auto; line-height: 0px;">
+    <div class="inline-block"></div><div class="inline-block"></div>
+  </div>
+</div>